Sample records for physiologically relevant time
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Attention modifies sound level detection in young children.
Sussman, Elyse S; Steinschneider, Mitchell
2011-07-01
Have you ever shouted your child's name from the kitchen while they were watching television in the living room to no avail, so you shout their name again, only louder? Yet, still no response. The current study provides evidence that young children process loudness changes differently than pitch changes when they are engaged in another task such as watching a video. Intensity level changes were physiologically detected only when they were behaviorally relevant, but frequency level changes were physiologically detected without task relevance in younger children. This suggests that changes in pitch rather than changes in volume may be more effective in evoking a response when sounds are unexpected. Further, even though behavioral ability may appear to be similar in younger and older children, attention-based physiologic responses differ from automatic physiologic processes in children. Results indicate that 1) the automatic auditory processes leading to more efficient higher-level skills continue to become refined through childhood; and 2) there are different time courses for the maturation of physiological processes encoding the distinct acoustic attributes of sound pitch and sound intensity. The relevance of these findings to sound perception in real-world environments is discussed.
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Vuletic, L; Spalj, S; Peros, K
2016-02-01
The primary objective of this study was to assess whether exposing dental students to visual stimuli related to dental profession during the medical physiology seminar could affect their perception of the clinical relevance of the topic. A self-administered questionnaire on attitudes towards medical physiology was conducted amongst 105 students of the School of Dental Medicine in Zagreb, Croatia, aged 19-24 years (80% females) following a seminar on respiratory system physiology. Power-point presentation accompanying the seminar for a total of 52 students (study group) was enriched with pictures related to dental practice in order to assess whether these pictures could make the topic appear more clinically relevant for a future dentist. The results of the survey indicated that dental students in the study group perceived the topic of the seminar as more important for them as future dentists when compared to the perception of the control group (P = 0.025). The results of this survey encourage physiology lecturers to present medical physiology as clinically relevant for dental students whenever possible as this could increase students' interest in the subject and their motivation for learning. Such an approach could be particularly beneficial if there is a significant time gap between basic courses and involvement of students into clinical training for it could promote meaningful learning. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.
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Response of Vibrio fischeri to repeated exposures over time in an Online Toxicity Monitor
Online Toxicity Monitors have been developed to provide continuous, time-relevant information regarding water quality. These systems measure a physiological or behavioral response of a sentinel organism to changes water quality. One such system, the Microlan Toxcontrol, is base...
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Non-invasive cortisol measurements as indicators of physiological stress responses in guinea pigs
Pschernig, Elisabeth; Wallner, Bernard; Millesi, Eva
2016-01-01
Non-invasive measurements of glucocorticoid (GC) concentrations, including cortisol and corticosterone, serve as reliable indicators of adrenocortical activities and physiological stress loads in a variety of species. As an alternative to invasive analyses based on plasma, GC concentrations in saliva still represent single-point-of-time measurements, suitable for studying short-term or acute stress responses, whereas fecal GC metabolites (FGMs) reflect overall stress loads and stress responses after a species-specific time frame in the long-term. In our study species, the domestic guinea pig, GC measurements are commonly used to indicate stress responses to different environmental conditions, but the biological relevance of non-invasive measurements is widely unknown. We therefore established an experimental protocol based on the animals’ natural stress responses to different environmental conditions and compared GC levels in plasma, saliva, and fecal samples during non-stressful social isolations and stressful two-hour social confrontations with unfamiliar individuals. Plasma and saliva cortisol concentrations were significantly increased directly after the social confrontations, and plasma and saliva cortisol levels were strongly correlated. This demonstrates a high biological relevance of GC measurements in saliva. FGM levels measured 20 h afterwards, representing the reported mean gut passage time based on physiological validations, revealed that the overall stress load was not affected by the confrontations, but also no relations to plasma cortisol levels were detected. We therefore measured FGMs in two-hour intervals for 24 h after another social confrontation and detected significantly increased levels after four to twelve hours, reaching peak concentrations already after six hours. Our findings confirm that non-invasive GC measurements in guinea pigs are highly biologically relevant in indicating physiological stress responses compared to circulating levels in plasma in the short- and long-term. Our approach also underlines the importance of detailed investigations on how to use and interpret non-invasive measurements, including the determination of appropriate time points for sample collections. PMID:26839750
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Yamamoto, Yumi; Välitalo, Pyry A.; Huntjens, Dymphy R.; Proost, Johannes H.; Vermeulen, An; Krauwinkel, Walter; Beukers, Margot W.; van den Berg, Dirk‐Jan; Hartman, Robin; Wong, Yin Cheong; Danhof, Meindert; van Hasselt, John G. C.
2017-01-01
Drug development targeting the central nervous system (CNS) is challenging due to poor predictability of drug concentrations in various CNS compartments. We developed a generic physiologically based pharmacokinetic (PBPK) model for prediction of drug concentrations in physiologically relevant CNS compartments. System‐specific and drug‐specific model parameters were derived from literature and in silico predictions. The model was validated using detailed concentration‐time profiles from 10 drugs in rat plasma, brain extracellular fluid, 2 cerebrospinal fluid sites, and total brain tissue. These drugs, all small molecules, were selected to cover a wide range of physicochemical properties. The concentration‐time profiles for these drugs were adequately predicted across the CNS compartments (symmetric mean absolute percentage error for the model prediction was <91%). In conclusion, the developed PBPK model can be used to predict temporal concentration profiles of drugs in multiple relevant CNS compartments, which we consider valuable information for efficient CNS drug development. PMID:28891201
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Moody, George B; Mark, Roger G; Goldberger, Ary L
2011-01-01
PhysioNet provides free web access to over 50 collections of recorded physiologic signals and time series, and related open-source software, in support of basic, clinical, and applied research in medicine, physiology, public health, biomedical engineering and computing, and medical instrument design and evaluation. Its three components (PhysioBank, the archive of signals; PhysioToolkit, the software library; and PhysioNetWorks, the virtual laboratory for collaborative development of future PhysioBank data collections and PhysioToolkit software components) connect researchers and students who need physiologic signals and relevant software with researchers who have data and software to share. PhysioNet's annual open engineering challenges stimulate rapid progress on unsolved or poorly solved questions of basic or clinical interest, by focusing attention on achievable solutions that can be evaluated and compared objectively using freely available reference data.
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Understanding the Onset of Health Impacts Caused by Disturbances
2015-09-30
will define the PCoD Health stage in a way that we can start to integrate ecological and physiological PCoD research. OBJECTIVES In order to...for the first time assess the relevance of adipose transcriptomic and metabolomic biomarkers as measures relevant to PCoD in cetaceans. We aim to...individuals. APPROACH The Population Consequences of Disturbances ( PCoD ) paradigm provides a mean to link perturbations of individual phenotypic
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What is the physiological time to recovery after concussion? A systematic review.
Kamins, Joshua; Bigler, Erin; Covassin, Tracey; Henry, Luke; Kemp, Simon; Leddy, John J; Mayer, Andrew; McCrea, Michael; Prins, Mayumi; Schneider, Kathryn J; Valovich McLeod, Tamara C; Zemek, Roger; Giza, Christopher C
2017-06-01
The aim of this study is to consolidate studies of physiological measures following sport-related concussion (SRC) to determine if a time course of postinjury altered neurobiology can be outlined. This biological time course was considered with respect to clinically relevant outcomes such as vulnerability to repeat injury and safe timing of return to physical contact risk. Systematic review. PubMed, CINAHL, Cochrane Central, PsychINFO. Studies were included if they reported original research on physiological or neurobiological changes after SRC. Excluded were cases series <5 subjects, reviews, meta-analyses, editorials, animal research and research not pertaining to SRC. A total of 5834 articles were identified, of which 80 were included for full-text data extraction and review. Relatively few longitudinal studies exist that follow both physiological dysfunction and clinical measures to recovery. Modalities of measuring physiological change after SRC were categorised into the following: functional MRI, diffusion tensor imaging, magnetic resonance spectroscopy, cerebral blood flow, electrophysiology, heart rate, exercise, fluid biomarkers and transcranial magnetic stimulation. Due to differences in modalities, time course, study design and outcomes, it is not possible to define a single 'physiological time window' for SRC recovery. Multiple studies suggest physiological dysfunction may outlast current clinical measures of recovery, supporting a buffer zone of gradually increasing activity before full contact risk. Future studies need to use generalisable populations, longitudinal designs following to physiological and clinical recovery and careful correlation of neurobiological modalities with clinical measures. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.
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The recovery time course of the endothelial-cell glycocalyx in vivo and its implications in vitro
Potter, Daniel R.; Jiang, John; Damiano, Edward R.
2009-01-01
Compelling evidence continues to emerge suggesting that the glycocalyx surface layer on vascular endothelial cells plays a determining role in numerous physiological processes including inflammation, microvascular permeability, and endothelial mechanotransduction. Previous research has shown that enzymes degrade the glycocalyx, while inflammation causes shedding of the layer. To track the endogenous recovery of the glycocalyx in vivo, we used fluorescent micro-particle image velocimetry (µ-PIV) in mouse cremaster-muscle venules to estimate the hydrodynamically relevant glycocalyx thickness 1, 3, 5, and 7 days after enzymatic or cytokine-mediated degradation of the layer. Results indicate that after acute degradation of the glycocalyx, 5–7 days are required for the layer to endogenously restore itself to its native hydrodynamically relevant thickness in vivo. In light of these findings, and since demonstrable evidence has emerged that standard cell-culture conditions are not conducive to providing the environment and/or cellular conditions necessary to produce and maintain a physiologically relevant cell-surface glycocalyx in vitro, we sought to determine if merely the passage of time would be sufficient to promote the production of a hydrodynamically relevant glycocalyx on a confluent monolayer of human umbilical vein endothelial cells (HUVECs). Using µ-PIV, we found that the hydrodynamically relevant glycocalyx was substantially absent 7 days post-confluence on HUVEC-lined cylindrical collagen microchannels maintained under standard culture conditions. Thus it remains to be determined how a hydrodynamically relevant glycocalyx surface layer can be synthesized and maintained in culture before the endothelial-cell culture model can be used to elucidate glycocalyx-mediated mechanisms of endothelial-cell function. PMID:19443840
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Electrical Impedance Tomography of Electrolysis
Meir, Arie; Rubinsky, Boris
2015-01-01
The primary goal of this study is to explore the hypothesis that changes in pH during electrolysis can be detected with Electrical Impedance Tomography (EIT). The study has relevance to real time control of minimally invasive surgery with electrolytic ablation. To investigate the hypothesis, we compare EIT reconstructed images to optical images acquired using pH-sensitive dyes embedded in a physiological saline agar gel phantom treated with electrolysis. We further demonstrate the biological relevance of our work using a bacterial E.Coli model, grown on the phantom. The results demonstrate the ability of EIT to image pH changes in a physiological saline phantom and show that these changes correlate with cell death in the E.coli model. The results are promising, and invite further experimental explorations. PMID:26039686
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NASA Astrophysics Data System (ADS)
Budhwani, Karim Ismail
The tremendous quality of life impact notwithstanding, cardiovascular diseases and Cancer add up to over US$ 700bn each year in financial costs alone. Aging and population growth are expected to further expand the problem space while drug research and development remain expensive. However, preclinical costs can be substantially mitigated by substituting animal models with in vitro devices that accurately model human cardiovascular transport. Here we present a novel physiologically relevant lab-on-a-brane that simulates in vivo pressure, flow, strain, and shear waveforms associated with normal and pathological conditions in large and small blood vessels for studying molecular transport across the endothelial monolayer. The device builds upon previously demonstrated integrated microfluidic loop design by: (a) introducing nanoscale pores in the substrate membrane to enable transmembrane molecular transport, (b) transforming the substrate membrane into a nanofibrous matrix for 3D smooth muscle cell (SMC) tissue culture, (c) integrating electrospinning fabrication methods, (d) engineering an invertible sandwich cell culture device architecture, and (e) devising a healthy co-culture mechanism for human arterial endothelial cell (HAEC) monolayer and multiple layers of human smooth muscle cells (HSMC) to accurately mimic arterial anatomy. Structural and mechanical characterization was conducted using confocal microscopy, SEM, stress/strain analysis, and infrared spectroscopy. Transport was characterized using FITC-Dextran hydraulic permeability protocol. Structure and transport characterization successfully demonstrate device viability as a physiologically relevant arterial mimic for testing transendothelial transport. Thus, our lab-on-a-brane provides a highly effective and efficient, yet considerably inexpensive, physiologically relevant alternative for pharmacokinetic evaluation; possibly reducing animals used in pre-clinical testing, clinical trials cost from false starts, and time-to-market. Furthermore, this platform can be easily configured for testing targeted therapeutic delivery and in multiple simultaneous arrays for personalized and precision medicine applications.
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NASA Astrophysics Data System (ADS)
Lin, Aijing; Liu, Kang K. L.; Bartsch, Ronny P.; Ivanov, Plamen Ch.
2016-05-01
Within the framework of `Network Physiology', we ask a fundamental question of how modulations in cardiac dynamics emerge from networked brain-heart interactions. We propose a generalized time-delay approach to identify and quantify dynamical interactions between physiologically relevant brain rhythms and the heart rate. We perform empirical analysis of synchronized continuous EEG and ECG recordings from 34 healthy subjects during night-time sleep. For each pair of brain rhythm and heart interaction, we construct a delay-correlation landscape (DCL) that characterizes how individual brain rhythms are coupled to the heart rate, and how modulations in brain and cardiac dynamics are coordinated in time. We uncover characteristic time delays and an ensemble of specific profiles for the probability distribution of time delays that underly brain-heart interactions. These profiles are consistently observed in all subjects, indicating a universal pattern. Tracking the evolution of DCL across different sleep stages, we find that the ensemble of time-delay profiles changes from one physiologic state to another, indicating a strong association with physiologic state and function. The reported observations provide new insights on neurophysiological regulation of cardiac dynamics, with potential for broad clinical applications. The presented approach allows one to simultaneously capture key elements of dynamic interactions, including characteristic time delays and their time evolution, and can be applied to a range of coupled dynamical systems.
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Kamstrup, Danna; Berthelsen, Ragna; Sassene, Philip Jonas; Selen, Arzu; Müllertz, Anette
2017-02-01
The focus on drug delivery for the pediatric population has been steadily increasing in the last decades. In terms of developing in vitro models simulating characteristics of the targeted pediatric population, with the purpose of predicting drug product performance after oral administration, it is important to simulate the gastro-intestinal conditions and processes the drug will encounter upon oral administration. When a drug is administered in the fed state, which is commonly the case for neonates, as they are typically fed every 3 h, the digestion of the milk will affect the composition of the fluid available for drug dissolution/solubilization. Therefore, in order to predict the solubilized amount of drug available for absorption, an in vitro model simulating digestion in the gastro-intestinal tract should be utilized. In order to simulate the digestion process and the drug solubilization taking place in vivo, the following aspects should be considered; physiologically relevant media, media volume, use of physiological enzymes in proper amounts, as well as correct pH and addition of relevant co-factors, e.g., bile salts and co-enzymes. Furthermore, physiological transit times and appropriate mixing should be considered and mimicked as close as possible. This paper presents a literature review on physiological factors relevant for digestion and drug solubilization in neonates. Based on the available literature data, a novel in vitro digestion model simulating digestion and drug solubilization in the neonate and young infant pediatric population (2 months old and younger) was designed.
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Gunderson, Alex R; Armstrong, Eric J; Stillman, Jonathon H
2016-01-01
Abiotic conditions (e.g., temperature and pH) fluctuate through time in most marine environments, sometimes passing intensity thresholds that induce physiological stress. Depending on habitat and season, the peak intensity of different abiotic stressors can occur in or out of phase with one another. Thus, some organisms are exposed to multiple stressors simultaneously, whereas others experience them sequentially. Understanding these physicochemical dynamics is critical because how organisms respond to multiple stressors depends on the magnitude and relative timing of each stressor. Here, we first discuss broad patterns of covariation between stressors in marine systems at various temporal scales. We then describe how these dynamics will influence physiological responses to multi-stressor exposures. Finally, we summarize how multi-stressor effects are currently assessed. We find that multi-stressor experiments have rarely incorporated naturalistic physicochemical variation into their designs, and emphasize the importance of doing so to make ecologically relevant inferences about physiological responses to global change.
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Personalized physiological medicine.
Ince, Can
2017-12-28
This paper introduces the concept of personalized physiological medicine that is specifically directed at the needs of the critically ill patient. This differs from the conventional view of personalized medicine, characterized by biomarkers and gene profiling, instead focusing on time-variant changes in the pathophysiology and regulation of various organ systems and their cellular and subcellular constituents. I propose that personalized physiological medicine is composed of four pillars relevant to the critically ill patient. Pillar 1 is defined by the frailty and fitness of the patient and their physiological reserve to cope with the stress of critical illness and therapy. Pillar 2 involves monitoring of the key physiological variables of the different organ systems and their response to disease and therapy. Pillar 3 concerns the evaluation of the success of resuscitation by assessment of the hemodynamic coherence between the systemic and microcirculation and parenchyma of the organ systems. Finally, pillar 4 is defined by the integration of the physiological and clinical data into a time-learning adaptive model of the patient to provide feedback about the function of organ systems and to guide and assess the response to disease and therapy. I discuss each pillar and describe the challenges to research and development that will allow the realization of personalized physiological medicine to be practiced at the bedside for critically ill patients.
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Perioperative abstinence from cigarettes: physiologic and clinical consequences.
Warner, David O
2006-02-01
Chronic exposure to cigarette smoke produces profound changes in physiology that may alter responses to perioperative interventions and contribute to perioperative morbidity. Because of smoke-free policies in healthcare facilities, all smokers undergoing surgery are abstinent from cigarettes for at least some period of time so that all are in various stages of recovery from the effects of smoke. Understanding this recovery process will help perioperative physicians better treat these patients. This review examines current knowledge regarding how both short-term (duration ranging from hours to weeks) and long-term smoking cessation affects selected physiology and pathophysiology of particular relevance to perioperative outcomes and how these changes affect perioperative risk. It will also consider current evidence regarding how nicotine replacement therapy, a valuable adjunct to help patients maintain abstinence, may affect perioperative physiology.
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Papp, Lauren M.; Pendry, Patricia; Adam, Emma K.
2010-01-01
In this study, the authors examined parent-adolescent cortisol associations in 45 families with adolescent children (24 girls; M age = 15.78 years, SD = 1.44 years). Family members’ salivary cortisol levels were measured 7 times a day on 2 typical weekdays. Family members provided reports of demographic and health variables, and adolescents rated parent-child relationship characteristics. After accounting for the effects of time of day and relevant demographic and health control variables on cortisol levels, hierarchical linear models indicated the presence of significant covariation over time in mother-adolescent cortisol (i.e., physiological synchrony). Furthermore, moderating tests revealed that mother-adolescent cortisol synchrony was strengthened among dyads characterized by mothers and adolescents spending more time together, and in families rated higher on levels of parent-youth shared activities and parental monitoring/supervision. Analysis of momentary characteristics indicated that maternal presence at the time of cortisol sampling lowered adolescent cortisol levels but did not account for mother-adolescent cortisol synchrony. Within-family physiological synchrony was amplified in momentary contexts of elevated maternal negative affect and elevated adolescent negative affect. PMID:20001147
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Papp, Lauren M; Pendry, Patricia; Adam, Emma K
2009-12-01
In this study, the authors examined parent-adolescent cortisol associations in 45 families with adolescent children (24 girls; M age = 15.78 years, SD = 1.44 years). Family members' salivary cortisol levels were measured seven times a day on 2 typical weekdays. Family members provided reports of demographic and health variables, and adolescents rated parent-child relationship characteristics. After accounting for the effects of time of day and relevant demographic and health control variables on cortisol levels, hierarchical linear models indicated the presence of significant covariation over time in mother-adolescent cortisol (i.e., physiological synchrony). Furthermore, moderating tests revealed that mother-adolescent cortisol synchrony was strengthened among dyads characterized by mothers and adolescents spending more time together, and in families rated higher on levels of parent-youth shared activities and parental monitoring or supervision. Analysis of momentary characteristics indicated that maternal presence at the time of cortisol sampling lowered adolescent cortisol levels but did not account for mother-adolescent cortisol synchrony. Within-family physiological synchrony was amplified in momentary contexts of elevated maternal negative affect and elevated adolescent negative affect.
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The promise of the state space approach to time series analysis for nursing research.
Levy, Janet A; Elser, Heather E; Knobel, Robin B
2012-01-01
Nursing research, particularly related to physiological development, often depends on the collection of time series data. The state space approach to time series analysis has great potential to answer exploratory questions relevant to physiological development but has not been used extensively in nursing. The aim of the study was to introduce the state space approach to time series analysis and demonstrate potential applicability to neonatal monitoring and physiology. We present a set of univariate state space models; each one describing a process that generates a variable of interest over time. Each model is presented algebraically and a realization of the process is presented graphically from simulated data. This is followed by a discussion of how the model has been or may be used in two nursing projects on neonatal physiological development. The defining feature of the state space approach is the decomposition of the series into components that are functions of time; specifically, slowly varying level, faster varying periodic, and irregular components. State space models potentially simulate developmental processes where a phenomenon emerges and disappears before stabilizing, where the periodic component may become more regular with time, or where the developmental trajectory of a phenomenon is irregular. The ultimate contribution of this approach to nursing science will require close collaboration and cross-disciplinary education between nurses and statisticians.
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Physiological limits to endurance exercise performance: influence of sex
2017-01-01
Abstract This brief review summarizes factors associated with elite endurance performance, trends in distance running training, and participation by men and more recently women. It is framed in the context of key ideas about the physiological determinants of endurance performance but also touches on some historical and sociological factors relevant to the overall topic. Historical trends that served to increase women's participation in elite endurance events are also discussed as is the role of increased volume and intensity of training. The rapid improvement in women's world record marathon times in the 1970s and 80s are emblematic of these trends and represent a combination of increased training volume and intensity and more competitive opportunities. This occurred as bans on participation by women in endurance events were lifted. For men these same trends evolved over a much longer time frame. The main physiological factor responsible for 10–12% slower times in women compared to men at the elite level are also considered and probably centre aroundV˙O2 max . PMID:28028816
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2014-11-01
response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and...over time , when a bipha- sic soft tissue is subjected to dynamic loading. Also, after the initial transient, the variation of solid skeleton stresses...will be naturally calculated as the fluid phase pressure dissipates over time . This is important for developing physiologically- relevant degradation
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Ambulatory instrumentation suitable for long-term monitoring of cattle health.
Schoenig, S A; Hildreth, T S; Nagl, L; Erickson, H; Spire, M; Andresen, D; Warren, S
2004-01-01
The benefits of real-time health diagnoses of cattle are potentially tremendous. Early detection of transmissible disease, whether from natural or terrorist events, could help to avoid huge financial losses in the agriculture industry while also improving meat quality. This work discusses physiological and behavioral parameters relevant to cattle state-of-health assessment. These parameters, along with a potentially harsh monitoring environment, drive a set of design considerations that must be addressed when building systems to acquire long-term, real-time measurements in the field. A prototype system is presented that supports the measurement of suitable physiologic parameters and begins to address the design constraints for continuous state-of-health determination in free-roaming cattle.
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Four-Channel Biosignal Analysis and Feature Extraction for Automatic Emotion Recognition
NASA Astrophysics Data System (ADS)
Kim, Jonghwa; André, Elisabeth
This paper investigates the potential of physiological signals as a reliable channel for automatic recognition of user's emotial state. For the emotion recognition, little attention has been paid so far to physiological signals compared to audio-visual emotion channels such as facial expression or speech. All essential stages of automatic recognition system using biosignals are discussed, from recording physiological dataset up to feature-based multiclass classification. Four-channel biosensors are used to measure electromyogram, electrocardiogram, skin conductivity and respiration changes. A wide range of physiological features from various analysis domains, including time/frequency, entropy, geometric analysis, subband spectra, multiscale entropy, etc., is proposed in order to search the best emotion-relevant features and to correlate them with emotional states. The best features extracted are specified in detail and their effectiveness is proven by emotion recognition results.
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Papp, Lauren M.; Pendry, Patricia; Simon, Clarissa D.; Adam, Emma K.
2012-01-01
In this study, associations were examined between cortisol levels of wives and husbands in 47 heterosexual married couples. Both partners’ salivary cortisol levels were measured at the same moments seven times a day on 2 typical weekdays. After accounting for the effects of the diurnal rhythm of cortisol and relevant control variables, dyadic hierarchical linear modeling indicated significant positive linkages between partners’ cortisol levels, consistent with the hypothesized within-couple physiological synchrony. Variables reflecting more (spousal presence) or less connectedness (loneliness, being alone) were also collected at the time of each cortisol sample. Results indicated that husbands’ cortisol levels were higher at moments they reported feeling lonelier and lower at moments they were in the presence of their spouse. Wives’ cortisol levels were higher at moments they were alone. In addition, wife-husband cortisol synchrony was stronger for husbands who spent relatively more time with their spouse across the study period—even after accounting for time spent with others in general. These findings suggest that marital partners evidence positive within-couple cortisol associations, and that connectedness (particularly physical closeness) may underpin spouses’ physiological synchrony. PMID:23763687
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Circulatory shear flow alters the viability and proliferation of circulating colon cancer cells
NASA Astrophysics Data System (ADS)
Fan, Rong; Emery, Travis; Zhang, Yongguo; Xia, Yuxuan; Sun, Jun; Wan, Jiandi
2016-06-01
During cancer metastasis, circulating tumor cells constantly experience hemodynamic shear stress in the circulation. Cellular responses to shear stress including cell viability and proliferation thus play critical roles in cancer metastasis. Here, we developed a microfluidic approach to establish a circulatory microenvironment and studied circulating human colon cancer HCT116 cells in response to a variety of magnitude of shear stress and circulating time. Our results showed that cell viability decreased with the increase of circulating time, but increased with the magnitude of wall shear stress. Proliferation of cells survived from circulation could be maintained when physiologically relevant wall shear stresses were applied. High wall shear stress (60.5 dyne/cm2), however, led to decreased cell proliferation at long circulating time (1 h). We further showed that the expression levels of β-catenin and c-myc, proliferation regulators, were significantly enhanced by increasing wall shear stress. The presented study provides a new insight to the roles of circulatory shear stress in cellular responses of circulating tumor cells in a physiologically relevant model, and thus will be of interest for the study of cancer cell mechanosensing and cancer metastasis.
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NASA Astrophysics Data System (ADS)
Gurkov, Anton; Shchapova, Ekaterina; Bedulina, Daria; Baduev, Boris; Borvinskaya, Ekaterina; Meglinski, Igor; Timofeyev, Maxim
2016-11-01
Remote in vivo scanning of physiological parameters is a major trend in the development of new tools for the fields of medicine and animal physiology. For this purpose, a variety of implantable optical micro- and nanosensors have been designed for potential medical applications. At the same time, the important area of environmental sciences has been neglected in the development of techniques for remote physiological measurements. In the field of environmental monitoring and related research, there is a constant demand for new effective and quick techniques for the stress assessment of aquatic animals, and the development of proper methods for remote physiological measurements in vivo may significantly increase the precision and throughput of analyses in this field. In the present study, we apply pH-sensitive microencapsulated biomarkers to remotely monitor the pH of haemolymph in vivo in endemic amphipods from Lake Baikal, and we compare the suitability of this technique for stress assessment with that of common biochemical methods. For the first time, we demonstrate the possibility of remotely detecting a change in a physiological parameter in an aquatic organism under ecologically relevant stressful conditions and show the applicability of techniques using microencapsulated biomarkers for remote physiological measurements in environmental monitoring.
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Helmuth, Brian; Broitman, Bernardo R; Yamane, Lauren; Gilman, Sarah E; Mach, Katharine; Mislan, K A S; Denny, Mark W
2010-03-15
Predicting when, where and with what magnitude climate change is likely to affect the fitness, abundance and distribution of organisms and the functioning of ecosystems has emerged as a high priority for scientists and resource managers. However, even in cases where we have detailed knowledge of current species' range boundaries, we often do not understand what, if any, aspects of weather and climate act to set these limits. This shortcoming significantly curtails our capacity to predict potential future range shifts in response to climate change, especially since the factors that set range boundaries under those novel conditions may be different from those that set limits today. We quantitatively examine a nine-year time series of temperature records relevant to the body temperatures of intertidal mussels as measured using biomimetic sensors. Specifically, we explore how a 'climatology' of body temperatures, as opposed to long-term records of habitat-level parameters such as air and water temperatures, can be used to extrapolate meaningful spatial and temporal patterns of physiological stress. Using different metrics that correspond to various aspects of physiological stress (seasonal means, cumulative temperature and the return time of extremes) we show that these potential environmental stressors do not always occur in synchrony with one another. Our analysis also shows that patterns of animal temperature are not well correlated with simple, commonly used metrics such as air temperature. Detailed physiological studies can provide guidance to predicting the effects of global climate change on natural ecosystems but only if we concomitantly record, archive and model environmental signals at appropriate scales.
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Age-Related Change in Mobility: Perspectives From Life Course Epidemiology and Geroscience
Cooper, Rachel; Shardell, Michelle; Simonsick, Eleanor M.; Schrack, Jennifer A.; Kuh, Diana
2016-01-01
Mobility is the most studied and most relevant physical ability affecting quality of life with strong prognostic value for disability and survival. Natural selection has built the “engine” of mobility with great robustness, redundancy, and functional reserve. Efficient patterns of mobility can be acquired during development even by children affected by severe impairments. Analogously, age-associated impairments in mobility-related physiological systems are compensated and overt limitations of mobility only occur when the severity can no longer be compensated. Mobility loss in older persons usually results from multiple impairments in the central nervous system, muscles, joints, and energetic and sensory physiological systems. Early preclinical changes in these physiological systems that precede mobility loss have been poorly studied. Peak performance, rate of decline, compensatory behaviors, or subclinical deterioration of physiological resources may cumulatively influence both timing of mobility loss and chances of recovery, but their role as risk factors has not been adequately characterized. Understanding the natural history of these early changes and intervening on them would likely be the most effective strategy to reduce the burden of disability in the population. For example, young women with low bone peak mass could be counseled to start strength resistance exercise to reduce their high risk of developing osteoporosis and fracture later in life. Expanding this approach to other physiological domains requires collecting and interpreting data from life course epidemiological studies, establishing normative measures of mobility, physical function, and physical activity, and connecting them with life course trajectories of the mobility-relevant physiological domains. PMID:26975983
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Nielsen, Dorte Guldbrand; Gotzsche, Ole; Sonne, Ole; Eika, Berit
2012-10-01
Two major views on the relationship between basic science knowledge and clinical knowledge stand out; the Two-world view seeing basic science and clinical science as two separate knowledge bases and the encapsulated knowledge view stating that basic science knowledge plays an overt role being encapsulated in the clinical knowledge. However, resent research has implied that a more complex relationship between the two knowledge bases exists. In this study, we explore the relationship between immediate relevant basic science (physiology) and clinical knowledge within a specific domain of medicine (echocardiography). Twenty eight medical students in their 3rd year and 45 physicians (15 interns, 15 cardiology residents and 15 cardiology consultants) took a multiple-choice test of physiology knowledge. The physicians also viewed images of a transthoracic echocardiography (TTE) examination and completed a checklist of possible pathologies found. A total score for each participant was calculated for the physiology test, and for all physicians also for the TTE checklist. Consultants scored significantly higher on the physiology test than did medical students and interns. A significant correlation between physiology test scores and TTE checklist scores was found for the cardiology residents only. Basic science knowledge of immediate relevance for daily clinical work expands with increased work experience within a specific domain. Consultants showed no relationship between physiology knowledge and TTE interpretation indicating that experts do not use basic science knowledge in routine daily practice, but knowledge of immediate relevance remains ready for use.
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Magnetic Resonance Imaging of Electrolysis.
Meir, Arie; Hjouj, Mohammad; Rubinsky, Liel; Rubinsky, Boris
2015-01-01
This study explores the hypothesis that Magnetic Resonance Imaging (MRI) can image the process of electrolysis by detecting pH fronts. The study has relevance to real time control of cell ablation with electrolysis. To investigate the hypothesis we compare the following MR imaging sequences: T1 weighted, T2 weighted and Proton Density (PD), with optical images acquired using pH-sensitive dyes embedded in a physiological saline agar solution phantom treated with electrolysis and discrete measurements with a pH microprobe. We further demonstrate the biological relevance of our work using a bacterial E. Coli model, grown on the phantom. The results demonstrate the ability of MRI to image electrolysis produced pH changes in a physiological saline phantom and show that these changes correlate with cell death in the E. Coli model grown on the phantom. The results are promising and invite further experimental research. PMID:25659942
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NASA Astrophysics Data System (ADS)
Davies-Shaw, Dana; Huser, Thomas R.
2008-02-01
We report on the successful development of a custom in vitro system that provides a physiologically relevant means of demonstrating optical methodologies for the calibration and validation of oxygen delivery and hemoglobin oxygen binding dynamics in the brain. While measured optical signals have generally been equated to heme absorbance values that are, in turn, presumed to correspond to oxygen delivery, there has been little specific study of the sigmoidal oxygen binding dynamics of hemoglobin, a tetrameric protein, within physiologically relevant parameters. Our development of this novel analytical device addresses this issue, and is a significant step towards the minimally invasive and real-time monitoring of spatially resolved cognitive processes. As such, it is of particular interest for the detection of autistic brain activity in infants and young children. Moreover, our device and approach bring with them the ability to quantify and spatially resolve oxygen delivery down to volumes relevant to individual cell oxygen uptake, without any oxygen consumption, and with a temporal resolution that is physically unachievable by any oxygen tracking modality such as fMRI etc. Such a capability opens up myriad possibilities for further investigation, such as real-time tumor biopsy and resection; the tracking and quantification of cellular proliferation, as well as metabolic measures of tissue viability, to name but a few. Our system has also been engineered to be synergistic with virtually all imaging techniques, optical and otherwise.
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Physiologically Relevant Prosthetic Limb Movement Feedback for Upper and Lower Extremity Amputees
2016-10-01
upper arm (elbow movement), Upper leg (knee movement) and lower leg ( ankle movement) to provide a physiologically relevant sense of limb movement...Additionally a BOA cable tensioning system is passed through these plates and anchored to the external surface of the socket. When tension is applied the
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Knowledge Retention of Exercise Physiology Content between Athletes and Nonathletes
ERIC Educational Resources Information Center
Clark, Brian; Webster, Collin; Druger, Marvin
2006-01-01
Based on the idea that learning is linked to personal relevance, this study examined knowledge retention of exercise physiology content between college athletes and nonathletes. No differences were observed between the groups. These findings have implications on understanding the relationship between personal relevance and memory. (Contains 1…
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Models and signal processing for an implanted ethanol bio-sensor.
Han, Jae-Joon; Doerschuk, Peter C; Gelfand, Saul B; O'Connor, Sean J
2008-02-01
The understanding of drinking patterns leading to alcoholism has been hindered by an inability to unobtrusively measure ethanol consumption over periods of weeks to months in the community environment. An implantable ethanol sensor is under development using microelectromechanical systems technology. For safety and user acceptability issues, the sensor will be implanted subcutaneously and, therefore, measure peripheral-tissue ethanol concentration. Determining ethanol consumption and kinetics in other compartments from the time course of peripheral-tissue ethanol concentration requires sophisticated signal processing based on detailed descriptions of the relevant physiology. A statistical signal processing system based on detailed models of the physiology and using extended Kalman filtering and dynamic programming tools is described which can estimate the time series of ethanol concentration in blood, liver, and peripheral tissue and the time series of ethanol consumption based on peripheral-tissue ethanol concentration measurements.
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Baczkowski, Blazej M; Johnstone, Tom; Walter, Henrik; Erk, Susanne; Veer, Ilya M
2017-06-01
We evaluated whether sliding-window analysis can reveal functionally relevant brain network dynamics during a well-established fear conditioning paradigm. To this end, we tested if fMRI fluctuations in amygdala functional connectivity (FC) can be related to task-induced changes in physiological arousal and vigilance, as reflected in the skin conductance level (SCL). Thirty-two healthy individuals participated in the study. For the sliding-window analysis we used windows that were shifted by one volume at a time. Amygdala FC was calculated for each of these windows. Simultaneously acquired SCL time series were averaged over time frames that corresponded to the sliding-window FC analysis, which were subsequently regressed against the whole-brain seed-based amygdala sliding-window FC using the GLM. Surrogate time series were generated to test whether connectivity dynamics could have occurred by chance. In addition, results were contrasted against static amygdala FC and sliding-window FC of the primary visual cortex, which was chosen as a control seed, while a physio-physiological interaction (PPI) was performed as cross-validation. During periods of increased SCL, the left amygdala became more strongly coupled with the bilateral insula and anterior cingulate cortex, core areas of the salience network. The sliding-window analysis yielded a connectivity pattern that was unlikely to have occurred by chance, was spatially distinct from static amygdala FC and from sliding-window FC of the primary visual cortex, but was highly comparable to that of the PPI analysis. We conclude that sliding-window analysis can reveal functionally relevant fluctuations in connectivity in the context of an externally cued task. Copyright © 2017 Elsevier Inc. All rights reserved.
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Paralikar, Swapnil; Shah, Chinmay
2015-01-01
Over the past several years, an opinion has emerged in India that the current practical curricula in medical schools fail to meet many of the objectives for which they were instituted. Hence, this study has assessed the perception of physiology faculty members regarding the current experimental physiology curriculum in one Indian state, Gujarat. The faculty were of the opinion that many of the topics currently taught in experimental physiology (amphibian nerve-muscle and heart muscle experiments) were outdated and clinically irrelevant: Therefore, the faculty advocated that duration of teaching time devoted to some of these topics should be reduced and topics with clinical relevance should be introduced at the undergraduate level. The faculty also felt that more emphasis should be laid on highlighting the clinical aspect related to each concept taught in experimental physiology . Moreover, a majority of faculty members were in favour of replacing the current practice in Gujarat of teaching experimental physiology only by explanation of graphs obtained from experiments conducted in the previous years, with computer assisted learning in small groups.
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Rault, Aline; Bouix, Marielle; Béal, Catherine
2008-12-01
This study aimed at examining and comparing the relevance of various methods in order to discriminate different cellular states of Lactobacillus bulgaricus CFL1 and to improve knowledge on the dynamics of the cellular physiological state during growth and acidification. By using four fluorescent probes combined with multiparametric flow cytometry, membrane integrity, intracellular esterase activity, cellular vitality, membrane depolarization, and intracellular pH were quantified throughout fermentations. Results were compared and correlated with measurements of cultivability, acidification activity (Cinac system), and cellular ability to recover growth in fresh medium (Bioscreen system). The Cinac system and flow cytometry were relevant to distinguish different physiological states throughout growth. Lb. bulgaricus cells maintained their high viability, energetic state, membrane potential, and pH gradient in the late stationary phase, despite the gradual decrease of both cultivability and acidification activity. Viability and membrane integrity were maintained during acidification, at the expense of their cultivability and acidification activity. Finally, this study demonstrated that the physiological state during fermentation was strongly affected by intracellular pH and the pH gradient. The critical pHi of Lb. bulgaricus CFL1 was found to be equal to pH 5.8. Through linear relationships between dpH and cultivability and pHi and acidification activity, pHi and dpH well described the time course of metabolic activity, cultivability, and viability in a single analysis.
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NASA Astrophysics Data System (ADS)
Quarles, C. C.; Gochberg, D. F.; Gore, J. C.; Yankeelov, T. E.
2009-10-01
Dynamic susceptibility contrast (DSC) MRI methods rely on compartmentalization of the contrast agent such that a susceptibility gradient can be induced between the contrast-containing compartment and adjacent spaces, such as between intravascular and extravascular spaces. When there is a disruption of the blood-brain barrier, as is frequently the case with brain tumors, a contrast agent leaks out of the vasculature, resulting in additional T1, T2 and T*2 relaxation effects in the extravascular space, thereby affecting the signal intensity time course and reducing the reliability of the computed hemodynamic parameters. In this study, a theoretical model describing these dynamic intra- and extravascular T1, T2 and T*2 relaxation interactions is proposed. The applicability of using the proposed model to investigate the influence of relevant MRI pulse sequences (e.g. echo time, flip angle), and physical (e.g. susceptibility calibration factors, pre-contrast relaxation rates) and physiological parameters (e.g. permeability, blood flow, compartmental volume fractions) on DSC-MRI signal time curves is demonstrated. Such a model could yield important insights into the biophysical basis of contrast-agent-extravasastion-induced effects on measured DSC-MRI signals and provide a means to investigate pulse sequence optimization and appropriate data analysis methods for the extraction of physiologically relevant imaging metrics.
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Lin, Aijing; Liu, Kang K. L.; Bartsch, Ronny P.; Ivanov, Plamen Ch.
2016-01-01
Within the framework of ‘Network Physiology’, we ask a fundamental question of how modulations in cardiac dynamics emerge from networked brain–heart interactions. We propose a generalized time-delay approach to identify and quantify dynamical interactions between physiologically relevant brain rhythms and the heart rate. We perform empirical analysis of synchronized continuous EEG and ECG recordings from 34 healthy subjects during night-time sleep. For each pair of brain rhythm and heart interaction, we construct a delay-correlation landscape (DCL) that characterizes how individual brain rhythms are coupled to the heart rate, and how modulations in brain and cardiac dynamics are coordinated in time. We uncover characteristic time delays and an ensemble of specific profiles for the probability distribution of time delays that underly brain–heart interactions. These profiles are consistently observed in all subjects, indicating a universal pattern. Tracking the evolution of DCL across different sleep stages, we find that the ensemble of time-delay profiles changes from one physiologic state to another, indicating a strong association with physiologic state and function. The reported observations provide new insights on neurophysiological regulation of cardiac dynamics, with potential for broad clinical applications. The presented approach allows one to simultaneously capture key elements of dynamic interactions, including characteristic time delays and their time evolution, and can be applied to a range of coupled dynamical systems. PMID:27044991
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Conservation physiology across scales: insights from the marine realm
Cooke, Steven J.; Killen, Shaun S.; Metcalfe, Julian D.; McKenzie, David J.; Mouillot, David; Jørgensen, Christian; Peck, Myron A.
2014-01-01
As the field of conservation physiology develops and becomes increasingly integrated with ecology and conservation science, the fundamental concept of scale is being recognized as important, particularly for ensuring that physiological knowledge is contextualized in a manner most relevant to policy makers, conservation practitioners and stakeholders. Failure to consider the importance of scale in conservation physiology—both the challenges and the opportunities that it creates—will impede the ability of this discipline to generate the scientific understanding needed to contribute to meaningful conservation outcomes. Here, we have focused on five aspects of scale: biological, spatial, temporal, allometric and phylogenetic. We also considered the scale of policy and policy application relevant to those five types of scale as well as the merits of upscaling and downscaling to explore and address conservation problems. Although relevant to all systems (e.g. freshwater, terrestrial) we have used examples from the marine realm, with a particular emphasis on fishes, given the fact that there is existing discourse regarding scale and its relevance for marine conservation and management. Our synthesis revealed that all five aspects of scale are relevant to conservation physiology, with many aspects inherently linked. It is apparent that there are both opportunities and challenges afforded by working across scales but, to understand mechanisms underlying conservation problems, it is essential to consider scale of all sorts and to work across scales to the greatest extent possible. Moreover, given that the scales in biological processes will often not match policy and management scales, conservation physiology needs to show how it is relevant to aspects at different policy/management scales, change the scales at which policy/management intervention is applied or be prepared to be ignored. PMID:27293645
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ERIC Educational Resources Information Center
Marton, Janos
1983-01-01
Citation data of 16 biochemistry and plant physiology journals show that reasons for lower citation potentials of plant physiology articles are: (1) readership is narrower for plant physiology journals; (2) plant physiologists can cite fewer thematically relevant new articles; and (3) plant physiology research fields are more isolated. References…
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Krga, Irena; Monfoulet, Laurent-Emmanuel; Konic-Ristic, Aleksandra; Mercier, Sylvie; Glibetic, Maria; Morand, Christine; Milenkovic, Dragan
2016-06-01
An increasing number of evidence suggests a protective role of dietary anthocyanins against cardiovascular diseases. Anthocyanins' extensive metabolism indicates that their metabolites could be responsible for the protective effects associated with consumption of anthocyanin-rich foods. The aim of this work was to investigate the effect of plasma anthocyanins and their metabolites on the adhesion of monocytes to TNFα-activated endothelial cells and on the expression of genes encoding cell adhesion molecules. Human umbilical vein endothelial cells (HUVECs) were exposed to circulating anthocyanins: cyanidin-3-arabinoside, cyanidin-3-galactoside, cyanidin-3-glucoside, delphinidin-3-glucoside, peonidin-3-glucoside, anthocyanin degradation product: 4-hydroxybenzaldehyde, or to their gut metabolites: protocatechuic, vanillic, ferulic and hippuric acid, at physiologically-relevant concentrations (0.1-2 μM) and time of exposure. Both anthocyanins and gut metabolites decreased the adhesion of monocytes to HUVECs, with a magnitude ranging from 18.1% to 47%. The mixture of anthocyanins and that of gut metabolites also reduced monocyte adhesion. However, no significant effect on the expression of genes encoding E-selectin, ICAM1 and VCAM1 was observed, suggesting that other molecular targets are involved in the observed effect. In conclusion, this study showed the potency of anthocyanins and their gut metabolites to modulate the adhesion of monocytes to endothelial cells, the initial step in atherosclerosis development, under physiologically-relevant conditions. Copyright © 2016 Elsevier Inc. All rights reserved.
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Yang, Yiwei; Xu, Yuejin; Miu, Jichang; Zhou, Linghong; Xiao, Zhongju
2012-10-01
To apply the classic leakage integrate-and-fire models, based on the mechanism of the generation of physiological auditory stimulation, in the information processing coding of cochlear implants to improve the auditory result. The results of algorithm simulation in digital signal processor (DSP) were imported into Matlab for a comparative analysis. Compared with CIS coding, the algorithm of membrane potential integrate-and-fire (MPIF) allowed more natural pulse discharge in a pseudo-random manner to better fit the physiological structures. The MPIF algorithm can effectively solve the problem of the dynamic structure of the delivered auditory information sequence issued in the auditory center and allowed integration of the stimulating pulses and time coding to ensure the coherence and relevance of the stimulating pulse time.
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An Organotypic Liver System for Tumor Progression
2006-04-01
a physiologically relevant microreactor that has proved suitable for organotypic liver culture to investigate metastatic seeding. The sub-millimeter...metastasis. Our objective is to utilize a physiologically relevant microreactor that has proved suitable for organotypic liver culture (3) to...C Yates, D B Stolz, L Griffith, A Wells (2004) Direct Visualization of Prostate Cancer Progression Utilizing a Bioreactor. American Association
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Reichelt, Wieland N; Haas, Florian; Sagmeister, Patrick; Herwig, Christoph
2017-01-01
Microbial bioprocesses need to be designed to be transferable from lab scale to production scale as well as between setups. Although substantial effort is invested to control technological parameters, usually the only true constant parameter is the actual producer of the product: the cell. Hence, instead of solely controlling technological process parameters, the focus should be increasingly laid on physiological parameters. This contribution aims at illustrating a workflow of data life cycle management with special focus on physiology. Information processing condenses the data into physiological variables, while information mining condenses the variables further into physiological descriptors. This basis facilitates data analysis for a physiological explanation for observed phenomena in productivity. Targeting transferability, we demonstrate this workflow using an industrially relevant Escherichia coli process for recombinant protein production and substantiate the following three points: (1) The postinduction phase is independent in terms of productivity and physiology from the preinduction variables specific growth rate and biomass at induction. (2) The specific substrate uptake rate during induction phase was found to significantly impact the maximum specific product titer. (3) The time point of maximum specific titer can be predicted by an easy accessible physiological variable: while the maximum specific titers were reached at different time points (19.8 ± 7.6 h), those maxima were reached all within a very narrow window of cumulatively consumed substrate dSn (3.1 ± 0.3 g/g). Concluding, this contribution provides a workflow on how to gain a physiological view on the process and illustrates potential benefits. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 33:261-270, 2017. © 2016 American Institute of Chemical Engineers.
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Bove, Thierry; François, Katrien; De Wolf, Daniel
2015-01-01
The surgical treatment of tetralogy of Fallot can be considered as a success story in the history of congenital heart diseases. Since the early outcome is no longer the main issue, the focus moved to the late sequelae of TOF repair, i.e. the pulmonary insufficiency and the secondary adaptation of the right ventricle. This review provides recent insights into the pathophysiological alterations of the right ventricle in relation to the reconstruction of the right ventricular outflow tract after repair of tetralogy of Fallot. Its clinical relevance is documented by addressing the policy changes regarding the optimal management at the time of surgical repair as well as properly defining criteria and timing for late pulmonary valve implantation.
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Monitoring peripheral perfusion and microcirculation.
Dubin, Arnaldo; Henriquez, Elizabeth; Hernández, Glenn
2018-06-01
Microcirculatory alterations play a major role in the pathogenesis of shock. Monitoring tissue perfusion might be a relevant goal for shock resuscitation. The goal of this review was to revise the evidence supporting the monitoring of peripheral perfusion and microcirculation as goals of resuscitation. For this purpose, we mainly focused on skin perfusion and sublingual microcirculation. Although there are controversies about the reproducibility of capillary refill time in monitoring peripheral perfusion, it is a sound physiological variable and suitable for the ICU settings. In addition, observational studies showed its strong ability to predict outcome. Moreover, a preliminary study suggested that it might be a valuable goal for resuscitation. These results should be confirmed by the ongoing ANDROMEDA-SHOCK randomized controlled trial. On the other hand, the monitoring of sublingual microcirculation might also provide relevant physiological and prognostic information. On the contrary, methodological drawbacks mainly related to video assessment hamper its clinical implementation at the present time. Measurements of peripheral perfusion might be useful as goal of resuscitation. The results of the ANDROMEDA-SHOCK will clarify the role of skin perfusion as a guide for the treatment of shock. In contrast, the assessment of sublingual microcirculation mainly remains as a research tool.
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Comparability and repeatability of three commonly used methods for measuring endurance capacity.
Baxter-Gilbert, James; Mühlenhaupt, Max; Whiting, Martin J
2017-12-01
Measures of endurance (time to exhaustion) have been used to address a wide range of questions in ecomorphological and physiological research, as well as being used as a proxy for survival and fitness. Swimming, stationary (circular) track running, and treadmill running are all commonly used methods for measuring endurance. Despite the use of these methods across a broad range of taxa, how comparable these methods are to one another, and whether they are biologically relevant, is rarely examined. We used Australian water dragons (Intellagama lesueurii), a species that is morphologically adept at climbing, swimming, and running, to compare these three methods of endurance and examined if there is repeatability within and between trial methods. We found that time to exhaustion was not highly repeatable within a method, suggesting that single measures or a mean time to exhaustion across trials are not appropriate. Furthermore, we compared mean maximal endurance times among the three methods, and found that the two running methods (i.e., stationary track and treadmill) were similar, but swimming was distinctly different, resulting in lower mean maximal endurance times. Finally, an individual's endurance rank was not repeatable across methods, suggesting that the three endurance trial methods are not providing similar information about an individual's performance capacity. Overall, these results highlight the need to carefully match a measure of performance capacity with the study species and the research questions being asked so that the methods being used are behaviorally, ecologically, and physiologically relevant. © 2018 Wiley Periodicals, Inc.
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Creating Simulated Microgravity Patient Models
NASA Technical Reports Server (NTRS)
Hurst, Victor; Doerr, Harold K.; Bacal, Kira
2004-01-01
The Medical Operational Support Team (MOST) has been tasked by the Space and Life Sciences Directorate (SLSD) at the NASA Johnson Space Center (JSC) to integrate medical simulation into 1) medical training for ground and flight crews and into 2) evaluations of medical procedures and equipment for the International Space Station (ISS). To do this, the MOST requires patient models that represent the physiological changes observed during spaceflight. Despite the presence of physiological data collected during spaceflight, there is no defined set of parameters that illustrate or mimic a 'space normal' patient. Methods: The MOST culled space-relevant medical literature and data from clinical studies performed in microgravity environments. The areas of focus for data collection were in the fields of cardiovascular, respiratory and renal physiology. Results: The MOST developed evidence-based patient models that mimic the physiology believed to be induced by human exposure to a microgravity environment. These models have been integrated into space-relevant scenarios using a human patient simulator and ISS medical resources. Discussion: Despite the lack of a set of physiological parameters representing 'space normal,' the MOST developed space-relevant patient models that mimic microgravity-induced changes in terrestrial physiology. These models are used in clinical scenarios that will medically train flight surgeons, biomedical flight controllers (biomedical engineers; BME) and, eventually, astronaut-crew medical officers (CMO).
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Controlled drug-release system based on pH-sensitive chloride-triggerable liposomes.
Wehunt, Mark P; Winschel, Christine A; Khan, Ali K; Guo, Tai L; Abdrakhmanova, Galya R; Sidorov, Vladimir
2013-03-01
New pH-sensitive lipids were synthesized and utilized in formulations of liposomes suitable for controlled drug release. These liposomes contain various amounts of NaCl in the internal aqueous compartments. The release of the drug model is triggered by an application of HCl cotransporter and exogenous physiologically relevant NaCl solution. HCl cotransporter allows an uptake of HCl by liposomes to the extent of their being proportional to the transmembrane Cl(-) gradient. Therefore, each set of liposomes undergoes internal acidification, which, ultimately, leads to the hydrolysis of the pH-sensitive lipids and content release at the desired time. The developed system releases the drug model in a stepwise fashion, with the release stages separated by periods of low activity. These liposomes were found to be insensitive to physiological concentrations of human serum albumin and to be nontoxic to cells at concentrations exceeding pharmacological relevance. These results render this new drug-release model potentially suitable for in vivo applications.
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Dolezal, Adam G; Carrillo-Tripp, Jimena; Miller, W Allen; Bonning, Bryony C; Toth, Amy L
2016-02-01
Honey bees are exposed to a variety of environmental factors that impact their health, including nutritional stress, pathogens, and pesticides. In particular, there has been increasing evidence that sublethal exposure to pesticides can cause subtle, yet important effects on honey bee health and behavior. Here, we add to this body of knowledge by presenting data on bee-collected pollen containing sublethal levels of cyhalothrin, a pyrethroid insecticide, which, when fed to young honey bees, resulted in significant changes in lifespan, nutritional physiology,and behavior. For the first time, we show that when young, nest-aged bees are presented with pollen containing field-relevant levels of cyhalothrin, they reduce their consumption of contaminated pollen. This indicates that, at least for some chemicals, young bees are able to detect contamination in pollen and change their behavioral response, even if the contamination levels do not prevent foraging honey bees from collecting the contaminated pollen.
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In-cell thermodynamics and a new role for protein surfaces.
Smith, Austin E; Zhou, Larry Z; Gorensek, Annelise H; Senske, Michael; Pielak, Gary J
2016-02-16
There is abundant, physiologically relevant knowledge about protein cores; they are hydrophobic, exquisitely well packed, and nearly all hydrogen bonds are satisfied. An equivalent understanding of protein surfaces has remained elusive because proteins are almost exclusively studied in vitro in simple aqueous solutions. Here, we establish the essential physiological roles played by protein surfaces by measuring the equilibrium thermodynamics and kinetics of protein folding in the complex environment of living Escherichia coli cells, and under physiologically relevant in vitro conditions. Fluorine NMR data on the 7-kDa globular N-terminal SH3 domain of Drosophila signal transduction protein drk (SH3) show that charge-charge interactions are fundamental to protein stability and folding kinetics in cells. Our results contradict predictions from accepted theories of macromolecular crowding and show that cosolutes commonly used to mimic the cellular interior do not yield physiologically relevant information. As such, we provide the foundation for a complete picture of protein chemistry in cells.
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Bruegger, Joel J; Smith, Brian C; Wynia-Smith, Sarah L; Marletta, Michael A
2018-04-27
Cysteine S -nitrosation is a reversible post-translational modification mediated by nitric oxide ( • NO)-derived agents. S -Nitrosation participates in cellular signaling and is associated with several diseases such as cancer, cardiovascular diseases, and neuronal disorders. Despite the physiological importance of this nonclassical • NO-signaling pathway, little is understood about how much S -nitrosation affects protein function. Moreover, identifying physiologically relevant targets of S -nitrosation is difficult because of the dynamics of transnitrosation and a limited understanding of the physiological mechanisms leading to selective protein S -nitrosation. To identify proteins whose activities are modulated by S -nitrosation, we performed a metabolomics study comparing WT and endothelial nitric-oxide synthase knockout mice. We integrated our results with those of a previous proteomics study that identified physiologically relevant S -nitrosated cysteines, and we found that the activity of at least 21 metabolic enzymes might be regulated by S -nitrosation. We cloned, expressed, and purified four of these enzymes and observed that S -nitrosation inhibits the metabolic enzymes 6-phosphogluconate dehydrogenase, Δ1-pyrroline-5-carboxylate dehydrogenase, catechol- O -methyltransferase, and d-3-phosphoglycerate dehydrogenase. Furthermore, using site-directed mutagenesis, we identified the predominant cysteine residue influencing the observed activity changes in each enzyme. In summary, using an integrated metabolomics approach, we have identified several physiologically relevant S -nitrosation targets, including metabolic enzymes, which are inhibited by this modification, and we have found the cysteines modified by S -nitrosation in each enzyme. © 2018 by The American Society for Biochemistry and Molecular Biology, Inc.
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Hu, Jianxin; Stern, Matthew; Gimenez, Luis E; Wanka, Lizzy; Zhu, Lu; Rossi, Mario; Meister, Jaroslawna; Inoue, Asuka; Beck-Sickinger, Annette G; Gurevich, Vsevolod V; Wess, Jürgen
2016-04-08
Designerreceptorsexclusivelyactivated by adesignerdrug (DREADDs) are clozapine-N-oxide-sensitive designer G protein-coupled receptors (GPCRs) that have emerged as powerful novel chemogenetic tools to study the physiological relevance of GPCR signaling pathways in specific cell types or tissues. Like endogenous GPCRs, clozapine-N-oxide-activated DREADDs do not only activate heterotrimeric G proteins but can also trigger β-arrestin-dependent (G protein-independent) signaling. To dissect the relative physiological relevance of G protein-mediatedversusβ-arrestin-mediated signaling in different cell types or physiological processes, the availability of G protein- and β-arrestin-biased DREADDs would be highly desirable. In this study, we report the development of a mutationally modified version of a non-biased DREADD derived from the M3muscarinic receptor that can activate Gq/11with high efficacy but lacks the ability to interact with β-arrestins. We also demonstrate that this novel DREADD is activein vivoand that cell type-selective expression of this new designer receptor can provide novel insights into the physiological roles of G protein (Gq/11)-dependentversusβ-arrestin-dependent signaling in hepatocytes. Thus, this novel Gq/11-biased DREADD represents a powerful new tool to study the physiological relevance of Gq/11-dependent signaling in distinct tissues and cell types, in the absence of β-arrestin-mediated cellular effects. Such studies should guide the development of novel classes of functionally biased ligands that show high efficacy in various pathophysiological conditions but display a reduced incidence of side effects. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.
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Bosma, Reggie; Witt, Gesa; Vaas, Lea A. I.; Josimovic, Ivana; Gribbon, Philip; Vischer, Henry F.; Gul, Sheraz; Leurs, Rob
2017-01-01
The pharmacodynamics of drug-candidates is often optimized by metrics that describe target binding (Kd or Ki value) or target modulation (IC50). However, these metrics are determined at equilibrium conditions, and consequently information regarding the onset and offset of target engagement and modulation is lost. Drug-target residence time is a measure for the lifetime of the drug-target complex, which has recently been receiving considerable interest, as target residence time is shown to have prognostic value for the in vivo efficacy of several drugs. In this study, we have investigated the relation between the increased residence time of antihistamines at the histamine H1 receptor (H1R) and the duration of effective target-inhibition by these antagonists. Hela cells, endogenously expressing low levels of the H1R, were incubated with a series of antihistamines and dissociation was initiated by washing away the unbound antihistamines. Using a calcium-sensitive fluorescent dye and a label free, dynamic mass redistribution based assay, functional recovery of the H1R responsiveness was measured by stimulating the cells with histamine over time, and the recovery was quantified as the receptor recovery time. Using these assays, we determined that the receptor recovery time for a set of antihistamines differed more than 40-fold and was highly correlated to their H1R residence times, as determined with competitive radioligand binding experiments to the H1R in a cell homogenate. Thus, the receptor recovery time is proposed as a cell-based and physiologically relevant metric for the lead optimization of G protein-coupled receptor antagonists, like the H1R antagonists. Both, label-free or real-time, classical signaling assays allow an efficient and physiologically relevant determination of kinetic properties of drug molecules. PMID:29033838
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Cantow, Kathleen; Arakelyan, Karen; Seeliger, Erdmann; Niendorf, Thoralf; Pohlmann, Andreas
2016-01-01
In vivo assessment of renal perfusion and oxygenation under (patho)physiological conditions by means of noninvasive diagnostic imaging is conceptually appealing. Blood oxygen level-dependent (BOLD) magnetic resonance imaging (MRI) and quantitative parametric mapping of the magnetic resonance (MR) relaxation times T 2* and T 2 are thought to provide surrogates of renal tissue oxygenation. The validity and efficacy of this technique for quantitative characterization of local tissue oxygenation and its changes under different functional conditions have not been systematically examined yet and remain to be established. For this purpose, the development of an integrative multimodality approaches is essential. Here we describe an integrated hybrid approach (MR-PHYSIOL) that combines established quantitative physiological measurements with T 2* (T 2) mapping and MR-based kidney size measurements. Standardized reversible (patho)physiologically relevant interventions, such as brief periods of aortic occlusion, hypoxia, and hyperoxia, are used for detailing the relation between the MR-PHYSIOL parameters, in particular between renal T 2* and tissue oxygenation.
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Mining functionally relevant gene sets for analyzing physiologically novel clinical expression data.
Turcan, Sevin; Vetter, Douglas E; Maron, Jill L; Wei, Xintao; Slonim, Donna K
2011-01-01
Gene set analyses have become a standard approach for increasing the sensitivity of transcriptomic studies. However, analytical methods incorporating gene sets require the availability of pre-defined gene sets relevant to the underlying physiology being studied. For novel physiological problems, relevant gene sets may be unavailable or existing gene set databases may bias the results towards only the best-studied of the relevant biological processes. We describe a successful attempt to mine novel functional gene sets for translational projects where the underlying physiology is not necessarily well characterized in existing annotation databases. We choose targeted training data from public expression data repositories and define new criteria for selecting biclusters to serve as candidate gene sets. Many of the discovered gene sets show little or no enrichment for informative Gene Ontology terms or other functional annotation. However, we observe that such gene sets show coherent differential expression in new clinical test data sets, even if derived from different species, tissues, and disease states. We demonstrate the efficacy of this method on a human metabolic data set, where we discover novel, uncharacterized gene sets that are diagnostic of diabetes, and on additional data sets related to neuronal processes and human development. Our results suggest that our approach may be an efficient way to generate a collection of gene sets relevant to the analysis of data for novel clinical applications where existing functional annotation is relatively incomplete.
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Behavioral neuroscience of emotion in aging.
Kaszniak, Alfred W; Menchola, Marisa
2012-01-01
Recent research on emotion and aging has revealed a stability of emotional experience from adulthood to older age, despite aging-related decrements in the perception and categorization of emotionally relevant stimuli. Research also shows that emotional expression remains intact with aging. In contrast, other studies provide evidence for an age-related decrease in autonomic nervous system physiological arousal, particularly in response to emotionally negative stimuli, and for shifts in central nervous system physiologic response to emotional stimuli, with increased prefrontal cortex activation and decreased amygdala activation in aging. Research on attention and memory for emotional information supports a decreased processing of negative emotional stimuli (i.e., a decrease in the negativity effect seen in younger adults), and a relative increase in the processing of emotionally positive stimuli (positivity effect). These physiological response and attentional/memory preference differences across increasingly older groups have been interpreted, within socioemotional selectivity theory, as reflecting greater motivation for emotion regulation with aging. According to this theory, as persons age, their perceived future time horizon shrinks, and a greater value is placed upon cultivating close, familiar, and meaningful relationships and other situations that give rise to positive emotional experience, and avoiding, or shifting attention from, those people and situations that are likely to elicit negative emotion. Even though there are central nervous system structural changes in emotion-relevant brain regions with aging, this shift in socioemotional selectivity, and perhaps the decreased autonomic nervous system physiological arousal of emotion with aging, facilitate enhanced emotion regulation with aging.
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Shamout, Farah E; Pouliopoulos, Antonios N; Lee, Patrizia; Bonaccorsi, Simone; Towhidi, Leila; Krams, Rob; Choi, James J
2015-09-01
Sonoporation has been associated with drug delivery across cell membranes and into target cells, yet several limitations have prohibited further advancement of this technology. Higher delivery rates were associated with increased cellular death, thus implying a safety-efficacy trade-off. Meanwhile, there has been no reported study of safe in vitro sonoporation in a physiologically relevant flow environment. The objective of our study was not only to evaluate sonoporation under physiologically relevant flow conditions, such as fluid velocity, shear stress and temperature, but also to design ultrasound parameters that exploit the presence of flow to maximize sonoporation efficacy while minimizing or avoiding cellular damage. Human umbilical vein endothelial cells (EA.hy926) were seeded in flow chambers as a monolayer to mimic the endothelium. A peristaltic pump maintained a constant fluid velocity of 12.5 cm/s. A focused 0.5 MHz transducer was used to sonicate the cells, while an inserted focused 7.5 MHz passive cavitation detector monitored microbubble-seeded cavitation emissions. Under these conditions, propidium iodide, which is normally impermeable to the cell membrane, was traced to determine whether it could enter cells after sonication. Meanwhile, calcein-AM was used as a cell viability marker. A range of focused ultrasound parameters was explored, with several unique bioeffects observed: cell detachment, preservation of cell viability with no membrane penetration, cell death and preservation of cell viability with sonoporation. The parameters were then modified further to produce safe sonoporation with minimal cell death. To increase the number of favourable cavitation events, we lowered the ultrasound exposure pressure to 40 kPapk-neg and increased the number of cavitation nuclei by 50 times to produce a trans-membrane delivery rate of 62.6% ± 4.3% with a cell viability of 95% ± 4.2%. Furthermore, acoustic cavitation analysis showed that the low pressure sonication produced stable and non-inertial cavitation throughout the pulse sequence. To our knowledge, this is the first study to demonstrate a high drug delivery rate coupled with high cell viability in a physiologically relevant in vitro flow system. Copyright © 2015. Published by Elsevier Inc.
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I.M. Sechenov (1829 - 1905) and the scientific self-understanding for medical sciences.
Kofler, Walter
2007-01-01
There is no discussion about the historic relevance of I. Sechenov for physiology and neurosciences as the "father of Russian modern physiology". But he is relevant for modern natural science too because of his basic epistemological and ontological work. He did not accept the up to now basic paradigm of "Ignorabimus" which can be seen as the reason to exclude even the generalizable aspects of individuality, creativity and spontaneity from natural science. He developed techniques for empirical based science to deal with materialistic and idealistic aspects of the comprehensive person the "ignoramus" according to the actual stay of knowledge and the acceptable ontologies. He demonstrated that ontologies ("paradigms") can be used as tools according to the given problem which should be solved. So Sechenov can be seen as a precursor of the so efficient philosophical positions of Einstein and Th. Kuhn. The stay of the art in physiology and neurosciences changed since the time of Sechenov dramatically. Therefore the philosophical positions of the 19th century should be discussed. Maybe this is indispensable for the needed linkage between materialistic and idealistic aspects of a person. For this the proposals of Sechenov are helpful up to now but nearly unknown. There is no discussion about the historic relevance of I. Sechenov as the "father of Russian physiology." But he is relevant for modern natural science too because of his epistemological and ontological work. He did not accept the up to now basic paradigm of "Ignorabimus" that can be seen as the reason to exclude even the generalizable aspects of individuality, creativity, and spontaneity from natural science. He demonstrated that ontologies ("paradigms") and epistemology can be used as tools according to the given problem. So Sechenov can be seen as a precursor of the so efficient philosophical positions of Einstein and Th. Kuhn. The state of the art changed dramatically. Therefore, the philosophical positions of the nineteenth century should be questioned. Maybe this is indispensable for the needed link between materialistic and idealistic aspects of a person as a whole. In this respect the proposals of Sechenov are helpful for medical science in the twenty-first century too but nearly unknown.
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Nutritional Systems Biology Modeling: From Molecular Mechanisms to Physiology
de Graaf, Albert A.; Freidig, Andreas P.; De Roos, Baukje; Jamshidi, Neema; Heinemann, Matthias; Rullmann, Johan A.C.; Hall, Kevin D.; Adiels, Martin; van Ommen, Ben
2009-01-01
The use of computational modeling and simulation has increased in many biological fields, but despite their potential these techniques are only marginally applied in nutritional sciences. Nevertheless, recent applications of modeling have been instrumental in answering important nutritional questions from the cellular up to the physiological levels. Capturing the complexity of today's important nutritional research questions poses a challenge for modeling to become truly integrative in the consideration and interpretation of experimental data at widely differing scales of space and time. In this review, we discuss a selection of available modeling approaches and applications relevant for nutrition. We then put these models into perspective by categorizing them according to their space and time domain. Through this categorization process, we identified a dearth of models that consider processes occurring between the microscopic and macroscopic scale. We propose a “middle-out” strategy to develop the required full-scale, multilevel computational models. Exhaustive and accurate phenotyping, the use of the virtual patient concept, and the development of biomarkers from “-omics” signatures are identified as key elements of a successful systems biology modeling approach in nutrition research—one that integrates physiological mechanisms and data at multiple space and time scales. PMID:19956660
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Mejía-Mejía, Elisa; Torres, Robinson; Restrepo, Diana
2018-06-01
Physiological coherence has been related with a general sense of well-being and improvements in health and physical, social, and cognitive performance. The aim of this study was to evaluate the relationship between acute stress, controlled breathing, and physiological coherence, and the degree of body systems synchronization during a coherence-generation exercise. Thirty-four university employees were evaluated during a 20-min test consisting of four stages of 5-min duration each, during which basal measurements were obtained (Stage 1), acute stress was induced using validated mental stressors (Stroop test and mental arithmetic task, during Stage 2 and 3, respectively), and coherence states were generated using a controlled breathing technique (Stage 4). Physiological coherence and cardiorespiratory synchronization were assessed during each stage from heart rate variability, pulse transit time, and respiration. Coherence measurements derived from the three analyzed variables increased during controlled respiration. Moreover, signals synchronized during the controlled breathing stage, implying a cardiorespiratory synchronization was achieved by most participants. Hence, physiological coherence and cardiopulmonary synchronization, which could lead to improvements in health and better life quality, can be achieved using slow, controlled breathing exercises. Meanwhile, coherence measured during basal state and stressful situations did not show relevant differences using heart rate variability and pulse transit time. More studies are needed to evaluate the ability of coherence ratio to reflect acute stress. © 2017 Society for Psychophysiological Research.
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Voyvodic, James T.; Glover, Gary H.; Greve, Douglas; Gadde, Syam
2011-01-01
Functional magnetic resonance imaging (fMRI) is based on correlating blood oxygen-level dependent (BOLD) signal fluctuations in the brain with other time-varying signals. Although the most common reference for correlation is the timing of a behavioral task performed during the scan, many other behavioral and physiological variables can also influence fMRI signals. Variations in cardiac and respiratory functions in particular are known to contribute significant BOLD signal fluctuations. Variables such as skin conduction, eye movements, and other measures that may be relevant to task performance can also be correlated with BOLD signals and can therefore be used in image analysis to differentiate multiple components in complex brain activity signals. Combining real-time recording and data management of multiple behavioral and physiological signals in a way that can be routinely used with any task stimulus paradigm is a non-trivial software design problem. Here we discuss software methods that allow users control of paradigm-specific audio–visual or other task stimuli combined with automated simultaneous recording of multi-channel behavioral and physiological response variables, all synchronized with sub-millisecond temporal accuracy. We also discuss the implementation and importance of real-time display feedback to ensure data quality of all recorded variables. Finally, we discuss standards and formats for storage of temporal covariate data and its integration into fMRI image analysis. These neuroinformatics methods have been adopted for behavioral task control at all sites in the Functional Biomedical Informatics Research Network (FBIRN) multi-center fMRI study. PMID:22232596
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Siebig, Sylvia; Kuhls, Silvia; Imhoff, Michael; Langgartner, Julia; Reng, Michael; Schölmerich, Jürgen; Gather, Ursula; Wrede, Christian E
2010-03-01
Monitoring of physiologic parameters in critically ill patients is currently performed by threshold alarm systems with high sensitivity but low specificity. As a consequence, a multitude of alarms are generated, leading to an impaired clinical value of these alarms due to reduced alertness of the intensive care unit (ICU) staff. To evaluate a new alarm procedure, we currently generate a database of physiologic data and clinical alarm annotations. Data collection is taking place at a 12-bed medical ICU. Patients with monitoring of at least heart rate, invasive arterial blood pressure, and oxygen saturation are included in the study. Numerical physiologic data at 1-second intervals, monitor alarms, and alarm settings are extracted from the surveillance network. Bedside video recordings are performed with network surveillance cameras. Based on the extracted data and the video recordings, alarms are clinically annotated by an experienced physician. The alarms are categorized according to their technical validity and clinical relevance by a taxonomy system that can be broadly applicable. Preliminary results showed that only 17% of the alarms were classified as relevant, and 44% were technically false. The presented system for collecting real-time bedside monitoring data in conjunction with video-assisted annotations of clinically relevant events is the first allowing the assessment of 24-hour periods and reduces the bias usually created by bedside observers in comparable studies. It constitutes the basis for the development and evaluation of "smart" alarm algorithms, which may help to reduce the number of alarms at the ICU, thereby improving patient safety. Copyright 2010 Elsevier Inc. All rights reserved.
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Ultraflexible, large-area, physiological temperature sensors for multipoint measurements
Yokota, Tomoyuki; Inoue, Yusuke; Terakawa, Yuki; Reeder, Jonathan; Kaltenbrunner, Martin; Ware, Taylor; Yang, Kejia; Mabuchi, Kunihiko; Murakawa, Tomohiro; Sekino, Masaki; Voit, Walter; Sekitani, Tsuyoshi; Someya, Takao
2015-01-01
We report a fabrication method for flexible and printable thermal sensors based on composites of semicrystalline acrylate polymers and graphite with a high sensitivity of 20 mK and a high-speed response time of less than 100 ms. These devices exhibit large resistance changes near body temperature under physiological conditions with high repeatability (1,800 times). Device performance is largely unaffected by bending to radii below 700 µm, which allows for conformal application to the surface of living tissue. The sensing temperature can be tuned between 25 °C and 50 °C, which covers all relevant physiological temperatures. Furthermore, we demonstrate flexible active-matrix thermal sensors which can resolve spatial temperature gradients over a large area. With this flexible ultrasensitive temperature sensor we succeeded in the in vivo measurement of cyclic temperatures changes of 0.1 °C in a rat lung during breathing, without interference from constant tissue motion. This result conclusively shows that the lung of a warm-blooded animal maintains surprising temperature stability despite the large difference between core temperature and inhaled air temperature. PMID:26554008
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Ultraflexible, large-area, physiological temperature sensors for multipoint measurements.
Yokota, Tomoyuki; Inoue, Yusuke; Terakawa, Yuki; Reeder, Jonathan; Kaltenbrunner, Martin; Ware, Taylor; Yang, Kejia; Mabuchi, Kunihiko; Murakawa, Tomohiro; Sekino, Masaki; Voit, Walter; Sekitani, Tsuyoshi; Someya, Takao
2015-11-24
We report a fabrication method for flexible and printable thermal sensors based on composites of semicrystalline acrylate polymers and graphite with a high sensitivity of 20 mK and a high-speed response time of less than 100 ms. These devices exhibit large resistance changes near body temperature under physiological conditions with high repeatability (1,800 times). Device performance is largely unaffected by bending to radii below 700 µm, which allows for conformal application to the surface of living tissue. The sensing temperature can be tuned between 25 °C and 50 °C, which covers all relevant physiological temperatures. Furthermore, we demonstrate flexible active-matrix thermal sensors which can resolve spatial temperature gradients over a large area. With this flexible ultrasensitive temperature sensor we succeeded in the in vivo measurement of cyclic temperatures changes of 0.1 °C in a rat lung during breathing, without interference from constant tissue motion. This result conclusively shows that the lung of a warm-blooded animal maintains surprising temperature stability despite the large difference between core temperature and inhaled air temperature.
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Zynda, Evan R; Grimm, Melissa J; Yuan, Min; Zhong, Lingwen; Mace, Thomas A; Capitano, Maegan; Ostberg, Julie R; Lee, Kelvin P; Pralle, Arnd; Repasky, Elizabeth A
2015-01-01
Maintenance of normal core body temperature is vigorously defended by long conserved, neurovascular homeostatic mechanisms that assist in heat dissipation during prolonged, heat generating exercise or exposure to warm environments. Moreover, during febrile episodes, body temperature can be significantly elevated for at least several hours at a time. Thus, as blood cells circulate throughout the body, physiologically relevant variations in surrounding tissue temperature can occur; moreover, shifts in core temperature occur during daily circadian cycles. This study has addressed the fundamental question of whether the threshold of stimulation needed to activate lymphocytes is influenced by temperature increases associated with physiologically relevant increases in temperature. We report that the need for co-stimulation of CD4+ T cells via CD28 ligation for the production of IL-2 is significantly reduced when cells are exposed to fever-range temperature. Moreover, even in the presence of sufficient CD28 ligation, provision of extra heat further increases IL-2 production. Additional in vivo and in vitro data (using both thermal and chemical modulation of membrane fluidity) support the hypothesis that the mechanism by which temperature modulates co-stimulation is linked to increases in membrane fluidity and membrane macromolecular clustering in the plasma membrane. Thermally-regulated changes in plasma membrane organization in response to physiological increases in temperature may assist in the geographical control of lymphocyte activation, i.e., stimulating activation in lymph nodes rather than in cooler surface regions, and further, may temporarily and reversibly enable CD4+ T cells to become more quickly and easily activated during times of infection during fever. PMID:26131730
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Automated myocardial perfusion from coronary x-ray angiography
NASA Astrophysics Data System (ADS)
Storm, Corstiaan J.; Slump, Cornelis H.
2010-03-01
The purpose of our study is the evaluation of an algorithm to determine the physiological relevance of a coronary lesion as seen in a coronary angiogram. The aim is to extract as much as possible information from a standard coronary angiogram to decide if an abnormality, percentage of stenosis, as seen in the angiogram, results in physiological impairment of the blood supply of the region nourished by the coronary artery. Coronary angiography, still the golden standard, is used to determine the cause of angina pectoris based on the demonstration of an important stenose in a coronary artery. Dimensions of a lesion such as length and percentage of narrowing can at present easily be calculated by using an automatic computer algorithm such as Quantitative Coronary Angiography (QCA) techniques resulting in just anatomical information ignoring the physiological relevance of the lesion. In our study we analyze myocardial perfusion images in standard coronary angiograms in rest and in artificial hyperemic phases, using a drug e.g. papaverine intracoronary. Setting a Region of Interest (ROI) in the angiogram without overlying major vessels makes it possible to calculate contrast differences as a function of time, so called time-density curves, in the basal and hyperemic phases. In minimizing motion artifacts, end diastolic images are selected ECG based in basal and hyperemic phase in an identical ROI in the same angiographic projection. The development of new algorithms for calculating differences in blood supply in the region as set are presented together with the results of a small clinical case study using the standard angiographic procedure.
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Pair Comparison Study of the Relevance of Nine Basic Science Courses
ERIC Educational Resources Information Center
Spilman, Edra L.; Spilman, Helen W.
1975-01-01
Reports a survey study in which basic science courses were rated according to relevance. Notes approaches for making the anatomy disciplines more relevant because results showed them of lowest relevancy compared with physiology, pathology, and pharmacology which were rated of highest relevance and with biochemistry and microbiology which fell…
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Teaching Stress Physiology Using Zebrafish ("Danio Rerio")
ERIC Educational Resources Information Center
Cooper, Michael; Dhawale, Shree; Mustafa, Ahmed
2009-01-01
A straightforward and inexpensive laboratory experiment is presented that investigates the physiological stress response of zebrafish after a 5 degree C increase in water temperature. This experiment is designed for an undergraduate physiology lab and allows students to learn the scientific method and relevant laboratory techniques without causing…
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Phun Week: Understanding Physiology
ERIC Educational Resources Information Center
Limson, Mel; Matyas, Marsha Lakes
2009-01-01
Topics such as sports, exercise, health, and nutrition can make the science of physiology relevant and engaging for students. In addition, many lessons on these topics, such as those on the cardiovascular, respiratory, and digestive systems, align with national and state life science education standards. Physiology Understanding Week (PhUn…
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Modeling Diet-Induced Obesity with Obesity-Prone Rats: Implications for Studies in Females
Giles, Erin D.; Jackman, Matthew R.; MacLean, Paul S.
2016-01-01
Obesity is a worldwide epidemic, and the comorbidities associated with obesity are numerous. Over the last two decades, we and others have employed an outbred rat model to study the development and persistence of obesity, as well as the metabolic complications that accompany excess weight. In this review, we summarize the strengths and limitations of this model and how it has been applied to further our understanding of human physiology in the context of weight loss and weight regain. We also discuss how the approach has been adapted over time for studies in females and female-specific physiological conditions, such as menopause and breast cancer. As excess weight and the accompanying metabolic complications have become common place in our society, we expect that this model will continue to provide a valuable translational tool to establish physiologically relevant connections to the basic science studies of obesity and body weight regulation. PMID:27933296
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Optical imaging of localized chemical events using programmable diamond quantum nanosensors
NASA Astrophysics Data System (ADS)
Rendler, Torsten; Neburkova, Jitka; Zemek, Ondrej; Kotek, Jan; Zappe, Andrea; Chu, Zhiqin; Cigler, Petr; Wrachtrup, Jörg
2017-03-01
Development of multifunctional nanoscale sensors working under physiological conditions enables monitoring of intracellular processes that are important for various biological and medical applications. By attaching paramagnetic gadolinium complexes to nanodiamonds (NDs) with nitrogen-vacancy (NV) centres through surface engineering, we developed a hybrid nanoscale sensor that can be adjusted to directly monitor physiological species through a proposed sensing scheme based on NV spin relaxometry. We adopt a single-step method to measure spin relaxation rates enabling time-dependent measurements on changes in pH or redox potential at a submicrometre-length scale in a microfluidic channel that mimics cellular environments. Our experimental data are reproduced by numerical simulations of the NV spin interaction with gadolinium complexes covering the NDs. Considering the versatile engineering options provided by polymer chemistry, the underlying mechanism can be expanded to detect a variety of physiologically relevant species and variables.
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Basallote, Manuel G; Martínez, Manuel; Vázquez, Marta
2014-07-28
In view of the relevance of the reactivity of inert tetraamine Co(III) complexes having two substitutionally active cis positions capable of interact with biologically relevant ligands, the study of the reaction of cis-[Co(cyclen)(H2O)2](3+) and [Co(tren)(H2O)2](3+) with chlorides, inorganic phosphate and 5'-CMP (5'-cytidinemonophosphate) has been pursued at physiological pH. The results indicate that, in addition to the actuation of the expected labilising conjugate-base mechanism, the formation of mono and inert bis hydroxo-bridged species is relevant for understanding their speciation and reactivity. The reactivity pattern observed also indicates the key role played by the "innocent" buffers frequently used in most in vitro studies, which can make the results unreliable in many cases. The differences between the reactivity of inorganic and biologically relevant phosphates has also been found to be remarkable, with outer-sphere hydrogen bonding interactions being a dominant factor for the process. While for the inorganic phosphate substitution process the formation of μ-η(2)-OPO2O represents the termination of the reactivity monitored, for 5'-CMP only the formation of η(1)-OPO3 species is observed, which evolve with time to the final dead-end bis hydroxo-bridged complexes. The promoted hydrolysis of the 5'-CMP phosphate has not been observed in any of the processes studied.
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Hou, Liping; Xu, Hongyan; Ying, Guangguo; Yang, Yang; Shu, Hu; Zhao, Jianliang; Cheng, Xuemei
2017-11-01
Progesterone (P4) is a natural and synthetic steroid, widely distributed in the aquatic environments. It can lead to adverse effects on the endocrine system in aquatic organisms. This study investigated the toxicological effects of exposure to environmentally relevant concentrations (4, 44, and 410ng/L) of progesterone for 42 d on adult female mosquitofish, Gambusia affinis. We performed morphological and histological analyses on gonads, anal fins, liver, and gills after the exposure of mosquito fish to P4. The expression levels of genes (vtg, er, and ar isoforms) related to fish reproduction and detoxification (cyp1a) in the liver were quantified by quantitative real-time polymerase chain reaction. The results showed that the progesterone exposure induced slight masculinization in female mosquitofish, influenced the oocyte maturation as revealed by histology of the ovaries, and caused severe damages to the liver and gills of adult female mosquitofish. It also suppressed the mRNAs expression of vtg, er, cyp1a, and significantly enhanced the expression of ar mRNA in the liver. This study reveals the molecular and physiological effects of progesterone at environmentally relevant concentrations, which might further be translated to alterations in the reproduction of mosquitofish. Copyright © 2017 Elsevier B.V. All rights reserved.
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The conservation physiology toolbox: status and opportunities
Love, Oliver P; Hultine, Kevin R
2018-01-01
Abstract For over a century, physiological tools and techniques have been allowing researchers to characterize how organisms respond to changes in their natural environment and how they interact with human activities or infrastructure. Over time, many of these techniques have become part of the conservation physiology toolbox, which is used to monitor, predict, conserve, and restore plant and animal populations under threat. Here, we provide a summary of the tools that currently comprise the conservation physiology toolbox. By assessing patterns in articles that have been published in ‘Conservation Physiology’ over the past 5 years that focus on introducing, refining and validating tools, we provide an overview of where researchers are placing emphasis in terms of taxa and physiological sub-disciplines. Although there is certainly diversity across the toolbox, metrics of stress physiology (particularly glucocorticoids) and studies focusing on mammals have garnered the greatest attention, with both comprising the majority of publications (>45%). We also summarize the types of validations that are actively being completed, including those related to logistics (sample collection, storage and processing), interpretation of variation in physiological traits and relevance for conservation science. Finally, we provide recommendations for future tool refinement, with suggestions for: (i) improving our understanding of the applicability of glucocorticoid physiology; (ii) linking multiple physiological and non-physiological tools; (iii) establishing a framework for plant conservation physiology; (iv) assessing links between environmental disturbance, physiology and fitness; (v) appreciating opportunities for validations in under-represented taxa; and (vi) emphasizing tool validation as a core component of research programmes. Overall, we are confident that conservation physiology will continue to increase its applicability to more taxa, develop more non-invasive techniques, delineate where limitations exist, and identify the contexts necessary for interpretation in captivity and the wild. PMID:29942517
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Handheld Microneedle-Based Electrolyte Sensing Platform.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Miller, Philip R.; Rivas, Rhiana; Johnson, David
2015-11-01
Sandia National Laboratories will provide technical assistance, within time and budget, to Requester on testing and analyzing a microneedle-based electrolyte sensing platform. Hollow microneedles will be fabricated at Sandia and integrated with a fluidic chip using plastic laminate prototyping technology available at Sandia. In connection with commercial ion selective electrodes the sensing platform will be tested for detection of electrolytes (sodium and/or potassium) within physiological relevant concent ration ranges.
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Cohen, Mitchell J; Grossman, Adam D; Morabito, Diane; Knudson, M Margaret; Butte, Atul J; Manley, Geoffrey T
2010-01-01
Advances in technology have made extensive monitoring of patient physiology the standard of care in intensive care units (ICUs). While many systems exist to compile these data, there has been no systematic multivariate analysis and categorization across patient physiological data. The sheer volume and complexity of these data make pattern recognition or identification of patient state difficult. Hierarchical cluster analysis allows visualization of high dimensional data and enables pattern recognition and identification of physiologic patient states. We hypothesized that processing of multivariate data using hierarchical clustering techniques would allow identification of otherwise hidden patient physiologic patterns that would be predictive of outcome. Multivariate physiologic and ventilator data were collected continuously using a multimodal bioinformatics system in the surgical ICU at San Francisco General Hospital. These data were incorporated with non-continuous data and stored on a server in the ICU. A hierarchical clustering algorithm grouped each minute of data into 1 of 10 clusters. Clusters were correlated with outcome measures including incidence of infection, multiple organ failure (MOF), and mortality. We identified 10 clusters, which we defined as distinct patient states. While patients transitioned between states, they spent significant amounts of time in each. Clusters were enriched for our outcome measures: 2 of the 10 states were enriched for infection, 6 of 10 were enriched for MOF, and 3 of 10 were enriched for death. Further analysis of correlations between pairs of variables within each cluster reveals significant differences in physiology between clusters. Here we show for the first time the feasibility of clustering physiological measurements to identify clinically relevant patient states after trauma. These results demonstrate that hierarchical clustering techniques can be useful for visualizing complex multivariate data and may provide new insights for the care of critically injured patients.
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Cadaret, Caitlin N; Yates, Dustin T
2018-06-01
Studies have shown that practicing temporally spaced retrieval of previously learned information via formal assessments increases student retention of the information. Our objective was to determine the impact of online homework administered as a first retrieval practice 1 or 5 days after introduction of physiology topics on long-term information retention. Students in two undergraduate courses, Anatomy and Physiology (ASCI 240) and Animal Physiological Systems (ASCI 340), were presented with information on a specific physiological system during each weekly laboratory and then completed an online homework assignment either 1 or 5 days later. Information retention was assessed via an in-class quiz the following week and by a comprehensive final exam at semester's end (4-13 wk later). Performance on homework assignments was generally similar between groups for both courses. Information retention at 1 wk did not differ due to timing of homework in either course. In both courses, however, students who received homework 5 days after class performed better on final exam questions relevant to that week's topic compared with their day 1 counterparts. These findings indicate that the longer period between introducing physiology information in class and assigning the first retrieval practice was more beneficial to long-term information retention than the shorter period, despite seemingly equivalent benefits in the shorter term. Since information is typically forgotten over time, we speculate that the longer interval necessitates greater retrieval effort in much the same way as built-in desirable difficulties, thus allowing for stronger conceptual connections and deeper comprehension.
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NASA Astrophysics Data System (ADS)
Wahlquist, Joseph A.
This work focused on characterizing the mechanical behavior of biological material in physiologically relevant conditions and at sub millimeter length scales. Elucidating the time, length scale, and directionally dependent mechanical behavior of cartilage and other biological materials is critical to adequately recapitulate native mechanosensory cues for cells, create computational models that mimic native tissue behavior, and assess disease progression. This work focused on three broad aspects of characterizing the mechanical behavior of articular cartilage. First, we sought to reveal the causes of time-dependent deformation and variation of mechanical properties with distance from the articular surface. Second, we investigated size dependence of mechanical properties. Finally, we examined material anisotropy of both the calcified and uncalcified tissues of the osteochondral interface. This research provides insight into how articular cartilage serves to support physiologic loads and simultaneously sustain chondrocyte viability.
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Outevsky, David; Martin, Blake Cw
2015-12-01
Dancesport, the competitive branch of ballroom dancing, places high physiological and psychological demands on its practitioners, but pedagogical resources in these areas for this dance form are limited. Dancesport competitors could benefit from strategies used in other aesthetic sports. In this review, we identify conditioning methodologies from gymnastics, figure skating, and contemporary, modern, and ballet dance forms that could have relevance and suitability for dancesport training, and propose several strategies for inclusion in the current dancesport curriculum. We reviewed articles derived from Google Scholar, PubMed, ScienceDirect, Taylor & Francis Online, and Web of Science search engines and databases, with publication dates from 1979 to 2013. The keywords included MeSH terms: dancing, gymnastics, physiology, energy metabolism, physical endurance, and range of motion. Out of 47 papers examined, 41 papers met the inclusion criteria (validity of scientific methods, topic relevance, transferability to dancesport, publication date). Quality and validity of the data were assessed by examining the methodologies in each study and comparing studies on similar populations as well as across time using the PRISMA 2009 checklist and flowchart. The relevant research suggests that macro-cycle periodization planning, aerobic and anaerobic conditioning, range of motion and muscular endurance training, and performance psychology methods have potential for adaptation for dancesport training. Dancesport coaches may help their students fulfill their ambitions as competitive athletes and dance artists by adapting the relevant performance enhancement strategies from gymnastics, figure skating, and concert dance forms presented in this paper.
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Physiologically Relevant Changes in Serotonin Resolved by Fast Microdialysis
2013-01-01
Online microdialysis is a sampling and detection method that enables continuous interrogation of extracellular molecules in freely moving subjects under behaviorally relevant conditions. A majority of recent publications using brain microdialysis in rodents report sample collection times of 20–30 min. These long sampling times are due, in part, to limitations in the detection sensitivity of high performance liquid chromatography (HPLC). By optimizing separation and detection conditions, we decreased the retention time of serotonin to 2.5 min and the detection threshold to 0.8 fmol. Sampling times were consequently reduced from 20 to 3 min per sample for online detection of serotonin (and dopamine) in brain dialysates using a commercial HPLC system. We developed a strategy to collect and to analyze dialysate samples continuously from two animals in tandem using the same instrument. Improvements in temporal resolution enabled elucidation of rapid changes in extracellular serotonin levels associated with mild stress and circadian rhythms. These dynamics would be difficult or impossible to differentiate using conventional microdialysis sampling rates. PMID:23614776
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Vasconcelos, Mailton; Stein, Dirson João; de Almeida, Rosa Maria M
2015-01-01
Social defeat (SD) in rats, which results from male intraspecific confrontations, is ethologically relevant and useful to understand stress effects on physiology and behavior. A systematic review of studies about biomarkers induced by the SD protocol and published from 2002 to 2013 was carried out in the electronic databases PubMed, Web of Knowledge and ScienceDirect. The search terms were: social defeat, rat, neurotrophins, neuroinflammatory markers, and transcriptional factors. Classical and recently discovered biomarkers were found to be relevant in stress-induced states. Findings were summarized in accordance to the length of exposure to stress: single, repeated, intermittent and continuous SD. This review found that the brain-derived neurotrophic factor (BDNF) is a distinct marker of stress adaptation. Along with glucocorticoids and catecholamines, BDNF seems to be important in understanding stress physiology. The SD model provides a relevant tool to study stress response features, development of addictive behaviors, clinic depression and anxiety, as well as individual differences in vulnerability and resilience to stress.
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Long-term variability of global statistical properties of epileptic brain networks
NASA Astrophysics Data System (ADS)
Kuhnert, Marie-Therese; Elger, Christian E.; Lehnertz, Klaus
2010-12-01
We investigate the influence of various pathophysiologic and physiologic processes on global statistical properties of epileptic brain networks. We construct binary functional networks from long-term, multichannel electroencephalographic data recorded from 13 epilepsy patients, and the average shortest path length and the clustering coefficient serve as global statistical network characteristics. For time-resolved estimates of these characteristics we observe large fluctuations over time, however, with some periodic temporal structure. These fluctuations can—to a large extent—be attributed to daily rhythms while relevant aspects of the epileptic process contribute only marginally. Particularly, we could not observe clear cut changes in network states that can be regarded as predictive of an impending seizure. Our findings are of particular relevance for studies aiming at an improved understanding of the epileptic process with graph-theoretical approaches.
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Characteristics of the sequence effect in Parkinson's disease.
Kang, Suk Yun; Wasaka, Toshiaki; Shamim, Ejaz A; Auh, Sungyoung; Ueki, Yoshino; Lopez, Grisel J; Kida, Tetsuo; Jin, Seung-Hyun; Dang, Nguyet; Hallett, Mark
2010-10-15
The sequence effect (SE) in Parkinson's disease (PD) is progressive slowing of sequential movements. It is a feature of bradykinesia, but is separate from a general slowness without deterioration over time. It is commonly seen in PD, but its physiology is unclear. We measured general slowness and the SE separately with a computer-based, modified Purdue pegboard in 11 patients with advanced PD. We conducted a placebo-controlled, four-way crossover study to learn whether levodopa and repetitive transcranial magnetic stimulation (rTMS) could improve general slowness or the SE. We also examined the correlation between the SE and clinical fatigue. Levodopa alone and rTMS alone improved general slowness, but rTMS showed no additive effect on levodopa. Levodopa alone, rTMS alone, and their combination did not alleviate the SE. There was no correlation between the SE and fatigue. This study suggests that dopaminergic dysfunction and abnormal motor cortex excitability are not the relevant mechanisms for the SE. Additionally, the SE is not a component of clinical fatigue. Further work is needed to establish the physiology and clinical relevance of the SE. © 2010 Movement Disorder Society.
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Frontiers in the Teaching of Physiology. Computer Literacy and Simulation.
ERIC Educational Resources Information Center
Tidball, Charles S., Ed.; Shelesnyak, M. C., Ed.
Provided is a collection of papers on computer literacy and simulation originally published in The Physiology Teacher, supplemented by additional papers and a glossary of terms relevant to the field. The 12 papers are presented in five sections. An affirmation of conventional physiology laboratory exercises, coping with computer terminology, and…
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Sezgin, Erdinc; Levental, Ilya; Mayor, Satyajit; Eggeling, Christian
2017-01-01
Cellular plasma membranes are laterally heterogeneous, featuring a variety of distinct subcompartments that differ in their biophysical properties and composition. A large body of research has focused on understanding the basis for this heterogeneity and its physiological relevance. The membrane raft hypothesis formalized a physicochemical principle for a subtype of such lateral membrane heterogeneity, wherein the preferential associations of cholesterol and saturated lipids drives the formation of relatively packed (ordered) membrane domains that selectively recruit certain lipids and proteins. Recent years have yielded new insights into this concept and its in vivo relevance, primarily owing to the development of biochemical and biophysical technologies. PMID:28356571
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Kageyama, Ikuo; Yoshimura, Ken; Satoh, Yoshihide; Nanayakkara, Chinthani D; Pallegama, Ranjith W; Iwasaki, Shin-Ichi
2016-07-01
We coordinated anatomy and physiology lectures and practicals to facilitate an integrated understanding of morphology and function in a basic medical science program for dental students and to reduce the time spent on basic science education. This method is a means to provide the essential information and skills in less time. The overall impression was that the practice of joint central nervous system lectures and practicals was an efficient method for students, which suggests that joint lectures might also be useful for clinical subjects. About two-thirds of students felt that the joint anatomy and physiology lecture on the central nervous system was useful and necessary in understanding the relationship between morphology and function, at least for this subject. One-third of students were neutral on the effectiveness of this method. However, the survey results suggest that improvements are needed in the method and timing of joint lectures and practicals. The present teaching approach can be further improved by conducting combined lectures in which the form and function of anatomic structures are presented by the relevant departments during the same lecture. Finally, joint lecturers and practicals offer an opportunity to increase student understanding of the importance of new research findings by the present authors and other researchers.
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A systematic review of standing and treadmill desks in the workplace.
MacEwen, Brittany T; MacDonald, Dany J; Burr, Jamie F
2015-01-01
Standing and treadmill desks are intended to reduce the amount of time spent sitting in today's otherwise sedentary office. Proponents of these desks suggest that health benefits may be acquired as standing desk use discourages long periods of sitting, which has been identified as an independent health risk factor. Our objectives were thus to analyze the evidence for standing and treadmill desk use in relation to physiological (chronic disease prevention and management) and psychological (worker productivity, well-being) outcomes. A computer-assisted systematic search of Medline, PubMed, PsycINFO, SPORTDiscus, CINAHL, CENTRAL, and EMBASE databases was employed to identify all relevant articles related to standing and treadmill desk use. Treadmill desks led to the greatest improvement in physiological outcomes including postprandial glucose, HDL cholesterol, and anthropometrics, while standing desk use was associated with few physiological changes. Standing and treadmill desks both showed mixed results for improving psychological well-being with little impact on work performance. Standing and treadmill desks show some utility for breaking up sitting time and potentially improving select components of health. At present; however, there exist substantial evidence gaps to comprehensively evaluate the utility of each type of desk to enhance health benefits by reducing sedentary time. Copyright © 2014 Elsevier Inc. All rights reserved.
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Yoder, Kathleen M.; Vicario, David S.
2012-01-01
Gonadal hormones modulate behavioral responses to sexual stimuli, and communication signals can also modulate circulating hormone levels. In several species, these combined effects appear to underlie a two-way interaction between circulating gonadal hormones and behavioral responses to socially salient stimuli. Recent work in songbirds has shown that manipulating local estradiol levels in the auditory forebrain produces physiological changes that affect discrimination of conspecific vocalizations and can affect behavior. These studies provide new evidence that estrogens can directly alter auditory processing and indirectly alter the behavioral response to a stimulus. These studies show that: 1. Local estradiol action within an auditory area is necessary for socially-relevant sounds to induce normal physiological responses in the brains of both sexes; 2. These physiological effects occur much more quickly than predicted by the classical time-frame for genomic effects; 3. Estradiol action within the auditory forebrain enables behavioral discrimination among socially-relevant sounds in males; and 4. Estradiol is produced locally in the male brain during exposure to particular social interactions. The accumulating evidence suggests a socio-neuro-endocrinology framework in which estradiol is essential to auditory processing, is increased by a socially relevant stimulus, acts rapidly to shape perception of subsequent stimuli experienced during social interactions, and modulates behavioral responses to these stimuli. Brain estrogens are likely to function similarly in both songbird sexes because aromatase and estrogen receptors are present in both male and female forebrain. Estrogenic modulation of perception in songbirds and perhaps other animals could fine-tune male advertising signals and female ability to discriminate them, facilitating mate selection by modulating behaviors. Keywords: Estrogens, Songbird, Social Context, Auditory Perception PMID:22201281
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Coen, S J
2011-06-01
Functional neuroimaging has been used extensively in conjunction with gastric balloon distension in an attempt to unravel the relationship between the brain, regulation of hunger, satiety, and food intake tolerance. A number of researchers have also adopted a more physiological approach using intra-gastric administration of a liquid meal which has revealed different brain responses to gastric balloon distension. These differences are important as they question the utility and relevance of non-physiological models such as gastric balloon distension, especially when investigating mechanisms of feeding behavior such as satiety. However, an assessment of the relevance of physiological versus non-physiological gastric distension has been problematic due to differences in distension volumes between studies. In this issue of Neurogastroenterology and Motility, Geeraerts et al. compare brain activity during volume matched nutrient gastric distension and balloon distension in healthy volunteers. Gastric balloon distension activated the 'visceral pain neuromatrix'. This network of brain regions was deactivated during nutrient infusion, supporting the notion that brain activity during physiological versus non-physiological distension is indeed different. The authors suggest deactivation of the pain neuromatrix during nutrient infusion serves as a prerequisite for tolerance of normal meal volumes in health. © 2011 Blackwell Publishing Ltd.
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Magnesium degradation observed in situ under flow by synchrotron radiation based microtomography
NASA Astrophysics Data System (ADS)
Feyerabend, Frank; Dose, Thomas; Xu, Yuling; Beckmann, Felix; Stekker, Michael; Willumeit-Römer, Regine; Schreyer, Andreas; Wilde, Fabian; Hammel, Jörg U.
2016-10-01
The use of degradable magnesium based implants is becoming clinically relevant, e.g. for the use as bone screws. Still there is a lack of analyzing techniques to characterize the in vitro degradation behavior of implant prototypes. The aim of this study was to design an in situ environment to continuously monitor the degradation processes under physiological conditions by time-lapse SRμCT. The use of physiological conditions was chosen to get a better approach to the in vivo situation, as it could be shown by many studies, that these conditions change on the one hand the degradation rate and on the other hand also the formed degradation products. The resulting in situ environment contains a closed bioreactor system to control and monitor the relevant parameters (37°C, 5 % O2, 20 % CO2) and to grant sterility of the setup. A flow cell was designed and manufactured from polyether etherketone (PEEK), which was chosen because of the good mechanical properties, high thermal and chemical resistance and radiographic translucency. Sterilization of the system including the sample was reached by a transient flush with 70 % ethanol and subsequent replacement by physiological medium (Modified Eagle Medium alpha). As proof of principle it could be shown that the system remained sterile during a beamtime of several days and that the continuous SRμCT imaging was feasible.
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Charles, Michelle A; Johnson, Ian T; Belshaw, Nigel J
2012-07-01
The micronutrients folate and selenium may modulate DNA methylation patterns by affecting intracellular levels of the methyl donor S-adenosylmethionine (SAM) and/or the product of methylation reactions S-adenosylhomocysteine (SAH). WI-38 fibroblasts and FHC colon epithelial cells were cultured in the presence of two forms of folate or four forms of selenium at physiologically-relevant doses, and their effects on LINE-1 methylation, gene-specific CpG island (CGI) methylation and intracellular SAM:SAH were determined. At physiologically-relevant doses the forms of folate or selenium had no effect on LINE-1 or CGI methylation, nor on intracellular SAM:SAH. However the commercial cell culture media used for the selenium studies, containing supra-physiological concentrations of folic acid, induced LINE-1 hypomethylation, CGI hypermethylation and decreased intracellular SAM:SAH in both cell lines. We conclude that the exposure of normal human cells to supra-physiological folic acid concentrations present in commercial cell culture media perturbs the intracellular SAM:SAH ratio and induces aberrant DNA methylation.
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Kuzmiak-Glancy, Sarah; Jaimes, Rafael; Wengrowski, Anastasia M; Kay, Matthew W
2015-06-01
What is the topic of this review? This review discusses how the function and electrophysiology of isolated perfused hearts are affected by oxygenation and energy utilization. The impact of oxygenation on fluorescence measurements in perfused hearts is also discussed. What advances does it highlight? Recent studies have illuminated the inherent differences in electromechanical function, energy utilization rate and oxygen requirements between the primary types of excised heart preparations. A summary and analysis of how these variables affect experimental results are necessary to elevate the physiological relevance of these approaches in order to advance the field of whole-heart research. The ex vivo perfused heart recreates important aspects of in vivo conditions to provide insight into whole-organ function. In this review we discuss multiple types of ex vivo heart preparations, explain how closely each mimic in vivo function, and discuss how changes in electromechanical function and inadequate oxygenation of ex vivo perfused hearts may affect measurements of physiology. Hearts that perform physiological work have high oxygen demand and are likely to experience hypoxia when perfused with a crystalloid perfusate. Adequate myocardial oxygenation is critically important for obtaining physiologically relevant measurements, so when designing experiments the type of ex vivo preparation and the capacity of perfusate to deliver oxygen must be carefully considered. When workload is low, such as during interventions that inhibit contraction, oxygen demand is also low, which could dramatically alter a physiological response to experimental variables. Changes in oxygenation also alter the optical properties of cardiac tissue, an effect that may influence optical signals measured from both endogenous and exogenous fluorophores. Careful consideration of oxygen supply, working condition, and wavelengths used to acquire optical signals is critical for obtaining physiologically relevant measurements during ex vivo perfused heart studies. © 2015 The Authors. Experimental Physiology © 2015 The Physiological Society.
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Peterman, W E; Semlitsch, R D
2014-10-01
Many patterns observed in ecology, such as species richness, life history variation, habitat use, and distribution, have physiological underpinnings. For many ectothermic organisms, temperature relationships shape these patterns, but for terrestrial amphibians, water balance may supersede temperature as the most critical physiologically limiting factor. Many amphibian species have little resistance to water loss, which restricts them to moist microhabitats, and may significantly affect foraging, dispersal, and courtship. Using plaster models as surrogates for terrestrial plethodontid salamanders (Plethodon albagula), we measured water loss under ecologically relevant field conditions to estimate the duration of surface activity time across the landscape. Surface activity time was significantly affected by topography, solar exposure, canopy cover, maximum air temperature, and time since rain. Spatially, surface activity times were highest in ravine habitats and lowest on ridges. Surface activity time was a significant predictor of salamander abundance, as well as a predictor of successful recruitment; the probability of a juvenile salamander occupying an area with high surface activity time was two times greater than an area with limited predicted surface activity. Our results suggest that survival, recruitment, or both are demographic processes that are affected by water loss and the ability of salamanders to be surface-active. Results from our study extend our understanding of plethodontid salamander ecology, emphasize the limitations imposed by their unique physiology, and highlight the importance of water loss to spatial population dynamics. These findings are timely for understanding the effects that fluctuating temperature and moisture conditions predicted for future climates will have on plethodontid salamanders.
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Discovery of a New Cellular Motion and Its Relevance to Breast Cancer and Involution
2014-02-01
motion (CAMo), live cell imaging , confocal microscopy Overall Project Summary: During this first year of funding we have concentrated our work to...cell types in 3D cultures and in vivo. Subtask 1.1a: Real time live cell imaging using confocal microscopy will be used to image cellular movement...exciting as they are important steps in understanding behavior of normal myoepithelial cells using live cell imaging in physiologically
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Gao, Ning; Zhou, Wei; Jiang, Xiaocheng; Hong, Guosong; Fu, Tian-Ming; Lieber, Charles M
2015-03-11
Transistor-based nanoelectronic sensors are capable of label-free real-time chemical and biological detection with high sensitivity and spatial resolution, although the short Debye screening length in high ionic strength solutions has made difficult applications relevant to physiological conditions. Here, we describe a new and general strategy to overcome this challenge for field-effect transistor (FET) sensors that involves incorporating a porous and biomolecule permeable polymer layer on the FET sensor. This polymer layer increases the effective screening length in the region immediately adjacent to the device surface and thereby enables detection of biomolecules in high ionic strength solutions in real-time. Studies of silicon nanowire field-effect transistors with additional polyethylene glycol (PEG) modification show that prostate specific antigen (PSA) can be readily detected in solutions with phosphate buffer (PB) concentrations as high as 150 mM, while similar devices without PEG modification only exhibit detectable signals for concentrations ≤10 mM. Concentration-dependent measurements exhibited real-time detection of PSA with a sensitivity of at least 10 nM in 100 mM PB with linear response up to the highest (1000 nM) PSA concentrations tested. The current work represents an important step toward general application of transistor-based nanoelectronic detectors for biochemical sensing in physiological environments and is expected to open up exciting opportunities for in vitro and in vivo biological sensing relevant to basic biology research through medicine.
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Ravichandran, Akhilandeshwari; Wen, Feng; Lim, Jing; Chong, Mark Seow Khoon; Chan, Jerry K Y; Teoh, Swee-Hin
2018-04-01
Cells respond to physiological mechanical stresses especially during early fetal development. Adopting a biomimetic approach, it is necessary to develop bioreactor systems to explore the effects of physiologically relevant mechanical strains and shear stresses for functional tissue growth and development. This study introduces a multimodal bioreactor system that allows application of cyclic compressive strains on premature bone grafts that are cultured under biaxial rotation (chamber rotation about 2 axes) conditions for bone tissue engineering. The bioreactor is integrated with sensors for dissolved oxygen levels and pH that allow real-time, non-invasive monitoring of the culture parameters. Mesenchymal stem cells-seeded polycaprolactone-β-tricalcium phosphate scaffolds were cultured in this bioreactor over 2 weeks in 4 different modes-static, cyclic compression, biaxial rotation, and multimodal (combination of cyclic compression and biaxial rotation). The multimodal culture resulted in 1.8-fold higher cellular proliferation in comparison with the static controls within the first week. Two weeks of culture in the multimodal bioreactor utilizing the combined effects of optimal fluid flow conditions and cyclic compression led to the upregulation of osteogenic genes alkaline phosphatase (3.2-fold), osteonectin (2.4-fold), osteocalcin (10-fold), and collagen type 1 α1 (2-fold) in comparison with static cultures. We report for the first time, the independent and combined effects of mechanical stimulation and biaxial rotation for bone tissue engineering using a bioreactor platform with non-invasive sensing modalities. The demonstrated results show leaning towards the futuristic vision of using a physiologically relevant bioreactor system for generation of autologous bone grafts for clinical implantation. Copyright © 2018 John Wiley & Sons, Ltd.
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Women and Women's Issues in Industrial and Physiological Psychology.
ERIC Educational Resources Information Center
Knight, Patrick A.; And Others
In the area of industrial/organizational (I/O) psychology and physiological psychology, issues of gender have only begun to be addressed. An examination of the recent literatures in I/O and physiological psychology was undertaken to document the extent to which women are used as research subjects, to determine whether or not research relevant to…
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Multidrug Efflux Systems in Microaerobic and Anaerobic Bacteria
Xu, Zeling; Yan, Aixin
2015-01-01
Active drug efflux constitutes an important mechanism of antibiotic and multidrug resistance in bacteria. Understanding the distribution, expression, and physiological functions of multidrug efflux pumps, especially under physiologically and clinically relevant conditions of the pathogens, is the key to combat drug resistance. In animal hosts, most wounded, infected and inflamed tissues display low oxygen tensions. In this article, we summarize research development on multidrug efflux pumps in the medicinally relevant microaerobic and anaerobic pathogens and their implications in the effort to combat drug-resistant infections. PMID:27025630
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Medical student attitudes toward kidney physiology and nephrology: a qualitative study.
Roberts, John K; Sparks, Matthew A; Lehrich, Ruediger W
2016-11-01
Interest in nephrology among trainees is waning in the USA. Early perceptions and attitudes to subject matter can be linked to the quality of pre-clinical curricula. We wanted to explore these attitudes in the setting of modern curriculum redesign. We utilized Q methodology to understand first-year medical student attitudes after an innovative kidney physiology curriculum redesign that focuses on blending multiple learning methods. First-year medical students were invited to take a Q sort survey at the conclusion of a kidney physiology course. Students prioritized statements related to their understanding of kidney physiology, learning preferences, preferred course characteristics, perceived clinical relevance of kidney physiology, and interest in nephrology as a career. Factor analysis was performed to identify different student viewpoints. At the conclusion of our modified course, all students (n = 108) were invited to take the survey and 44 (41%) Q sorts were returned. Two dominant viewpoints were defined according to interest in nephrology. The Potentials are students who understand kidney physiology, perceive kidney physiology as clinically relevant, attend class sessions, utilize videos, and are willing to shadow a nephrologist. The Uninterested are students who are less satisfied with their kidney physiology knowledge, prefer to study alone with a textbook, avoid lectures, and are not interested in learning about nephrology. In an updated renal physiology course, students that use multiple learning methods also have favorable attitudes toward learning kidney physiology. Thus, modern curriculum changes that accommodate a variety of learning styles may promote positive attitudes toward nephrology.
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National Aeronautics and Space Administration Biological Specimen Repository
NASA Technical Reports Server (NTRS)
McMonigal, Kathleen A.; Pietrzyk, Robert a.; Johnson, Mary Anne
2008-01-01
The National Aeronautics and Space Administration Biological Specimen Repository (Repository) is a storage bank that is used to maintain biological specimens over extended periods of time and under well-controlled conditions. Samples from the International Space Station (ISS), including blood and urine, will be collected, processed and archived during the preflight, inflight and postflight phases of ISS missions. This investigation has been developed to archive biosamples for use as a resource for future space flight related research. The International Space Station (ISS) provides a platform to investigate the effects of microgravity on human physiology prior to lunar and exploration class missions. The storage of crewmember samples from many different ISS flights in a single repository will be a valuable resource with which researchers can study space flight related changes and investigate physiological markers. The development of the National Aeronautics and Space Administration Biological Specimen Repository will allow for the collection, processing, storage, maintenance, and ethical distribution of biosamples to meet goals of scientific and programmatic relevance to the space program. Archiving of the biosamples will provide future research opportunities including investigating patterns of physiological changes, analysis of components unknown at this time or analyses performed by new methodologies.
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Nonstandard working schedules and health: the systematic search for a comprehensive model.
Merkus, Suzanne L; Holte, Kari Anne; Huysmans, Maaike A; van Mechelen, Willem; van der Beek, Allard J
2015-10-23
Theoretical models on shift work fall short of describing relevant health-related pathways associated with the broader concept of nonstandard working schedules. Shift work models neither combine relevant working time characteristics applicable to nonstandard schedules nor include the role of rest periods and recovery in the development of health complaints. Therefore, this paper aimed to develop a comprehensive model on nonstandard working schedules to address these shortcomings. A literature review was conducted using a systematic search and selection process. Two searches were performed: one associating the working time characteristics time-of-day and working time duration with health and one associating recovery after work with health. Data extracted from the models were used to develop a comprehensive model on nonstandard working schedules and health. For models on the working time characteristics, the search strategy yielded 3044 references, of which 26 met the inclusion criteria that contained 22 distinctive models. For models on recovery after work, the search strategy yielded 896 references, of which seven met the inclusion criteria containing seven distinctive models. Of the models on the working time characteristics, three combined time-of-day with working time duration, 18 were on time-of-day (i.e. shift work), and one was on working time duration. The model developed in the paper has a comprehensive approach to working hours and other work-related risk factors and proposes that they should be balanced by positive non-work factors to maintain health. Physiological processes leading to health complaints are circadian disruption, sleep deprivation, and activation that should be counterbalanced by (re-)entrainment, restorative sleep, and recovery, respectively, to maintain health. A comprehensive model on nonstandard working schedules and health was developed. The model proposes that work and non-work as well as their associated physiological processes need to be balanced to maintain good health. The model gives researchers a useful overview over the various risk factors and pathways associated with health that should be considered when studying any form of nonstandard working schedule.
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Physiological relevance of LL-37 induced bladder inflammation and mast cells.
Oottamasathien, Siam; Jia, Wanjian; Roundy, Lindsi McCoard; Zhang, Jianxing; Wang, Li; Ye, Xiangyang; Hill, A Cameron; Savage, Justin; Lee, Wong Yong; Hannon, Ann Marie; Milner, Sylvia; Prestwich, Glenn D
2013-10-01
We established the physiological relevance of LL-37 induced bladder inflammation. We hypothesized that 1) human urinary LL-37 is increased in pediatric patients with spina bifida, 2) LL-37 induced inflammation occurs in our mouse model via urothelial binding and is dose dependent and 3) LL-37 induced inflammation involves mast cells. To test our first hypothesis, we obtained urine samples from 56 pediatric patients with spina bifida and 22 normal patients. LL-37 was measured by enzyme-linked immunosorbent assay. Our second hypothesis was tested in C57Bl/6 mice challenged with 7 LL-37 concentrations intravesically for 1 hour. At 24 hours tissues were examined histologically and myeloperoxidase assay was done to quantitate inflammation. In separate experiments fluorescent LL-37 was instilled and tissues were obtained immediately (time = 0) and at 24 hours (time = 24). To test our final hypothesis, we performed immunohistochemistry for mast cell tryptase and evaluated 5 high power fields per bladder to determine the mean number of mast cells per mm(2). Urinary LL-37 was 89-fold higher in patients with spina bifida. Mouse LL-37 dose escalation experiments revealed increased inflammation at higher LL-37 concentrations. Fluorescent LL-37 demonstrated global urothelial binding at time = 0 but was not visible at time = 24. Immunohistochemistry for tryptase revealed mast cell infiltration in all tissue layers. At higher concentrations the LL-37 challenge led to significantly greater mast cell infiltration. Urinary LL-37 was significantly increased in pediatric patients with spina bifida. To our knowledge we report for the first time that LL-37 can elicit profound, dose dependent bladder inflammation involving the urothelium. Finally, inflammation propagation involves mast cells. Copyright © 2013 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.
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Physiological Relevance of LL-37 Induced Bladder Inflammation and Mast Cells
Roundy, Lindsi McCoard; Zhang, Jianxing; Wang, Li; Ye, Xiangyang; Hill, A. Cameron; Savage, Justin; Lee, Wong Yong; Hannon, Ann Marie; Milner, Sylvia; Prestwich, Glenn D.
2014-01-01
Purpose We established the physiological relevance of LL-37 induced bladder inflammation. We hypothesized that 1) human urinary LL-37 is increased in pediatric patients with spina bifida, 2) LL-37 induced inflammation occurs in our mouse model via urothelial binding and is dose dependent and 3) LL-37 induced inflammation involves mast cells. Materials and Methods To test our first hypothesis, we obtained urine samples from 56 pediatric patients with spina bifida and 22 normal patients. LL-37 was measured by enzyme-linked immunosorbent assay. Our second hypothesis was tested in C57Bl/6 mice challenged with 7 LL-37 concentrations intravesically for 1 hour. At 24 hours tissues were examined histologically and myeloperoxidase assay was done to quantitate inflammation. In separate experiments fluorescent LL-37 was instilled and tissues were obtained immediately (time = 0) and at 24 hours (time = 24). To test our final hypothesis, we performed immunohistochemistry for mast cell tryptase and evaluated 5 high power fields per bladder to determine the mean number of mast cells per mm2. Results Urinary LL-37 was 89-fold higher in patients with spina bifida. Mouse LL-37 dose escalation experiments revealed increased inflammation at higher LL-37 concentrations. Fluorescent LL-37 demonstrated global urothelial binding at time = 0 but was not visible at time = 24. Immunohistochemistry for tryptase revealed mast cell infiltration in all tissue layers. At higher concentrations the LL-37 challenge led to significantly greater mast cell infiltration. Conclusions Urinary LL-37 was significantly increased in pediatric patients with spina bifida. To our knowledge we report for the first time that LL-37 can elicit profound, dose dependent bladder inflammation involving the urothelium. Finally, inflammation propagation involves mast cells. PMID:23313203
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Girondé, Alexandra; Poret, Marine; Etienne, Philippe; Trouverie, Jacques; Bouchereau, Alain; Le Cahérec, Françoise; Leport, Laurent; Niogret, Marie-Françoise; Avice, Jean-Christophe
2015-01-01
Winter oilseed rape is characterized by a low N use efficiency related to a weak leaf N remobilization efficiency (NRE) at vegetative stages. By investigating the natural genotypic variability of leaf NRE, our goal was to characterize the relevant physiological traits and the main protease classes associated with an efficient proteolysis and high leaf NRE in response to ample or restricted nitrate supply. The degradation rate of soluble proteins and D1 protein (a thylakoid-bound protein) were correlated to N remobilization, except for the genotype Samouraï which showed a low NRE despite high levels of proteolysis. Under restricted nitrate conditions, high levels of soluble protein degradation were associated with serine, cysteine and aspartic proteases at acidic pH. Low leaf NRE was related to a weak proteolysis of both soluble and thylakoid-bound proteins. The results obtained on the genotype Samouraï suggest that the timing between the onset of proteolysis and abscission could be a determinant. The specific involvement of acidic proteases suggests that autophagy and/or senescence-associated vacuoles are implicated in N remobilization under low N conditions. The data revealed that the rate of D1 degradation could be a relevant indicator of leaf NRE and might be used as a tool for plant breeding. PMID:27135221
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Do infants find snakes aversive? Infants' physiological responses to "fear-relevant" stimuli.
Thrasher, Cat; LoBue, Vanessa
2016-02-01
In the current research, we sought to measure infants' physiological responses to snakes-one of the world's most widely feared stimuli-to examine whether they find snakes aversive or merely attention grabbing. Using a similar method to DeLoache and LoBue (Developmental Science, 2009, Vol. 12, pp. 201-207), 6- to 9-month-olds watched a series of multimodal (both auditory and visual) stimuli: a video of a snake (fear-relevant) or an elephant (non-fear-relevant) paired with either a fearful or happy auditory track. We measured physiological responses to the pairs of stimuli, including startle magnitude, latency to startle, and heart rate. Results suggest that snakes capture infants' attention; infants showed the fastest startle responses and lowest average heart rate to the snakes, especially when paired with a fearful voice. Unexpectedly, they also showed significantly reduced startle magnitude during this same snake video plus fearful voice combination. The results are discussed with respect to theoretical perspectives on fear acquisition. Copyright © 2015 Elsevier Inc. All rights reserved.
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Deng, Ge; Wu, Kristi; Cruce, Alex A; Bowman, Michael K; Vincent, John B
2015-02-01
Transferrin, the major iron transport protein in the blood, also transports trivalent chromium in vivo. Recent in vitro studies have, however, suggested that the binding of chromic ions to apotransferrin is too slow to be biologically relevant. Nevertheless, the in vitro studies have generally failed to adequately take physiological bicarbonate concentrations into account. In aqueous buffer (with ambient (bi)carbonate concentrations), the binding of chromium to transferrin is too slow to be physiologically relevant, taking days to reach equilibrium with the protein's associated conformational changes. However, in the presence of 25mM (bi)carbonate, the concentration in human blood, chromic ions bind rapidly and tightly to transferrin. Details of the kinetics of chromium binding to human serum transferrin and conalbumin (egg white transferrin) in the presence of bicarbonate and other major potential chromium ligands are described and are consistent with transferrin being the major chromic ion transporter from the blood to tissues. Copyright © 2014 Elsevier Inc. All rights reserved.
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Oral Exposure and Absorption of Toxicants
This chapter provides an overview of the toxicokinetics of orally absorbed xenobiotics. This includes a description of the basic anatomy and physiology of the digestive tract most relevant to the absorption process. In addition, differences in anatomy and physiology between human...
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Predicting physiological capacity of human load carriage - a review.
Drain, Jace; Billing, Daniel; Neesham-Smith, Daniel; Aisbett, Brad
2016-01-01
This review article aims to evaluate a proposed maximum acceptable work duration model for load carriage tasks. It is contended that this concept has particular relevance to physically demanding occupations such as military and firefighting. Personnel in these occupations are often required to perform very physically demanding tasks, over varying time periods, often involving load carriage. Previous research has investigated concepts related to physiological workload limits in occupational settings (e.g. industrial). Evidence suggests however, that existing (unloaded) workload guidelines are not appropriate for load carriage tasks. The utility of this model warrants further work to enable prediction of load carriage durations across a range of functional workloads for physically demanding occupations. If the maximum duration for which personnel can physiologically sustain a load carriage task could be accurately predicted, commanders and supervisors could better plan for and manage tasks to ensure operational imperatives were met whilst minimising health risks for their workers. Copyright © 2015 Elsevier Ltd and The Ergonomics Society. All rights reserved.
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Flint, Richard; Windsor, John A
2004-04-01
The physiological response to treatment is a better predictor of outcome in acute pancreatitis than are traditional static measures. Retrospective diagnostic test study. The criterion standard was Organ Failure Score (OFS) and Acute Physiology and Chronic Health Evaluation II (APACHE II) score at the time of hospital admission. Intensive care unit of a tertiary referral center, Auckland City Hospital, Auckland, New Zealand. Consecutive sample of 92 patients (60 male, 32 female; median age, 61 years; range, 24-79 years) with severe acute pancreatitis. Twenty patients were not included because of incomplete data. The cause of pancreatitis was gallstones (42%), alcohol use (27%), or other (31%). At hospital admission, the mean +/- SD OFS was 8.1 +/- 6.1, and the mean +/- SD APACHE II score was 19.9 +/- 8.2. All cases were managed according to a standardized protocol. There was no randomization or testing of any individual interventions. Survival and death. There were 32 deaths (pretest probability of dying was 35%). The physiological response to treatment was more accurate in predicting the outcome than was OFS or APACHE II score at hospital admission. For example, 17 patients had an initial OFS of 7-8 (posttest probability of dying was 58%); after 48 hours, 7 had responded to treatment (posttest probability of dying was 28%), and 10 did not respond (posttest probability of dying was 82%). The effect of the change in OFS and APACHE II score was graphically depicted by using a series of logistic regression equations. The resultant sigmoid curve suggests that there is a midrange of scores (the steep portion of the graph) within which the probability of death is most affected by the response to intensive care treatment. Measuring the initial severity of pancreatitis combined with the physiological response to intensive care treatment is a practical and clinically relevant approach to predicting death in patients with severe acute pancreatitis.
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D, Savitha; Vaz, Manjulika; Vaz, Mario
2017-06-01
Integrating medical ethics into the physiology teaching-learning program has been largely unexplored in India. The objective of this exercise was to introduce an interactive and integrated ethics program into the Physiology course of first-year medical students and to evaluate their perceptions. Sixty medical students (30 men, 30 women) underwent 11 sessions over a 7-mo period. Two of the Physiology faculty conducted these sessions (20-30 min each) during the routine physiology (theory/practicals) classes that were of shorter duration and could, therefore, accommodate the discussion of related ethical issues. This exercise was in addition to the separate ethics classes conducted by the Medical Ethics department. The sessions were open ended, student centered, and designed to stimulate critical thinking. The students' perceptions were obtained through a semistructured questionnaire and focused group discussions. The students found the program unique, thought provoking, fully integrated, and relevant. It seldom interfered with the physiology teaching. They felt that the program sensitized them about ethical issues and prepared them for their clinical years, to be "ethical doctors." Neutral observers who evaluated each session felt that the integrated program was relevant to the preclinical year and that the program was appropriate in its content, delivery, and student involvement. An ethics course taught in integration with Physiology curriculum was found to be beneficial, feasible, and compatible with Physiology by students as well as neutral observers. Copyright © 2017 the American Physiological Society.
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Relevance of human anatomy in daily clinical practice.
Arráez-Aybar, Luis-Alfonso; Sánchez-Montesinos, Indalecio; Mirapeix, Rosa-M; Mompeo-Corredera, Blanca; Sañudo-Tejero, Jose-Ramón
2010-12-20
the aim of this study has been to evaluate the relevance of gross human anatomy in daily clinical practice and to compare it to that of other basic sciences (biochemistry, bioethics, cytohistology, microbiology, pharmacology, physiology, psychology). a total of 1250 questionnaires were distributed among 38 different medical speciality professionals. Answers were analyzed taking into account speciality (medical, surgery and others), professional status (training physician or staff member) and professional experience. the response rate was 42.9% (n=536). Gross human anatomy was considered the most relevant basic discipline for surgical specialists, while pharmacology and physiology were most relevant for medical specialists. Knowledge of anatomy was also considered fundamental for understanding neurological or musculoskeletal disorders. In undergraduate programmes, the most important focuses in teaching anatomy were radiological, topographical and functional anatomy followed by systematic anatomy. In daily medical practice anatomy was considered basic for physical examination, symptom interpretation and interpretation of radiological images. When professional status or professional experience was considered, small variations were shown and there were no significant differences related to gender or community. our results underline the relevance of basic sciences (gross anatomy, physiology, and pharmacology) in daily professional activity. Evidence-based studies such as ours, lend greater credibility and objectivity to the role of gross anatomy in the undergraduate training of health professionals and should help to establish a more appropriate curriculum for future professionals. 2010 Elsevier GmbH. All rights reserved.
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Sexton, Kristian J.; Zhao, Yan; Davis, Scott C.; Jiang, Shudong; Pogue, Brian W.
2017-01-01
The design of fluorescence imaging instruments for surgical guidance is rapidly evolving, and a key issue is to efficiently capture signals with high ambient room lighting. Here, we introduce a novel time-gated approach to fluorescence imaging synchronizing acquisition to the 120 Hz light of the room, with pulsed LED excitation and gated ICCD detection. It is shown that under bright ambient room light this technique allows for the detection of physiologically relevant nanomolar fluorophore concentrations, and in particular reduces the light fluctuations present from the room lights, making low concentration measurements more reliable. This is particularly relevant for the light bands near 700nm that are more dominated by ambient lights. PMID:28663895
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Spaceflight and Neurosurgery: A Comprehensive Review of the Relevant Literature.
Swinney, Christian C; Allison, Zain
2018-01-01
Spaceflight and the associated gravitational fluctuations may impact various components of the central nervous system. These include changes in intracranial pressure, the spine, and neurocognitive performance. The implications of altered astronaut performance on critical spaceflight missions are potentially significant. The current body of research on this important topic is extremely limited, and a comprehensive review has not been published. Herein, the authors address this notable gap, as well as the role of the neurosurgeon in optimizing potential diagnostic and therapeutic modalities. A literature search was conducted using the PubMed, EMBASE, and Google Scholar databases, with no time constraints. Significant manuscripts on physiologic changes associated with spaceflight and microgravity were identified and reviewed. Manifestations were separated into 1 of 3 general categories, including changes in intracranial pressure, the spine, and neurocognitive performance. A comprehensive literature review yielded 27 studies with direct relevance to the impact of microgravity and spaceflight on nervous system physiology. This included 7 studies related to intracranial pressure fluctuations, 17 related to changes in the spinal column, and 3 related to neurocognitive change. The microgravity environment encountered during spaceflight impacts intracranial physiology. This includes changes in intracranial pressure, the spinal column, and neurocognitive performance. Herein, we present a systematic review of the published literature on this issue. Neurosurgeons should have a key role in the continued study of this important topic, contributing to both diagnostic and therapeutic understanding. Copyright © 2017 Elsevier Inc. All rights reserved.
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Neuromodulators: available agents, physiology, and anatomy.
Nettar, Kartik; Maas, Corey
2011-12-01
Neuromodulators have risen to the forefront of aesthetic medicine. By reversibly relaxing target muscles, neuromodulators exhibit their effect by softening hyperfunctional lines. An understanding of their physiology, relevant facial anatomy, and current agents is imperative for a successful aesthetic practice. © Thieme Medical Publishers.
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Multifunctional enzymes from reduced genomes - model proteins for simple primordial metabolism?
Seelig, Burckhard
2017-08-01
Billions of years of evolution have yielded today's complex metabolic networks driven by efficient and highly specialized enzymes. In contrast, the metabolism of the earliest cellular life forms was likely much simpler with only a few enzymes of comparatively low activity. It has been speculated that these early enzymes had low specificities and in turn were able to perform multiple functions. In this issue of Molecular Microbiology, Ferla et al. describe examples of enzymes that catalyze chemically distinct reactions while using the same active site. Most importantly, the authors demonstrated that the comparatively weak activities of these multifunctional enzymes are each physiologically relevant. These findings contrast with simply promiscuous enzyme activities, which have been described numerous times but are not physiologically relevant. Ferla et al. elegantly combined initial bioinformatics searches for enzyme candidates with sound kinetic measurements, evolutionary considerations and even structural discussions. The phenomenon of multifunctionality appears to be a mechanism for bacteria with reduced genomes to compensate for their lack of certain enzymes. In the broader context of evolution, these organisms could be considered living model systems to study features of long-extinct early cellular life. © 2017 John Wiley & Sons Ltd.
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NASA Astrophysics Data System (ADS)
Cigognini, Daniela; Gaspar, Diana; Kumar, Pramod; Satyam, Abhigyan; Alagesan, Senthilkumar; Sanz-Nogués, Clara; Griffin, Matthew; O'Brien, Timothy; Pandit, Abhay; Zeugolis, Dimitrios I.
2016-08-01
Modular tissue engineering is based on the cells’ innate ability to create bottom-up supramolecular assemblies with efficiency and efficacy still unmatched by man-made devices. Although the regenerative potential of such tissue substitutes has been documented in preclinical and clinical setting, the prolonged culture time required to develop an implantable device is associated with phenotypic drift and/or cell senescence. Herein, we demonstrate that macromolecular crowding significantly enhances extracellular matrix deposition in human bone marrow mesenchymal stem cell culture at both 20% and 2% oxygen tension. Although hypoxia inducible factor - 1α was activated at 2% oxygen tension, increased extracellular matrix synthesis was not observed. The expression of surface markers and transcription factors was not affected as a function of oxygen tension and macromolecular crowding. The multilineage potential was also maintained, albeit adipogenic differentiation was significantly reduced in low oxygen tension cultures, chondrogenic differentiation was significantly increased in macromolecularly crowded cultures and osteogenic differentiation was not affected as a function of oxygen tension and macromolecular crowding. Collectively, these data pave the way for the development of bottom-up tissue equivalents based on physiologically relevant developmental processes.
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Cigognini, Daniela; Gaspar, Diana; Kumar, Pramod; Satyam, Abhigyan; Alagesan, Senthilkumar; Sanz-Nogués, Clara; Griffin, Matthew; O’Brien, Timothy; Pandit, Abhay; Zeugolis, Dimitrios I.
2016-01-01
Modular tissue engineering is based on the cells’ innate ability to create bottom-up supramolecular assemblies with efficiency and efficacy still unmatched by man-made devices. Although the regenerative potential of such tissue substitutes has been documented in preclinical and clinical setting, the prolonged culture time required to develop an implantable device is associated with phenotypic drift and/or cell senescence. Herein, we demonstrate that macromolecular crowding significantly enhances extracellular matrix deposition in human bone marrow mesenchymal stem cell culture at both 20% and 2% oxygen tension. Although hypoxia inducible factor - 1α was activated at 2% oxygen tension, increased extracellular matrix synthesis was not observed. The expression of surface markers and transcription factors was not affected as a function of oxygen tension and macromolecular crowding. The multilineage potential was also maintained, albeit adipogenic differentiation was significantly reduced in low oxygen tension cultures, chondrogenic differentiation was significantly increased in macromolecularly crowded cultures and osteogenic differentiation was not affected as a function of oxygen tension and macromolecular crowding. Collectively, these data pave the way for the development of bottom-up tissue equivalents based on physiologically relevant developmental processes. PMID:27478033
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THE PASSIVE PROPERTIES OF MUSCLE FIBERS ARE VELOCITY DEPENDENT
Rehorn, Michael R.; Schroer, Alison K.; Blemker, Silvia S.
2014-01-01
The passive properties of skeletal muscle play an important role in muscle function. While the passive quasi-static elastic properties of muscle fibers have been well characterized, the dynamic visco-elastic passive behavior of fibers has garnered less attention. In particular, it is unclear how the visco-elastic properties are influenced by lengthening velocity, in particular for the range of physiologically relevant velocities. The goals of this work were to: (i) measure the effects of lengthening velocity on the peak stresses within single muscle fibers to determine how passive behavior changes over a range of physiologically relevant lengthening rates (0.1–10 Lo/s), and (ii) develop a mathematical model of fiber viscoelasticity based on these measurements. We found that passive properties depend on strain rate, in particular at the low loading rates (0.1–3 Lo/s), and that the measured behavior can be predicted across a range of loading rates and time histories with a quasi-linear viscoelastic model. In the future, these results can be used to determine the impact of viscoelastic behavior on intramuscular stresses and forces during a variety of dynamic movements. PMID:24360198
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Toll-like receptor signaling and its relevance to intestinal inflammation.
Cario, Elke; Podolsky, Daniel K
2006-08-01
This review discusses the current progress in the understanding of how commensal-mediated activation of toll-like receptors (TLRs) may be involved in the regulation of physiological and pathophysiological processes of the intestinal mucosa including tissue regeneration and inflammation. While regulation of TLRs and their downstream signaling mediators might be used to prevent and treat inflammatory bowel diseases, paradoxically, at this time, it remains uncertain whether this would be more effectively accomplished by enhancing or inhibiting these pathways.
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The cardiovascular system after exercise.
Romero, Steven A; Minson, Christopher T; Halliwill, John R
2017-04-01
Recovery from exercise refers to the time period between the end of a bout of exercise and the subsequent return to a resting or recovered state. It also refers to specific physiological processes or states occurring after exercise that are distinct from the physiology of either the exercising or the resting states. In this context, recovery of the cardiovascular system after exercise occurs across a period of minutes to hours, during which many characteristics of the system, even how it is controlled, change over time. Some of these changes may be necessary for long-term adaptation to exercise training, yet some can lead to cardiovascular instability during recovery. Furthermore, some of these changes may provide insight into when the cardiovascular system has recovered from prior training and is physiologically ready for additional training stress. This review focuses on the most consistently observed hemodynamic adjustments and the underlying causes that drive cardiovascular recovery and will highlight how they differ following resistance and aerobic exercise. Primary emphasis will be placed on the hypotensive effect of aerobic and resistance exercise and associated mechanisms that have clinical relevance, but if left unchecked, can progress to symptomatic hypotension and syncope. Finally, we focus on the practical application of this information to strategies to maximize the benefits of cardiovascular recovery, or minimize the vulnerabilities of this state. We will explore appropriate field measures, and discuss to what extent these can guide an athlete's training. Copyright © 2017 the American Physiological Society.
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Sinusoidal voltage protocols for rapid characterisation of ion channel kinetics.
Beattie, Kylie A; Hill, Adam P; Bardenet, Rémi; Cui, Yi; Vandenberg, Jamie I; Gavaghan, David J; de Boer, Teun P; Mirams, Gary R
2018-03-24
Ion current kinetics are commonly represented by current-voltage relationships, time constant-voltage relationships and subsequently mathematical models fitted to these. These experiments take substantial time, which means they are rarely performed in the same cell. Rather than traditional square-wave voltage clamps, we fitted a model to the current evoked by a novel sum-of-sinusoids voltage clamp that was only 8 s long. Short protocols that can be performed multiple times within a single cell will offer many new opportunities to measure how ion current kinetics are affected by changing conditions. The new model predicts the current under traditional square-wave protocols well, with better predictions of underlying currents than literature models. The current under a novel physiologically relevant series of action potential clamps is predicted extremely well. The short sinusoidal protocols allow a model to be fully fitted to individual cells, allowing us to examine cell-cell variability in current kinetics for the first time. Understanding the roles of ion currents is crucial to predict the action of pharmaceuticals and mutations in different scenarios, and thereby to guide clinical interventions in the heart, brain and other electrophysiological systems. Our ability to predict how ion currents contribute to cellular electrophysiology is in turn critically dependent on our characterisation of ion channel kinetics - the voltage-dependent rates of transition between open, closed and inactivated channel states. We present a new method for rapidly exploring and characterising ion channel kinetics, applying it to the hERG potassium channel as an example, with the aim of generating a quantitatively predictive representation of the ion current. We fitted a mathematical model to currents evoked by a novel 8 second sinusoidal voltage clamp in CHO cells overexpressing hERG1a. The model was then used to predict over 5 minutes of recordings in the same cell in response to further protocols: a series of traditional square step voltage clamps, and also a novel voltage clamp comprising a collection of physiologically relevant action potentials. We demonstrate that we can make predictive cell-specific models that outperform the use of averaged data from a number of different cells, and thereby examine which changes in gating are responsible for cell-cell variability in current kinetics. Our technique allows rapid collection of consistent and high quality data, from single cells, and produces more predictive mathematical ion channel models than traditional approaches. © 2018 The Authors. The Journal of Physiology published by John Wiley & Sons Ltd on behalf of The Physiological Society.
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New reasons and new ways to study birth physiology.
Odent, M
2001-11-01
The age of cesarean sections on request, epidurals and drips of oxytocin is a turning point in the history of childbirth. Until recently women could not give birth without releasing a complex cocktail of 'love hormones'. Today, in many countries, most women have babies without releasing these specific hormones. The questions must be raised in terms of civilization. This turning point occurs at the very time when several scientific disciplines suggest that the way human beings are born has long-term consequences, particularly in terms of sociability, aggressiveness or, in other words, 'capacity to love'. I find it relevant to combine data provided by perspectives as diverse as ethology, animal experiments, studies of the behavioral effects of hormones that fluctuate in the perinatal period, and a branch of epidemiology I call 'Primal Health Research'. This combination of data offers new reasons to disturb the physiological processes as little as possible. We are also at a time when a physiological approach can help to rediscover the basic needs of women in labor. These women firstly need to be protected against any sort of neocortical stimulation. We must keep in mind what the main stimuli of neocortical activity are: language, bright lights, the 'feeling of being observed' and situations associated with a release of catecholamines.
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New reasons and new ways to study birth physiology.
Odent, M
2001-11-01
The age of cesarean sections on request, epidurals and drips of oxytocin is a turning point in the history of childbirth. Until recently women could not give birth without releasing a complex cocktail of 'love hormones'. Today, in many countries, most women have babies without releasing these specific hormones. The questions must be raised in terms of civilization. This turning point occurs at the very time when several scientific disciplines suggest that the way human beings are born has long-term consequences, particularly in terms of sociability, aggressiveness or, in other words, 'capacity to love'. I find it relevant to combine data provided by perspectives as diverse as ethology, animal experiments, studies of the behavioral effects of hormones that fluctuate in the perinatal period, and a branch of epidemiology I call 'Primal Health Research'. This combination of data offers new reasons to disturb the physiological processes as little as possible. We are also at a time when a physiological approach can help to rediscover the basic needs of women in labor. These women firstly need to be protected against any sort of neocortical stimulation. We must keep in mind what the main stimuli of neocortical activity are: language, bright lights, the 'feeling of being observed' and situations associated with a release of catecholamines. © 2001 International Federation of Gynecology and Obstetrics.
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Comparison of PIV with 4D-Flow in a physiological accurate flow phantom
NASA Astrophysics Data System (ADS)
Sansom, Kurt; Balu, Niranjan; Liu, Haining; Aliseda, Alberto; Yuan, Chun; Canton, Maria De Gador
2016-11-01
Validation of 4D MRI flow sequences with planar particle image velocimetry (PIV) is performed in a physiologically-accurate flow phantom. A patient-specific phantom of a carotid artery is connected to a pulsatile flow loop to simulate the 3D unsteady flow in the cardiovascular anatomy. Cardiac-cycle synchronized MRI provides time-resolved 3D blood velocity measurements in clinical tool that is promising but lacks a robust validation framework. PIV at three different Reynolds numbers (540, 680, and 815, chosen based on +/- 20 % of the average velocity from the patient-specific CCA waveform) and four different Womersley numbers (3.30, 3.68, 4.03, and 4.35, chosen to reflect a physiological range of heart rates) are compared to 4D-MRI measurements. An accuracy assessment of raw velocity measurements and a comparison of estimated and measureable flow parameters such as wall shear stress, fluctuating velocity rms, and Lagrangian particle residence time, will be presented, with justification for their biomechanics relevance to the pathophysiology of arterial disease: atherosclerosis and intimal hyperplasia. Lastly, the framework is applied to a new 4D-Flow MRI sequence and post processing techniques to provide a quantitative assessment with the benchmarked data. Department of Education GAANN Fellowship.
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Rodríguez-Marroyo, J A; Villa, J G; López-Satue, J; Pernía, R; Carballo, B; García-López, J; Foster, C
2011-11-01
The aim of this study was to analyse the physiological strain of firefighters, using heart rate (HR) and core temperature, during real wildfire suppression according to the type of attack performed (direct, indirect or mixed). Three intensity zones were established according to the HR corresponding to the ventilatory threshold (VT) and respiratory compensation threshold (RCT): zone 1,
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Paillard, Thierry
2011-12-01
The article by Del Vecchio, et al. (2011) provides relevant information to trainers about the effort-pause ratio during mixed martial arts matches. Taking into account the physiological profiles of fighters would increase interest in these findings.
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Wanner, Samuel Penna; Prímola-Gomes, Thales Nicolau; Pires, Washington; Guimarães, Juliana Bohnen; Hudson, Alexandre Sérvulo Ribeiro; Kunstetter, Ana Cançado; Fonseca, Cletiana Gonçalves; Drummond, Lucas Rios; Damasceno, William Coutinho; Teixeira-Coelho, Francisco
2015-01-01
Rats are used worldwide in experiments that aim to investigate the physiological responses induced by a physical exercise session. Changes in body temperature regulation, which may affect both the performance and the health of exercising rats, are evident among these physiological responses. Despite the universal use of rats in biomedical research involving exercise, investigators often overlook important methodological issues that hamper the accurate measurement of clear thermoregulatory responses. Moreover, much debate exists regarding whether the outcome of rat experiments can be extrapolated to human physiology, including thermal physiology. Herein, we described the impact of different exercise intensities, durations and protocols and environmental conditions on running-induced thermoregulatory changes. We focused on treadmill running because this type of exercise allows for precise control of the exercise intensity and the measurement of autonomic thermoeffectors associated with heat production and loss. Some methodological issues regarding rat experiments, such as the sites for body temperature measurements and the time of day at which experiments are performed, were also discussed. In addition, we analyzed the influence of a high body surface area-to-mass ratio and limited evaporative cooling on the exercise-induced thermoregulatory responses of running rats and then compared these responses in rats to those observed in humans. Collectively, the data presented in this review represent a reference source for investigators interested in studying exercise thermoregulation in rats. In addition, the present data indicate that the thermoregulatory responses of exercising rats can be extrapolated, with some important limitations, to human thermal physiology.
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Emotion recognition based on physiological changes in music listening.
Kim, Jonghwa; André, Elisabeth
2008-12-01
Little attention has been paid so far to physiological signals for emotion recognition compared to audiovisual emotion channels such as facial expression or speech. This paper investigates the potential of physiological signals as reliable channels for emotion recognition. All essential stages of an automatic recognition system are discussed, from the recording of a physiological dataset to a feature-based multiclass classification. In order to collect a physiological dataset from multiple subjects over many weeks, we used a musical induction method which spontaneously leads subjects to real emotional states, without any deliberate lab setting. Four-channel biosensors were used to measure electromyogram, electrocardiogram, skin conductivity and respiration changes. A wide range of physiological features from various analysis domains, including time/frequency, entropy, geometric analysis, subband spectra, multiscale entropy, etc., is proposed in order to find the best emotion-relevant features and to correlate them with emotional states. The best features extracted are specified in detail and their effectiveness is proven by classification results. Classification of four musical emotions (positive/high arousal, negative/high arousal, negative/low arousal, positive/low arousal) is performed by using an extended linear discriminant analysis (pLDA). Furthermore, by exploiting a dichotomic property of the 2D emotion model, we develop a novel scheme of emotion-specific multilevel dichotomous classification (EMDC) and compare its performance with direct multiclass classification using the pLDA. Improved recognition accuracy of 95\\% and 70\\% for subject-dependent and subject-independent classification, respectively, is achieved by using the EMDC scheme.
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Wanner, Samuel Penna; Prímola-Gomes, Thales Nicolau; Pires, Washington; Guimarães, Juliana Bohnen; Hudson, Alexandre Sérvulo Ribeiro; Kunstetter, Ana Cançado; Fonseca, Cletiana Gonçalves; Drummond, Lucas Rios; Damasceno, William Coutinho; Teixeira-Coelho, Francisco
2015-01-01
Rats are used worldwide in experiments that aim to investigate the physiological responses induced by a physical exercise session. Changes in body temperature regulation, which may affect both the performance and the health of exercising rats, are evident among these physiological responses. Despite the universal use of rats in biomedical research involving exercise, investigators often overlook important methodological issues that hamper the accurate measurement of clear thermoregulatory responses. Moreover, much debate exists regarding whether the outcome of rat experiments can be extrapolated to human physiology, including thermal physiology. Herein, we described the impact of different exercise intensities, durations and protocols and environmental conditions on running-induced thermoregulatory changes. We focused on treadmill running because this type of exercise allows for precise control of the exercise intensity and the measurement of autonomic thermoeffectors associated with heat production and loss. Some methodological issues regarding rat experiments, such as the sites for body temperature measurements and the time of day at which experiments are performed, were also discussed. In addition, we analyzed the influence of a high body surface area-to-mass ratio and limited evaporative cooling on the exercise-induced thermoregulatory responses of running rats and then compared these responses in rats to those observed in humans. Collectively, the data presented in this review represent a reference source for investigators interested in studying exercise thermoregulation in rats. In addition, the present data indicate that the thermoregulatory responses of exercising rats can be extrapolated, with some important limitations, to human thermal physiology. PMID:27227066
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pH and chloride recordings in living cells using two-photon fluorescence lifetime imaging microscopy
NASA Astrophysics Data System (ADS)
Lahn, Mattes; Hille, Carsten; Koberling, Felix; Kapusta, Peter; Dosche, Carsten
2010-02-01
Today fluorescence lifetime imaging microscopy (FLIM) has become an extremely powerful technique in life sciences. The independency of the fluorescence decay time on fluorescence dye concentration and emission intensity circumvents many artefacts arising from intensity based measurements. To minimize cell damage and improve scan depth, a combination with two-photon (2P) excitation is quite promising. Here, we describe the implementation of a 2P-FLIM setup for biological applications. For that we used a commercial fluorescence lifetime microscope system. 2P-excitation at 780nm was achieved by a non-tuneable, but inexpensive and easily manageable mode-locked fs-fiber laser. Time-resolved fluorescence image acquisition was performed by objective-scanning with the reversed time-correlated single photon counting (TCSPC) technique. We analyzed the suitability of the pH-sensitive dye BCECF and the chloride-sensitive dye MQAE for recordings in an insect tissue. Both parameters are quite important, since they affect a plethora of physiological processes in living tissues. We performed a straight forward in situ calibration method to link the fluorescence decay time with the respective ion concentration and carried out spatially resolved measurements under resting conditions. BCECF still offered only a limited dynamic range regarding fluorescence decay time changes under physiologically pH values. However, MQAE proofed to be well suited to record chloride concentrations in the physiologically relevant range. Subsequently, several chloride transport pathways underlying the intracellular chloride homeostasis were investigated pharmacologically. In conclusion, 2P-FLIM is well suited for ion detection in living tissues due to precise and reproducible decay time measurements in combination with reduced cell and dye damages.
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A simple sensing mechanism for wireless, passive pressure sensors.
Drazan, John F; Wassick, Michael T; Dahle, Reena; Beardslee, Luke A; Cady, Nathaniel C; Ledet, Eric H
2016-08-01
We have developed a simple wireless pressure sensor that consists of only three electrically isolated components. Two conductive spirals are separated by a closed cell foam that deforms when exposed to changing pressures. This deformation changes the capacitance and thus the resonant frequency of the sensors. Prototype sensors were submerged and wirelessly interrogated while being exposed to physiologically relevant pressures from 10 to 130 mmHg. Sensors consistently exhibited a sensitivity of 4.35 kHz/mmHg which is sufficient for resolving physiologically relevant pressure changes in vivo. These simple sensors have the potential for in vivo pressure sensing.
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Ercan, Onur; Bisschops, Markus M M; Overkamp, Wout; Jørgensen, Thomas R; Ram, Arthur F; Smid, Eddy J; Pronk, Jack T; Kuipers, Oscar P; Daran-Lapujade, Pascale; Kleerebezem, Michiel
2015-09-01
The current knowledge of the physiology and gene expression of industrially relevant microorganisms is largely based on laboratory studies under conditions of rapid growth and high metabolic activity. However, in natural ecosystems and industrial processes, microbes frequently encounter severe calorie restriction. As a consequence, microbial growth rates in such settings can be extremely slow and even approach zero. Furthermore, uncoupling microbial growth from product formation, while cellular integrity and activity are maintained, offers perspectives that are economically highly interesting. Retentostat cultures have been employed to investigate microbial physiology at (near-)zero growth rates. This minireview compares information from recent physiological and gene expression studies on retentostat cultures of the industrially relevant microorganisms Lactobacillus plantarum, Lactococcus lactis, Bacillus subtilis, Saccharomyces cerevisiae, and Aspergillus niger. Shared responses of these organisms to (near-)zero growth rates include increased stress tolerance and a downregulation of genes involved in protein synthesis. Other adaptations, such as changes in morphology and (secondary) metabolite production, were species specific. This comparison underlines the industrial and scientific significance of further research on microbial (near-)zero growth physiology. Copyright © 2015, American Society for Microbiology. All Rights Reserved.
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Controversial constitutive TSHR activity: patients, physiology, and in vitro characterization.
Huth, S; Jaeschke, H; Schaarschmidt, J; Paschke, R
2014-06-01
G protein-coupled receptors constitute a large family of transmembrane receptors, which activate cellular responses by signal transmission and regulation of second messenger metabolism after ligand binding. For several of these receptors it is known that they also signal ligand-independently. The G protein-coupled thyroid stimulating hormone receptor (TSHR) is characterized by a high level of constitutive activity in the wild type state. However, little is known yet concerning the physiological relevance of the constitutive wild type TSHR activity. Certainly, knowledge of the physiological relevance of constitutive wild type receptor activity is necessary to better understand thyroid physiology and it is a prerequisite for the development of better therapies for nonautoimmune hyperthyroidism and thyroid cancer. Based on a literature search regarding all published TSHR mutations, this review covers several mutations which are clearly associated with a hyperthyroidism-phenotype, but interestingly show a lack of constitutive activity determined by in vitro characterization. Possible reasons for the observed discrepancies between clinical phenotypes and in vitro characterization results for constitutive TSHR activity are reviewed. All current in vitro characterization methods for constitutive TSHR mutations are "preliminary attempts" and may well be revised by more comprehensive and even better approaches. However, a standardized approach for the determination of constitutive activity can help to identify TSHR mutations for which the investigation of additional signaling mechanisms would be most interesting to find explanations for the current clinical phenotype/in vitro discrepancies and thereby also define suitable methods to explore the physiological relevance of constitutive wild type TSHR activity. © Georg Thieme Verlag KG Stuttgart · New York.
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Bioprinting towards Physiologically Relevant Tissue Models for Pharmaceutics.
Peng, Weijie; Unutmaz, Derya; Ozbolat, Ibrahim T
2016-09-01
Improving the ability to predict the efficacy and toxicity of drug candidates earlier in the drug discovery process will speed up the introduction of new drugs into clinics. 3D in vitro systems have significantly advanced the drug screening process as 3D tissue models can closely mimic native tissues and, in some cases, the physiological response to drugs. Among various in vitro systems, bioprinting is a highly promising technology possessing several advantages such as tailored microarchitecture, high-throughput capability, coculture ability, and low risk of cross-contamination. In this opinion article, we discuss the currently available tissue models in pharmaceutics along with their limitations and highlight the possibilities of bioprinting physiologically relevant tissue models, which hold great potential in drug testing, high-throughput screening, and disease modeling. Copyright © 2016 Elsevier Ltd. All rights reserved.
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Optical diagnostics of osteoblast cells and osteogenic drug screening
NASA Astrophysics Data System (ADS)
Kolanti, Elayaraja; Veerla, Sarath C.; Khajuria, Deepak K.; Roy Mahapatra, D.
2016-02-01
Microfluidic device based diagnostics involving optical fibre path, in situ imaging and spectroscopy are gaining importance due to recent advances in diagnostics instrumentation and methods, besides other factors such as low amount of reagent required for analysis, short investigation times, and potential possibilities to replace animal model based study in near future. It is possible to grow and monitor tissues in vitro in microfluidic lab-on-chip. It may become a transformative way of studying how cells interact with drugs, pathogens and biomaterials in physiologically relevant microenvironments. To a large extent, progress in developing clinically viable solutions has been constrained because of (i) contradiction between in vitro and in vivo results and (ii) animal model based and clinical studies which is very expensive. Our study here aims to evaluate the usefulness of microfluidic device based 3D tissue growth and monitoring approach to better emulate physiologically and clinically relevant microenvironments in comparison to conventional in vitro 2D culture. Moreover, the microfluidic methodology permits precise high-throughput investigations through real-time imaging while using very small amounts of reagents and cells. In the present study, we report on the details of an osteoblast cell based 3D microfluidic platform which we employ for osteogenic drug screening. The drug formulation is functionalized with fluorescence and other biomarkers for imaging and spectroscopy, respectively. Optical fibre coupled paths are used to obtain insight regarding the role of stress/flow pressure fluctuation and nanoparticle-drug concentration on the osteoblast growth and osteogenic properties of bone.
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PROPOSED MODELS FOR ESTIMATING RELEVANT DOSE RESULTING FROM EXPOSURES BY THE GASTROINTESTINAL ROUTE
Simple first-order intestinal absorption commonly used in physiologically-based pharmacokinetic(PBPK) models can be made to fit many clinical administrations but may not provide relevant information to extrapolate to real-world exposure scenarios for risk assessment. Small hydr...
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Anatomy and physiology of the aging neck.
Shadfar, Scott; Perkins, Stephen W
2014-05-01
This article discusses the surgically relevant anatomic and physiologic tenets of the aging neck. Procedures performed to rejuvenate and contour the aging neck can be challenging. A thorough understanding of the underlying neck anatomy, as well as the physiology associated with aging, is critical for surgical planning, execution, and achieving aesthetically pleasing outcomes. These topics are reviewed and used as the foundation for a discussion of various other techniques. Copyright © 2014 Elsevier Inc. All rights reserved.
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How is physiology relevant to behavior analysis?
Reese, Hayne W.
1996-01-01
Physiology is an important biological science; but behavior analysis is not a biological science, and behavior analysts can safely ignore biological processes. However, ignoring products of biological processes might be a serious mistake. The important products include behavior, instinctive drift, behavior potentials, hunger, and many developmental milestones and events. Physiology deals with the sources of such products; behavior analysis can deal with how the products affect behavior, which can be understood without understanding their sources. PMID:22478240
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Sheard, Michael A; Ghent, Matthew V; Cabral, Daniel J; Lee, Joanne C; Khankaldyyan, Vazgen; Ji, Lingyun; Wu, Samuel Q; Kang, Min H; Sposto, Richard; Asgharzadeh, Shahab; Reynolds, C Patrick
2015-05-15
Cancer cells typically exhibit increased glycolysis and decreased mitochondrial oxidative phosphorylation, and they continue to exhibit some elevation in glycolysis even under aerobic conditions. However, it is unclear whether cancer cell lines employ a high level of glycolysis comparable to that of the original cancers from which they were derived, even if their culture conditions are changed to physiologically relevant oxygen concentrations. From three childhood acute lymphoblastic leukemia (ALL) patients we established three new pairs of cell lines in both atmospheric (20%) and physiologic (bone marrow level, 5%) oxygen concentrations. Cell lines established in 20% oxygen exhibited lower proliferation, survival, expression of glycolysis genes, glucose consumption, and lactate production. Interestingly, the effects of oxygen concentration used during cell line initiation were only partially reversible when established cell cultures were switched from one oxygen concentration to another for eight weeks. These observations indicate that ALL cell lines established at atmospheric oxygen concentration can exhibit relatively low levels of glycolysis and these levels are semi-permanent, suggesting that physiologic oxygen concentrations may be needed from the time of cell line initiation to preserve the high level of glycolysis commonly exhibited by leukemias in vivo. Copyright © 2015. Published by Elsevier Inc.
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ERIC Educational Resources Information Center
McGeown, J. Graham
2006-01-01
Capillary filtration is a key area in the understanding of cardiovascular function and has both physiological and pathophysiological relevance in nearly every organ system. This article describes how classic papers in the Legacy collection of American Physiological Society publications can be used in a teaching symposium exploring the evidence…
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Birmingham, Wendy C; Holt-Lunstad, Julianne
2018-04-05
There is a rich literature on social support and physical health, but research has focused primarily on the protective effects of social relationship. The stress buffering model asserts that relationships may be protective by being a source of support when coping with stress, thereby blunting health relevant physiological responses. Research also indicates relationships can be a source of stress, also influencing health. In other words, the social buffering influence may have a counterpart, a social aggravating influence that has an opposite or opposing effect. Drawing upon existing conceptual models, we expand these to delineate how social relationships may influence stress processes and ultimately health. This review summarizes the existing literature that points to the potential deleterious physiological effects of our relationships when they are sources of stress or exacerbate stress. Copyright © 2018 Elsevier B.V. All rights reserved.
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Mechanisms and disease relevance of neutrophil extracellular trap formation.
Van Avondt, Kristof; Hartl, Dominik
2018-03-15
While the microscopic appearance of neutrophil extracellular traps (NETs) has fascinated basic researchers since its discovery, the (patho)physiological mechanisms triggering NET release, the disease relevance and clinical translatability of this unconventional cellular mechanism remained poorly understood. Here, we summarize and discuss current concepts of the mechanisms and disease relevance of NET formation. © 2018 Stichting European Society for Clinical Investigation Journal Foundation.
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Chan, Renee W Y; Chan, Michael C W; Nicholls, John M; Malik Peiris, J S
2013-12-05
The tropism of influenza viruses for the human respiratory tract is a key determinant of host-range, and consequently, of pathogenesis and transmission. Insights can be obtained from clinical and autopsy studies of human disease and relevant animal models. Ex vivo cultures of the human respiratory tract and in vitro cultures of primary human cells can provide complementary information provided they are physiologically comparable in relevant characteristics to human tissues in vivo, e.g. virus receptor distribution, state of differentiation. We review different experimental models for their physiological relevance and summarize available data using these cultures in relation to highly pathogenic avian influenza H5N1, in comparison where relevant, with other influenza viruses. Transformed continuous cell-lines often differ in important ways to the corresponding tissues in vivo. The state of differentiation of primary human cells (respiratory epithelium, macrophages) can markedly affect virus tropism and host responses. Ex vivo cultures of human respiratory tissues provide a close resemblance to tissues in vivo and may be used to risk assess animal viruses for pandemic threat. Physiological factors (age, inflammation) can markedly affect virus receptor expression and virus tropism. Taken together with data from clinical studies on infected humans and relevant animal models, data from ex vivo and in vitro cultures of human tissues and cells can provide insights into virus transmission and pathogenesis and may provide understanding that leads to novel therapeutic interventions. Copyright © 2013 Elsevier B.V. All rights reserved.
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Wu, John Z; Cutlip, Robert G; Welcome, Daniel; Dong, Ren G
2006-01-01
Knowledge of viscoelastic properties of soft tissues is essential for the finite element modelling of the stress/strain distributions in finger-pad during vibratory loading, which is important in exploring the mechanism of hand-arm vibration syndrome. In conventional procedures, skin and subcutaneous tissue have to be separated for testing the viscoelastic properties. In this study, a novel method has been proposed to simultaneously determine the viscoelastic properties of skin and subcutaneous tissue in uniaxial stress relaxation tests. A mathematical approach has been derived to obtain the creep and relaxation characteristics of skin and subcutaneous tissue using uniaxial stress relaxation data of skin/subcutaneous composite specimens. The micro-structures of collagen fiber networks in the soft tissue, which underline the tissue mechanical characteristics, will be intact in the proposed method. Therefore, the viscoelastic properties of soft tissues obtained using the proposed method would be more physiologically relevant than those obtained using the conventional method. The proposed approach has been utilized to measure the viscoelastic properties of soft tissues of pig. The relaxation curves of pig skin and subcutaneous tissue obtained in the current study agree well with those in literature. Using the proposed approach, reliable material properties of soft tissues can be obtained in a cost- and time-efficient manner, which simultaneously improves the physiological relevance.
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Automated patch clamp on mESC-derived cardiomyocytes for cardiotoxicity prediction.
Stoelzle, Sonja; Haythornthwaite, Alison; Kettenhofen, Ralf; Kolossov, Eugen; Bohlen, Heribert; George, Michael; Brüggemann, Andrea; Fertig, Niels
2011-09-01
Cardiovascular side effects are critical in drug development and have frequently led to late-stage project terminations or even drug withdrawal from the market. Physiologically relevant and predictive assays for cardiotoxicity are hence strongly demanded by the pharmaceutical industry. To identify a potential impact of test compounds on ventricular repolarization, typically a variety of ion channels in diverse heterologously expressing cells have to be investigated. Similar to primary cells, in vitro-generated stem cell-derived cardiomyocytes simultaneously express cardiac ion channels. Thus, they more accurately represent the native situation compared with cell lines overexpressing only a single type of ion channel. The aim of this study was to determine if stem cell-derived cardiomyocytes are suited for use in an automated patch clamp system. The authors show recordings of cardiac ion currents as well as action potential recordings in readily available stem cell-derived cardiomyocytes. Besides monitoring inhibitory effects of reference compounds on typical cardiac ion currents, the authors revealed for the first time drug-induced modulation of cardiac action potentials in an automated patch clamp system. The combination of an in vitro cardiac cell model with higher throughput patch clamp screening technology allows for a cost-effective cardiotoxicity prediction in a physiologically relevant cell system.
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AGING AND TOXIC RESPONSE: ISSUES RELEVANT TO RISK ASSESSMENT (FINAL)
EPA has released a final report entitled, Aging and Toxic Response: Issues Relevant to Risk Assessment. This document contributes to the Agency's efforts to better understand the physiology of aging in order to protect the health of older persons, and identifies several d...
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In silico methods provide a rapid, inexpensive means of screening a wide array of environmentally relevant pollutants, pesticides, fungicides and consumer products for further toxicity testing. Physiologically based pharmacokinetic (PBPK) models bridge the gap between in vitro as...
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Heritability of climate-relevant traits in a rainforest skink.
Martins, Felipe; Kruuk, Loeske; Llewelyn, John; Moritz, Craig; Phillips, Ben
2018-05-22
There is justified concern about the impact of global warming on the persistence of tropical ectotherms. There is also growing evidence for strong selection on climate-relevant physiological traits. Understanding the evolutionary potential of populations is especially important for low dispersal organisms in isolated populations, because these populations have little choice but to adapt. Despite this, direct estimates of heritability and genetic correlations for physiological traits in ectotherms-which will determine their evolutionary responses to selection-are sparse, especially for reptiles. Here we examine the heritabilities and genetic correlations for a set of four morphological and six climate-relevant physiological traits in an isolated population of an Australian rainforest lizard, Lampropholis coggeri. These traits show considerable variation across populations in this species, suggesting local adaptation. From laboratory crosses, we estimated very low to moderate heritability of temperature-related physiological traits (h 2 < 0.31), but significant and higher heritability of desiccation resistance (h 2 ~0.42). These values contrasted with uniformly higher heritabilities (h 2 > 0.51) for morphological traits. At the phenotypic level, there were positive associations among the morphological traits and between thermal limits. Growth rate was positively correlated with thermal limits, but there was no indication that morphology and physiology were linked in any other way. We found some support for a specialist-generalist trade-off in the thermal performance curve, but otherwise there was no evidence for evolutionary constraints, suggesting broadly labile multivariate trait structure. Our results indicate little potential to respond to selection on thermal traits in this population and provide new insights into the capacity of tropical ectotherms to adapt in situ to rapid climate change.
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Physiological Parameters for Oral Delivery and In vitro Testing
Mudie, Deanna M.; Amidon, Gordon L.; Amidon, Gregory E.
2010-01-01
Pharmaceutical solid oral dosage forms must undergo dissolution in the intestinal fluids of the gastrointestinal tract before they can be absorbed and reach the systemic circulation. Therefore, dissolution is a critical part of the drug-delivery process. The rate and extent of drug dissolution and absorption depend on the characteristics of the active ingredient as well as properties of the dosage form. Just as importantly, characteristics of the physiological environment such as buffer species, pH, bile salts, gastric emptying rate, intestinal motility, and hydrodynamics can significantly impact dissolution and absorption. While significant progress has been made since 1970 when the first compendial dissolution test was introduced (USP Apparatus 1), current dissolution testing does not take full advantage of the extensive physiologic information that is available. For quality control purposes, where the question is one of lot-to-lot consistency in performance, using nonphysiologic test conditions that match drug and dosage form properties with practical dissolution media and apparatus may be appropriate. However, where in vitro – in vivo correlations are desired, it is logical to consider and utilize knowledge of the in vivo condition. This publication critically reviews the literature that is relevant to oral human drug delivery. Physiologically relevant information must serve as a basis for the design of dissolution test methods and systems that are more representative of the human condition. As in vitro methods advance in their physiological relevance, better in vitro - in vivo correlations will be possible. This will, in turn, lead to in vitro systems that can be utilized to more effectively design dosage forms that have improved and more consistent oral bioperformance. PMID:20822152
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Matsubara, Shizue; Förster, Britta; Waterman, Melinda; Robinson, Sharon A.; Pogson, Barry J.; Gunning, Brian; Osmond, Barry
2012-01-01
Half a century of research into the physiology and biochemistry of sun–shade acclimation in diverse plants has provided reality checks for contemporary understanding of thylakoid membrane dynamics. This paper reviews recent insights into photosynthetic efficiency and photoprotection from studies of two xanthophyll cycles in old shade leaves from the inner canopy of the tropical trees Inga sapindoides and Persea americana (avocado). It then presents new physiological data from avocado on the time frames of the slow coordinated photosynthetic development of sink leaves in sunlight and on the slow renovation of photosynthetic properties in old leaves during sun to shade and shade to sun acclimation. In so doing, it grapples with issues in vivo that seem relevant to our increasingly sophisticated understanding of ΔpH-dependent, xanthophyll-pigment-stabilized non-photochemical quenching in the antenna of PSII in thylakoid membranes in vitro. PMID:23148277
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Heat stroke risk for open-water swimmers during long-distance events.
Macaluso, Filippo; Barone, Rosario; Isaacs, Ashwin W; Farina, Felicia; Morici, Giuseppe; Di Felice, Valentina
2013-12-01
Open-water swimming is a rapidly growing sport discipline worldwide, and clinical problems associated with long-distance swimming are now better recognized and managed more effectively. The most prevalent medical risk associated with an open-water swimming event is hypothermia; therefore, the Federation Internationale De Natation (FINA) has instituted 2 rules to reduce this occurrence related to the minimum water temperature and the time taken to complete the race. Another medical risk that is relevant to open-water swimmers is heat stroke, a condition that can easily go unnoticed. The purpose of this review is to shed light on this physiological phenomenon by examining the physiological response of swimmers during long-distance events, to define a maximum water temperature limit for competitions. We conclude that competing in water temperatures exceeding 33°C should be avoided. Copyright © 2013 Wilderness Medical Society. Published by Elsevier Inc. All rights reserved.
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Microgravity-Induced Fluid Shift and Ophthalmic Changes
Nelson, Emily S.; Mulugeta, Lealem; Myers, Jerry G.
2014-01-01
Although changes to visual acuity in spaceflight have been observed in some astronauts since the early days of the space program, the impact to the crew was considered minor. Since that time, missions to the International Space Station have extended the typical duration of time spent in microgravity from a few days or weeks to many months. This has been accompanied by the emergence of a variety of ophthalmic pathologies in a significant proportion of long-duration crewmembers, including globe flattening, choroidal folding, optic disc edema, and optic nerve kinking, among others. The clinical findings of affected astronauts are reminiscent of terrestrial pathologies such as idiopathic intracranial hypertension that are characterized by high intracranial pressure. As a result, NASA has placed an emphasis on determining the relevant factors and their interactions that are responsible for detrimental ophthalmic response to space. This article will describe the Visual Impairment and Intracranial Pressure syndrome, link it to key factors in physiological adaptation to the microgravity environment, particularly a cephalad shifting of bodily fluids, and discuss the implications for ocular biomechanics and physiological function in long-duration spaceflight. PMID:25387162
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Electrophysiology of connection current spikes.
Fish, Raymond M; Geddes, Leslie A
2008-12-01
Connection to a 60-Hz or other voltage source can result in cardiac dysrhythmias, a startle reaction, muscle contractions, and a variety of other physiological responses. Such responses can lead to injury, especially if significant ventricular cardiac dysrhythmias occur, or if a person is working at some height above ground and falls as a result of a musculoskeletal response. Physiological reactions are known to relate to intensity and duration of current exposure. The connection current that flows is a function of the applied voltage at the instant of connection, and the electrical impedance encountered by the voltage source in contact with the skin or other body tissues. In this article we describe a rarely investigated phenomenon, namely a contact, or connection, current spike that is many times higher than the steady-state current. This current spike occurs when an electrical connection is made at a non-zero voltage time in a sine wave or other waveform. Such current spikes may occur when electronic or manual switching or connecting of conductors occurs in electronic instrumentation connected to a patient. These findings are relevant to medical devices and instrumentation and to electrical safety in general.
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Tobin, Elizabeth D.; Grünbaum, Daniel; Patterson, Johnathan; Cattolico, Rose Ann
2013-01-01
Many species of harmful algae transition between a motile, vegetative stage in the water column and a non-motile, resting stage in the sediments. Physiological and behavioral traits expressed during benthic-pelagic transition potentially regulate the timing, location and persistence of blooms. The roles of key physiological and behavioral traits involved in resting cell emergence and bloom formation were examined in two geographically distinct strains of the harmful alga, Heterosigma akashiwo. Physiological measures of cell viability, division and population growth, and cell fatty acid content were made using flow cytometry and gas chromatography – mass spectrometry techniques as cells transitioned between the benthic resting stage and the vegetative pelagic stage. Video-based tracking was used to quantify cell-level swimming behaviors. Data show increased temperature and light triggered rapid emergence from the resting stage and initiated cell swimming. Algal strains varied in important physiological and behavioral traits, including survivorship during life-stage transitions, population growth rates and swimming velocities. Collectively, these traits function as “population growth strategies” that can influence bloom formation. Many resting cells regained the up-swimming capacity necessary to cross an environmentally relevant halocline and the ability to aggregate in near-surface waters within hours after vegetative growth supporting conditions were restored. Using a heuristic model, we illustrate how strain-specific population growth strategies can govern the timescales over which H. akashiwo blooms form. Our findings highlight the need for identification and quantification of strain-specific physiological and behavioral traits to improve mechanistic understanding of bloom formation and successful bloom prediction. PMID:24124586
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NASA Astrophysics Data System (ADS)
Perrin, Laura; Probert, Ian; Langer, Gerald; Aloisi, Giovanni
2016-11-01
Coccolithophores are unicellular calcifying marine algae that play an important role in the oceanic carbon cycle via their cellular processes of photosynthesis (a CO2 sink) and calcification (a CO2 source). In contrast to the well-studied, surface-water coccolithophore blooms visible from satellites, the lower photic zone is a poorly known but potentially important ecological niche for coccolithophores in terms of primary production and carbon export to the deep ocean. In this study, the physiological responses of an Emiliania huxleyi strain to conditions simulating the deep niche in the oligotrophic gyres along the BIOSOPE transect in the South Pacific Gyre were investigated. We carried out batch culture experiments with an E. huxleyi strain isolated from the BIOSOPE transect, reproducing the in situ conditions of light and nutrient (nitrate and phosphate) limitation. By simulating coccolithophore growth using an internal stores (Droop) model, we were able to constrain fundamental physiological parameters for this E. huxleyi strain. We show that simple batch experiments, in conjunction with physiological modelling, can provide reliable estimates of fundamental physiological parameters for E. huxleyi that are usually obtained experimentally in more time-consuming and costly chemostat experiments. The combination of culture experiments, physiological modelling and in situ data from the BIOSOPE cruise show that E. huxleyi growth in the deep BIOSOPE niche is limited by availability of light and nitrate. This study contributes more widely to the understanding of E. huxleyi physiology and behaviour in a low-light and oligotrophic environment of the ocean.
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Schampaert, Stéphanie; Rutten, Marcel C M; van T Veer, Marcel; van Nunen, Lokien X; Tonino, Pim A L; Pijls, Nico H J; van de Vosse, Frans N
2013-01-01
Because of the large number of interaction factors involved, the effects of the intra-aortic balloon pump (IABP) have not been investigated deeply. To enhance its clinical efficiency and to better define indications for use, advanced models are required to test the interaction between the IABP and the cardiovascular system. A patient with mild blood pressure depression and a lowered cardiac output is modeled in a lumped parameter computational model, developed with physiologically representative elements for relevant components of circulation and device. IABP support is applied, and the moments of balloon inflation and deflation are varied around their conventional timing modes. For validation purposes, timing is adapted within acceptable ranges in ten patients undergoing IABP therapy for typical clinical indications. In both model and patients, the IABP induces a diastolic blood pressure augmentation as well as a systolic reduction in afterload. The support capabilities of the IABP benefit the most when the balloon is deflated simultaneously with ventricular contraction, whereas inflation before onset of diastole unconditionally interferes with ejection. The physiologic response makes the model an excellent tool for testing the interaction between the IABP and the cardiovascular system, and how alterations of specific IABP parameters (i.e., timing) affect this coupling.
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Bufalari, Ilaria; Porciello, Giuseppina; Sperduti, Marco; Minio-Paluello, Ilaria
2015-04-01
The illusory subjective experience of looking at one's own face while in fact looking at another person's face can surprisingly be induced by simple synchronized visuotactile stimulation of the two faces. A recent study (Apps MA, Tajadura-Jiménez A, Sereno M, Blanke O, Tsakiris M. Cereb Cortex. First published August 20, 2013; doi:10.1093/cercor/bht199) investigated for the first time the role of visual unimodal and temporoparietal multimodal brain areas in the enfacement illusion and suggested a model in which multisensory mechanisms are crucial to construct and update self-face representation. Copyright © 2015 the American Physiological Society.
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The cardiovascular system after exercise
Romero, Steven A.; Minson, Christopher T.
2017-01-01
Recovery from exercise refers to the time period between the end of a bout of exercise and the subsequent return to a resting or recovered state. It also refers to specific physiological processes or states occurring after exercise that are distinct from the physiology of either the exercising or the resting states. In this context, recovery of the cardiovascular system after exercise occurs across a period of minutes to hours, during which many characteristics of the system, even how it is controlled, change over time. Some of these changes may be necessary for long-term adaptation to exercise training, yet some can lead to cardiovascular instability during recovery. Furthermore, some of these changes may provide insight into when the cardiovascular system has recovered from prior training and is physiologically ready for additional training stress. This review focuses on the most consistently observed hemodynamic adjustments and the underlying causes that drive cardiovascular recovery and will highlight how they differ following resistance and aerobic exercise. Primary emphasis will be placed on the hypotensive effect of aerobic and resistance exercise and associated mechanisms that have clinical relevance, but if left unchecked, can progress to symptomatic hypotension and syncope. Finally, we focus on the practical application of this information to strategies to maximize the benefits of cardiovascular recovery, or minimize the vulnerabilities of this state. We will explore appropriate field measures, and discuss to what extent these can guide an athlete’s training. PMID:28153943
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Heat stress and dehydration in adapting for performance: Good, bad, both, or neither?
Akerman, Ashley Paul; Tipton, Michael; Minson, Christopher T.; Cotter, James David
2016-01-01
ABSTRACT Physiological systems respond acutely to stress to minimize homeostatic disturbance, and typically adapt to chronic stress to enhance tolerance to that or a related stressor. It is legitimate to ask whether dehydration is a valuable stressor in stimulating adaptation per se. While hypoxia has had long-standing interest by athletes and researchers as an ergogenic aid, heat and nutritional stressors have had little interest until the past decade. Heat and dehydration are highly interlinked in their causation and the physiological strain they induce, so their individual roles in adaptation are difficult to delineate. The effectiveness of heat acclimation as an ergogenic aid remains unclear for team sport and endurance athletes despite several recent studies on this topic. Very few studies have examined the potential ergogenic (or ergolytic) adaptations to ecologically-valid dehydration as a stressor in its own right, despite longstanding evidence of relevant fluid-regulatory adaptations from short-term hypohydration. Transient and self-limiting dehydration (e.g., as constrained by thirst), as with most forms of stress, might have a time and a place in physiological or behavioral adaptations independently or by exacerbating other stressors (esp. heat); it cannot be dismissed without the appropriate evidence. The present review did not identify such evidence. Future research should identify how the magnitude and timing of dehydration might augment or interfere with the adaptive processes in behaviorally constrained versus unconstrained humans. PMID:28349082
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Heat stress and dehydration in adapting for performance: Good, bad, both, or neither?
Akerman, Ashley Paul; Tipton, Michael; Minson, Christopher T; Cotter, James David
2016-01-01
Physiological systems respond acutely to stress to minimize homeostatic disturbance, and typically adapt to chronic stress to enhance tolerance to that or a related stressor. It is legitimate to ask whether dehydration is a valuable stressor in stimulating adaptation per se . While hypoxia has had long-standing interest by athletes and researchers as an ergogenic aid, heat and nutritional stressors have had little interest until the past decade. Heat and dehydration are highly interlinked in their causation and the physiological strain they induce, so their individual roles in adaptation are difficult to delineate. The effectiveness of heat acclimation as an ergogenic aid remains unclear for team sport and endurance athletes despite several recent studies on this topic. Very few studies have examined the potential ergogenic (or ergolytic) adaptations to ecologically-valid dehydration as a stressor in its own right, despite longstanding evidence of relevant fluid-regulatory adaptations from short-term hypohydration. Transient and self-limiting dehydration (e.g., as constrained by thirst), as with most forms of stress, might have a time and a place in physiological or behavioral adaptations independently or by exacerbating other stressors (esp. heat); it cannot be dismissed without the appropriate evidence. The present review did not identify such evidence. Future research should identify how the magnitude and timing of dehydration might augment or interfere with the adaptive processes in behaviorally constrained versus unconstrained humans.
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Sindhurakar, Anil; Mishra, Asht M; Gupta, Disha; Iaci, Jennifer F; Parry, Tom J; Carmel, Jason B
2017-04-01
4-Aminopyridine (4-AP) is a Food and Drug Administration-approved drug to improve motor function in people with multiple sclerosis. Preliminary results suggest the drug may act on intact neural circuits and not just on demyelinated ones. To determine if 4-AP at clinically relevant levels alters the excitability of intact motor circuits. In anesthetized rats, electrodes were placed over motor cortex and the dorsal cervical spinal cord for electrical stimulation, and electromyogram electrodes were inserted into biceps muscle to measure responses. The motor responses to brain and spinal cord stimulation were measured before and for 5 hours after 4-AP administration both in uninjured rats and rats with a cut lesion of the pyramidal tract. Blood was collected at the same time as electrophysiology to determine drug plasma concentration with a goal of 20 to 100 ng/mL. We first determined that a bolus infusion of 0.32 mg/kg 4-AP was optimal: it produced on average 61.5 ± 1.8 ng/mL over the 5 hours after infusion. This dose of 4-AP increased responses to spinal cord stimulation by 1.3-fold in uninjured rats and 3-fold in rats with pyramidal tract lesion. Responses to cortical stimulation also increased by 2-fold in uninjured rats and up to 4-fold in the injured. Clinically relevant levels of 4-AP strongly augment physiological responses in intact circuits, an effect that was more robust after partial injury, demonstrating its broad potential in treating central nervous system injuries.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
De Vos, Winnok H., E-mail: winnok.devos@uantwerpen.be; Cell Systems and Imaging Research Group, Department of Molecular Biotechnology, Ghent University, Ghent; Beghuin, Didier
As commercial space flights have become feasible and long-term extraterrestrial missions are planned, it is imperative that the impact of space travel and the space environment on human physiology be thoroughly characterized. Scrutinizing the effects of potentially detrimental factors such as ionizing radiation and microgravity at the cellular and tissue level demands adequate visualization technology. Advanced light microscopy (ALM) is the leading tool for non-destructive structural and functional investigation of static as well as dynamic biological systems. In recent years, technological developments and advances in photochemistry and genetic engineering have boosted all aspects of resolution, readout and throughput, rendering ALMmore » ideally suited for biological space research. While various microscopy-based studies have addressed cellular response to space-related environmental stressors, biological endpoints have typically been determined only after the mission, leaving an experimental gap that is prone to bias results. An on-board, real-time microscopical monitoring device can bridge this gap. Breadboards and even fully operational microscope setups have been conceived, but they need to be rendered more compact and versatile. Most importantly, they must allow addressing the impact of gravity, or the lack thereof, on physiologically relevant biological systems in space and in ground-based simulations. In order to delineate the essential functionalities for such a system, we have reviewed the pending questions in space science, the relevant biological model systems, and the state-of-the art in ALM. Based on a rigorous trade-off, in which we recognize the relevance of multi-cellular systems and the cellular microenvironment, we propose a compact, but flexible concept for space-related cell biological research that is based on light sheet microscopy.« less
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From Claude Bernard to the Batcave and Beyond: Using Batman as a Hook for Physiology Education
ERIC Educational Resources Information Center
Zehr, E. Paul
2011-01-01
Communicating physiology to the general public and popularizing science can be tremendously rewarding activities. Providing relevant and compelling points of linkage, however, between the scientific experiences and the interests of the general public can be challenging. One avenue for popularizing science is to link scientific concepts to images,…
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The Emergent Coordination of Cognitive Function
ERIC Educational Resources Information Center
Kello, Christopher T.; Beltz, Brandon C.; Holden, John G.; Van Orden, Guy C.
2007-01-01
1/f scaling has been observed throughout human physiology and behavior, but its origins and meaning remain a matter of debate. Some argue that it is a byproduct of ongoing processes in the brain or body and therefore of limited relevance to psychological theory. Others argue that 1/f scaling reflects a fundamental aspect of all physiological and…
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Challenges of physiological monitoring in a Navy operational setting
NASA Technical Reports Server (NTRS)
Banta, Guy R.
1988-01-01
Challenges to physiological monitoring in the Navy include environmental extremes, acceptance of use by test subjects, data transfer, data interpretation, and capability of relating collected data to valid operational relevant criterion measures. These problems are discussed with respect to diving, electrophysiological monitoring, in-flight monitoring, aircrew fatigue, in-flight cardiac stress, and in-flight monitoring devices.
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Glycinergic inhibition tunes coincidence detection in the auditory brainstem
Myoga, Michael H.; Lehnert, Simon; Leibold, Christian; Felmy, Felix; Grothe, Benedikt
2014-01-01
Neurons in the medial superior olive (MSO) detect microsecond differences in the arrival time of sounds between the ears (interaural time differences or ITDs), a crucial binaural cue for sound localization. Synaptic inhibition has been implicated in tuning ITD sensitivity, but the cellular mechanisms underlying its influence on coincidence detection are debated. Here we determine the impact of inhibition on coincidence detection in adult Mongolian gerbil MSO brain slices by testing precise temporal integration of measured synaptic responses using conductance-clamp. We find that inhibition dynamically shifts the peak timing of excitation, depending on its relative arrival time, which in turn modulates the timing of best coincidence detection. Inhibitory control of coincidence detection timing is consistent with the diversity of ITD functions observed in vivo and is robust under physiologically relevant conditions. Our results provide strong evidence that temporal interactions between excitation and inhibition on microsecond timescales are critical for binaural processing. PMID:24804642
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Goodman, Barbara E; Ikiugu, Moses N
2017-09-01
Recently, the Occupational Therapy Department requested a custom-designed medical physiology course for the students in the new occupational therapy doctoral program. The first author, a physiologist with extensive experience in teaching both undergraduate preprofessional and medical students in human physiology, was recruited to design and implement the course. The course was designed to be consistent with the constructivist philosophy that guides the occupational therapy curriculum. The course was offered for the first time during fall/spring 2015/2016 and included both first- and second-year occupational therapy doctoral students. A number of anonymous assessment tools were used to evaluate students' perceptions regarding the effectiveness of various pedagogies used in the course in enhancing their learning. A summative course assessment survey with comments was used at the end of the course. This paper describes the model of course design and the student feedback, which generated some suggestions for improvement of the course. This approach in designing a new course for a new disciplinary group of students should be helpful to other faculty involved in developing courses for health career programs populated by students with variable physiology backgrounds and different educational needs. The final relevant feedback from the course would be to have the students evaluate the usefulness of the course to their future careers immediately following their certification examinations in a year or two and during their subsequent clinical experiences; however, that information will likely be more difficult to obtain. Copyright © 2017 the American Physiological Society.
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The G protein-coupled receptor GPR34 - The past 20 years of a grownup.
Schöneberg, Torsten; Meister, Jaroslawna; Knierim, Alexander Bernd; Schulz, Angela
2018-04-22
Research on GPR34, which was discovered in 1999 as an orphan G protein-coupled receptor of the rhodopsin-like class, disclosed its physiologic relevance only piece by piece. Being present in all recent vertebrate genomes analyzed so far it seems to improve the fitness of species although it is not essential for life and reproduction as GPR34-deficient mice demonstrate. However, closer inspection of macrophages and microglia, where it is mainly expressed, revealed its relevance in immune cell function. Recent data clearly demonstrate that GPR34 function is required to arrest microglia in the M0 homeostatic non-phagocytic phenotype. Herein, we summarize the current knowledge on its evolution, genomic and structural organization, physiology, pharmacology and relevance in human diseases including neurodegenerative diseases and cancer, which accumulated over the last 20 years. Copyright © 2018 Elsevier Inc. All rights reserved.
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Zhang, Zhenwei; VanSwearingen, Jessie; Brach, Jennifer S.; Perera, Subashan
2016-01-01
Human gait is a complex interaction of many nonlinear systems and stride intervals exhibit self-similarity over long time scales that can be modeled as a fractal process. The scaling exponent represents the fractal degree and can be interpreted as a biomarker of relative diseases. The previous study showed that the average wavelet method provides the most accurate results to estimate this scaling exponent when applied to stride interval time series. The purpose of this paper is to determine the most suitable mother wavelet for the average wavelet method. This paper presents a comparative numerical analysis of sixteen mother wavelets using simulated and real fractal signals. Simulated fractal signals were generated under varying signal lengths and scaling exponents that indicate a range of physiologically conceivable fractal signals. The five candidates were chosen due to their good performance on the mean square error test for both short and long signals. Next, we comparatively analyzed these five mother wavelets for physiologically relevant stride time series lengths. Our analysis showed that the symlet 2 mother wavelet provides a low mean square error and low variance for long time intervals and relatively low errors for short signal lengths. It can be considered as the most suitable mother function without the burden of considering the signal length. PMID:27960102
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Cellular and Physiological Effects of Anthrax Exotoxin and Its Relevance to Disease
Lowe, David E.; Glomski, Ian J.
2012-01-01
Bacillus anthracis, the causative agent of anthrax, secretes a tri-partite exotoxin that exerts pleiotropic effects on the host. The purification of the exotoxin components, protective antigen, lethal factor, and edema factor allowed the rapid characterization of their physiologic effects on the host. As molecular biology matured, interest focused on the molecular mechanisms and cellular alterations induced by intoxication. Only recently have researchers begun to connect molecular and cellular knowledge back to the broader physiological effects of the exotoxin. This review focuses on the progress that has been made bridging molecular knowledge back to the exotoxin’s physiological effects on the host. PMID:22919667
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Lamb, Iain R; Novielli, Nicole M; Murrant, Coral L
2018-04-15
The current theory behind matching blood flow to metabolic demand of skeletal muscle suggests redundant interactions between metabolic vasodilators. Capillaries play an important role in blood flow control given their ability to respond to muscle contraction by causing conducted vasodilatation in upstream arterioles that control their perfusion. We sought to determine whether redundancies occur between vasodilators at the level of the capillary by stimulating the capillaries with muscle contraction and vasodilators relevant to muscle contraction. We identified redundancies between potassium and both adenosine and nitric oxide, between nitric oxide and potassium, and between adenosine and both potassium and nitric oxide. During muscle contraction, we demonstrate redundancies between potassium and nitric oxide as well as between potassium and adenosine. Our data show that redundancy is physiologically relevant and involved in the coordination of the vasodilator response during muscle contraction at the level of the capillaries. We sought to determine if redundancy between vasodilators is physiologically relevant during active hyperaemia. As inhibitory interactions between vasodilators are indicative of redundancy, we tested whether vasodilators implicated in mediating active hyperaemia (potassium (K + ), adenosine (ADO) and nitric oxide (NO)) inhibit one another's vasodilatory effects through direct application of pharmacological agents and during muscle contraction. Using the hamster cremaster muscle and intravital microscopy, we locally stimulated capillaries with one vasodilator in the absence and the presence of a second vasodilator (10 -7 m S-nitroso-N-acetylpenicillamine (SNAP), 10 -7 m ADO, 10 mm KCl) applied sequentially and simultaneously, and observed the response in the associated upstream 4A arteriole controlling the perfusion of the stimulated capillary. We found that KCl significantly attenuated SNAP- and ADO-induced vasodilatations by ∼49.7% and ∼128.0% respectively and ADO significantly attenuated KCl- and SNAP-induced vasodilatations by ∼94.7% and ∼59.6%, respectively. NO significantly attenuated KCl vasodilatation by 93.8%. Further, during muscle contraction we found that inhibition of NO production using l-N G -nitroarginine methyl ester and inhibition of ADO receptors using xanthine amine congener was effective at inhibiting contraction-induced vasodilatation but only in the presence of K + release channel inhibition. Thus, only when the inhibiting vasodilator K + was blocked was the second vasodilator, NO or ADO, able to produce effective vasodilatation. Therefore, we show that there are inhibitory interactions between specific vasodilators at the level of the capillary. Further, these inhibitions can be observed during muscle contraction indicating that redundancies between vasodilators are physiologically relevant and influence vasodilatation during active hyperaemia. © 2018 The Authors. The Journal of Physiology © 2018 The Physiological Society.
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Real-time high dynamic range laser scanning microscopy
NASA Astrophysics Data System (ADS)
Vinegoni, C.; Leon Swisher, C.; Fumene Feruglio, P.; Giedt, R. J.; Rousso, D. L.; Stapleton, S.; Weissleder, R.
2016-04-01
In conventional confocal/multiphoton fluorescence microscopy, images are typically acquired under ideal settings and after extensive optimization of parameters for a given structure or feature, often resulting in information loss from other image attributes. To overcome the problem of selective data display, we developed a new method that extends the imaging dynamic range in optical microscopy and improves the signal-to-noise ratio. Here we demonstrate how real-time and sequential high dynamic range microscopy facilitates automated three-dimensional neural segmentation. We address reconstruction and segmentation performance on samples with different size, anatomy and complexity. Finally, in vivo real-time high dynamic range imaging is also demonstrated, making the technique particularly relevant for longitudinal imaging in the presence of physiological motion and/or for quantification of in vivo fast tracer kinetics during functional imaging.
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Levichkina, Ekaterina; Saalmann, Yuri B; Vidyasagar, Trichur R
2017-03-01
Primate posterior parietal cortex (PPC) is known to be involved in controlling spatial attention. Neurons in one part of the PPC, the lateral intraparietal area (LIP), show enhanced responses to objects at attended locations. Although many are selective for object features, such as the orientation of a visual stimulus, it is not clear how LIP circuits integrate feature-selective information when providing attentional feedback about behaviorally relevant locations to the visual cortex. We studied the relationship between object feature and spatial attention properties of LIP cells in two macaques by measuring the cells' orientation selectivity and the degree of attentional enhancement while performing a delayed match-to-sample task. Monkeys had to match both the location and orientation of two visual gratings presented separately in time. We found a wide range in orientation selectivity and degree of attentional enhancement among LIP neurons. However, cells with significant attentional enhancement had much less orientation selectivity in their response than cells which showed no significant modulation by attention. Additionally, orientation-selective cells showed working memory activity for their preferred orientation, whereas cells showing attentional enhancement also synchronized with local neuronal activity. These results are consistent with models of selective attention incorporating two stages, where an initial feature-selective process guides a second stage of focal spatial attention. We suggest that LIP contributes to both stages, where the first stage involves orientation-selective LIP cells that support working memory of the relevant feature, and the second stage involves attention-enhanced LIP cells that synchronize to provide feedback on spatial priorities. © 2017 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.
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Collet, C; Guillot, A; Petit, C
2010-05-01
The impact of cell (mobile) phone use on driving performance has been widely questioned for 20 years. This paper reviews the literature to evaluate the extent to which phoning may impact behaviour with a risk to affect safety. After analysing epidemiological studies that give an overview of cell phone use, this paper examines the experimental results and focuses on variables showing that driving is impacted by holding a mobile-phone conversation. Information processing (e.g. reaction time and detection rate of cues related to driving information) and variables associated with vehicle control (e.g. lane-keeping, headway and vehicle speed) seem the most relevant. Although less studied than behavioural indices, physiological data give information about the supplementary potential strain that the driver may undergo under dual-task conditions. This first part of the review highlights common findings, questionable results and differences among studies, which originate from specific experimental designs with particular dependent variables, i.e. self-report, behavioural and physiological indicators. Finally, how drivers try to compensate for the additional load brought by phone use is described. STATEMENT OF RELEVANCE: The two papers review the influence of mobile-phone use on driving performance. While there is ample evidence that this dual task is likely to increase the risk of car crash, the review analyses the variables eliciting detrimental conditions and, conversely, those that may preserve acceptable conditions for safety, close to usual driving. The decision of answering or initiating a cell phone call while driving depends upon the complex interaction among several variables, including driving conditions and driver's own characteristics. In addition, this decision remains under driver's awareness of being able or not to manage the two tasks simultaneously.
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Physiology undergraduate degree requirements in the U.S.
VanRyn, Valerie S; Poteracki, James M; Wehrwein, Erica A
2017-12-01
Course-level learning objectives and core concepts for undergraduate physiology teaching exist. The next step is to consider how these resources fit into generalizable program-level guidelines for Bachelor of Science (BS) degrees in Physiology. In the absence of program-level guidelines for Physiology degree programs, we compiled a selective internal report to review degree requirements from 18 peer BS programs entitled "Physiology" in the United States (U.S.). There was a range of zero to three required semesters of math, physics, physics laboratory, general biology, biology laboratory, general chemistry, chemistry laboratory, organic chemistry, organic chemistry laboratory, biochemistry, biochemistry laboratory, anatomy, anatomy laboratory, core systems physiology, and physiology laboratory. Required upper division credits ranged from 11 to 31 and included system-specific, exercise and environmental, clinically relevant, pathology/disease-related, and basic science options. We hope that this information will be useful for all programs that consider themselves to be physiology, regardless of name. Reports such as this can serve as a starting point for collaboration among BS programs to improve physiology undergraduate education and best serve our students. Copyright © 2017 the American Physiological Society.
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A Novel Disintegration Tester for Solid Dosage Forms Enabling Adjustable Hydrodynamics.
Kindgen, Sarah; Rach, Regine; Nawroth, Thomas; Abrahamsson, Bertil; Langguth, Peter
2016-08-01
A modified in vitro disintegration test device was designed that enables the investigation of the influence of hydrodynamic conditions on disintegration of solid oral dosage forms. The device represents an improved derivative of the compendial PhEur/USP disintegration test device. By the application of a computerized numerical control, a variety of physiologically relevant moving velocities and profiles can be applied. With the help of computational fluid dynamics, the hydrodynamic and mechanical forces present in the probe chamber were characterized for a variety of device moving speeds. Furthermore, a proof of concept study aimed at the investigation of the influence of hydrodynamic conditions on disintegration times of immediate release tablets. The experiments demonstrated the relevance of hydrodynamics for tablet disintegration, especially in media simulating the fasted state. Disintegration times increased with decreasing moving velocity. A correlation between experimentally determined disintegration times and computational fluid dynamics predicted shear stress on tablet surface was established. In conclusion, the modified disintegration test device is a valuable tool for biorelevant in vitro disintegration testing of solid oral dosage forms. Copyright © 2016 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.
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[Clinical, morphological and molecular biological characteristics of the aging eye].
Böhm, M R R; Thomasen, H; Parnitzke, F; Steuhl, K-P
2017-02-01
The physiological aging of the eye is associated with loss of visual function. Age-related changes of the eye can result in ophthalmological diseases. The aim of this article is to display morphological, histological and molecular biological alterations of the aging eye. A web-based search and review of the literature for aging of the visual system including cornea, lens, vitreous humor, retina, retinal pigment epithelium (RPE), choroidea and optic nerve were carried out. The most important results related to morphological, histological and molecular biological changes are summarized. Age-related, morphological alterations can be found in preretinal structures, e. g. cornea, lens and vitreous humor, as well as neuronal structures, such as the retina. In addition to negligible clinical signs of the aging eye, there are clinically relevant changes which can develop into pathological ophthalmological diseases. These transitions from age-related alterations to relevant ophthalmological diseases, e. g. age-related macular degeneration and glaucoma are continuous. An understanding of aging could provide predictive factors to detect the conversion of physiological aging into pathological conditions. The derivation of physiological markers or new approaches to detection and treatment of disease-related entities associated with the risk factor aging are desirable. Translational approaches in clinical and basic science are necessary to provide new therapeutic options for relevant ophthalmological diseases in the future.
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Metabolic survey of Botryococcus braunii: Impact of the physiological state on product formation.
Blifernez-Klassen, Olga; Chaudhari, Swapnil; Klassen, Viktor; Wördenweber, Robin; Steffens, Tim; Cholewa, Dominik; Niehaus, Karsten; Kalinowski, Jörn; Kruse, Olaf
2018-01-01
The microalga Botryococcus braunii is widely regarded as a potential renewable and sustainable source for industrial applications because of its capability to produce large amounts of metabolically expensive (exo-) polysaccharides and lipids, notably hydrocarbons. A comprehensive and systematic metabolic characterization of the Botryococcus braunii race A strain CCAP 807/2 was conducted within the present study, including the detailed analysis of growth-associated and physiological parameters. In addition, the intracellular metabolome was profiled for the first time and showed growth- and product-specific fluctuations in response to the different availability of medium resources during the cultivation course. Among the identified metabolites, a constant expression of raffinose was observed for the first time under standard conditions, which has until now only been described for higher plants. Overall, the multilayered analysis during the cultivation of strain CCAP 807/2 allowed the differentiation of four distinct physiological growth phases and revealed differences in the production profiles and content of liquid hydrocarbons and carbohydrates with up to 84% of organic dry weight (oDW). In the process, an enhanced production of carbohydrates with up to 63% of oDW (1.36±0.03 g L-1) could be observed during the late linear growth phase, whereas the highest accumulation of extracellular hydrocarbons with up to 24% of oDW (0.66±0.12 g L-1) occurred mainly during the stationary growth phase. Altogether, the knowledge obtained is potentially useful for the general understanding of the overall physiology of Botryococcus braunii and provide important insights into the growth behavior and product formation of this microalga, and is thus relevant for large scale biofuel production and industrial applications.
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Innis, Charles J; Merigo, Constance; Cavin, Julie M; Hunt, Kathleen; Dodge, Kara L; Lutcavage, Molly
2014-01-01
The physiological status of seven leatherback turtles (Dermochelys coriacea) was assessed at two time points during ecological research capture events in the northwestern Atlantic Ocean. Data were collected as soon as possible after securing each turtle onboard the capture vessel and again immediately prior to release. Measured parameters included sea surface temperature, body temperature, morphometric data, sex, heart rate, respiratory rate and various haematological and blood biochemical variables. Results indicated generally stable physiological status in comparison to previously published studies of this species. However, blood pH and blood potassium concentrations increased significantly between the two time points (P = 0.0018 and P = 0.0452, respectively). Turtles were affected by a mild initial acidosis (mean [SD] temperature-corrected pH = 7.29 [0.07]), and blood pH increased prior to release (mean [SD] = 7.39 [0.07]). Initial blood potassium concentrations were considered normal (mean [SD] = 4.2 [0.9] mmol/l), but turtles experienced a mild to moderate increase in blood potassium concentrations during the event (mean [SD] pre-release potassium = 5.9 [1.7] mmol/l, maximum = 8.5 mmol/l). While these data support the general safety of direct capture for study of this species, the observed changes in blood potassium concentrations are of potential concern due to possible adverse effects of hyperkalaemia on cardiac function. The results of this study highlight the importance of physiological monitoring during scientific capture events. The results are also likely to be relevant to unintentional leatherback capture events (e.g. fisheries interactions), when interactions may be more prolonged or extreme.
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Kay, Katherine; Shah, Dhaval K; Rohan, Lisa; Bies, Robert
2018-05-01
A physiologically-based pharmacokinetic (PBPK) model of the vaginal space was developed with the aim of predicting concentrations in the vaginal and cervical space. These predictions can be used to optimize the probability of success of vaginally administered dapivirine (DPV) for HIV prevention. We focus on vaginal delivery using either a ring or film. A PBPK model describing the physiological structure of the vaginal tissue and fluid was defined mathematically and implemented in MATLAB. Literature reviews provided estimates for relevant physiological and physiochemical parameters. Drug concentration-time profiles were simulated in luminal fluids, vaginal tissue and plasma after administration of ring or film. Patient data were extracted from published clinical trials and used to test model predictions. The DPV ring simulations tested the two dosing regimens and predicted PK profiles and area under the curve of luminal fluids (29 079 and 33 067 mg h l -1 in groups A and B, respectively) and plasma (0.177 and 0.211 mg h l -1 ) closely matched those reported (within one standard deviation). While the DPV film study reported drug concentration at only one time point per patient, our simulated profiles pass through reported concentration range. HIV is a major public health issue and vaginal microbicides have the potential to provide a crucial, female-controlled option for protection. The PBPK model successfully simulated realistic representations of drug PK. It provides a reliable, inexpensive and accessible platform where potential effectiveness of new compounds and the robustness of treatment modalities for pre-exposure prophylaxis can be evaluated. © 2018 The Authors. British Journal of Clinical Pharmacology published by John Wiley & Sons Ltd on behalf of British Pharmacological Society.
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Physiological parameter values in greyhounds before and after high-intensity exercise.
Pellegrino, Francisco Javier; Risso, Analía; Vaquero, Pablo G; Corrada, Yanina A
2018-01-01
Dog sports competitions have greatly expanded. The availability of reference values for each type of activity could help assess fitness accurately. Heart rate (HR), blood lactate (BL) and rectal temperature (RT) are relevant physiological parameters to determine the dogs response to effort. Previous studies in greyhounds have reported the effect of high-intensity exercise on many physiological parameters immediately after completing different racing distances and recovery times. However, there are no studies concerning physiological changes over shorter racing distances. We therefore assessed the effect of sprint exercise on HR, BL and RT in nine greyhounds performing sprint exercise over a 100-m distance chasing a lure. After the exercise, dogs underwent a passive 10-min recovery phase. Before the exercise, immediately after it and at 5 and 10 min during recovery, HR and RT were assessed and blood samples were collected for BL determination. HR, BL and RT values increased significantly after the exercise (P<0.01). Whereas HR returned to pre-exercise values at 10 min during the recovery phase (P>0.1), BL concentration and RT remained increased (P<0.01). The abrupt increase in HR, BL and RT values observed immediately after the exercise indicates the high intensity of the effort performed. Similarly, BL concentration after the exercise exceeded the 4 mmol/L lactate threshold, suggesting a predominant anaerobic metabolism during effort. Although HR returned to pre-exercise values 10 min after the exercise, a more extensive recovery phase would be necessary for a total return to resting values, particularly for BL and RT. In greyhounds subjected to high-intensity exercise, HR, BL and RT were reliable physiological parameters to accurately assess the physiological response to effort. The use of sprint exercises over short racing distances could be useful for appropriately monitoring fitness in sporting dogs.
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Migliavacca, Mirco; Reichstein, Markus; Richardson, Andrew D; Mahecha, Miguel D; Cremonese, Edoardo; Delpierre, Nicolas; Galvagno, Marta; Law, Beverly E; Wohlfahrt, Georg; Black, T Andrew; Carvalhais, Nuno; Ceccherini, Guido; Chen, Jiquan; Gobron, Nadine; Koffi, Ernest; Munger, J William; Perez-Priego, Oscar; Robustelli, Monica; Tomelleri, Enrico; Cescatti, Alessandro
2015-01-01
Understanding the environmental and biotic drivers of respiration at the ecosystem level is a prerequisite to further improve scenarios of the global carbon cycle. In this study we investigated the relevance of physiological phenology, defined as seasonal changes in plant physiological properties, for explaining the temporal dynamics of ecosystem respiration (RECO) in deciduous forests. Previous studies showed that empirical RECO models can be substantially improved by considering the biotic dependency of RECO on the short-term productivity (e.g., daily gross primary production, GPP) in addition to the well-known environmental controls of temperature and water availability. Here, we use a model-data integration approach to investigate the added value of physiological phenology, represented by the first temporal derivative of GPP, or alternatively of the fraction of absorbed photosynthetically active radiation, for modeling RECO at 19 deciduous broadleaved forests in the FLUXNET La Thuile database. The new data-oriented semiempirical model leads to an 8% decrease in root mean square error (RMSE) and a 6% increase in the modeling efficiency (EF) of modeled RECO when compared to a version of the model that does not consider the physiological phenology. The reduction of the model-observation bias occurred mainly at the monthly time scale, and in spring and summer, while a smaller reduction was observed at the annual time scale. The proposed approach did not improve the model performance at several sites, and we identified as potential causes the plant canopy heterogeneity and the use of air temperature as a driver of ecosystem respiration instead of soil temperature. However, in the majority of sites the model-error remained unchanged regardless of the driving temperature. Overall, our results point toward the potential for improving current approaches for modeling RECO in deciduous forests by including the phenological cycle of the canopy. © 2014 John Wiley & Sons Ltd.
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Cancer cell motility: lessons from migration in confined spaces
Paul, Colin D.; Mistriotis, Panagiotis; Konstantopoulos, Konstantinos
2017-01-01
Time-lapse, deep-tissue imaging made possible by advances in intravital microscopy has demonstrated the importance of tumour cell migration through confining tracks in vivo. These tracks may either be endogenous features of tissues or be created by tumour or tumour-associated cells. Importantly, migration mechanisms through confining microenvironments are not predicted by 2D migration assays. Engineered in vitro models have been used to delineate the mechanisms of cell motility through confining spaces encountered in vivo. Understanding cancer cell locomotion through physiologically relevant confining tracks could be useful in developing therapeutic strategies to combat metastasis. PMID:27909339
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Hunt, Kathleen E.; Moore, Michael J.; Rolland, Rosalind M.; Kellar, Nicholas M.; Hall, Ailsa J.; Kershaw, Joanna; Raverty, Stephen A.; Davis, Cristina E.; Yeates, Laura C.; Fauquier, Deborah A.; Rowles, Teresa K.; Kraus, Scott D.
2013-01-01
Large whales are subjected to a variety of conservation pressures that could be better monitored and managed if physiological information could be gathered readily from free-swimming whales. However, traditional approaches to studying physiology have been impractical for large whales, because there is no routine method for capture of the largest species and there is presently no practical method of obtaining blood samples from free-swimming whales. We review the currently available techniques for gathering physiological information on large whales using a variety of non-lethal and minimally invasive (or non-invasive) sample matrices. We focus on methods that should produce information relevant to conservation physiology, e.g. measures relevant to stress physiology, reproductive status, nutritional status, immune response, health, and disease. The following four types of samples are discussed: faecal samples, respiratory samples (‘blow’), skin/blubber samples, and photographs. Faecal samples have historically been used for diet analysis but increasingly are also used for hormonal analyses, as well as for assessment of exposure to toxins, pollutants, and parasites. Blow samples contain many hormones as well as respiratory microbes, a diverse array of metabolites, and a variety of immune-related substances. Biopsy dart samples are widely used for genetic, contaminant, and fatty-acid analyses and are now being used for endocrine studies along with proteomic and transcriptomic approaches. Photographic analyses have benefited from recently developed quantitative techniques allowing assessment of skin condition, ectoparasite load, and nutritional status, along with wounds and scars from ship strikes and fishing gear entanglement. Field application of these techniques has the potential to improve our understanding of the physiology of large whales greatly, better enabling assessment of the relative impacts of many anthropogenic and ecological pressures. PMID:27293590
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Zenker, Sven
2010-08-01
Combining mechanistic mathematical models of physiology with quantitative observations using probabilistic inference may offer advantages over established approaches to computerized decision support in acute care medicine. Particle filters (PF) can perform such inference successively as data becomes available. The potential of PF for real-time state estimation (SE) for a model of cardiovascular physiology is explored using parallel computers and the ability to achieve joint state and parameter estimation (JSPE) given minimal prior knowledge tested. A parallelized sequential importance sampling/resampling algorithm was implemented and its scalability for the pure SE problem for a non-linear five-dimensional ODE model of the cardiovascular system evaluated on a Cray XT3 using up to 1,024 cores. JSPE was implemented using a state augmentation approach with artificial stochastic evolution of the parameters. Its performance when simultaneously estimating the 5 states and 18 unknown parameters when given observations only of arterial pressure, central venous pressure, heart rate, and, optionally, cardiac output, was evaluated in a simulated bleeding/resuscitation scenario. SE was successful and scaled up to 1,024 cores with appropriate algorithm parametrization, with real-time equivalent performance for up to 10 million particles. JSPE in the described underdetermined scenario achieved excellent reproduction of observables and qualitative tracking of enddiastolic ventricular volumes and sympathetic nervous activity. However, only a subset of the posterior distributions of parameters concentrated around the true values for parts of the estimated trajectories. Parallelized PF's performance makes their application to complex mathematical models of physiology for the purpose of clinical data interpretation, prediction, and therapy optimization appear promising. JSPE in the described extremely underdetermined scenario nevertheless extracted information of potential clinical relevance from the data in this simulation setting. However, fully satisfactory resolution of this problem when minimal prior knowledge about parameter values is available will require further methodological improvements, which are discussed.
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Diffusion in Single Supported Lipid Bilayers
NASA Astrophysics Data System (ADS)
Armstrong, C. L.; Trapp, M.; Rheinstädter, M. C.
2011-03-01
Despite their potential relevance for the development of functionalized surfaces and biosensors, the study of single supported membranes using neutron scattering has been limited by the challenge of obtaining relevant dynamic information from a sample with minimal material. Using state of the art neutron instrumentation we have, for the first time, modeled lipid diffusion in single supported lipid bilayers. While we find that the diffusion coefficient for the single bilayer system is comparable to a multi-lamellar lipid system, the molecular mechanism for lipid motion in the single bilayer is a continuous diffusion process with no sign of the flow-like ballistic motion reported in the stacked membrane system. In the future, these membranes will be used to hold and align proteins, mimicking physiological conditions enabling the study of protein structure, function and interactions in relevant and highly topical membrane/protein systems with minimal sample material. C.L. Armstrong, M.D. Kaye, M. Zamponi, E. Mamontov, M. Tyagi, T. Jenkins and M.C. Rheinstädter, Soft Matter Communication, 2010, Advance Article, DOI: 10.1039/C0SM00637H
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Alvarez-Meza, Andres M.; Orozco-Gutierrez, Alvaro; Castellanos-Dominguez, German
2017-01-01
We introduce Enhanced Kernel-based Relevance Analysis (EKRA) that aims to support the automatic identification of brain activity patterns using electroencephalographic recordings. EKRA is a data-driven strategy that incorporates two kernel functions to take advantage of the available joint information, associating neural responses to a given stimulus condition. Regarding this, a Centered Kernel Alignment functional is adjusted to learning the linear projection that best discriminates the input feature set, optimizing the required free parameters automatically. Our approach is carried out in two scenarios: (i) feature selection by computing a relevance vector from extracted neural features to facilitating the physiological interpretation of a given brain activity task, and (ii) enhanced feature selection to perform an additional transformation of relevant features aiming to improve the overall identification accuracy. Accordingly, we provide an alternative feature relevance analysis strategy that allows improving the system performance while favoring the data interpretability. For the validation purpose, EKRA is tested in two well-known tasks of brain activity: motor imagery discrimination and epileptic seizure detection. The obtained results show that the EKRA approach estimates a relevant representation space extracted from the provided supervised information, emphasizing the salient input features. As a result, our proposal outperforms the state-of-the-art methods regarding brain activity discrimination accuracy with the benefit of enhanced physiological interpretation about the task at hand. PMID:29056897
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Drosophila melanogaster as a High-Throughput Model for Host-Microbiota Interactions.
Trinder, Mark; Daisley, Brendan A; Dube, Josh S; Reid, Gregor
2017-01-01
Microbiota research often assumes that differences in abundance and identity of microorganisms have unique influences on host physiology. To test this concept mechanistically, germ-free mice are colonized with microbial communities to assess causation. Due to the cost, infrastructure challenges, and time-consuming nature of germ-free mouse models, an alternative approach is needed to investigate host-microbial interactions. Drosophila melanogaster (fruit flies) can be used as a high throughput in vivo screening model of host-microbiome interactions as they are affordable, convenient, and replicable. D. melanogaster were essential in discovering components of the innate immune response to pathogens. However, axenic D. melanogaster can easily be generated for microbiome studies without the need for ethical considerations. The simplified microbiota structure enables researchers to evaluate permutations of how each microbial species within the microbiota contribute to host phenotypes of interest. This enables the possibility of thorough strain-level analysis of host and microbial properties relevant to physiological outcomes. Moreover, a wide range of mutant D. melanogaster strains can be affordably obtained from public stock centers. Given this, D. melanogaster can be used to identify candidate mechanisms of host-microbe symbioses relevant to pathogen exclusion, innate immunity modulation, diet, xenobiotics, and probiotic/prebiotic properties in a high throughput manner. This perspective comments on the most promising areas of microbiota research that could immediately benefit from using the D. melanogaster model.
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Research on Infancy of Special Relevance for Mental Health. Matrix No. 11A.
ERIC Educational Resources Information Center
Provence, Sally
Research relevant to planning and practice in the area of infant mental health is discussed in this paper. First, three examples of research approaches that reflect current attitudes are given. The first example represents those studies in which there is an effort to closely coordinate physiological and behavioral studies. The second example…
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Sleep mechanisms: Sleep deprivation and detection of changing levels of consciousness
NASA Technical Reports Server (NTRS)
Dement, W. C.; Barchas, J. D.
1972-01-01
An attempt was made to obtain information relevant to assessing the need to sleep and make up for lost sleep. Physiological and behavioral parameters were used as measuring parameters. Sleep deprivation in a restricted environment, derivation of data relevant to determining sleepiness from EEG, and the development of the Sanford Sleepiness Scale were discussed.
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Managing fatigue in operational settings. 1: Physiological considerations and countermeasures
NASA Technical Reports Server (NTRS)
Rosekind, M. R.; Gander, P. H.; Gregory, K. B.; Smith, R. M.; Miller, D. L.; Oyung, R.; Webbon, L. L.; Johnson, J. M.
1996-01-01
The authors consider three aspects of managing fatigue in the workplace. They provide a brief overview of important scientific findings related to sleep and circadian physiology that establish the psychobiological foundation of fatigue. Their major focus is on the relevance of these findings to operational settings. In addition, they provide examples to describe practical fatigue countermeasures that can be used in operational settings.
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Modeling road-cycling performance.
Olds, T S; Norton, K I; Lowe, E L; Olive, S; Reay, F; Ly, S
1995-04-01
This paper presents a complete set of equations for a "first principles" mathematical model of road-cycling performance, including corrections for the effect of winds, tire pressure and wheel radius, altitude, relative humidity, rotational kinetic energy, drafting, and changed drag. The relevant physiological, biophysical, and environmental variables were measured in 41 experienced cyclists completing a 26-km road time trial. The correlation between actual and predicted times was 0.89 (P < or = 0.0001), with a mean difference of 0.74 min (1.73% of mean performance time) and a mean absolute difference of 1.65 min (3.87%). Multiple simulations were performed where model inputs were randomly varied using a normal distribution about the measured values with a SD equivalent to the estimated day-to-day variability or technical error of measurement in each of the inputs. This analysis yielded 95% confidence limits for the predicted times. The model suggests that the main physiological factors contributing to road-cycling performance are maximal O2 consumption, fractional utilization of maximal O2 consumption, mechanical efficiency, and projected frontal area. The model is then applied to some practical problems in road cycling: the effect of drafting, the advantage of using smaller front wheels, the effects of added mass, the importance of rotational kinetic energy, the effect of changes in drag due to changes in bicycle configuration, the normalization of performances under different conditions, and the limits of human performance.
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Shiue, Ivy; Matzarakis, Andreas
2011-07-01
Existing tourism-related climate information and evaluation are typically based on mean monthly conditions of air temperature and precipitation and do not include thermal perception and other climate parameters relevant for tourists. Here, we quantify climate based on the climate facets relevant to tourism (thermal, physical, aesthetical), and apply the results to the Climate-Tourism-Information-Scheme (CTIS). This paper presents bioclimatic and tourism climatological conditions in the Hunter Region-one of Australia's most popular tourist destinations. In the Hunter Region, generally, temperatures below 15°C occur from April through October, temperatures less than 25°C are expected throughout the whole year, while humidity sits around 50%. As expected, large differences between air temperature and physiologically equivalent temperature (PET) were clearly identified. The widest differences were seen in summer time rather than in the winter period. In addition, cold stress was observed less than 10% of the time in winter while around 40-60% of heat stress was observed in summer time. This correlates with the highest numbers of international visitors, who usually seek a warmer weather, at the beginning of summer time (November and December) and also to the number of domestic visitors, who tend to seek cooler places for recreation and leisure, in late summer (January-March). It was concluded that thermal bioclimate assessment such as PET and CTIS can be applied in the Hunter region, and that local governments and the tourism industry should take an integrated approach to providing more relevant weather and climate information for both domestic and international tourists in the near future.
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Estimation of the tourism climate in the Hunter Region, Australia, in the early twenty-first century
NASA Astrophysics Data System (ADS)
Shiue, Ivy; Matzarakis, Andreas
2011-07-01
Existing tourism-related climate information and evaluation are typically based on mean monthly conditions of air temperature and precipitation and do not include thermal perception and other climate parameters relevant for tourists. Here, we quantify climate based on the climate facets relevant to tourism (thermal, physical, aesthetical), and apply the results to the Climate-Tourism-Information-Scheme (CTIS). This paper presents bioclimatic and tourism climatological conditions in the Hunter Region—one of Australia's most popular tourist destinations. In the Hunter Region, generally, temperatures below 15°C occur from April through October, temperatures less than 25°C are expected throughout the whole year, while humidity sits around 50%. As expected, large differences between air temperature and physiologically equivalent temperature (PET) were clearly identified. The widest differences were seen in summer time rather than in the winter period. In addition, cold stress was observed less than 10% of the time in winter while around 40-60% of heat stress was observed in summer time. This correlates with the highest numbers of international visitors, who usually seek a warmer weather, at the beginning of summer time (November and December) and also to the number of domestic visitors, who tend to seek cooler places for recreation and leisure, in late summer (January-March). It was concluded that thermal bioclimate assessment such as PET and CTIS can be applied in the Hunter region, and that local governments and the tourism industry should take an integrated approach to providing more relevant weather and climate information for both domestic and international tourists in the near future.
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Higgins-Opitz, Susan B; Tufts, Mark
2014-06-01
Health Science students at the University of KwaZulu-Natal perform better in their professional modules compared with their physiology modules. The pass rates of physiology service modules have steadily declined over the years. While a system is in place to identify "at-risk" students, it is only activated after the first semester. As a result, it is only from the second semester of their first year studies onward that at-risk students can be formally assisted. The challenge is thus to devise an appropriate strategy to identify struggling students earlier in the semester. Using questionnaires, students were asked about attendance, financing of their studies, and relevance of physiology. After the first class test, failing students were invited to complete a second questionnaire. In addition, demographic data were also collected and analyzed. Correlation analyses were undertaken of performance indicators based on the demographical data collected. The 2011 class comprised mainly sport science students (57%). The pass rate of sport science students was lower than the pass rates of other students (42% vs. 70%, P < 0.001). Most students were positive about physiology and recognized its relevance. Key issues identified were problems understanding concepts and terminology, poor study environment and skills, and lack of matriculation biology. The results of the first class test and final module marks correlated well. It is clear from this study that student performance in the first class test is a valuable tool to identify struggling students and that appropriate testing should be held as early as possible. Copyright © 2014 The American Physiological Society.
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Rubel, Carrie E.; Schisler, Jonathan C.; Hamlett, Eric D.; DeKroon, Robert M.; Gautel, Mathias; Alzate, Oscar; Patterson, Cam
2013-01-01
The ubiquitin-proteasome system (UPS) plays a central role in maintaining protein homeostasis, emphasized by a myriad of diseases that are associated with altered UPS function such as cancer, muscle-wasting, and neurodegeneration. Protein ubiquitination plays a central role in both the promotion of proteasomal degradation as well as cellular signaling through regulation of the stability of transcription factors and other signaling molecules. Substrate specificity is a critical regulatory step of ubiquitination and is mediated by ubiquitin ligases. Recent studies implicate ubiquitin ligases in multiple models of cardiac diseases such as cardiac hypertrophy, atrophy, and ischemia/reperfusion injury, both in a cardioprotective and maladaptive role. Therefore, identifying physiological substrates of cardiac ubiquitin ligases provides both mechanistic insights into heart disease as well as possible therapeutic targets. Current methods identifying substrates for ubiquitin ligases rely heavily upon non-physiologic in vitro methods, impeding the unbiased discovery of physiological substrates in relevant model systems. Here we describe a novel method for identifying ubiquitin ligase substrates utilizing Tandem Ubiquitin Binding Entities (TUBE) technology, two-dimensional differential in gel electrophoresis (2-D DIGE), and mass spectrometry, validated by the identification of both known and novel physiological substrates of the ubiquitin ligase MuRF1 in primary cardiomyocytes. This method can be applied to any ubiquitin ligase, both in normal and disease model systems, in order to identify relevant physiological substrates under various biological conditions, opening the door to a clearer mechanistic understanding of ubiquitin ligase function and broadening their potential as therapeutic targets. PMID:23695782
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Invited review article: Advanced light microscopy for biological space research.
De Vos, Winnok H; Beghuin, Didier; Schwarz, Christian J; Jones, David B; van Loon, Jack J W A; Bereiter-Hahn, Juergen; Stelzer, Ernst H K
2014-10-01
As commercial space flights have become feasible and long-term extraterrestrial missions are planned, it is imperative that the impact of space travel and the space environment on human physiology be thoroughly characterized. Scrutinizing the effects of potentially detrimental factors such as ionizing radiation and microgravity at the cellular and tissue level demands adequate visualization technology. Advanced light microscopy (ALM) is the leading tool for non-destructive structural and functional investigation of static as well as dynamic biological systems. In recent years, technological developments and advances in photochemistry and genetic engineering have boosted all aspects of resolution, readout and throughput, rendering ALM ideally suited for biological space research. While various microscopy-based studies have addressed cellular response to space-related environmental stressors, biological endpoints have typically been determined only after the mission, leaving an experimental gap that is prone to bias results. An on-board, real-time microscopical monitoring device can bridge this gap. Breadboards and even fully operational microscope setups have been conceived, but they need to be rendered more compact and versatile. Most importantly, they must allow addressing the impact of gravity, or the lack thereof, on physiologically relevant biological systems in space and in ground-based simulations. In order to delineate the essential functionalities for such a system, we have reviewed the pending questions in space science, the relevant biological model systems, and the state-of-the art in ALM. Based on a rigorous trade-off, in which we recognize the relevance of multi-cellular systems and the cellular microenvironment, we propose a compact, but flexible concept for space-related cell biological research that is based on light sheet microscopy.
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Invited Review Article: Advanced light microscopy for biological space research
NASA Astrophysics Data System (ADS)
De Vos, Winnok H.; Beghuin, Didier; Schwarz, Christian J.; Jones, David B.; van Loon, Jack J. W. A.; Bereiter-Hahn, Juergen; Stelzer, Ernst H. K.
2014-10-01
As commercial space flights have become feasible and long-term extraterrestrial missions are planned, it is imperative that the impact of space travel and the space environment on human physiology be thoroughly characterized. Scrutinizing the effects of potentially detrimental factors such as ionizing radiation and microgravity at the cellular and tissue level demands adequate visualization technology. Advanced light microscopy (ALM) is the leading tool for non-destructive structural and functional investigation of static as well as dynamic biological systems. In recent years, technological developments and advances in photochemistry and genetic engineering have boosted all aspects of resolution, readout and throughput, rendering ALM ideally suited for biological space research. While various microscopy-based studies have addressed cellular response to space-related environmental stressors, biological endpoints have typically been determined only after the mission, leaving an experimental gap that is prone to bias results. An on-board, real-time microscopical monitoring device can bridge this gap. Breadboards and even fully operational microscope setups have been conceived, but they need to be rendered more compact and versatile. Most importantly, they must allow addressing the impact of gravity, or the lack thereof, on physiologically relevant biological systems in space and in ground-based simulations. In order to delineate the essential functionalities for such a system, we have reviewed the pending questions in space science, the relevant biological model systems, and the state-of-the art in ALM. Based on a rigorous trade-off, in which we recognize the relevance of multi-cellular systems and the cellular microenvironment, we propose a compact, but flexible concept for space-related cell biological research that is based on light sheet microscopy.
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Soto-Padilla, Andrea; Ruijsink, Rick; Sibon, Ody C M; van Rijn, Hedderik; Billeter, Jean-Christophe
2018-04-12
Temperature influences physiology and behavior of all organisms. For ectotherms, which lack central temperature regulation, temperature adaptation requires sheltering from or moving to a heat source. As temperature constrains the rate of metabolic reactions, it can directly affect ectotherm physiology and thus behavioral performance. This direct effect is particularly relevant for insects whose small body readily equilibrates with ambient temperature. In fact, models of enzyme kinetics applied to insect behavior predict performance at different temperatures, suggesting that thermal physiology governs behavior. However, insects also possess thermosensory neurons critical for locating preferred temperatures, showing cognitive control. This suggests that temperature-related behavior can emerge directly from a physiological effect, indirectly as consequence of thermosensory processing, or through both. To separate the roles of thermal physiology and cognitive control, we developed an arena that allows fast temperature changes in time and space, and in which animals' movements are automatically quantified. We exposed wild-type and thermosensory receptor mutants Drosophila melanogaster to a dynamic temperature environment and tracked their movements. The locomotor speed of wild-type flies closely matched models of enzyme kinetics, but the behavior of thermosensory mutants did not. Mutations in thermosensory receptor dTrpA1 ( Transient receptor potential ) expressed in the brain resulted in a complete lack of response to temperature changes, while mutation in peripheral thermosensory receptor Gr28b(D) resulted in diminished response. We conclude that flies react to temperature through cognitive control, informed by interactions between various thermosensory neurons, whose behavioral output resembles that of enzyme kinetics. © 2018. Published by The Company of Biologists Ltd.
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Ecosystems Biology Approaches To Determine Key Fitness Traits of Soil Microorganisms
NASA Astrophysics Data System (ADS)
Brodie, E.; Zhalnina, K.; Karaoz, U.; Cho, H.; Nuccio, E. E.; Shi, S.; Lipton, M. S.; Zhou, J.; Pett-Ridge, J.; Northen, T.; Firestone, M.
2014-12-01
The application of theoretical approaches such as trait-based modeling represent powerful tools to explain and perhaps predict complex patterns in microbial distribution and function across environmental gradients in space and time. These models are mostly deterministic and where available are built upon a detailed understanding of microbial physiology and response to environmental factors. However as most soil microorganisms have not been cultivated, for the majority our understanding is limited to insights from environmental 'omic information. Information gleaned from 'omic studies of complex systems should be regarded as providing hypotheses, and these hypotheses should be tested under controlled laboratory conditions if they are to be propagated into deterministic models. In a semi-arid Mediterranean grassland system we are attempting to dissect microbial communities into functional guilds with defined physiological traits and are using a range of 'omics approaches to characterize their metabolic potential and niche preference. Initially, two physiologically relevant time points (peak plant activity and prior to wet-up) were sampled and metagenomes sequenced deeply (600-900 Gbp). Following assembly, differential coverage and nucleotide frequency binning were carried out to yield draft genomes. In addition, using a range of cultivation media we have isolated a broad range of bacteria representing abundant bacterial genotypes and with genome sequences of almost 40 isolates are testing genomic predictions regarding growth rate, temperature and substrate utilization in vitro. This presentation will discuss the opportunities and challenges in parameterizing microbial functional guilds from environmental 'omic information for use in trait-based models.
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Cue-reactivity in behavioral addictions: A meta-analysis and methodological considerations.
Starcke, Katrin; Antons, Stephanie; Trotzke, Patrick; Brand, Matthias
2018-05-23
Background and aims Recent research has applied cue-reactivity paradigms to behavioral addictions. The aim of the current meta-analysis is to systematically analyze the effects of learning-based cue-reactivity in behavioral addictions. Methods The current meta-analysis includes 18 studies (29 data sets, 510 participants) that have used a cue-reactivity paradigm in persons with gambling (eight studies), gaming (nine studies), or buying (one study) disorders. We compared subjective, peripheral physiological, electroencephal, and neural responses toward addiction-relevant cues in patients versus control participants and toward addiction-relevant cues versus control cues in patients. Results Persons with behavioral addictions showed higher cue-reactivity toward addiction-relevant cues compared with control participants: subjective cue-reactivity (d = 0.84, p = .01) and peripheral physiological and electroencephal measures of cue-reactivity (d = 0.61, p < .01). Increased neural activation was found in the caudate nucleus, inferior frontal gyrus, median cingulate cortex, subgenual cingulate, and precentral gyrus. Persons with gambling, gaming, or buying disorders also showed higher cue-reactivity toward addiction-relevant cues compared with control cues: subjective cue-reactivity (d = 0.39, p = .11) and peripheral physiological and electroencephal measures of cue-reactivity (d = 0.47, p = .05). Increased neural activation was found in the caudate nucleus, inferior frontal gyrus, angular gyrus, inferior network, and precuneus. Discussion and conclusions Cue-reactivity not only exists in substance-use disorders but also in gambling, gaming, and buying disorders. Future research should differentiate between cue-reactivity in addictive behaviors and cue-reactivity in functional excessive behaviors such as passions, hobbies, or professions.
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Peterson, Zoë D.; Janssen, Erick; Goodrich, David; Heiman, Julia R.
2015-01-01
Men’s sexually aggressive behavior potentially could relate to either physiological hyporeactivity or hyperreactivity, and these two different physiological profiles could be associated with different underlying causes of sexual aggression. Thus, measurement of physiological reactivity could provide insight into mechanisms relevant to the etiology of sexual aggression. The relationship between sexual aggression and physiological reactivity was investigated in 78 community men (38 sexually aggressive and 40 non-aggressive men). In a laboratory protocol, the men were exposed to neutral, negative-affect-inducing, and positive-affect-inducing stimuli. Men’s salivary cortisol concentrations and electrodermal activity (EDA) were measured throughout the laboratory procedure. Sexually aggressive men demonstrated (1) lower overall cortisol levels and (2) lower EDA reactivity in some conditions as compared to non-aggressive men. Results of this study were consistent with the idea that men’s sexual aggression is associated with physiological hyporeactivity, a physiological profile that has been found to be associated with externalizing behaviors and psychopathic traits. PMID:24310818
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Peterson, Zoë D; Janssen, Erick; Goodrich, David; Heiman, Julia R
2014-01-01
Men's sexually aggressive behavior potentially could relate to either physiological hyporeactivity or hyperreactivity, and these two different physiological profiles could be associated with different underlying causes of sexual aggression. Thus, measurement of physiological reactivity could provide insight into mechanisms relevant to the etiology of sexual aggression. The relationship between sexual aggression and physiological reactivity was investigated in 78 community men (38 sexually aggressive and 40 non-aggressive men). In a laboratory protocol, the men were exposed to neutral, negative-affect-inducing, and positive-affect-inducing stimuli. Men's salivary cortisol concentrations and electrodermal activity (EDA) were measured throughout the laboratory procedure. Sexually aggressive men demonstrated (1) lower overall cortisol levels and (2) lower EDA reactivity in some conditions as compared to non-aggressive men. Results of this study were consistent with the idea that men's sexual aggression is associated with physiological hyporeactivity, a physiological profile that has been found to be associated with externalizing behaviors and psychopathic traits. © 2013 Wiley Periodicals, Inc.
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Cappellin, Luca; Loreto, Francesco; Aprea, Eugenio; Romano, Andrea; del Pulgar, José Sánchez; Gasperi, Flavia; Biasioli, Franco
2013-01-01
Proton Transfer Reaction Mass Spectrometry (PTR-MS) has evolved in the last decade as a fast and high sensitivity sensor for the real-time monitoring of volatile compounds. Its applications range from environmental sciences to medical sciences, from food technology to bioprocess monitoring. Italian scientists and institutions participated from the very beginning in fundamental and applied research aiming at exploiting the potentialities of this technique and providing relevant methodological advances and new fundamental indications. In this review we describe this activity on the basis of the available literature. The Italian scientific community has been active mostly in food science and technology, plant physiology and environmental studies and also pioneered the applications of the recently released PTR-ToF-MS (Proton Transfer Reaction-Time of Flight-Mass Spectrometry) in food science and in plant physiology. In the very last years new results related to bioprocess monitoring and health science have been published as well. PTR-MS data analysis, particularly in the case of the ToF based version, and the application of advanced chemometrics and data mining are also aspects characterising the activity of the Italian community. PMID:24021966
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Real-time high dynamic range laser scanning microscopy
Vinegoni, C.; Leon Swisher, C.; Fumene Feruglio, P.; Giedt, R. J.; Rousso, D. L.; Stapleton, S.; Weissleder, R.
2016-01-01
In conventional confocal/multiphoton fluorescence microscopy, images are typically acquired under ideal settings and after extensive optimization of parameters for a given structure or feature, often resulting in information loss from other image attributes. To overcome the problem of selective data display, we developed a new method that extends the imaging dynamic range in optical microscopy and improves the signal-to-noise ratio. Here we demonstrate how real-time and sequential high dynamic range microscopy facilitates automated three-dimensional neural segmentation. We address reconstruction and segmentation performance on samples with different size, anatomy and complexity. Finally, in vivo real-time high dynamic range imaging is also demonstrated, making the technique particularly relevant for longitudinal imaging in the presence of physiological motion and/or for quantification of in vivo fast tracer kinetics during functional imaging. PMID:27032979
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Treadmill Exercise Within LBNP as an Integrated Coutermeasure to Microgravity
NASA Technical Reports Server (NTRS)
Lee, Stuart; Hargens, A. R.; Schneider, S. M.; Watenpaugh, D. E.
2010-01-01
An integrated exercise countermeasure for microgravity is needed to protect multiple physiologic systems and save crew time. Such a countermeasure should protect orthostatic tolerance, upright ambulatory capability (including sprinting), aerobic capacity, muscle strength/endurance, and other physiologic parameters relevant to human performance. We developed a novel physiologic countermeasure, treadmill exercise within LBNP, for preventing cardiovascular and musculoskeletal deconditioning associated with prolonged bed rest and spaceflight. We evaluated 40 min of daily LBNP treadmill exercise by a battery of physiologic parameters relevant to maintaining exercise performance and health of both women and men during bed-rest (simulated microgravity) studies lasting from 5 to 60 days. For 30 day studies, we employed identical twins with one twin as the control and the other twin as the exerciser to improve comparative power. During the WISE 60-day HDT study, the treadmill exercise within LBNP was performed 3-4 days each week and resistive exercise was performed 2-3 days each week. Our treadmill within LBNP protocol maintained plasma volume and sprint speed (30 day HDT bed-rest studies of identical twins), orthostatic tolerance to a degree, upright exercise capacity, muscle strength and endurance, and some bone parameters during 30 day (twin studies) and 60 day (WISE-2005) bed-rest simulations of microgravity. When combining treadmill exercise within LBNP and resistive exercise (WISE), cardiac mass increased significantly in the exercise (EX) group during bed rest relative to controls (CON). Upright peak VO2, and knee extensor strength and endurance decreased significantly in CON subjects; but these parameters were preserved in the EX group. In the 60 day WISE study, each LBNP exercise session was followed immediately by 10 minutes of static LBNP, and the last such session occurred three days before the end of bed rest. Still, orthostatic tolerance was better maintained in the EX group than in the CON group. Therefore, these collective peer-reviewed results document that our treadmill exercise within LBNP countermeasure safely and efficiently protects multiple physiologic systems in women and men during bed-rest studies of up to 60 days. Supported by NASA grants NNJ04HF71G and NAG 9-1425, NIH grant GCRC M01 RR00827 and by WISE support from ESA, NASA, CSA, and CNES.
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Olowo-Ofayoku, Anthony; Moxham, Bernard John
2014-10-01
Marked changes are occurring within both the medical and dental curricula and new ways of teaching the basic sciences have been devised and traditional methods (e.g., dissection for gross anatomy and of bench-based animal preparations for physiology) are increasingly no longer the norm. Although there is much anecdotal evidence that students are not in favor of such changes, there is little evidence for this based on quantitative analyses of students' attitudes. Using Thurstone and Chave attitude analyses, we assessed the attitudes of first year medical and dental students at Cardiff University toward gross anatomy and physiology in terms of their perceived clinical importance. In addition, we investigated the appropriateness ("fitness for purpose") of teaching methodologies used for anatomy and physiology. The hypotheses tested recognized the possibility that medical and dental students differed in their opinions, but that they had a preference to being taught gross anatomy through the use of dissection and had no preference for physiology teaching. It was found that both medical and dental students displayed positive attitudes toward the clinical relevance of gross anatomy and that they preferred to be taught by means of dissection. Although both medical and dental students displayed positives attitudes toward the clinical relevance of physiology, this was greater for the medical students. Both medical and dental students showed a preference for being taught physiology through didactic teaching in small groups but the medical students also appreciated being taught by means of practicals. Overall, this study highlights the expectations that students have for the basic science foundation teaching within their professional training and signals a preference for being taught experientially/practically. Differences were discerned between medical and dental students that might reflect the direct association between systems physiology and pathophysiology and the application of this knowledge within the medical field in comparison to the dental field, which is heavily skill-based. © 2014 Wiley Periodicals, Inc.
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Video games and rehabilitation: using design principles to enhance engagement in physical therapy.
Lohse, Keith; Shirzad, Navid; Verster, Alida; Hodges, Nicola; Van der Loos, H F Machiel
2013-12-01
Patient nonadherence with therapy is a major barrier to rehabilitation. Recovery is often limited and requires prolonged, intensive rehabilitation that is time-consuming, expensive, and difficult. We review evidence for the potential use of video games in rehabilitation with respect to the behavioral, physiological, and motivational effects of gameplay. In this Special Interest article, we offer a method to evaluate effects of video game play on motor learning and their potential to increase patient engagement with therapy, particularly commercial games that can be interfaced with adapted control systems. We take the novel approach of integrating research across game design, motor learning, neurophysiology changes, and rehabilitation science to provide criteria by which therapists can assist patients in choosing games appropriate for rehabilitation. Research suggests that video games are beneficial for cognitive and motor skill learning in both rehabilitation science and experimental studies with healthy subjects. Physiological data suggest that gameplay can induce neuroplastic reorganization that leads to long-term retention and transfer of skill; however, more clinical research in this area is needed. There is interdisciplinary evidence suggesting that key factors in game design, including choice, reward, and goals, lead to increased motivation and engagement. We maintain that video game play could be an effective supplement to traditional therapy. Motion controllers can be used to practice rehabilitation-relevant movements, and well-designed game mechanics can augment patient engagement and motivation in rehabilitation. We recommend future research and development exploring rehabilitation-relevant motions to control games and increase time in therapy through gameplay.Video Abstract available (see Video, Supplemental Digital Content 1, http://links.lww.com/JNPT/A61) for more insights from the authors.
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Lab-on-a-brane: nanofibrous polymer membranes to recreate organ-capillary interfaces
NASA Astrophysics Data System (ADS)
Budhwani, Karim I.; Thomas, Vinoy; Sethu, Palaniappan
2016-03-01
Drug discovery is a complex and time consuming process involving significant basic research and preclinical evaluation prior to testing in patients. Preclinical studies rely extensively on animal models which often fail in human trials. Biomimetic microphysiological systems (MPS) using human cells can be a promising alternative to animal models; where critical interactions between different organ systems are recreated to provide physiologically relevant in vitro human models. Central here are blood-vessel networks, the interface controlling transport of cellular and biomolecular components between the circulating fluid and underlying tissue. Here we present a novel lab-on-a-brane (or lab-on-a-membrane) nanofluidics MPS that combines the elegance of lab-on-a-chip with the more realistic morphology of 3D fibrous tissue-engineering constructs. Our blood-vessel lab-on-a-brane effectively simulates in vivo vessel-tissue interface for evaluating transendothelial transport in various pharmacokinetic and nanomedicine applications. Attributes of our platform include (a) nanoporous barrier interface enabling transmembrane molecular transport, (b) transformation of substrate into nanofibrous 3D tissue matrix, (c) invertible-sandwich architecture, and (d) simple co-culture mechanism for endothelial and smooth muscle layers to accurately mimic arterial anatomy. Structural, mechanical, and transport characterization using scanning electron microscopy, stress/strain analysis, infrared spectroscopy, immunofluorescence, and FITC-Dextran hydraulic permeability confirm viability of this in vitro system. Thus, our lab-on-a-brane provides an effective and efficient, yet considerably inexpensive, physiologically relevant alternative for pharmacokinetic evaluation; possibly reducing animals used in preclinical testing, costs from false starts, and time-to-market. Furthermore, it can be configured in multiple simultaneous arrays for personalized and precision medicine applications and for evaluating localized and targeted therapeutic delivery.
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Schoenknecht, Carola; Andersen, Gaby; Schieberle, Peter
2016-11-15
The bio-active compounds of ginger (Zingiber officinale Roscoe), the gingerols, are gaining considerable attention due to their numerous beneficial health effects. In order to elucidate the physiological relevance of the ascribed effects their bioavailability has to be determined taking their metabolization into account. To quantitate in vivo generated [6]-, [8]- and [10]-gingerol glucuronides in human plasma and urine after ginger tea consumption, a simultaneous and direct liquid chromatography-tandem mass spectrometry method based on stable isotope dilution assays was established and validated. The respective references as well as the isotopically labeled substances were synthesized and characterized by mass spectrometry and NMR. Selective isolation of gingerol glucuronides from human plasma and urine by a mixed-phase anion-exchange SPE method led to recovery rates between 80.8 and 98.2%. LC-MS/MS analyses in selected reaction monitoring modus enabled a highly sensitive quantitation of gingerol glucuronides with LoQs between 3.9-9.8nmol/L in plasma and 39.3-161.1nmol/L in urine. The method precision in plasma and urine varied in the range±15%, whereas the intra-day accuracy in plasma and urine showed values between 78 and 122%. The developed method was then applied to a pilot study in which two volunteers consumed one liter ginger tea. Pharmacokinetic parameters like the maximum concentration (c max ), the time to reach c max (t max ), area under the curve (AUC), elimination rate constant (k el ) and elimination half-life (t 1/2 ) were calculated from the concentration-time curve of each gingerol glucuronide. The obtained results will enable more detailed investigation of gingerol glucuronides as bioactives in their physiologically relevant concentrations. Copyright © 2016 Elsevier B.V. All rights reserved.
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The role of heart rate variability in sports physiology
DONG, JIN-GUO
2016-01-01
Heart rate variability (HRV) is a relevant marker reflecting cardiac modulation by sympathetic and vagal components of the autonomic nervous system (ANS). Although the clinical application of HRV is mainly associated with the prediction of sudden cardiac death and assessing cardiovascular and metabolic illness progression, recent observations have suggested its applicability to physical exercise training. HRV is becoming one of the most useful tools for tracking the time course of training adaptation/maladaptation of athletes and in setting the optimal training loads leading to improved performances. However, little is known regarding the role of HRV and the internal effects of physical exercise on an athlete, which may be useful in designing fitness programs ensuring sufficient training load that may correspond with the specific ability of the athlete. In this review, we offer a comprehensive assessment of investigations concerning the interrelation between HRV and ANS, and examine how the application of HRV to physical exercise may play a role in sports physiology. PMID:27168768
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The role of heart rate variability in sports physiology.
Dong, Jin-Guo
2016-05-01
Heart rate variability (HRV) is a relevant marker reflecting cardiac modulation by sympathetic and vagal components of the autonomic nervous system (ANS). Although the clinical application of HRV is mainly associated with the prediction of sudden cardiac death and assessing cardiovascular and metabolic illness progression, recent observations have suggested its applicability to physical exercise training. HRV is becoming one of the most useful tools for tracking the time course of training adaptation/maladaptation of athletes and in setting the optimal training loads leading to improved performances. However, little is known regarding the role of HRV and the internal effects of physical exercise on an athlete, which may be useful in designing fitness programs ensuring sufficient training load that may correspond with the specific ability of the athlete. In this review, we offer a comprehensive assessment of investigations concerning the interrelation between HRV and ANS, and examine how the application of HRV to physical exercise may play a role in sports physiology.
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Does selection for short sleep duration explain human vulnerability to Alzheimer’s disease?
Nesse, Randolph M; Finch, Caleb E; Nunn, Charles L
2017-01-01
Abstract Compared with other primates, humans sleep less and have a much higher prevalence of Alzheimer ’s disease (AD) pathology. This article reviews evidence relevant to the hypothesis that natural selection for shorter sleep time in humans has compromised the efficacy of physiological mechanisms that protect against AD during sleep. In particular, the glymphatic system drains interstitial fluid from the brain, removing extra-cellular amyloid beta (eAβ) twice as fast during sleep. In addition, melatonin—a peptide hormone that increases markedly during sleep—is an effective antioxidant that inhibits the polymerization of soluble eAβ into insoluble amyloid fibrils that are associated with AD. Sleep deprivation increases plaque formation and AD, which itself disrupts sleep, potentially creating a positive feedback cycle. These and other physiological benefits of sleep may be compromised by short sleep durations. Our hypothesis highlights possible long-term side effects of medications that reduce sleep, and may lead to potential new strategies for preventing and treating AD. PMID:28096295
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Molecular imaging of photodynamic therapy
NASA Astrophysics Data System (ADS)
Chang, Sung K.; Errabelli, Divya; Rizvi, Imran; Solban, Nicolas; O'Riordan, Katherine; Hasan, Tayyaba
2006-02-01
Recent advances in light sources, detectors and other optical imaging technologies coupled with the development of novel optical contrast agents have enabled real-time, high resolution, in vivo monitoring of molecular targets. Noninvasive monitoring of molecular targets is particularly relevant to photodynamic therapy (PDT), including the delivery of photosensitizer in the treatment site and monitoring of molecular and physiological changes following treatment. Our lab has developed optical imaging technologies to investigate these various aspects of photodynamic therapy (PDT). We used a laser scanning confocal microscope to monitor the pharmacokinetics of various photosensitizers in in vitro as well as ex vivo samples, and developed an intravital fluorescence microscope to monitor photosensitizer delivery in vivo in small animals. A molecular specific contrast agent that targets the vascular endothelial growth factor (VEGF) was developed to monitor the changes in the protein expression following PDT. We were then able to study the physiological changes due to post-treatment VEGF upregulation by quantifying vascular permeability with in vivo imaging.
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Memory-updating abrogates extinction of learned immunosuppression.
Hadamitzky, Martin; Bösche, Katharina; Wirth, Timo; Buck, Benjamin; Beetz, Oliver; Christians, Uwe; Schniedewind, Björn; Lückemann, Laura; Güntürkün, Onur; Engler, Harald; Schedlowski, Manfred
2016-02-01
When memories are recalled, they enter a transient labile phase in which they can be impaired or enhanced followed by a new stabilization process termed reconsolidation. It is unknown, however, whether reconsolidation is restricted to neurocognitive processes such as fear memories or can be extended to peripheral physiological functions as well. Here, we show in a paradigm of behaviorally conditioned taste aversion in rats memory-updating in learned immunosuppression. The administration of sub-therapeutic doses of the immunosuppressant cyclosporin A together with the conditioned stimulus (CS/saccharin) during retrieval blocked extinction of conditioned taste aversion and learned suppression of T cell cytokine (interleukin-2; interferon-γ) production. This conditioned immunosuppression is of clinical relevance since it significantly prolonged the survival time of heterotopically transplanted heart allografts in rats. Collectively, these findings demonstrate that memories can be updated on both neural and behavioral levels as well as on the level of peripheral physiological systems such as immune functioning. Copyright © 2015 Elsevier Inc. All rights reserved.
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Don't Worry, Be Happy: Endocannabinoids and Cannabis at the Intersection of Stress and Reward.
Volkow, Nora D; Hampson, Aidan J; Baler, Ruben D
2017-01-06
Cannabis enables and enhances the subjective sense of well-being by stimulating the endocannabinoid system (ECS), which plays a key role in modulating the response to stress, reward, and their interactions. However, over time, repeated activation of the ECS by cannabis can trigger neuroadaptations that may impair the sensitivity to stress and reward. This effect, in vulnerable individuals, can lead to addiction and other adverse consequences. The recent shift toward legalization of medical or recreational cannabis has renewed interest in investigating the physiological role of the ECS as well as the potential health effects, both adverse and beneficial, of cannabis. Here we review our current understanding of the ECS and its complex physiological roles. We discuss the implications of this understanding vis-á-vis the ECS's modulation of stress and reward and its relevance to mental disorders in which these processes are disrupted (i.e., addiction, depression, posttraumatic stress disorder, schizophrenia), along with the therapeutic potential of strategies to manipulate the ECS for these conditions.
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Evolution of time-keeping mechanisms: early emergence and adaptation to photoperiod
Hut, R. A.; Beersma, D. G. M.
2011-01-01
Virtually all species have developed cellular oscillations and mechanisms that synchronize these cellular oscillations to environmental cycles. Such environmental cycles in biotic (e.g. food availability and predation risk) or abiotic (e.g. temperature and light) factors may occur on a daily, annual or tidal time scale. Internal timing mechanisms may facilitate behavioural or physiological adaptation to such changes in environmental conditions. These timing mechanisms commonly involve an internal molecular oscillator (a ‘clock’) that is synchronized (‘entrained’) to the environmental cycle by receptor mechanisms responding to relevant environmental signals (‘Zeitgeber’, i.e. German for time-giver). To understand the evolution of such timing mechanisms, we have to understand the mechanisms leading to selective advantage. Although major advances have been made in our understanding of the physiological and molecular mechanisms driving internal cycles (proximate questions), studies identifying mechanisms of natural selection on clock systems (ultimate questions) are rather limited. Here, we discuss the selective advantage of a circadian system and how its adaptation to day length variation may have a functional role in optimizing seasonal timing. We discuss various cases where selective advantages of circadian timing mechanisms have been shown and cases where temporarily loss of circadian timing may cause selective advantage. We suggest an explanation for why a circadian timing system has emerged in primitive life forms like cyanobacteria and we evaluate a possible molecular mechanism that enabled these bacteria to adapt to seasonal variation in day length. We further discuss how the role of the circadian system in photoperiodic time measurement may explain differential selection pressures on circadian period when species are exposed to changing climatic conditions (e.g. global warming) or when they expand their geographical range to different latitudes or altitudes. PMID:21690131
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Peptidase inhibitors in tick physiology.
Parizi, L F; Ali, A; Tirloni, L; Oldiges, D P; Sabadin, G A; Coutinho, M L; Seixas, A; Logullo, C; Termignoni, C; DA Silva Vaz, I
2018-06-01
Peptidase inhibitors regulate a wide range of physiological processes involved in the interaction between hematophagous parasites and their hosts, including tissue remodeling, the immune response and blood coagulation. In tick physiology, peptidase inhibitors have a crucial role in adaptation to improve parasitism mechanisms, facilitating blood feeding by interfering with defense-related host peptidases. Recently, a larger number of studies on this topic led to the description of several new tick inhibitors displaying interesting novel features, for example a role in pathogen transmission to the host. A comprehensive review discussing these emerging concepts can therefore shed light on peptidase inhibitor functions, their relevance to tick physiology and their potential applications. Here, we summarize and examine the general characteristics, functional diversity and action of tick peptidase inhibitors with known physiological roles in the tick-host-pathogen interaction. © 2017 The Royal Entomological Society.
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NASA Astrophysics Data System (ADS)
Cox, Christopher
Low-order numerical methods are widespread in academic solvers and ubiquitous in industrial solvers due to their robustness and usability. High-order methods are less robust and more complicated to implement; however, they exhibit low numerical dissipation and have the potential to improve the accuracy of flow simulations at a lower computational cost when compared to low-order methods. This motivates our development of a high-order compact method using Huynh's flux reconstruction scheme for solving unsteady incompressible flow on unstructured grids. We use Chorin's classic artificial compressibility formulation with dual time stepping to solve unsteady flow problems. In 2D, an implicit non-linear lower-upper symmetric Gauss-Seidel scheme with backward Euler discretization is used to efficiently march the solution in pseudo time, while a second-order backward Euler discretization is used to march in physical time. We verify and validate implementation of the high-order method coupled with our implicit time stepping scheme using both steady and unsteady incompressible flow problems. The current implicit time stepping scheme is proven effective in satisfying the divergence-free constraint on the velocity field in the artificial compressibility formulation. The high-order solver is extended to 3D and parallelized using MPI. Due to its simplicity, time marching for 3D problems is done explicitly. The feasibility of using the current implicit time stepping scheme for large scale three-dimensional problems with high-order polynomial basis still remains to be seen. We directly use the aforementioned numerical solver to simulate pulsatile flow of a Newtonian blood-analog fluid through a rigid 180-degree curved artery model. One of the most physiologically relevant forces within the cardiovascular system is the wall shear stress. This force is important because atherosclerotic regions are strongly correlated with curvature and branching in the human vasculature, where the shear stress is both oscillatory and multidirectional. Also, the combined effect of curvature and pulsatility in cardiovascular flows produces unsteady vortices. The aim of this research as it relates to cardiovascular fluid dynamics is to predict the spatial and temporal evolution of vortical structures generated by secondary flows, as well as to assess the correlation between multiple vortex pairs and wall shear stress. We use a physiologically (pulsatile) relevant flow rate and generate results using both fully developed and uniform entrance conditions, the latter being motivated by the fact that flow upstream of a curved artery may not have sufficient straight entrance length to become fully developed. Under the two pulsatile inflow conditions, we characterize the morphology and evolution of various vortex pairs and their subsequent effect on relevant haemodynamic wall shear stress metrics.
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Magnesium degradation under physiological conditions - Best practice.
Gonzalez, Jorge; Hou, Rui Qing; Nidadavolu, Eshwara P S; Willumeit-Römer, Regine; Feyerabend, Frank
2018-06-01
This review focusses on the application of physiological conditions for the mechanistic understanding of magnesium degradation. Despite the undisputed relevance of simplified laboratory setups for alloy screening purposes, realistic and predictive in vitro setups are needed. Due to the complexity of these systems, the review gives an overview about technical measures, defines some caveats and can be used as a guideline for the establishment of harmonized laboratory approaches.
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Basson, Christine H; Clusella-Trullas, Susana
2015-01-01
Environmental variability occurring at different timescales can significantly reduce performance, resulting in evolutionary fitness costs. Shifts in thermoregulatory behavior, metabolism, and water loss via phenotypic plasticity can compensate for thermal variation, but the relative contribution of each mechanism and how they may influence each other are largely unknown. Here, we take an ecologically relevant experimental approach to dissect these potential responses at two temporal scales: weather transients and seasons. Using acclimation to cold, average, or warm conditions in summer and winter, we measure the direction and magnitude of plasticity of resting metabolic rate (RMR), water loss rate (WLR), and preferred body temperature (Tpref) in the lizard Cordylus oelofseni within and between seasons. In summer, lizards selected lower Tpref when acclimated to warm versus cold but had no plasticity of either RMR or WLR. By contrast, winter lizards showed partial compensation of RMR but no behavioral compensation. Between seasons, both behavioral and physiological shifts took place. By integrating ecological reality into laboratory assays, we demonstrate that behavioral and physiological responses of C. oelofseni can be contrasting, depending on the timescale investigated. Incorporating ecologically relevant scenarios and the plasticity of multiple traits is thus essential when attempting to forecast extinction risk to climate change.
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Distribution and Biological Effects of Nanoparticles in the Reproductive System.
Liu, Ying; Li, Hongxia; Xiao, Kai
2016-01-01
Nanoparticles have shown great potential in biomedical applications such as imaging probes and drug delivery. However, the increasing use of nanoparticles has raised concerns about their adverse effects on human health and environment. Reproductive tissues and gametes represent highly delicate biological systems with the essential function of transmitting genetic information to the offspring, which is highly sensitive to environmental toxicants. This review aims to summarzie the penetration of physiological barriers (blood-testis barrier and placental barrier), distribution and biological effects of nanoparticles in the reproductive system, which is essential to control the beneficial effects of nanoparticles applications and to avoid their adverse effects on the reproductive system. We referred to a large number of relevant peer-reviewed research articles about the reproductive toxicity of nanoparticles. The comprehensive information was summarized into two parts: physiological barrier penetration and biological effects of nanoparticles in male or female reproductive system; distribution and metabolism of nanoparticles in the reproductive system. The representative examples were also presented in four tables. The in vitro and in vivo studies imply that some nanoparticles are able to cross the blood-testis barrier or placental barrier, and their penetration depends on the physicochemical characteristics of nanoparticles (e.g., composition, shape, particle size and surface coating). The toxicity assays indicate that nanoparticles might induce adverse physiological effects and impede fertility or embryogenesis. The barrier penetration, adverse physiological effects, distribution and metabolism are closely related to physicochemical characteristics of nanoparticles. Further systematic and mechanistic studies using well-characterized nanoparticles, relevant administration routes, and doses relevant to the expected exposure level are required to improve our understanding of biological effects of nanoparticles on the reproductive system.
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Evaluation of a computer-based approach to teaching acid/base physiology.
Rawson, Richard E; Quinlan, Kathleen M
2002-12-01
Because acid/base physiology is a difficult subject for most medical and veterinary students, the first author designed a software program, Acid/Base Primer, that would help students with this topic. The Acid/Base Primer was designed and evaluated within a conceptual framework of basic educational principles. Seventy-five first-year veterinary students (of 81; 93% response rate) participated in this study. Students took both a pre- and posttest of content understanding. After completing the Acid/Base Primer in pairs, each student filled out a survey evaluating the features of the program and describing his/her use and experience of it. Four pairs of students participated in interviews that elaborated on the surveys. Scores improved from 53 +/- 2% on the pretest to 74 +/- 1% on an immediate posttest. On surveys and in interviews, students reported that the program helped them construct their own understanding of acid/base physiology and prompted discussions in pairs of students when individual understandings differed. The case-based format provided anchors and a high degree of relevance. Repetition of concepts helped students develop a more complex network of understanding. Questions in the program served to scaffold the learning process by providing direction, accentuating the relevant features of the cases, and provoking discussion. Guidelines for software development were generated on the basis of the findings and relevant educational literature.
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A conceptual framework for homeostasis: development and validation.
McFarland, Jenny; Wenderoth, Mary Pat; Michael, Joel; Cliff, William; Wright, Ann; Modell, Harold
2016-06-01
We have developed and validated a conceptual framework for understanding and teaching organismal homeostasis at the undergraduate level. The resulting homeostasis conceptual framework details critical components and constituent ideas underlying the concept of homeostasis. It has been validated by a broad range of physiology faculty members from community colleges, primarily undergraduate institutions, research universities, and medical schools. In online surveys, faculty members confirmed the relevance of each item in the framework for undergraduate physiology and rated the importance and difficulty of each. The homeostasis conceptual framework was constructed as a guide for teaching and learning of this critical core concept in physiology, and it also paves the way for the development of a concept inventory for homeostasis. Copyright © 2016 The American Physiological Society.
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Does emotion help or hinder reasoning? The moderating role of relevance.
Blanchette, Isabelle; Gavigan, Sarah; Johnston, Kathryn
2014-06-01
Some prior research has shown that emotion impairs logicality in deductive reasoning tasks, while other research suggests improved performance with emotional contents. We suggest that relevance, whether the affective state is associated with the semantic contents of the reasoning task, may be crucial in explaining these apparently inconsistent findings. This hypothesis is based on a framework distinguishing between integral emotions, where affective responses are evoked by the semantic contents of the target task, and incidental emotions, where affective responses are not related to the task. In 4 experiments we examined the effect of emotion on conditional reasoning when affective responses were relevant and irrelevant. We used images presented simultaneously with the reasoning stimuli (Experiments 1, 2, and 3) or videos presented prior to the reasoning stimuli (Experiment 4) that were either emotional or neutral and semantically related or not to the conditional statements. Results showed that emotion decreased the proportion of normatively correct responses only in the irrelevant condition. In the relevant condition, emotion did not produce reliable deleterious effects. We used reaction time and skin conductance measures to investigate the physiological and cognitive correlates of these effects. Results are discussed in terms of the distinction between incidental and integral emotions. PsycINFO Database Record (c) 2014 APA, all rights reserved.
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A Laboratory Program for Bioinorganic Chemistry
ERIC Educational Resources Information Center
Ochiai, Ei-ichiro
1973-01-01
Outlines a laboratory course entitled Inorganic Chemistry for Biological Sciences'' which is designed primarily for juniors in biochemistry, physiology, and soil sciences. Inclusion of relevant environmental topics is indicated. (CC)
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Waveform shape analysis: extraction of physiologically relevant information from Doppler recordings.
Ramsay, M M; Broughton Pipkin, F; Rubin, P C; Skidmore, R
1994-05-01
1. Doppler recordings were made from the brachial artery of healthy female subjects during a series of manoeuvres which altered the pressure-flow characteristics of the vessel. 2. Changes were induced in the peripheral circulation of the forearm by the application of heat or ice-packs. A sphygmomanometer cuff was used to create graded occlusion of the vessel above and below the point of measurement. Recordings were also made whilst the subjects performed a standardized Valsalva manoeuvre. 3. The Doppler recordings were analysed both with the standard waveform indices (systolic/diastolic ratio, pulsatility index and resistance index) and by the method of Laplace transform analysis. 4. The waveform parameters obtained by Laplace transform analysis distinguished the different changes in flow conditions; they thus had direct physiological relevance, unlike the standard waveform indices.
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[Signaling mechanisms involved in resolution of inflammation].
Cervantes-Villagrana, Rodolfo Daniel; Cervantes-Villagrana, Alberto Rafael; Presno-Bernal, José Miguel
2014-01-01
Inflammation is a physiological process, which eliminates pathogens and induces repair of damaged tissue. This process is controlled by negative feedback mechanisms, but if the inflammation persists, it generates a deleterious autoimmune process or can to contribute with diseases such as obesity or cancer. The inflammation resolution involves mechanisms such as decrease of proliferation and maturation of immune cells, phagocytosis and apoptosis of immune cells, and decrease of proinflammatory mediators. Therefore, is relevant to study the physiological effects of specific receptors that participate in inflammation resolution and the design of specific agonists as conventional anti-inflammatory therapeutics, without dramatic collateral effects. In this review, we study some mechanisms associated with inflammation inhibition, particularly the transduction of receptors for ligands with anti-inflammatory effects and that are relevant for their potential therapeutic.
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Sobolewski, Marissa; Allen, Joshua L.; Morris-Schaffer, Keith; Klocke, Carolyn; Conrad, Katherine; Cory-Slechta, Deborah A.
2017-01-01
Prenatal stress and nutrition are well-known to alter a broad range of physiological systems, notably metabolic, endocrine and neurobehavioral function. Commonly used methods for oral administration of xenobiotics can, by acting as a stressor or altering normal nutrition intake, alter these physiological systems as well. Taken together, oral administration methods may unintentionally introduce confounding physiological effects that can mask or enhance toxicity of xenobiotics, particularly if they share biological targets. Consequently, it should be preferable to develop alternative methods without these potential confounds. The aim of this study was to determine the suitability of mealworms as an alternative treat-based method to deliver xenobiotics via the orogastric route. Accurate oral administration is contingent on motivation and preference; mice reliably preferred mealworms over wafer cookie treats. Further, ingestion of wafer cookies significantly increased mouse blood glucose levels, whereas unaltered mealworms produced no such change. Mealworms functioned effectively to orally administer glucose, as glucose-spiked mealworms produced a rise in blood glucose equivalent to the ingestion of the wafer cookie. Mealworms did not interfere with the physiological function of orally administered d-amphetamine, as both mealworm and oral gavage administered d-amphetamine showed similar alterations in locomotor behavior (mice did not fully consume d-amphetamine-dosed cookies and thus could not be compared). Collectively, the findings indicate that mealworms are a preferred and readily consumed treat, which importantly mimics environmental-relevant nutritional intake, and mealworms per se do not alter glucose metabolic pathways. Additionally, mealworms accurately delivered xenobiotics into blood circulation and did not interfere with the physiological function of administered xenobiotics. Thus mealworm-based oral administration may be a preferable and accurate route of xenobiotic administration that eliminates physiological alterations associated with other methods of delivery. PMID:27094606
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Sobolewski, Marissa; Allen, Joshua L; Morris-Schaffer, Keith; Klocke, Carolyn; Conrad, Katherine; Cory-Slechta, Deborah A
2016-01-01
Prenatal stress and nutrition are well-known to alter a broad range of physiological systems, notably metabolic, endocrine and neurobehavioral function. Commonly used methods for oral administration of xenobiotics can, by acting as a stressor or altering normal nutrition intake, alter these physiological systems as well. Taken together, oral administration methods may unintentionally introduce confounding physiological effects that can mask or enhance toxicity of xenobiotics, particularly if they share biological targets. Consequently, it should be preferable to develop alternative methods without these potential confounds. The aim of this study was to determine the suitability of mealworms as an alternative treat-based method to deliver xenobiotics via the orogastric route. Accurate oral administration is contingent on motivation and preference; mice reliably preferred mealworms over wafer cookie treats. Further, ingestion of wafer cookies significantly increased mouse blood glucose levels, whereas unaltered mealworms produced no such change. Mealworms functioned effectively to orally administer glucose, as glucose-spiked mealworms produced a rise in blood glucose equivalent to the ingestion of the wafer cookie. Mealworms did not interfere with the physiological function of orally administered d-amphetamine, as both mealworm and oral gavage administered d-amphetamine showed similar alterations in locomotor behavior (mice did not fully consume d-amphetamine-dosed cookies and thus could not be compared). Collectively, the findings indicate that mealworms are a preferred and readily consumed treat, which importantly mimics environmental-relevant nutritional intake, and mealworms per se do not alter glucose metabolic pathways. Additionally, mealworms accurately delivered xenobiotics into blood circulation and did not interfere with the physiological function of administered xenobiotics. Thus mealworm-based oral administration may be a preferable and accurate route of xenobiotic administration that eliminates physiological alterations associated with other methods of delivery. Copyright © 2016. Published by Elsevier Inc.
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Typlt, Marei; Englitz, Bernhard; Sonntag, Mandy; Dehmel, Susanne; Kopp-Scheinpflug, Cornelia; Ruebsamen, Rudolf
2012-01-01
Multiple parallel auditory pathways ascend from the cochlear nucleus. It is generally accepted that the origin of these pathways are distinct groups of neurons differing in their anatomical and physiological properties. In extracellular in vivo recordings these neurons are typically classified on the basis of their peri-stimulus time histogram. In the present study we reconsider the question of classification of neurons in the anteroventral cochlear nucleus (AVCN) by taking a wider range of response properties into account. The study aims at a better understanding of the AVCN's functional organization and its significance as the source of different ascending auditory pathways. The analyses were based on 223 neurons recorded in the AVCN of the Mongolian gerbil. The range of analysed parameters encompassed spontaneous activity, frequency coding, sound level coding, as well as temporal coding. In order to categorize the unit sample without any presumptions as to the relevance of certain response parameters, hierarchical cluster analysis and additional principal component analysis were employed which both allow a classification on the basis of a multitude of parameters simultaneously. Even with the presently considered wider range of parameters, high number of neurons and more advanced analytical methods, no clear boundaries emerged which would separate the neurons based on their physiology. At the current resolution of the analysis, we therefore conclude that the AVCN units more likely constitute a multi-dimensional continuum with different physiological characteristics manifested at different poles. However, more complex stimuli could be useful to uncover physiological differences in future studies. PMID:22253838
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Sheard, Michael A., E-mail: msheard@chla.usc.edu; Ghent, Matthew V., E-mail: mattghent@gmail.com; Cabral, Daniel J., E-mail: dcabral14@gmail.com
2015-05-15
Cancer cells typically exhibit increased glycolysis and decreased mitochondrial oxidative phosphorylation, and they continue to exhibit some elevation in glycolysis even under aerobic conditions. However, it is unclear whether cancer cell lines employ a high level of glycolysis comparable to that of the original cancers from which they were derived, even if their culture conditions are changed to physiologically relevant oxygen concentrations. From three childhood acute lymphoblastic leukemia (ALL) patients we established three new pairs of cell lines in both atmospheric (20%) and physiologic (bone marrow level, 5%) oxygen concentrations. Cell lines established in 20% oxygen exhibited lower proliferation, survival,more » expression of glycolysis genes, glucose consumption, and lactate production. Interestingly, the effects of oxygen concentration used during cell line initiation were only partially reversible when established cell cultures were switched from one oxygen concentration to another for eight weeks. These observations indicate that ALL cell lines established at atmospheric oxygen concentration can exhibit relatively low levels of glycolysis and these levels are semi-permanent, suggesting that physiologic oxygen concentrations may be needed from the time of cell line initiation to preserve the high level of glycolysis commonly exhibited by leukemias in vivo. - Highlights: • Establishing new ALL cell lines in 5% oxygen resulted in higher glycolytic expression and function. • Establishing new ALL cell lines in 5% oxygen resulted in higher proliferation and lower cell death. • The divergent metabolic phenotypes selected in 5% and 20% oxygen are semi-permanent.« less
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Microbial ecology and host-microbiota interactions during early life stages
Collado, Maria Carmen; Cernada, Maria; Baüerl, Christine; Vento, Máximo; Pérez-Martínez, Gaspar
2012-01-01
The role of human microbiota has been redefined during recent years and its physiological role is now much more important than earlier understood. Intestinal microbial colonization is essential for the maturation of immune system and for the developmental regulation of the intestinal physiology. Alterations in this process of colonization have been shown to predispose and increase the risk to disease later in life. The first contact of neonates with microbes is provided by the maternal microbiota. Moreover, mode of delivery, type of infant feeding and other perinatal factors can influence the establishment of the infant microbiota. Taken into consideration all the available information it could be concluded that the exposure to the adequate microbes early in gestation and neonatal period seems to have a relevant role in health. Maternal microbial environment affects maternal and fetal immune physiology and, of relevance, this interaction with microbes at the fetal-maternal interface could be modulated by specific microbes administered to the pregnant mother. Indeed, probiotic interventions aiming to reduce the risk of immune-mediated diseases may appear effective during early life. PMID:22743759
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Bio-integrated electronics and sensor systems
NASA Astrophysics Data System (ADS)
Yeo, Woon-Hong; Webb, R. Chad; Lee, Woosik; Jung, Sungyoung; Rogers, John A.
2013-05-01
Skin-mounted epidermal electronics, a strategy for bio-integrated electronics, provide an avenue to non-invasive monitoring of clinically relevant physiological signals for healthcare applications. Current conventional systems consist of single-point sensors fastened to the skin with adhesives, and sometimes with conducting gels, which limits their use outside of clinical settings due to loss of adhesion and irritation to the user. In order to facilitate extended use of skin-mounted healthcare sensors without disrupting everyday life, we envision electronic monitoring systems that integrate seamlessly with the skin below the notice of the user. This manuscript reviews recent significant results towards our goal of wearable electronic sensor systems for long-term monitoring of physiological signals. Ultra-thin epidermal electronic systems (EES) are demonstrated for extended use on the skin, in a conformal manner, including during everyday bathing and sleeping activities. We describe the assessment of clinically relevant physiological parameters, such as electrocardiograms (ECG), electromyograms (EMG), electroencephalograms (EEG), temperature, mechanical strain and thermal conductivity, using examples of multifunctional EES devices. Additionally, we demonstrate capability for real life application of EES by monitoring the system functionality, which has no discernible change, during cyclic fatigue testing.
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Foster, Kenneth R; Glaser, Roland
2007-06-01
This article reviews thermal mechanisms of interaction between radiofrequency (RF) fields and biological systems, focusing on theoretical frameworks that are of potential use in setting guidelines for human exposure to RF energy. Several classes of thermal mechanisms are reviewed that depend on the temperature increase or rate of temperature increase and the relevant dosimetric considerations associated with these mechanisms. In addition, attention is drawn to possible molecular and physiological reactions that could be induced by temperature elevations below 0.1 degrees, which are normal physiological responses to heat, and to the so-called microwave auditory effect, which is a physiologically trivial effect resulting from thermally-induced acoustic stimuli. It is suggested that some reported "nonthermal" effects of RF energy may be thermal in nature; also that subtle thermal effects from RF energy exist but have no consequence to health or safety. It is proposed that future revisions of exposure guidelines make more explicit use of thermal models and empirical data on thermal effects in quantifying potential hazards of RF fields.
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Transition theory and its relevance to patients with chronic wounds.
Neil, J A; Barrell, L M
1998-01-01
A wound, in the broadest sense, is a disruption of normal anatomic structure and function. Acute wounds progress through a timely and orderly sequence of repair that leads to the restoration of functional integrity. In chronic wounds, this timely and orderly sequence goes awry. As a result, people with chronic wounds often face not only physiological difficulties but emotional ones as well. The study of body image and its damage as a result of a chronic wound fits well with Selder's transition theory. This article describes interviews with seven patients with chronic wounds. The themes that emerged from those interviews were compared with Selder's theory to describe patients' experience with chronic wounds as a transition process that can be identified and better understood by healthcare providers.
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Detection of generalized synchronization using echo state networks
NASA Astrophysics Data System (ADS)
Ibáñez-Soria, D.; Garcia-Ojalvo, J.; Soria-Frisch, A.; Ruffini, G.
2018-03-01
Generalized synchronization between coupled dynamical systems is a phenomenon of relevance in applications that range from secure communications to physiological modelling. Here, we test the capabilities of reservoir computing and, in particular, echo state networks for the detection of generalized synchronization. A nonlinear dynamical system consisting of two coupled Rössler chaotic attractors is used to generate temporal series consisting of time-locked generalized synchronized sequences interleaved with unsynchronized ones. Correctly tuned, echo state networks are able to efficiently discriminate between unsynchronized and synchronized sequences even in the presence of relatively high levels of noise. Compared to other state-of-the-art techniques of synchronization detection, the online capabilities of the proposed Echo State Network based methodology make it a promising choice for real-time applications aiming to monitor dynamical synchronization changes in continuous signals.
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NASA Technical Reports Server (NTRS)
Szallasi, Zoltan; Liang, Shoudan
2000-01-01
In this paper we show how Boolean genetic networks could be used to address complex problems in cancer biology. First, we describe a general strategy to generate Boolean genetic networks that incorporate all relevant biochemical and physiological parameters and cover all of their regulatory interactions in a deterministic manner. Second, we introduce 'realistic Boolean genetic networks' that produce time series measurements very similar to those detected in actual biological systems. Third, we outline a series of essential questions related to cancer biology and cancer therapy that could be addressed by the use of 'realistic Boolean genetic network' modeling.
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Epigenetics: a lasting impression?
Biddie, Simon C; Lightman, Stafford L
2011-02-01
Epigenetics is the term that has been classically used to describe inheritable nongenetic factors that regulate genes. Although these factors were originally thought to act in a long time domain only, it is now clear that they can also be highly dynamic, changing over minutes. Transcription factors, including the glucocorticoid, oestrogen and androgen receptors, interact with these epigenetic mechanisms in a very dynamic manner to modify transcription of genes and consequently contribute to physiological processes, health and disease. Modern usage of the term epigenetics encompasses both longer-term and transient changes and is relevant to multiple biological systems. © 2011 The Authors. Journal of Neuroendocrinology © 2011 Blackwell Publishing Ltd.
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New Pharmacology Studies on the ISS
NASA Technical Reports Server (NTRS)
Wotring, Virginia E.; Pour, S.
2015-01-01
It is known that medications degrade over time and that extreme storage conditions will hasten their degradation. This is the basis of the HRP Risk of Ineffective or Toxic Medications Due to Long Term Storage. Gaps include questions about the effects of the spaceflight environment and about the potential for safe use of medications beyond their expiration dates. There are also open questions regarding effects of the spaceflight environment on human physiology and subsequent changes in how medications act on the body; these unanswered questions gave rise to the HRP Concern of Clinically Relevant Unpredicted Effects of Medication. Studies designed to address this Risk and Concern are described below.
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Analysis of Size Correlations for Microdroplets Produced by Ultrasonic Atomization
Barba, Anna Angela; d'Amore, Matteo
2013-01-01
Microencapsulation techniques are widely applied in the field of pharmaceutical production to control drugs release in time and in physiological environments. Ultrasonic-assisted atomization is a new technique to produce microencapsulated systems by a mechanical approach. Interest in this technique is due to the advantages evidenceable (low level of mechanical stress in materials, reduced energy request, reduced apparatuses size) when comparing it to more conventional techniques. In this paper, the groundwork of atomization is introduced, the role of relevant parameters in ultrasonic atomization mechanism is discussed, and correlations to predict droplets size starting from process parameters and material properties are presented and tested. PMID:24501580
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Medical smart textiles based on fiber optic technology: an overview.
Massaroni, Carlo; Saccomandi, Paola; Schena, Emiliano
2015-04-13
The growing interest in the development of smart textiles for medical applications is driven by the aim to increase the mobility of patients who need a continuous monitoring of such physiological parameters. At the same time, the use of fiber optic sensors (FOSs) is gaining large acceptance as an alternative to traditional electrical and mechanical sensors for the monitoring of thermal and mechanical parameters. The potential impact of FOSs is related to their good metrological properties, their small size and their flexibility, as well as to their immunity from electromagnetic field. Their main advantage is the possibility to use textile based on fiber optic in a magnetic resonance imaging environment, where standard electronic sensors cannot be employed. This last feature makes FOSs suitable for monitoring biological parameters (e.g., respiratory and heartbeat monitoring) during magnetic resonance procedures. Research interest in combining FOSs and textiles into a single structure to develop wearable sensors is rapidly growing. In this review we provide an overview of the state-of-the-art of textiles, which use FOSs for monitoring of mechanical parameters of physiological interest. In particular we briefly describe the working principle of FOSs employed in this field and their relevant advantages and disadvantages. Also reviewed are their applications for the monitoring of mechanical parameters of physiological interest.
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α-Tocopherol and Hippocampal Neural Plasticity in Physiological and Pathological Conditions
Ambrogini, Patrizia; Betti, Michele; Galati, Claudia; Di Palma, Michael; Lattanzi, Davide; Savelli, David; Galli, Francesco; Cuppini, Riccardo; Minelli, Andrea
2016-01-01
Neuroplasticity is an “umbrella term” referring to the complex, multifaceted physiological processes that mediate the ongoing structural and functional modifications occurring, at various time- and size-scales, in the ever-changing immature and adult brain, and that represent the basis for fundamental neurocognitive behavioral functions; in addition, maladaptive neuroplasticity plays a role in the pathophysiology of neuropsychiatric dysfunctions. Experiential cues and several endogenous and exogenous factors can regulate neuroplasticity; among these, vitamin E, and in particular α-tocopherol (α-T), the isoform with highest bioactivity, exerts potent effects on many plasticity-related events in both the physiological and pathological brain. In this review, the role of vitamin E/α-T in regulating diverse aspects of neuroplasticity is analyzed and discussed, focusing on the hippocampus, a brain structure that remains highly plastic throughout the lifespan and is involved in cognitive functions. Vitamin E-mediated influences on hippocampal synaptic plasticity and related cognitive behavior, on post-natal development and adult hippocampal neurogenesis, as well as on cellular and molecular disruptions in kainate-induced temporal seizures are described. Besides underscoring the relevance of its antioxidant properties, non-antioxidant functions of vitamin E/α-T, mainly involving regulation of cell signaling molecules and their target proteins, have been highlighted to help interpret the possible mechanisms underlying the effects on neuroplasticity. PMID:27983697
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Medical Smart Textiles Based on Fiber Optic Technology: An Overview
Massaroni, Carlo; Saccomandi, Paola; Schena, Emiliano
2015-01-01
The growing interest in the development of smart textiles for medical applications is driven by the aim to increase the mobility of patients who need a continuous monitoring of such physiological parameters. At the same time, the use of fiber optic sensors (FOSs) is gaining large acceptance as an alternative to traditional electrical and mechanical sensors for the monitoring of thermal and mechanical parameters. The potential impact of FOSs is related to their good metrological properties, their small size and their flexibility, as well as to their immunity from electromagnetic field. Their main advantage is the possibility to use textile based on fiber optic in a magnetic resonance imaging environment, where standard electronic sensors cannot be employed. This last feature makes FOSs suitable for monitoring biological parameters (e.g., respiratory and heartbeat monitoring) during magnetic resonance procedures. Research interest in combining FOSs and textiles into a single structure to develop wearable sensors is rapidly growing. In this review we provide an overview of the state-of-the-art of textiles, which use FOSs for monitoring of mechanical parameters of physiological interest. In particular we briefly describe the working principle of FOSs employed in this field and their relevant advantages and disadvantages. Also reviewed are their applications for the monitoring of mechanical parameters of physiological interest. PMID:25871010
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Translational Modeling in Schizophrenia: Predicting Human Dopamine D2 Receptor Occupancy.
Johnson, Martin; Kozielska, Magdalena; Pilla Reddy, Venkatesh; Vermeulen, An; Barton, Hugh A; Grimwood, Sarah; de Greef, Rik; Groothuis, Geny M M; Danhof, Meindert; Proost, Johannes H
2016-04-01
To assess the ability of a previously developed hybrid physiology-based pharmacokinetic-pharmacodynamic (PBPKPD) model in rats to predict the dopamine D2 receptor occupancy (D2RO) in human striatum following administration of antipsychotic drugs. A hybrid PBPKPD model, previously developed using information on plasma concentrations, brain exposure and D2RO in rats, was used as the basis for the prediction of D2RO in human. The rat pharmacokinetic and brain physiology parameters were substituted with human population pharmacokinetic parameters and human physiological information. To predict the passive transport across the human blood-brain barrier, apparent permeability values were scaled based on rat and human brain endothelial surface area. Active efflux clearance in brain was scaled from rat to human using both human brain endothelial surface area and MDR1 expression. Binding constants at the D2 receptor were scaled based on the differences between in vitro and in vivo systems of the same species. The predictive power of this physiology-based approach was determined by comparing the D2RO predictions with the observed human D2RO of six antipsychotics at clinically relevant doses. Predicted human D2RO was in good agreement with clinically observed D2RO for five antipsychotics. Models using in vitro information predicted human D2RO well for most of the compounds evaluated in this analysis. However, human D2RO was under-predicted for haloperidol. The rat hybrid PBPKPD model structure, integrated with in vitro information and human pharmacokinetic and physiological information, constitutes a scientific basis to predict the time course of D2RO in man.
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Zhang, Rui Xue; Li, Jason; Zhang, Tian; Amini, Mohammad A; He, Chunsheng; Lu, Brian; Ahmed, Taksim; Lip, HoYin; Rauth, Andrew M; Wu, Xiao Yu
2018-05-01
Nanotechnology has been applied extensively in drug delivery to improve the therapeutic outcomes of various diseases. Tremendous efforts have been focused on the development of novel nanoparticles and delineation of the physicochemical properties of nanoparticles in relation to their biological fate and functions. However, in the design and evaluation of these nanotechnology-based drug delivery systems, the pharmacology of delivered drugs and the (patho-)physiology of the host have received less attention. In this review, we discuss important pharmacological mechanisms, physiological characteristics, and pathological factors that have been integrated into the design of nanotechnology-enabled drug delivery systems and therapies. Firsthand examples are presented to illustrate the principles and advantages of such integrative design strategies for cancer treatment by exploiting 1) intracellular synergistic interactions of drug-drug and drug-nanomaterial combinations to overcome multidrug-resistant cancer, 2) the blood flow direction of the circulatory system to maximize drug delivery to the tumor neovasculature and cells overexpressing integrin receptors for lung metastases, 3) endogenous lipoproteins to decorate nanocarriers and transport them across the blood-brain barrier for brain metastases, and 4) distinct pathological factors in the tumor microenvironment to develop pH- and oxidative stress-responsive hybrid manganese dioxide nanoparticles for enhanced radiotherapy. Regarding the application in diabetes management, a nanotechnology-enabled closed-loop insulin delivery system was devised to provide dynamic insulin release at a physiologically relevant time scale and glucose levels. These examples, together with other research results, suggest that utilization of the interplay of pharmacology, (patho-)physiology and nanotechnology is a facile approach to develop innovative drug delivery systems and therapies with high efficiency and translational potential.
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Role of GABAergic inhibition in hippocampal network oscillations.
Mann, Edward O; Paulsen, Ole
2007-07-01
Physiological rhythmic activity in cortical circuits relies on GABAergic inhibition to balance excitation and control spike timing. With a focus on recent experimental progress in the hippocampus, here we review the mechanisms by which synaptic inhibition can control the precise timing of spike generation, by way of effects of GABAergic events on membrane conductance ('shunting' inhibition) and membrane potential ('hyperpolarizing' inhibition). Synaptic inhibition itself can be synchronized by way of interactions within networks of GABAergic neurons, and by excitatory neurons. The importance of GABAergic mechanisms for generation of cortical rhythms is now well established. What remains to be resolved is how such inhibitory control of spike timing can be harnessed for long-range fast synchronization, and the relevance of these mechanisms to network function. This review is part of the INMED/TINS special issue Physiogenic and pathogenic oscillations: the beauty and the beast, based on presentations at the annual INMED/TINS symposium (http://inmednet.com).
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Clase, Kari L; Hein, Patrick W; Pelaez, Nancy J
2008-12-01
Physiology as a discipline is uniquely positioned to engage undergraduate students in interdisciplinary research in response to the 2006-2011 National Science Foundation Strategic Plan call for innovative transformational research, which emphasizes multidisciplinary projects. To prepare undergraduates for careers that cross disciplinary boundaries, students need to practice interdisciplinary communication in academic programs that connect students in diverse disciplines. This report surveys policy documents relevant to this emphasis on interdisciplinary training and suggests a changing role for physiology courses in bioscience and engineering programs. A role for a physiology course is increasingly recommended for engineering programs, but the study of physiology from an engineering perspective might differ from the study of physiology as a basic science. Indeed, physiology laboratory courses provide an arena where biomedical engineering and bioscience students can apply knowledge from both fields while cooperating in multidisciplinary teams under specified technical constraints. Because different problem-solving approaches are used by students of engineering and bioscience, instructional innovations are needed to break down stereotypes between the disciplines and create an educational environment where interdisciplinary teamwork is used to bridge differences.
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The use of real-time optical feedback to improve outcomes
NASA Astrophysics Data System (ADS)
Magaña, Isidro B.; Adhikari, Pratik; Yendluri, Raghuvara B.; Goodrich, Glenn P.; Schwartz, Jon A.; O'Neal, D. P.
2014-03-01
More than a decade into the development of gold nanoparticles for cancer therapies, with multiple clinical trials underway, ongoing pre-clinical research continues towards better understanding in vivo interactions with the goal of treatment optimization through improved best practices. In an effort to collect information for healthcare providers, enabling informed decisions in a relevant time frame, instrumentation for real-time plasma concentration (multi-wavelength pulse photometry) and protocols for rapid elemental analysis (energy dispersive X-Ray fluorescence) of biopsied tumor tissue have been developed in a murine model. An initial analysis, designed to demonstrate the robust nature and utility of the techniques, revealed that area under the bioavailability curve (AUC) alone does not currently inform tumor accumulation with a high degree of accuracy (R2=0.32), This finding suggests that the control of additional experimental and physiological variables may yield more predictable tumor accumulation. Subject core temperature are blood pressure were monitored, but did not demonstrate clear trends. An effort to modulate AUC has produced an adjuvant therapy which is employed to enhance circulation parameters, including the AUC, of nanorods and gold nanoshells. Preliminary studies demonstrated a greater than 300% increase in average AUC through the use of a reticuloendothelial blockade agent versus control groups. Given a better understanding of the relative importance of the physiological factors which impact rates of tumor accumulation, a proposed set of experimental best practices is presented.
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Hu, Yumei; Jiang, Xiaomei; Zhang, Laiying; Fan, Jiao; Wu, Weitai
2013-10-15
Noninvasive monitoring of glucose in tears is highly desirable in tight glucose control. The polymerized crystalline colloidal array (PCCA) that can be incorporated into contact lens represents one of the most promising materials for noninvasive monitoring of glucose in tears. However, low sensitivity and slow time response of the PCCA reported in previous arts has limited its clinical utility. This paper presents a new PCCA, denoted as NIR-PCCA, comprising a CCA of glucose-responsive sub-micrometered poly(styrene-co-acrylamide-co-3-acrylamidophenylboronic acid) microgels embedded within a slightly positive charged hydrogel matrix of poly(acrylamide-co-2-(dimethylamino)ethyl acrylate). This newly designed NIR-PCCA can reflect near-infrared (NIR) light, whose intensity (at 1722 nm) would decrease evidently with increasing glucose concentration over the physiologically relevant range in tears. The lowest glucose concentration reliably detectable was as low as ca. 6.1 μg/dL. The characteristic response time τ(sensing) was 22.1±0.2s when adding glucose to 7.5 mg/dL, and the higher the glucose concentration is, the faster the time response. Such a rationally designed NIR-PCCA is well suited for ratiometric NIR sensing of tear glucose under physiological conditions, thereby likely to bring this promising glucose-sensing material to the forefront of analytical devices for diabetes. Copyright © 2013 Elsevier B.V. All rights reserved.
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Hüsch, Jan; Gerbeth, Kathleen; Fricker, Gert; Setzer, Constanze; Zirkel, Jürgen; Rebmann, Herbert; Schubert-Zsilavecz, Manfred; Abdel-Tawab, Mona
2012-10-26
Boswellia serrata gum resin extracts are used widely for the treatment of inflammatory diseases. However, very low concentrations in the plasma and brain were observed for the boswellic acids (1-6, the active constituents of B. serrata). The present study investigated the effect of phospholipids alone and in combination with common co-surfactants (e.g., Tween 80, vitamin E-TPGS, pluronic f127) on the solubility of 1-6 in physiologically relevant media and on the permeability in the Caco-2 cell model. Because of the high lipophilicity of 1-6, the permeability experiments were adapted to physiological conditions using modified fasted state simulated intestinal fluid as apical (donor) medium and 4% bovine serum albumin in the basolateral (receiver) compartment. A formulation composed of extract/phospholipid/pluronic f127 (1:1:1 w/w/w) increased the solubility of 1-6 up to 54 times compared with the nonformulated extract and exhibited the highest mass net flux in the permeability tests. The oral administration of this formulation to rats (240 mg/kg) resulted in 26 and 14 times higher plasma levels for 11-keto-β-boswellic acid (1) and acetyl-11-keto-β-boswellic acid (2), respectively. In the brain, five times higher levels for 2 compared to the nonformulated extract were determined 8 h after oral administration.
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Overview of exocrine pancreatic pathobiology.
Pandiri, Arun R
2014-01-01
Exocrine pancreas is a source of several enzymes that are essential for the digestive process. The exocrine pancreatic secretion is tightly regulated by the neuroendocrine system. The endocrine pancreas is tightly integrated anatomically and physiologically with the exocrine pancreas and modulates its function. Compound-induced pancreatitis is not a common event in toxicology or drug development, but it becomes a significant liability when encountered. Understanding the species-specific differences in physiology is essential to understand the underlying pathobiology of pancreatic disease in animal models and its relevance to human disease. This review will mainly focus on understanding the morphology and physiology of the pancreas, unique islet-exocrine interactions, and pancreatitis.
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Murine epithelial cells: isolation and culture.
Davidson, Donald J; Gray, Michael A; Kilanowski, Fiona M; Tarran, Robert; Randell, Scott H; Sheppard, David N; Argent, Barry E; Dorin, Julia R
2004-08-01
We describe an air-liquid interface primary culture method for murine tracheal epithelial cells on semi-permeable membranes, forming polarized epithelia with a high transepithelial resistance, differentiation to ciliated and secretory cells, and physiologically appropriate expression of key genes and ion channels. We also describe the isolation of primary murine nasal epithelial cells for patch-clamp analysis, generating polarised cells with physiologically appropriate distribution and ion channel expression. These methods enable more physiologically relevant analysis of murine airway epithelial cells in vitro and ex vivo, better utilisation of transgenic mouse models of human pulmonary diseases, and have been approved by the European Working Group on CFTR expression.
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Gurnsey, Kate; Salisbury, Dean; Sweet, Robert A.
2016-01-01
Auditory refractoriness refers to the finding of smaller electroencephalographic (EEG) responses to tones preceded by shorter periods of silence. To date, its physiological mechanisms remain unclear, limiting the insights gained from findings of abnormal refractoriness in individuals with schizophrenia. To resolve this roadblock, we studied auditory refractoriness in the rhesus, one of the most important animal models of auditory function, using grids of up to 32 chronically implanted cranial EEG electrodes. Four macaques passively listened to sounds whose identity and timing was random, thus preventing animals from forming valid predictions about upcoming sounds. Stimulus onset asynchrony ranged between 0.2 and 12.8 s, thus encompassing the clinically relevant timescale of refractoriness. Our results show refractoriness in all 8 previously identified middle- and long-latency components that peaked between 14 and 170 ms after tone onset. Refractoriness may reflect the formation and gradual decay of a basic sensory memory trace that may be mirrored by the expenditure and gradual recovery of a limited physiological resource that determines generator excitability. For all 8 components, results were consistent with the assumption that processing of each tone expends ∼65% of the available resource. Differences between components are caused by how quickly the resource recovers. Recovery time constants of different components ranged between 0.5 and 2 s. This work provides a solid conceptual, methodological, and computational foundation to dissect the physiological mechanisms of auditory refractoriness in the rhesus. Such knowledge may, in turn, help develop novel pharmacological, mechanism-targeted interventions. PMID:27512021
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A novel unsupervised analysis of electrophysiological signals reveals new sleep substages in mice.
Katsageorgiou, Vasiliki-Maria; Sona, Diego; Zanotto, Matteo; Lassi, Glenda; Garcia-Garcia, Celina; Tucci, Valter; Murino, Vittorio
2018-05-01
Sleep science is entering a new era, thanks to new data-driven analysis approaches that, combined with mouse gene-editing technologies, show a promise in functional genomics and translational research. However, the investigation of sleep is time consuming and not suitable for large-scale phenotypic datasets, mainly due to the need for subjective manual annotations of electrophysiological states. Moreover, the heterogeneous nature of sleep, with all its physiological aspects, is not fully accounted for by the current system of sleep stage classification. In this study, we present a new data-driven analysis approach offering a plethora of novel features for the characterization of sleep. This novel approach allowed for identifying several substages of sleep that were hidden to standard analysis. For each of these substages, we report an independent set of homeostatic responses following sleep deprivation. By using our new substages classification, we have identified novel differences among various genetic backgrounds. Moreover, in a specific experiment with the Zfhx3 mouse line, a recent circadian mutant expressing both shortening of the circadian period and abnormal sleep architecture, we identified specific sleep states that account for genotypic differences at specific times of the day. These results add a further level of interaction between circadian clock and sleep homeostasis and indicate that dissecting sleep in multiple states is physiologically relevant and can lead to the discovery of new links between sleep phenotypes and genetic determinants. Therefore, our approach has the potential to significantly enhance the understanding of sleep physiology through the study of single mutations. Moreover, this study paves the way to systematic high-throughput analyses of sleep.
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Klein, Karen Oerter
2015-07-01
There are many questions which cannot be answered without a very sensitive estradiol assay. A recombinant cell bioassay (RCBA) for estradiol was developed in 1994. The sensitivity of the bioassay is 0.02-0.2 pg/ml (0.07-0.7 pmol/L), more than 20 times more sensitive than commercial RIAs and 10 times more sensitive than newer mass spectrometry assays. The RCBA for estradiol opened the door to study low levels of estradiol equivalents (EE) across the physiological spectrum of life from prepubertal children through menopause and across the spectrum from normal physiology, in boys as well as girls, to pathology, including: premature thelarche; estradiol suppression in children treated with GnRH analogues for precocious puberty; aromatase inhibition in boys with growth hormone deficiency; the differences between oral and transdermal routes of estrogen administration in girls with Turner's syndrome; women with breast cancer treated with aromatase inhibitors; and women with urogenital atrophy treated with low dose vaginal estrogen. A bioassay also allows study of endocrine disruptors, like phytoestrogens and other environmental compounds, which are relevant to public health and alternative medicine options. This paper reviews the assay and the last 20 years of applications. A bioassay for estrogen has a role because measuring biological effect is theoretically useful, increasing the understanding of physiology in addition to biochemical levels, giving different information than other assays, and opening the door to measure very low levels of estrogen activity in both humans and the environment. Copyright © 2014 Elsevier Inc. All rights reserved.
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Physiology education in North American dental schools: the basic science survey series.
Gautam, Medha; Shaw, David H; Pate, Ted D; Lambert, H Wayne
2014-06-01
As part of the Basic Science Survey Series for Dentistry, members of the American Dental Education Association (ADEA) Physiology, Pharmacology, and Therapeutics Section surveyed directors of physiology courses in North American dental schools. The survey was designed to assess, among other things, faculty affiliation and experience of course directors, teaching methods, general course content and emphasis, extent of interdisciplinary (shared) instruction, and impact of recent curricular changes. Responses were received from forty-four of sixty-seven (65.7 percent) U.S. and Canadian dental schools. The findings suggest the following: substantial variation exists in instructional hours, faculty affiliation, class size, and interdisciplinary nature of physiology courses; physiology course content emphasis is similar between schools; student contact hours in physiology, which have remained relatively stable in the past fifteen years, are starting to be reduced; recent curricular changes have often been directed towards enhancing the integrative and clinically relevant aspects of physiology instruction; and a trend toward innovative content delivery, such as use of computer-assisted instruction, is evident. Data from this study may be useful to physiology course directors, curriculum committees, and other dental educators with an interest in integrative and interprofessional education.
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Tufts, Mark
2014-01-01
Health Science students at the University of KwaZulu-Natal perform better in their professional modules compared with their physiology modules. The pass rates of physiology service modules have steadily declined over the years. While a system is in place to identify “at-risk” students, it is only activated after the first semester. As a result, it is only from the second semester of their first year studies onward that at-risk students can be formally assisted. The challenge is thus to devise an appropriate strategy to identify struggling students earlier in the semester. Using questionnaires, students were asked about attendance, financing of their studies, and relevance of physiology. After the first class test, failing students were invited to complete a second questionnaire. In addition, demographic data were also collected and analyzed. Correlation analyses were undertaken of performance indicators based on the demographical data collected. The 2011 class comprised mainly sport science students (57%). The pass rate of sport science students was lower than the pass rates of other students (42% vs. 70%, P < 0.001). Most students were positive about physiology and recognized its relevance. Key issues identified were problems understanding concepts and terminology, poor study environment and skills, and lack of matriculation biology. The results of the first class test and final module marks correlated well. It is clear from this study that student performance in the first class test is a valuable tool to identify struggling students and that appropriate testing should be held as early as possible. PMID:24913452
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Mammalian lipoxygenases and their biological relevance.
Kuhn, Hartmut; Banthiya, Swathi; van Leyen, Klaus
2015-04-01
Lipoxygenases (LOXs) form a heterogeneous class of lipid peroxidizing enzymes, which have been implicated not only in cell proliferation and differentiation but also in the pathogenesis of various diseases with major public health relevance. As other fatty acid dioxygenases LOXs oxidize polyunsaturated fatty acids to their corresponding hydroperoxy derivatives, which are further transformed to bioactive lipid mediators (eicosanoids and related substances). On the other hand, lipoxygenases are key players in the regulation of the cellular redox homeostasis, which is an important element in gene expression regulation. Although the first mammalian lipoxygenases were discovered 40 years ago and although the enzymes have been well characterized with respect to their structural and functional properties the biological roles of the different lipoxygenase isoforms are not completely understood. This review is aimed at summarizing the current knowledge on the physiological roles of different mammalian LOX-isoforms and their patho-physiological function in inflammatory, metabolic, hyperproliferative, neurodegenerative and infectious disorders. This article is part of a Special Issue entitled "Oxygenated metabolism of PUFA: analysis and biological relevance". Copyright © 2014 Elsevier B.V. All rights reserved.
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NASA Technical Reports Server (NTRS)
Nickerson, Cheryl A.; Ott, C. Mark; Wilson, James W.; Ramamurthy, Rajee; LeBlanc, Carly L.; Honer zu Bentrup, Kerstin; Hammond, Timothy; Pierson, Duane L.
2003-01-01
Bacteria inhabit an impressive variety of ecological niches and must adapt constantly to changing environmental conditions. While numerous environmental signals have been examined for their effect on bacteria, the effects of mechanical forces such as shear stress and gravity have only been investigated to a limited extent. However, several important studies have demonstrated a key role for the environmental signals of low shear and/or microgravity in the regulation of bacterial gene expression, physiology, and pathogenesis [Chem. Rec. 1 (2001) 333; Appl. Microbiol. Biotechnol. 54 (2000) 33; Appl. Environ. Microbiol. 63 (1997) 4090; J. Ind. Microbiol. 18 (1997) 22; Curr. Microbiol. 34(4) (1997) 199; Appl. Microbiol. Biotechnol. 56(3-4) (2001) 384; Infect Immun. 68(6) (2000) 3147; Cell 109(7) (2002) 913; Appl. Environ. Microbiol. 68(11) (2002) 5408; Proc. Natl. Acad. Sci. U. S. A. 99(21) (2002) 13807]. The response of bacteria to these environmental signals, which are similar to those encountered during prokaryotic life cycles, may provide insight into bacterial adaptations to physiologically relevant conditions. This review focuses on the current and potential future research trends aimed at understanding the effect of the mechanical forces of low shear and microgravity analogues on different bacterial parameters. In addition, this review also discusses the use of microgravity technology to generate physiologically relevant human tissue models for research in bacterial pathogenesis.
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TRI-Worthy Projects for the Deep Space Gateway
NASA Astrophysics Data System (ADS)
Wotring, V. E.; Strangman, G. E.; Donoviel, D.
2018-02-01
Preparations for exploration will require exposure to the actual deep space environment. The new TRI for Space Health proposes innovative projects using real space radiation to make medically-relevant measurements affecting human physiology.
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The relevance of phylogeny to studies of global change.
Edwards, Erika J; Still, Christopher J; Donoghue, Michael J
2007-05-01
Phylogenetic thinking has infiltrated many areas of biological research, but has had little impact on studies of global ecology or climate change. Here, we illustrate how phylogenetic information can be relevant to understanding vegetation-atmosphere dynamics at ecosystem or global scales by re-analyzing a data set of carbonic anhydrase (CA) activity in leaves that was used to estimate terrestrial gross primary productivity. The original calculations relied on what appeared to be low CA activity exclusively in C4 grasses, but our analyses indicate that such activity might instead characterize the PACCAD grass lineage, which includes many widespread C3 species. We outline how phylogenetics can guide better taxon sampling of key physiological traits, and discuss how the emerging field of phyloinformatics presents a promising new framework for scaling from organism physiology to global processes.
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Sex Differences in Androgen Regulation of Metabolism in Nonhuman Primates.
True, Cadence; Abbott, David H; Roberts, Charles T; Varlamov, Oleg
2017-01-01
The in-depth characterization of sex differences relevant to human physiology requires the judicious use of a variety of animal models and human clinical data. Nonhuman primates (NHPs) represent an important experimental system that bridges rodent studies and clinical investigations. NHP studies have been especially useful in understanding the role of sex hormones in development and metabolism and also allow the elucidation of the effects of pertinent dietary influences on physiology pertinent to disease states such as obesity and diabetes. This chapter summarizes the current state of our understanding of androgen effects on male and female NHP metabolism relevant to hypogonadism in human males and polycystic ovary syndrome in human females. This review will also focus on the interaction between altered androgen levels and dietary restriction and excess, in particular the Western-style diet that underlies significant human pathophysiology.
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SEX DIFFERENCES IN ANDROGEN REGULATION OF METABOLISM IN NONHUMAN PRIMATES
True, Cadence; Abbott, David H.; Roberts, Charles T.; Varlamov, Oleg
2018-01-01
The in-depth characterization of sex differences relevant to human physiology requires the judicious use of a variety of animal models and human clinical data. Nonhuman primates (NHPs) represent an important experimental system that bridges rodent studies and clinical investigations. NHP studies have been especially useful in understanding the role of sex hormones in development and metabolism and also allow the elucidation of the effects of pertinent dietary influences on physiology pertinent to disease states such as obesity and diabetes. This chapter summarizes the current state of our understanding of androgen effects on male and female NHP metabolism relevant to hypogonadism in human males and polycystic ovary syndrome in human females, as well as the interaction between altered androgen levels and dietary restriction and excess, in particular the western-style diet that underlies significant human pathophysiology. PMID:29224110
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Pathways of the Maillard reaction under physiological conditions.
Henning, Christian; Glomb, Marcus A
2016-08-01
Initially investigated as a color formation process in thermally treated foods, nowadays, the relevance of the Maillard reaction in vivo is generally accepted. Many chronic and age-related diseases such as diabetes, uremia, atherosclerosis, cataractogenesis and Alzheimer's disease are associated with Maillard derived advanced glycation endproducts (AGEs) and α-dicarbonyl compounds as their most important precursors in terms of reactivity and abundance. However, the situation in vivo is very challenging, because Maillard chemistry is paralleled by enzymatic reactions which can lead to both, increases and decreases in certain AGEs. In addition, mechanistic findings established under the harsh conditions of food processing might not be valid under physiological conditions. The present review critically discusses the relevant α-dicarbonyl compounds as central intermediates of AGE formation in vivo with a special focus on fragmentation pathways leading to formation of amide-AGEs.
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A physical action potential generator: design, implementation and evaluation.
Latorre, Malcolm A; Chan, Adrian D C; Wårdell, Karin
2015-01-01
The objective was to develop a physical action potential generator (Paxon) with the ability to generate a stable, repeatable, programmable, and physiological-like action potential. The Paxon has an equivalent of 40 nodes of Ranvier that were mimicked using resin embedded gold wires (Ø = 20 μm). These nodes were software controlled and the action potentials were initiated by a start trigger. Clinically used Ag-AgCl electrodes were coupled to the Paxon for functional testing. The Paxon's action potential parameters were tunable using a second order mathematical equation to generate physiologically relevant output, which was accomplished by varying the number of nodes involved (1-40 in incremental steps of 1) and the node drive potential (0-2.8 V in 0.7 mV steps), while keeping a fixed inter-nodal timing and test electrode configuration. A system noise floor of 0.07 ± 0.01 μV was calculated over 50 runs. A differential test electrode recorded a peak positive amplitude of 1.5 ± 0.05 mV (gain of 40x) at time 196.4 ± 0.06 ms, including a post trigger delay. The Paxon's programmable action potential like signal has the possibility to be used as a validation test platform for medical surface electrodes and their attached systems.
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Circadian variation and soccer performance: implications for training and match-play during Ramadan.
Drust, B; Ahmed, Q; Roky, R
2012-01-01
Ramadan results in a number of behavioural alterations in individuals when compared to their normal habits outside of this holy month. These changes in behaviour could impact upon the effectiveness of the activity of an elite athlete who has high daily activity levels and energy expenditures. Understanding the true impact of Ramadan on human physiology will also require an awareness of the key aspects of circadian rhythms. This article will present theoretical background content on circadian rhythms along with data on the potential influence of circadian variation on soccer performance. It will also attempt to provide an insight into the problems of partial sleep deprivation and travel for the elite player. The contents will suggest that there is a basis for the within-day variation in physiological and psychological function to impact soccer performance if games are played early in the day or very late at night. As competitive fixtures are uncommon at these times these influences may be more relevant to the timing and organisation of training sessions. It is also likely that a lack of sleep and excessive travel will provide conditions that are not conducive to optimal performance. This would indicate that teams should think carefully about their preparation strategies for important tournaments and games.
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Biological clocks: their relevance to immune-allergic diseases.
Paganelli, Roberto; Petrarca, Claudia; Di Gioacchino, Mario
2018-01-01
The 2017 Nobel Prize for Physiology or Medicine, awarded for the discoveries made in the past 15 years on the genetic and molecular mechanisms regulating many physiological functions, has renewed the attention to the importance of circadian rhythms. These originate from a central pacemaker in the suprachiasmatic nucleus in the brain, photoentrained via direct connection with melanopsin containing, intrinsically light-sensitive retinal ganglion cells, and it projects to periphery, thus creating an inner circadian rhythm. This regulates several activities, including sleep, feeding times, energy metabolism, endocrine and immune functions. Disturbances of these rhythms, mainly of wake/sleep, hormonal secretion and feeding, cause decrease in quality of life, as well as being involved in development of obesity, metabolic syndrome and neuropsychiatric disorders. Most immunological functions, from leukocyte numbers, activity and cytokine secretion undergo circadian variations, which might affect susceptibility to infections. The intensity of symptoms and disease severity show a 24 h pattern in many immunological and allergic diseases, including rheumatoid arthritis, bronchial asthma, atopic eczema and chronic urticaria. This is accompanied by altered sleep duration and quality, a major determinant of quality of life. Shift work and travel through time zones as well as artificial light pose new health threats by disrupting the circadian rhythms. Finally, the field of chronopharmacology uses these concepts for delivering drugs in synchrony with biological rhythms.
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Liu, Chengyu; Zheng, Dingchang; Zhao, Lina; Liu, Changchun
2014-01-01
It has been reported that Gaussian functions could accurately and reliably model both carotid and radial artery pressure waveforms (CAPW and RAPW). However, the physiological relevance of the characteristic features from the modeled Gaussian functions has been little investigated. This study thus aimed to determine characteristic features from the Gaussian functions and to make comparisons of them between normal subjects and heart failure patients. Fifty-six normal subjects and 51 patients with heart failure were studied with the CAPW and RAPW signals recorded simultaneously. The two signals were normalized first and then modeled by three positive Gaussian functions, with their peak amplitude, peak time, and half-width determined. Comparisons of these features were finally made between the two groups. Results indicated that the peak amplitude of the first Gaussian curve was significantly decreased in heart failure patients compared with normal subjects (P<0.001). Significantly increased peak amplitude of the second Gaussian curves (P<0.001) and significantly shortened peak times of the second and third Gaussian curves (both P<0.001) were also presented in heart failure patients. These results were true for both CAPW and RAPW signals, indicating the clinical significance of the Gaussian modeling, which should provide essential tools for further understanding the underlying physiological mechanisms of the artery pressure waveform.
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Dental Considerations in Pregnancy-A Critical Review on the Oral Care
VT, Hemalatha; T, Manigandan; T, Sarumathi; Nisha V, Aarthi; A, Amudhan
2013-01-01
Pregnancy is a dynamic physiological state which is evidenced by several transient changes. These can develop as various physical signs and symptoms that can affect the patients health, perceptions and interactions with others in the environment. The patients may not always understand the relevance of the adaptations of their bodies to the health of their foetuses. A gestational woman requires various levels of support throughout this time, such as medical monitoring or intervention, preventive care and physical and emotional assistance. The dental management of pregnant patients requires special attention. Dentists, for example, may delay certain elective procedures so that they coincide with the periods of pregnancy which are devoted to maturation versus organogenesis. At other times, the dental care professionals need to alter their normal pharmacological armamentarium to address the patients’ needs versus the foetal demands. Applying the basics of preventive dentistry at the primary level will broaden the scope of the prenatal care. Dentists should encourage all the patients of the childbearing ages to seek oral health counseling and examinations as soon as they learn that they are pregnant. This article has reviewed some of the physiologic changes and the oral pathologies which are associated with pregnancy, and how these alterations can affect the dental care of the patient. PMID:23814753
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Dental considerations in pregnancy-a critical review on the oral care.
Vt, Hemalatha; T, Manigandan; T, Sarumathi; Nisha V, Aarthi; A, Amudhan
2013-05-01
Pregnancy is a dynamic physiological state which is evidenced by several transient changes. These can develop as various physical signs and symptoms that can affect the patients health, perceptions and interactions with others in the environment. The patients may not always understand the relevance of the adaptations of their bodies to the health of their foetuses. A gestational woman requires various levels of support throughout this time, such as medical monitoring or intervention, preventive care and physical and emotional assistance. The dental management of pregnant patients requires special attention. Dentists, for example, may delay certain elective procedures so that they coincide with the periods of pregnancy which are devoted to maturation versus organogenesis. At other times, the dental care professionals need to alter their normal pharmacological armamentarium to address the patients' needs versus the foetal demands. Applying the basics of preventive dentistry at the primary level will broaden the scope of the prenatal care. Dentists should encourage all the patients of the childbearing ages to seek oral health counseling and examinations as soon as they learn that they are pregnant. This article has reviewed some of the physiologic changes and the oral pathologies which are associated with pregnancy, and how these alterations can affect the dental care of the patient.
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Crew activities, science, and hazards of manned missions to Mars
NASA Technical Reports Server (NTRS)
Clark, Benton C.
1988-01-01
The crew scientific and nonscientific activities that will occur at each stage of a mission to Mars are examined. Crew activities during the interplanetary flight phase will include simulations, maintenance and monitoring, communications, upgrading procedures and operations, solar activity monitoring, cross-training and sharpening of skills, physical conditioning, and free-time activities. Scientific activities will address human physiology, human psychology, sociology, astronomy, space environment effects, manufacturing, and space agriculture. Crew activities on the Martian surface will include exploration, construction, manufacturing, food production, maintenance and training, and free time. Studies of Martian geology and atmosphere, of the life forms that may exist there, and of the Martian moons will occur on the planet's surface. Crew activities and scientific studies that will occur in Mars orbit, and the hazards relevant to each stage of the mission, are also addressed.
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Desorption kinetics of organic chemicals from albumin.
Krause, Sophia; Ulrich, Nadin; Goss, Kai-Uwe
2018-03-01
When present in blood, most chemicals tend to bind to the plasma protein albumin. For distribution into surrounding tissues, desorption from albumin is necessary, because only the unbound form of a chemical is assumed to be able to cross cell membranes. For metabolism of chemicals, the liver is a particularly important organ. One potentially limiting step for hepatic uptake of the chemicals is desorption from albumin, because blood passes the human liver within seconds. Desorption kinetics from albumin can thus be an important parameter for our pharmacokinetic and toxicokinetic understanding of chemicals. This work presents a dataset of measured desorption rate constants and reveals a possibility for their prediction. Additionally, the obtained extraction profiles directly indicate physiological relevance of desorption kinetics, because desorption of the test chemicals is still incomplete after time frames comparable to the residence time of blood in the liver.
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What makes the learning of physiology in a PBL medical curriculum challenging? Student perceptions.
Tufts, Mark A; Higgins-Opitz, Susan B
2009-09-01
Physiology is an integral component of any medical curriculum. Traditionally, the learning of physiology has relied heavily on systems-based didactic lectures. In 2001, the Nelson R. Mandela School of Medicine (NRMSM; Durban, South Africa) embarked on a problem-based curriculum in which the learning of physiology was integrated with relevant clinical scenarios. Students are expected to gain an understanding of physiology through self-directed research with only certain aspects being covered in large-group resource sessions (LGRSs). It has gradually become evident that this approach has resulted in significant gaps in students' understanding of basic physiological concepts. A survey of student perceptions of needs for physiology was undertaken to gain a better understanding of their perceived problems and also to inform them of proposed curricular changes. Students were asked to what extent they thought physiology was essential for their understanding of pathology, interpretation of patients' clinical signs and presentation of symptoms, and analysis of laboratory results. Students were also invited to detail the difficulties they experienced in understanding in LGRSs on clinical and physiological topics. The results of the survey indicate that greater interaction of students with experts is needed. In particular, students felt that they lacked the basic conceptual foundations essential for the learning and understanding of physiology, since the difficulties that the students identified are mainly terminological and conceptual in nature.
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NASA Technical Reports Server (NTRS)
Vernikos, J.
1996-01-01
The universality of gravity (1 g) in our daily lives makes it difficult to appreciate its importance in morphology and physiology. Bone and muscle support systems were created, cellular pumps developed, neurons organised and receptors and transducers of gravitational force to biologically relevant signals evolved under 1g gravity. Spaceflight provides the only microgravity environment where systematic experimentation can expand our basic understanding of gravitational physiology and perhaps provide new insights into normal physiology and disease processes. These include the surprising extent of our body's dependence on perceptual information, and understanding the effect and importance of forces generated within the body's weightbearing structures such as muscle and bones. Beyond this exciting prospect is the importance of this work towards opening the solar system for human exploration. Although both appear promising, we are only just beginning to taste what lies ahead.
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Interpretation of physiological indicators of motivation: Caveats and recommendations.
Richter, Michael; Slade, Kate
2017-09-01
Motivation scientists employing physiological measures to gather information about motivation-related states are at risk of committing two fundamental errors: overstating the inferences that can be drawn from their physiological measures and circular reasoning. We critically discuss two complementary approaches, Cacioppo and colleagues' model of psychophysiological relations and construct validation theory, to highlight the conditions under which these errors are committed and provide guidance on how to avoid them. In particular, we demonstrate that the direct inference from changes in a physiological measure to changes in a motivation-related state requires the demonstration that the measure is not related to other relevant psychological states. We also point out that circular reasoning can be avoided by separating the definition of the motivation-related state from the hypotheses that are empirically tested. Copyright © 2017 Elsevier B.V. All rights reserved.
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Bart's familiar quotations: the enduring biological wisdom of George A. Bartholomew.
Huey, Raymond B; Bennett, Albert F
2008-01-01
George A. Bartholomew was one of the most influential organismal biologists of the twentieth century. His insights and research were fundamental to the establishment and growth of physiological ecology and evolutionary physiology. In the process of fostering that area of science, he created a body of literature that is striking in the clarity of its thought and presentation. Here we present some of his most insightful and important quotations, group them thematically, and comment on their original context and their continuing relevance.
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Role of Neuroactive Steroids in the Peripheral Nervous System
Melcangi, Roberto Cosimo; Giatti, Silvia; Pesaresi, Marzia; Calabrese, Donato; Mitro, Nico; Caruso, Donatella; Garcia-Segura, Luis Miguel
2011-01-01
Several reviews have so far pointed out on the relevant physiological and pharmacological role exerted by neuroactive steroids in the central nervous system. In the present review we summarize observations indicating that synthesis and metabolism of neuroactive steroids also occur in the peripheral nerves. Interestingly, peripheral nervous system is also a target of their action. Indeed, as here reported neuroactive steroids are physiological regulators of peripheral nerve functions and they may also represent interesting therapeutic tools for different types of peripheral neuropathy. PMID:22654839
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A conceptual framework for homeostasis: development and validation
Wenderoth, Mary Pat; Michael, Joel; Cliff, William; Wright, Ann; Modell, Harold
2016-01-01
We have developed and validated a conceptual framework for understanding and teaching organismal homeostasis at the undergraduate level. The resulting homeostasis conceptual framework details critical components and constituent ideas underlying the concept of homeostasis. It has been validated by a broad range of physiology faculty members from community colleges, primarily undergraduate institutions, research universities, and medical schools. In online surveys, faculty members confirmed the relevance of each item in the framework for undergraduate physiology and rated the importance and difficulty of each. The homeostasis conceptual framework was constructed as a guide for teaching and learning of this critical core concept in physiology, and it also paves the way for the development of a concept inventory for homeostasis. PMID:27105740
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[Review on infrared temperature characteristics of acupoints in recent 10 years].
Lin, Min; Wei, Haiyan; Zhao, Ling; Zhao, Jizhong; Cheng, Ke; Deng, Haiping; Shen, Xueyong; Zhang, Haimeng
2017-04-12
In the paper, the study was reviewed on the infrared temperature characteristics of acupoints in recent 10 years. CNKI, WANFANG, VIP, SciVerse ScienceDirect and Springer databases were retrieved, with"infrared thermal imaging" and "acupoint" as the key words. The retrieving time was from January 1, 2006 to December 31, 2016. Totally, 468 relevant papers were searched and 169 papers of them were read carefully on acupoint infrared temperature. In terms of physiological condition, pathological condition and the stimulation methods such as acupuncture, moxibustion, tuina , embedding therapy and cupping therapy, the general situation was reviewed on the infrared temperature characteristics of acupoints separately. It was found that the study on infrared temperature characteristics of acupoints in physiological condition was limited and the characteristics discovered were not enough to systematically review the physiological and physical properties of acupoints. The study in terms of the pathological condition objectively reflected the effects and rules of diseases. It was showed in the study of acupoint infrared temperature characteristics after stimulation that the changes of infrared thermal imaging tempe-rature at some specific region induced by different therapies and parameters might be used to deduce the potential mechanism and optimal parameters or schemes of intervention method and contributed to the formation and deve-lopment of quantitative diagnosis and treatment. The authors believe that the study on infrared temperature characteristics of acupoint provides the active significance in the exploration on the physiological and physical characteristics of acupoint, the effects and rules of diseases as well as the quantitative diagnosis and treatment.
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Computational model of cerebral blood flow redistribution during cortical spreading depression
NASA Astrophysics Data System (ADS)
Verisokin, Andrey Y.; Verveyko, Darya V.; Postnov, Dmitry E.
2016-04-01
In recent decades modelling studies on cortical spreading depression (CSD) and migraine waves successfully contributed to formation of modern view on these fundamental phenomena of brain physiology. However, due to the extreme complexity of object under study (brain cortex) and the diversity of involved physiological pathways, the development of new mathematical models of CSD is still a very relevant and challenging research problem. In our study we follow the functional modelling approach aimed to map the action of known physiological pathways to the specific nonlinear mechanisms that govern formation and evolution of CSD wave patterns. Specifically, we address the role of cerebral blood flow (CBF) redistribution that is caused by excessive neuronal activity by means of neurovascular coupling and mediates a spatial pattern of oxygen and glucose delivery. This in turn changes the local metabolic status of neural tissue. To build the model we simplify the web of known cell-to-cell interactions within a neurovascular unit by selecting the most relevant ones, such as local neuron-induced elevation of extracellular potassium concentration and biphasic response of arteriole radius. We propose the lumped description of distance-dependent hemodynamic coupling that fits the most recent experimental findings.
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Tunable Collagen I Hydrogels for Engineered Physiological Tissue Micro-Environments
Antoine, Elizabeth E.; Vlachos, Pavlos P.; Rylander, Marissa N.
2015-01-01
Collagen I hydrogels are commonly used to mimic the extracellular matrix (ECM) for tissue engineering applications. However, the ability to design collagen I hydrogels similar to the properties of physiological tissues has been elusive. This is primarily due to the lack of quantitative correlations between multiple fabrication parameters and resulting material properties. This study aims to enable informed design and fabrication of collagen hydrogels in order to reliably and reproducibly mimic a variety of soft tissues. We developed empirical predictive models relating fabrication parameters with material and transport properties. These models were obtained through extensive experimental characterization of these properties, which include compression modulus, pore and fiber diameter, and diffusivity. Fabrication parameters were varied within biologically relevant ranges and included collagen concentration, polymerization pH, and polymerization temperature. The data obtained from this study elucidates previously unknown fabrication-property relationships, while the resulting equations facilitate informed a priori design of collagen hydrogels with prescribed properties. By enabling hydrogel fabrication by design, this study has the potential to greatly enhance the utility and relevance of collagen hydrogels in order to develop physiological tissue microenvironments for a wide range of tissue engineering applications. PMID:25822731
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NASA Astrophysics Data System (ADS)
Curry, Dennis; Cameron, Amanda; MacDonald, Bruce; Nganou, Collins; Scheller, Hope; Marsh, James; Beale, Stefanie; Lu, Mingsheng; Shan, Zhi; Kaliaperumal, Rajendran; Xu, Heping; Servos, Mark; Bennett, Craig; Macquarrie, Stephanie; Oakes, Ken D.; Mkandawire, Martin; Zhang, Xu
2015-11-01
Gold nanomaterials have received great interest for their use in cancer theranostic applications over the past two decades. Many gold nanoparticle-based drug delivery system designs rely on adsorbed ligands such as DNA or cleavable linkers to load therapeutic cargo. The heightened research interest was recently demonstrated in the simple design of nanoparticle-drug conjugates wherein drug molecules are directly adsorbed onto the as-synthesized nanoparticle surface. The potent chemotherapeutic, doxorubicin often serves as a model drug for gold nanoparticle-based delivery platforms; however, the specific interaction facilitating adsorption in this system remains understudied. Here, for the first time, we propose empirical and theoretical evidence suggestive of the main adsorption process where (1) hydrophobic forces drive doxorubicin towards the gold nanoparticle surface before (2) cation-π interactions and gold-carbonyl coordination between the drug molecule and the cations on AuNP surface facilitate DOX adsorption. In addition, biologically relevant compounds, such as serum albumin and glutathione, were shown to enhance desorption of loaded drug molecules from AuNP at physiologically relevant concentrations, providing insight into the drug release and in vivo stability of such drug conjugates.Gold nanomaterials have received great interest for their use in cancer theranostic applications over the past two decades. Many gold nanoparticle-based drug delivery system designs rely on adsorbed ligands such as DNA or cleavable linkers to load therapeutic cargo. The heightened research interest was recently demonstrated in the simple design of nanoparticle-drug conjugates wherein drug molecules are directly adsorbed onto the as-synthesized nanoparticle surface. The potent chemotherapeutic, doxorubicin often serves as a model drug for gold nanoparticle-based delivery platforms; however, the specific interaction facilitating adsorption in this system remains understudied. Here, for the first time, we propose empirical and theoretical evidence suggestive of the main adsorption process where (1) hydrophobic forces drive doxorubicin towards the gold nanoparticle surface before (2) cation-π interactions and gold-carbonyl coordination between the drug molecule and the cations on AuNP surface facilitate DOX adsorption. In addition, biologically relevant compounds, such as serum albumin and glutathione, were shown to enhance desorption of loaded drug molecules from AuNP at physiologically relevant concentrations, providing insight into the drug release and in vivo stability of such drug conjugates. Electronic supplementary information (ESI) available: DOX-AuNP absorption spectra and colored solution images, citrate displacement data, original DOX-AuNP loading isotherm, XPS data and TEM micrographs, modelling data. See DOI: 10.1039/c5nr05826k
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Neubert, D; Gericke, C; Hanke, B; Beckmann, G; Baltes, M M; Kühl, K P; Bochert, G; Hartmann, J
2001-11-15
Data on possible acute effects of today's relevant low-level exposure to toluene are contradictory, and information on possible effects of exposure under occupational conditions is largely lacking. In a controlled, multi-center, blinded field trial, effects possibly associated with acute toluene exposure were evaluated in workers of 12 German rotogravure factories. Medical examinations (inquiries on subjective symptoms, and standard tests of psycho-physiological and psycho-motor functions) were performed on almost 1500 volunteers, of whom 1290 were toluene-exposed (1178 men and 112 women), and about 200 participants served as references (157 men and 37 women), but the main aim of the trial was to reveal dose-response relationships. All volunteers were of the morning work-shift (6 h exposure). Both individual ambient air concentrations (time-weighted average) during the work-shift, as well as blood toluene concentrations after the work-shift were measured. Therefore, the medical data could for the first time be correlated with the actual individual body burden (blood toluene level) at the time of testing. In order to largely exclude confounding by chronic toluene exposure, kinetic measurements as well as the psycho-physiological and psycho-motoric tests were performed before and after the work-shift. Except for minor statistical deviations, neither convincing dose-dependent acute effects could be demonstrated with regression analyses in male volunteers at the exposure levels evaluated, nor were significant differences found when applying group statistics (highly toluene-exposed group versus volunteers with negligible exposure). Due to the rather large number of participants, the predictive power of the study is high, especially when compared with previous publications. In two psycho-physiological tests, a few more female volunteers with quite low toluene body burdens (<340 microg/l blood) showed relatively low scores when compared with participants of the reference group. Although evidence for a medical relevance is meager, the small numbers of participants, in both the exposure and the reference groups, hamper a reliable interpretation of the results concerning exposure levels above 85 microg toluene/l blood, and it is difficult to take confounding factors adequately into account. For the end points evaluated and under occupational conditions, neither blood toluene levels of 850 to 1700 microg/l (in the highest exposure group [EXPO-IV] with 56 participants), as measured 1/2 (+/-1/2) h after the work-shift, nor ambient air concentrations (time-weighted average over 6 h) between 50 and 100 ppm (188-375 mg/m(3)) were convincingly associated with alterations in psycho-physiological and psycho-motoric performances or increased the frequency of subjective complaints in male volunteers. For higher dose ranges of toluene exposure (i.e. >1700 microg toluene/l blood [or >100 ppm in ambient air]), our data set is too small for far reaching conclusions. Our data are insufficient for conclusions on a possibly higher susceptibility to toluene of some female workers. Results of kinetic studies and possible effects of long-term exposure are discussed in two accompanying publications (Neubert et al., 2001; Gericke et al., 2001).
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Effects of Vibration and G-Loading on Heart Rate, Breathing Rate, and Response Time
NASA Technical Reports Server (NTRS)
Godinez, Angelica; Ayzenberg, Ruthie; Liston, Dorian B.; Stone, Leland S.
2013-01-01
Aerospace and applied environments commonly expose pilots and astronauts to G-loading and vibration, alone and in combination, with well-known sensorimotor (Cohen, 1970) and performance consequences (Adelstein et al., 2008). Physiological variables such as heart rate (HR) and breathing rate (BR) have been shown to increase with G-loading (Yajima et al., 1994) and vibration (e.g. Guignard, 1965, 1985) alone. To examine the effects of G-loading and vibration, alone and in combination, we measured heart rate and breathing rate under aerospace-relevant conditions (G-loads of 1 Gx and 3.8 Gx; vibration of 0.5 gx at 8, 12, and 16 Hz).
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Reviewing the relevance of fluorescence in biological systems.
Lagorio, M Gabriela; Cordon, Gabriela B; Iriel, Analia
2015-09-26
Fluorescence is emitted by diverse living organisms. The analysis and interpretation of these signals may give information about their physiological state, ways of communication among species and the presence of specific chemicals. In this manuscript we review the state of the art in the research on the fluorescence emitted by plant leaves, fruits, flowers, avians, butterflies, beetles, dragonflies, millipedes, cockroaches, bees, spiders, scorpions and sea organisms and discuss its relevance in nature.
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Association of enjoyable leisure activities with psychological and physical well-being.
Pressman, Sarah D; Matthews, Karen A; Cohen, Sheldon; Martire, Lynn M; Scheier, Michael; Baum, Andrew; Schulz, Richard
2009-09-01
To examine whether engaging in multiple enjoyable activities was associated with better psychological and physiological functioning. Few studies have examined the health benefits of the enjoyable activities that individuals participate in voluntarily in their free time. Participants from four different studies (n = 1399 total, 74% female, age = 19-89 years) completed a self-report measure (Pittsburgh Enjoyable Activities Test (PEAT)) assessing their participation in ten different types of leisure activities as well as measures assessing positive and negative psychosocial states. Resting blood pressure, cortisol (over 2 days), body mass index, waist circumference, and perceived physiological functioning were assessed. Higher PEAT scores were associated with lower blood pressure, total cortisol, waist circumference, and body mass index, and perceptions of better physical function. These associations withstood controlling for demographic measures. The PEAT was correlated with higher levels of positive psychosocial states and lower levels of depression and negative affect. Enjoyable leisure activities, taken in the aggregate, are associated with psychosocial and physical measures relevant for health and well-being. Future studies should determine the extent that these behaviors in the aggregate are useful predictors of disease and other health outcomes.
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Behavioral and biological interactions with small groups in confined microsocieties
NASA Technical Reports Server (NTRS)
Brady, Joseph V.
1986-01-01
Research on small group performance in confined microsocieties was focused upon the development of principles and procedures relevant to the selection and training of space mission personnel, upon the investigation of behavioral programming, preventive monitoring and corrective procedures to enhance space mission performance effectiveness, and upon the evaluation of behavioral and physiological countermeasures to the potentially disruptive effects of unfamiliar and stressful environments. An experimental microsociety environment was designed and developed for continuous residence of human volunteers over extended time periods. Studies were then undertaken to analyze experimentally: (1) conditions that sustain group cohesion and productivity and that prevent social fragmentation and performance deterioration, (2) motivational effects performance requirements, and (3) behavioral and physiological effects resulting from changes in group size and composition. The results show that both individual and group productivity can be enhanced under such conditions by the direct application of contingency management principles to designated high-value tasks. Similarly, group cohesiveness can be promoted and individual social isolation and/or alienation prevented by the application of contingency management principles to social interaction segments of the program.
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Does selection for short sleep duration explain human vulnerability to Alzheimer's disease?
Nesse, Randolph M; Finch, Caleb E; Nunn, Charles L
2017-01-16
Compared with other primates, humans sleep less and have a much higher prevalence of Alzheimer 's disease (AD) pathology. This article reviews evidence relevant to the hypothesis that natural selection for shorter sleep time in humans has compromised the efficacy of physiological mechanisms that protect against AD during sleep. In particular, the glymphatic system drains interstitial fluid from the brain, removing extra-cellular amyloid beta (eAβ) twice as fast during sleep. In addition, melatonin - a peptide hormone that increases markedly during sleep - is an effective antioxidant that inhibits the polymerization of soluble eAβ into insoluble amyloid fibrils that are associated with AD. Sleep deprivation increases plaque formation and AD, which itself disrupts sleep, potentially creating a positive feedback cycle. These and other physiological benefits of sleep may be compromised by short sleep durations. Our hypothesis highlights possible long-term side effects of medications that reduce sleep, and may lead to potential new strategies for preventing and treating AD. © The Author(s) 2017. Published by Oxford University Press on behalf of the Foundation for Evolution, Medicine, and Public Health.
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Dim light at night: physiological effects and ecological consequences for infectious disease.
Kernbach, Meredith E; Hall, Richard J; Burkett-Cadena, Nathan; Unnasch, Thomas R; Martin, Lynn B
2018-06-23
Light pollution has emerged as a pervasive component of land development over the past century. Several detrimental impacts of this anthropogenic influence have been identified in night shift workers, laboratory rodents, and a plethora of wildlife species. Circadian, or daily, patterns are interrupted by the presence of light at night and have the capacity to alter rhythmic physiological or behavioral characteristics. Indeed, biorhythm disruption can lead to metabolic, reproductive, and immunological dysfunction depending on the intensity, timing, duration and wavelength of light exposure. Light pollution, in many forms and by many pathways, is thus apt to affect the nature of host-pathogen interactions. However, no research has yet investigated this possibility. The goal of this manuscript is to outline how dim light at night (dLAN), a relevant and common form of light pollution, may affect disease dynamics by interrupting circadian rhythms and regulation of immune responses as well as opportunities for host-parasite interactions and subsequent transmission risk including spillover into humans. We close by proposing some promising interventions including alternative lighting methods or vector control efforts.
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Personality, emotion, and individual differences in physiological responses.
Stemmler, Gerhard; Wacker, Jan
2010-07-01
A dominant paradigm in biopsychological personality research seeks to establish links between emotional and motivational traits and habitual, transsituationally consistent individual differences in measures of physiological activity. An alternative approach conceptualizes traits as dispositions that are only operative in certain situational contexts and consequently predicts associations between emotional and motivational traits and physiological activity only for trait-relevant situational contexts in which the physiological systems underlying the traits in question are engaged. In the present paper we first examine and contrast these personistic and interactionistic conceptualizations of personality and personality-physiology associations and then present data from several large studies (N>100) in which electrocortical (e.g., frontal alpha asymmetry) and somatovisceral parameters were measured in various situational contexts (e.g., after the induction of either anger, or fear, or anxiety). As predicted by the interactionistic conceptualization of traits as dispositions the situational context and its subjective representation by the participants moderated the personality-physiology relationships for measures of both central and peripheral nervous system activity. We conclude by outlining the implications of the interactionistic approach for biopsychological personality research. Copyright © 2009 Elsevier B.V. All rights reserved.
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Physiologically relevant organs on chips
Yum, Kyungsuk; Hong, Soon Gweon; Lee, Luke P.
2015-01-01
Recent advances in integrating microengineering and tissue engineering have generated promising microengineered physiological models for experimental medicine and pharmaceutical research. Here we review the recent development of microengineered physiological systems, or organs on chips, that reconstitute the physiologically critical features of specific human tissues and organs and their interactions. This technology uses microengineering approaches to construct organ-specific microenvironments, reconstituting tissue structures, tissue–tissue interactions and interfaces, and dynamic mechanical and biochemical stimuli found in specific organs, to direct cells to assemble into functional tissues. We first discuss microengineering approaches to reproduce the key elements of physiologically important, dynamic mechanical microenvironments, biochemical microenvironments, and microarchitectures of specific tissues and organs in microfluidic cell culture systems. This is followed by examples of microengineered individual organ models that incorporate the key elements of physiological microenvironments into single microfluidic cell culture systems to reproduce organ-level functions. Finally, microengineered multiple organ systems that simulate multiple organ interactions to better represent human physiology, including human responses to drugs, is covered in this review. This emerging organs-on-chips technology has the potential to become an alternative to 2D and 3D cell culture and animal models for experimental medicine, human disease modeling, drug development, and toxicology. PMID:24357624
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Pajęcka, Kamilla, E-mail: kpaj@novonordisk.com; Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus; Nielsen, Malik Nygaard
Background and aims: Nephropathy involves pathophysiological changes to the glomerulus. The primary glomerular endothelial cells (GEnCs) have emerged as an important tool for studying glomerulosclerotic mechanisms and in the screening process for drug-candidates. The success of the studies is dependent on the quality of the cell model. Therefore, we set out to establish an easy, reproducible model of the quiescent endothelial monolayer with the use of commercially available extracellular matrices (ECMs). Methods: Primary hGEnCs were seeded on various ECMs. Cell adhesion was monitored by an impedance sensing system. The localization of junctional proteins was assessed by immunofluorescence and the barriermore » function by passage of fluorescent dextrans and magnitude of VEGF response. Results: All ECM matrices except recombinant human laminin 111 (rhLN111) supported comparable cell proliferation. Culturing hGEnCs on rhLN521, rhLN511 or fibronectin resulted in a physiologically relevant barrier to 70 kDa dextrans which was 82% tighter than that formed on collagen type IV. Furthermore, only hGEnCs cultured on rhLN521 or rhLN511 showed plasma-membrane localized zonula occludens-1 and vascular endothelial cadherin indicative of proper tight and adherens junctions (AJ). Conclusion: We recommend culturing hGEnCs on the mature glomerular basement membrane laminin - rhLN521 – which, as the only commercially available ECM, promotes all of the characteristics of the quiescent hGEnC monolayer: cobblestone morphology, well-defined AJs and physiological perm-selectivity. - Highlights: • rhLN521, rhLN511 and hFN assure physiologically relevant permeability. • rhLN521 and rhLN511 ensure best cell morphology and adherens junction formation. • Collagen IV and I based coating results in disorganized hGEnC monolayer. • Physiologically relevant ECM may lead to down-regulation of self-produced matrices.« less
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Cooke, Steven J; Hinch, Scott G; Donaldson, Michael R; Clark, Timothy D; Eliason, Erika J; Crossin, Glenn T; Raby, Graham D; Jeffries, Ken M; Lapointe, Mike; Miller, Kristi; Patterson, David A; Farrell, Anthony P
2012-06-19
Despite growing interest in conservation physiology, practical examples of how physiology has helped to understand or to solve conservation problems remain scarce. Over the past decade, an interdisciplinary research team has used a conservation physiology approach to address topical conservation concerns for Pacific salmon. Here, we review how novel applications of tools such as physiological telemetry, functional genomics and laboratory experiments on cardiorespiratory physiology have shed light on the effect of fisheries capture and release, disease and individual condition, and stock-specific consequences of warming river temperatures, respectively, and discuss how these findings have or have not benefited Pacific salmon management. Overall, physiological tools have provided remarkable insights into the effects of fisheries capture and have helped to enhance techniques for facilitating recovery from fisheries capture. Stock-specific cardiorespiratory thresholds for thermal tolerances have been identified for sockeye salmon and can be used by managers to better predict migration success, representing a rare example that links a physiological scope to fitness in the wild population. Functional genomics approaches have identified physiological signatures predictive of individual migration mortality. Although fisheries managers are primarily concerned with population-level processes, understanding the causes of en route mortality provides a mechanistic explanation and can be used to refine management models. We discuss the challenges that we have overcome, as well as those that we continue to face, in making conservation physiology relevant to managers of Pacific salmon.
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Cooke, Steven J.; Hinch, Scott G.; Donaldson, Michael R.; Clark, Timothy D.; Eliason, Erika J.; Crossin, Glenn T.; Raby, Graham D.; Jeffries, Ken M.; Lapointe, Mike; Miller, Kristi; Patterson, David A.; Farrell, Anthony P.
2012-01-01
Despite growing interest in conservation physiology, practical examples of how physiology has helped to understand or to solve conservation problems remain scarce. Over the past decade, an interdisciplinary research team has used a conservation physiology approach to address topical conservation concerns for Pacific salmon. Here, we review how novel applications of tools such as physiological telemetry, functional genomics and laboratory experiments on cardiorespiratory physiology have shed light on the effect of fisheries capture and release, disease and individual condition, and stock-specific consequences of warming river temperatures, respectively, and discuss how these findings have or have not benefited Pacific salmon management. Overall, physiological tools have provided remarkable insights into the effects of fisheries capture and have helped to enhance techniques for facilitating recovery from fisheries capture. Stock-specific cardiorespiratory thresholds for thermal tolerances have been identified for sockeye salmon and can be used by managers to better predict migration success, representing a rare example that links a physiological scope to fitness in the wild population. Functional genomics approaches have identified physiological signatures predictive of individual migration mortality. Although fisheries managers are primarily concerned with population-level processes, understanding the causes of en route mortality provides a mechanistic explanation and can be used to refine management models. We discuss the challenges that we have overcome, as well as those that we continue to face, in making conservation physiology relevant to managers of Pacific salmon. PMID:22566681
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Mesenchymal Stem Cells for Osteochondral Tissue Engineering
Ng, Johnathan; Bernhard, Jonathan; Vunjak-Novakovic, Gordana
2017-01-01
Summary Mesenchymal stem cells (MSC) are of major interest to regenerative medicine, because of the ease of harvesting from a variety of sources (including bone marrow and fat aspirates) and ability to form a range of mesenchymal tissues, in vitro and in vivo. We focus here on the use of MSCs for engineering of cartilage, bone, and complex osteochondral tissue constructs, using protocols that replicate some aspects of the natural mesodermal development. For engineering of human bone, we discuss some of the current advances, and highlight the use of perfusion bioreactors for supporting anatomically exact human bone grafts. For engineering of human cartilage, we discuss limitations of current approaches, and highlight engineering of stratified, mechanically functional human cartilage interfaced with bone by mesenchymal condensation of MSCs. Taken together, the current advances enable engineering physiologically relevant bone, cartilage and osteochondral composites, and physiologically relevant studies of osteochondral development and disease. PMID:27236665
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MicroRNAs and the metabolic hallmarks of aging.
Victoria, Berta; Nunez Lopez, Yury O; Masternak, Michal M
2017-11-05
Aging, the natural process of growing older, is characterized by a progressive deterioration of physiological homeostasis at the cellular, tissue, and organismal level. Metabolically, the aging process is characterized by extensive changes in body composition, multi-tissue/multi-organ insulin resistance, and physiological declines in multiple signaling pathways including growth hormone, insulin/insulin-like growth factor 1, and sex steroids regulation. With this review, we intend to consolidate published information about microRNAs that regulate critical metabolic processes relevant to aging. In certain occasions we uncover relationships likely relevant to aging, which has not been directly described before, such as the miR-451/AMPK axis. We have also included a provocative section highlighting the potential role in aging of a new designation of miRNAs, namely fecal miRNAs, recently discovered to regulate intestinal microbiota in mammals. Copyright © 2016. Published by Elsevier B.V.
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Mammalian lipoxygenases and their biological relevance
Kuhn, Hartmut; Banthiya, Swathi; van Leyen, Klaus
2015-01-01
Lipoxygenases (LOXs) form a heterogeneous class of lipid peroxidizing enzymes, which have been implicated in cell proliferation and differentiation but also in the pathogenesis of various diseases with major public health relevance. As other fatty acid dioxygenases LOX oxidize polyunsaturated fatty acids to their corresponding hydroperoxy derivatives, which are further transformed to bioactive lipid mediators (eicosanoids and related substances). On the other hand, lipoxygenases are key players in regulation of the cellular redox homeostasis, which is an important element in gene expression regulation. Although the first mammalian lipoxygenases were discovered 40 years ago and although the enzymes have been well characterized with respect to their structural and functional properties the biological roles of the different lipoxygenase isoforms are not completely understood. This review is aimed at summarizing the current knowledge on the physiological roles of different mammalian LOX-isoforms and their patho-physiological function in inflammatory, metabolic, hyperproliferative, neurodegenerative and infectious disorders. PMID:25316652
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Biological role of bacterial inclusion bodies: a model for amyloid aggregation.
García-Fruitós, Elena; Sabate, Raimon; de Groot, Natalia S; Villaverde, Antonio; Ventura, Salvador
2011-07-01
Inclusion bodies are insoluble protein aggregates usually found in recombinant bacteria when they are forced to produce heterologous protein species. These particles are formed by polypeptides that cross-interact through sterospecific contacts and that are steadily deposited in either the cell's cytoplasm or the periplasm. An important fraction of eukaryotic proteins form inclusion bodies in bacteria, which has posed major problems in the development of the biotechnology industry. Over the last decade, the fine dissection of the quality control system in bacteria and the recognition of the amyloid-like architecture of inclusion bodies have provided dramatic insights on the dynamic biology of these aggregates. We discuss here the relevant aspects, in the interface between cell physiology and structural biology, which make inclusion bodies unique models for the study of protein aggregation, amyloid formation and prion biology in a physiologically relevant background. © 2011 The Authors Journal compilation © 2011 FEBS.
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Pascual, Jesús; Cañal, María Jesús; Escandón, Mónica; Meijón, Mónica; Weckwerth, Wolfram
2017-01-01
Globally expected changes in environmental conditions, especially the increase of UV irradiation, necessitate extending our knowledge of the mechanisms mediating tree species adaptation to this stress. This is crucial for designing new strategies to maintain future forest productivity. Studies focused on environmentally realistic dosages of UV irradiation in forest species are scarce. Pinus spp. are commercially relevant trees and not much is known about their adaptation to UV. In this work, UV treatment and recovery of Pinus radiata plants with dosages mimicking future scenarios, based on current models of UV radiation, were performed in a time-dependent manner. The combined metabolome and proteome analysis were complemented with measurements of + physiological parameters and gene expression. Sparse PLS analysis revealed complex molecular interaction networks of molecular and physiological data. Early responses prevented phototoxicity by reducing photosystem activity and the electron transfer chain together with the accumulation of photoprotectors and photorespiration. Apart from the reduction in photosynthesis as consequence of the direct UV damage on the photosystems, the primary metabolism was rearranged to deal with the oxidative stress while minimizing ROS production. New protein kinases and proteases related to signaling, coordination, and regulation of UV stress responses were revealed. All these processes demonstrate a complex molecular interaction network extending the current knowledge on UV-stress adaptation in pine. PMID:28096192
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A Systems Approach to Stress, Stressors and Resilience in Humans
Oken, Barry S.; Chamine, Irina; Wakeland, Wayne
2014-01-01
The paper focuses on the biology of stress and resilience and their biomarkers in humans from the system science perspective. A stressor pushes the physiological system away from its baseline state towards a lower utility state. The physiological system may return towards the original state in one attractor basin but may be shifted to a state in another, lower utility attractor basin. While some physiological changes induced by stressors may benefit health, there is often a chronic wear and tear cost due to implementing changes to enable the return of the system to its baseline state and maintain itself in the high utility baseline attractor basin following repeated perturbations. This cost, also called allostatic load, is the utility reduction associated with both a change in state and with alterations in the attractor basin that affect system responses following future perturbations. This added cost can increase the time course of the return to baseline or the likelihood of moving into a different attractor basin following a perturbation. Opposite to this is the system’s resilience which influences its ability to return to the high utility attractor basin following a perturbation by increasing the likelihood and/or speed of returning to the baseline state following a stressor. This review paper is a qualitative systematic review; it covers areas most relevant for moving the stress and resilience field forward from a more quantitative and neuroscientific perspective. PMID:25549855
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Kobayashi, Tetsuo; Uehara, Kenji; Ota, Shusuke; Tobita, Kimimasa; Ambrosio, Fabrisia; Cummins, James H; Terada, Satoshi; Fu, Freddie H; Huard, Johnny
2013-01-15
Losartan (Los) is a Food and Drug Administration-approved antihypertensive medication that has a well-tolerated side effect profile. We have demonstrated that treatment with Los immediately after injury was effective at promoting muscle healing and inducing an antifibrotic effect in a murine model of skeletal muscle injury. We initially investigated the minimum effective dose of Los administration immediately after injury and subsequently determined whether the timing of administering a clinically relevant dose of Los would influence its effectiveness at improving muscle healing after muscle injury. In the first part of this study, mice were administered 3, 10, 30, or 300 mg·kg(-1)·day(-1) of Los immediately after injury, and the healing process was evaluated histologically and physiologically 4 wk after injury. In the second study, the clinically relevant dose of 10 mg·kg(-1)·day(-1) was administered immediately or started at 3 or 7 days postinjury. The administration of 300 mg·kg(-1)·day(-1) immediately following injury led to a significant increase in muscle regeneration, a significant decrease in fibrosis, and an improvement in muscle function. Moreover, we observed a significant decrease in fibrosis and a significant increase in muscle regeneration at 4 wk postinjury, when the clinically relevant dose of 10 mg·kg(-1)·day(-1) was administered at 3 or 7 days postinjury. Functional evaluation also demonstrated a significant improvement compared with the injured untreated control when Los treatment was initiated 3 days after injury. Our study revealed accelerated muscle healing when the 300 mg·kg(-1)·day(-1) of Los was administered immediately after injury and a clinically relevant dose of 10 mg·kg(-1)·day(-1) of Los was administered at 3 or 7 days postinjury.
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Wu, Rudolf S S; Siu, William H L; Shin, Paul K S
2005-01-01
A wide range of biological responses have been used to identify exposure to contaminants, monitor spatial and temporal changes in contamination levels, provide early warning of environmental deterioration and indicate occurrences of adverse ecological consequences. To be useful in environmental monitoring, a biological response must reflect the environmental stress over time in a quantitative way. We here argue that the time required for initial induction, maximum induction, adaptation and recovery of these stress responses must first be fully understood and considered before they can be used in environmental monitoring, or else erroneous conclusions (both false-negative and false-positive) may be drawn when interpreting results. In this study, data on initial induction, maximum induction, adaptation and recovery of stress responses at various biological hierarchies (i.e., molecular, biochemical, physiological, behavioral, cytological, population and community responses) upon exposure to environmentally relevant levels of contaminants (i.e., metals, oil, polycyclic aromatic hydrocarbons (PAHs), organochlorines, organophosphates, endocrine disruptors) were extracted from 922 papers in the biomarker literature and analyzed. Statistical analyses showed that: (a) many stress responses may decline with time after induction (i.e., adaptation), even if the level of stress remains constant; (b) times for maximum induction and recovery of biochemical responses are positively related; (c) there is no evidence to support the general belief that time for induction of responses at a lower biological hierarchy (i.e., molecular responses and biochemical responses) is shorter than that at higher hierarchy (i.e., physiological, cytological and behavioral responses), although longer recovery time is found for population and community responses; (d) there are significant differences in times required for induction and adaptation of biological responses caused by different types of contaminants; (e) times required for initial and maximum induction of physiological responses in fish are significantly longer than those in crustaceans; and (f) there is a paucity of data on adaptation and recovery of responses, especially those at population and community levels. The above analyses highlight: (1) the limitations and possible erroneous conclusions in the present use of biomarkers in biomonitoring programs, (2) the importance of understanding the details of temporal changes of biological responses before employing them in environmental management, and (3) the suitability of using specific animal groups as bioindicator species.
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Fully automated motion correction in first-pass myocardial perfusion MR image sequences.
Milles, Julien; van der Geest, Rob J; Jerosch-Herold, Michael; Reiber, Johan H C; Lelieveldt, Boudewijn P F
2008-11-01
This paper presents a novel method for registration of cardiac perfusion magnetic resonance imaging (MRI). The presented method is capable of automatically registering perfusion data, using independent component analysis (ICA) to extract physiologically relevant features together with their time-intensity behavior. A time-varying reference image mimicking intensity changes in the data of interest is computed based on the results of that ICA. This reference image is used in a two-pass registration framework. Qualitative and quantitative validation of the method is carried out using 46 clinical quality, short-axis, perfusion MR datasets comprising 100 images each. Despite varying image quality and motion patterns in the evaluation set, validation of the method showed a reduction of the average right ventricle (LV) motion from 1.26+/-0.87 to 0.64+/-0.46 pixels. Time-intensity curves are also improved after registration with an average error reduced from 2.65+/-7.89% to 0.87+/-3.88% between registered data and manual gold standard. Comparison of clinically relevant parameters computed using registered data and the manual gold standard show a good agreement. Additional tests with a simulated free-breathing protocol showed robustness against considerable deviations from a standard breathing protocol. We conclude that this fully automatic ICA-based method shows an accuracy, a robustness and a computation speed adequate for use in a clinical environment.
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NASA Astrophysics Data System (ADS)
Höppe, P.
With considerably increased coverage of weather information in the news media in recent years in many countries, there is also more demand for data that are applicable and useful for everyday life. Both the perception of the thermal component of weather as well as the appropriate clothing for thermal comfort result from the integral effects of all meteorological parameters relevant for heat exchange between the body and its environment. Regulatory physiological processes can affect the relative importance of meteorological parameters, e.g. wind velocity becomes more important when the body is sweating. In order to take into account all these factors, it is necessary to use a heat-balance model of the human body. The physiological equivalent temperature (PET) is based on the Munich Energy-balance Model for Individuals (MEMI), which models the thermal conditions of the human body in a physiologically relevant way. PET is defined as the air temperature at which, in a typical indoor setting (without wind and solar radiation), the heat budget of the human body is balanced with the same core and skin temperature as under the complex outdoor conditions to be assessed. This way PET enables a layperson to compare the integral effects of complex thermal conditions outside with his or her own experience indoors. On hot summer days, for example, with direct solar irradiation the PET value may be more than 20 K higher than the air temperature, on a windy day in winter up to 15 K lower.
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Heyland, Mark; Trepczynski, Adam; Duda, Georg N; Zehn, Manfred; Schaser, Klaus-Dieter; Märdian, Sven
2015-12-01
Selection of boundary constraints may influence amount and distribution of loads. The purpose of this study is to analyze the potential of inertia relief and follower load to maintain the effects of musculoskeletal loads even under large deflections in patient specific finite element models of intact or fractured bone compared to empiric boundary constraints which have been shown to lead to physiological displacements and surface strains. The goal is to elucidate the use of boundary conditions in strain analyses of bones. Finite element models of the intact femur and a model of clinically relevant fracture stabilization by locking plate fixation were analyzed with normal walking loading conditions for different boundary conditions, specifically re-balanced loading, inertia relief and follower load. Peak principal cortex surface strains for different boundary conditions are consistent (maximum deviation 13.7%) except for inertia relief without force balancing (maximum deviation 108.4%). Influence of follower load on displacements increases with higher deflection in fracture model (from 3% to 7% for force balanced model). For load balanced models, follower load had only minor influence, though the effect increases strongly with higher deflection. Conventional constraints of fixed nodes in space should be carefully reconsidered because their type and position are challenging to justify and for their potential to introduce relevant non-physiological reaction forces. Inertia relief provides an alternative method which yields physiological strain results. Copyright © 2015 IPEM. Published by Elsevier Ltd. All rights reserved.
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Detection of Volatile Metabolites Derived from Garlic (Allium sativum) in Human Urine
Scheffler, Laura; Sauermann, Yvonne; Heinlein, Anja; Sharapa, Constanze; Buettner, Andrea
2016-01-01
The metabolism and excretion of flavor constituents of garlic, a common plant used in flavoring foods and attributed with several health benefits, in humans is not fully understood. Likewise, the physiologically active principles of garlic have not been fully clarified to date. It is possible that not only the parent compounds present in garlic but also its metabolites are responsible for the specific physiological properties of garlic, including its influence on the characteristic body odor signature of humans after garlic consumption. Accordingly, the aim of this study was to investigate potential garlic-derived metabolites in human urine. To this aim, 14 sets of urine samples were obtained from 12 volunteers, whereby each set comprised one sample that was collected prior to consumption of food-relevant concentrations of garlic, followed by five to eight subsequent samples after garlic consumption that covered a time interval of up to 26 h. The samples were analyzed chemo-analytically using gas chromatography-mass spectrometry/olfactometry (GC-MS/O), as well as sensorially by a trained human panel. The analyses revealed three different garlic-derived metabolites in urine, namely allyl methyl sulfide (AMS), allyl methyl sulfoxide (AMSO) and allyl methyl sulfone (AMSO2), confirming our previous findings on human milk metabolite composition. The excretion rates of these metabolites into urine were strongly time-dependent with distinct inter-individual differences. These findings indicate that the volatile odorant fraction of garlic is heavily biotransformed in humans, opening up a window into substance circulation within the human body with potential wider ramifications in view of physiological effects of this aromatic plant that is appreciated by humans in their daily diet. PMID:27916960
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Ribaric, Samo; Kordas, Marjan
2011-06-01
Here, we report on a new tool for teaching cardiovascular physiology and pathophysiology that promotes qualitative as well as quantitative thinking about time-dependent physiological phenomena. Quantification of steady and presteady-state (transient) cardiovascular phenomena is traditionally done by differential equations, but this is time consuming and unsuitable for most undergraduate medical students. As a result, quantitative thinking about time-dependent physiological phenomena is often not extensively dealt with in an undergraduate physiological course. However, basic concepts of steady and presteady state can be explained with relative simplicity, without the introduction of differential equation, with equivalent electronic circuits (EECs). We introduced undergraduate medical students to the concept of simulating cardiovascular phenomena with EECs. EEC simulations facilitate the understanding of simple or complex time-dependent cardiovascular physiological phenomena by stressing the analogies between EECs and physiological processes. Student perceptions on using EEC to simulate, study, and understand cardiovascular phenomena were documented over a 9-yr period, and the impact of the course on the students' knowledge of selected basic facts and concepts in cardiovascular physiology was evaluated over a 3-yr period. We conclude that EECs are a valuable tool for teaching cardiovascular physiology concepts and that EECs promote active learning.
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Multiplexed fibre optic sensing in the distal lung (Conference Presentation)
NASA Astrophysics Data System (ADS)
Choudhary, Tushar R.; Tanner, Michael G.; Megia-Fernandez, Alicia; Harrington, Kerrianne; Wood, Harry A.; Chankeshwara, Sunay; Zhu, Patricia; Choudhury, Debaditya; Yu, Fei; Thomson, Robert R.; Duncan, Rory R.; Dhaliwal, Kevin; Bradley, Mark
2017-02-01
We present a toolkit for a multiplexed pH and oxygen sensing probe in the distal lung using multicore fibres. Measuring physiological relevant parameters like pH and oxygen is of significant importance in understanding changes associated with disease pathology. We present here, a single multicore fibre based pH and oxygen sensing probe which can be used with a standard bronchoscope to perform in vivo measurements in the distal lung. The multiplexed probe consists of fluorescent pH sensors (fluorescein based) and oxygen sensors (Palladium porphyrin complex based) covalently bonded to silica microspheres (10 µm) loaded on the distal facet of a 19 core (10 µm core diameter) multicore fibre (total diameter of 150 µm excluding coating). Pits are formed by selectively etching the cores using hydrofluoric acid, multiplexing is achieved through the self-location of individual probes on differing cores. This architecture can be expanded to include probes for further parameters. Robust measurements are demonstrated of self-referencing fluorophores, not limited by photobleaching, with short (100ms) measurement times at low ( 10µW) illumination powers. We have performed on bench calibration and tests of in vitro tissue models and in an ovine whole lung model to validate our sensors. The pH sensor is demonstrated in the physiologically relevant range of pH 5 to pH 8.5 and with an accuracy of ± 0.05 pH units. The oxygen sensor is demonstrated in gas mixtures downwards from 20% oxygen and in liquid saturated with 20% oxygen mixtures ( 8mg/L) down to full depletion (0mg/L) with 0.5mg/L accuracy.
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Guo, Zhongyuan; Martucci, Nicole J.; Moreno-Olivas, Fabiola; Tako, Elad; Mahler, Gretchen J.
2017-01-01
Ingestion of titanium dioxide (TiO2) nanoparticles from products such as agricultural chemicals, processed food, and nutritional supplements is nearly unavoidable. The gastrointestinal tract serves as a critical interface between the body and the external environment, and is the site of essential nutrient absorption. The goal of this study was to examine the effects of ingesting the 30 nm TiO2 nanoparticles with an in vitro cell culture model of the small intestinal epithelium, and to determine how acute or chronic exposure to nano-TiO2 influences intestinal barrier function, reactive oxygen species generation, proinflammatory signaling, nutrient absorption (iron, zinc, fatty acids), and brush border membrane enzyme function (intestinal alkaline phosphatase). A Caco-2/HT29-MTX cell culture model was exposed to physiologically relevant doses of TiO2 nanoparticles for acute (four hours) or chronic (five days) time periods. Exposure to TiO2 nanoparticles significantly decreased intestinal barrier function following chronic exposure. Reactive oxygen species (ROS) generation, proinflammatory signaling, and intestinal alkaline phosphatase activity all showed increases in response to nano-TiO2. Iron, zinc, and fatty acid transport were significantly decreased following exposure to TiO2 nanoparticles. This is because nanoparticle exposure induced a decrease in absorptive microvilli in the intestinal epithelial cells. Nutrient transporter protein gene expression was also altered, suggesting that cells are working to regulate the transport mechanisms disturbed by nanoparticle ingestion. Overall, these results show that intestinal epithelial cells are affected at a functional level by physiologically relevant exposure to nanoparticles commonly ingested from food. PMID:28944308
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Integrating physiological regulation with stem cell and tissue homeostasis
Nakada, Daisuke; Levi, Boaz P.; Morrison, Sean J.
2015-01-01
Summary Stem cells are uniquely able to self-renew, to undergo multilineage differentiation, and to persist throughout life in a number of tissues. Stem cells are regulated by a combination of shared and tissue-specific mechanisms and are distinguished from restricted progenitors by differences in transcriptional and epigenetic regulation. Emerging evidence suggests that other aspects of cellular physiology, including mitosis, signal transduction, and metabolic regulation also differ between stem cells and their progeny. These differences may allow stem cells to be regulated independently of differentiated cells in response to circadian rhythms, changes in metabolism, diet, exercise, mating, aging, infection, and disease. This allows stem cells to sustain homeostasis or to remodel relevant tissues in response to physiological change. Stem cells are therefore not only regulated by short-range signals that maintain homeostasis within their tissue of origin, but also by long-range signals that integrate stem cell function with systemic physiology. PMID:21609826
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Sommer, Felix; Bäckhed, Fredrik
2016-05-01
Interactions between the host and its associated microbiota differ spatially and the local cross talk determines organ function and physiology. Animals and their organs are not uniform but contain several functional and cellular compartments and gradients. In the intestinal tract, different parts of the gut carry out different functions, tissue structure varies accordingly, epithelial cells are differentially distributed and gradients exist for several physicochemical parameters such as nutrients, pH, or oxygen. Consequently, the microbiota composition also differs along the length of the gut, but also between lumen and mucosa of the same intestinal segment, and even along the crypt-villus axis in the epithelium. Thus, host-microbiota interactions are highly site-specific and the local cross talk determines intestinal function and physiology. Here we review recent advances in our understanding of site-specific host-microbiota interactions and discuss their functional relevance for host physiology. © 2016 WILEY Periodicals, Inc.
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Physiologic basis for understanding quantitative dehydration assessment.
Cheuvront, Samuel N; Kenefick, Robert W; Charkoudian, Nisha; Sawka, Michael N
2013-03-01
Dehydration (body water deficit) is a physiologic state that can have profound implications for human health and performance. Unfortunately, dehydration can be difficult to assess, and there is no single, universal gold standard for decision making. In this article, we review the physiologic basis for understanding quantitative dehydration assessment. We highlight how phenomenologic interpretations of dehydration depend critically on the type (dehydration compared with volume depletion) and magnitude (moderate compared with severe) of dehydration, which in turn influence the osmotic (plasma osmolality) and blood volume-dependent compensatory thresholds for antidiuretic and thirst responses. In particular, we review new findings regarding the biological variation in osmotic responses to dehydration and discuss how this variation can help provide a quantitative and clinically relevant link between the physiology and phenomenology of dehydration. Practical measures with empirical thresholds are provided as a starting point for improving the practice of dehydration assessment.
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DOT National Transportation Integrated Search
1978-04-01
Decongestants and antihistamines are known to produce effects capable of adversely modifying physiological function and psychomotor task performance. Because of relevance to safe pilot performance, the effects of single doses of two decongestant-anti...
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van Ede, Freek
2017-01-01
Beta and gamma oscillations are the dominant oscillatory activity in the human motor cortex (M1). However, their physiological basis and precise functional significance remain poorly understood. Here, we used transcranial magnetic stimulation (TMS) to examine the physiological basis and behavioral relevance of driving beta and gamma oscillatory activity in the human M1 using transcranial alternating current stimulation (tACS). tACS was applied using a sham-controlled crossover design at individualized intensity for 20 min and TMS was performed at rest (before, during, and after tACS) and during movement preparation (before and after tACS). We demonstrated that driving gamma frequency oscillations using tACS led to a significant, duration-dependent decrease in local resting-state GABAA inhibition, as quantified by short interval intracortical inhibition. The magnitude of this effect was positively correlated with the magnitude of GABAA decrease during movement preparation, when gamma activity in motor circuitry is known to increase. In addition, gamma tACS-induced change in GABAA inhibition was closely related to performance in a motor learning task such that subjects who demonstrated a greater increase in GABAA inhibition also showed faster short-term learning. The findings presented here contribute to our understanding of the neurophysiological basis of motor rhythms and suggest that tACS may have similar physiological effects to endogenously driven local oscillatory activity. Moreover, the ability to modulate local interneuronal circuits by tACS in a behaviorally relevant manner provides a basis for tACS as a putative therapeutic intervention. SIGNIFICANCE STATEMENT Gamma oscillations have a vital role in motor control. Using a combined tACS-TMS approach, we demonstrate that driving gamma frequency oscillations modulates GABAA inhibition in the human motor cortex. Moreover, there is a clear relationship between the change in magnitude of GABAA inhibition induced by tACS and the magnitude of GABAA inhibition observed during task-related synchronization of oscillations in inhibitory interneuronal circuits, supporting the hypothesis that tACS engages endogenous oscillatory circuits. We also show that an individual's physiological response to tACS is closely related to their ability to learn a motor task. These findings contribute to our understanding of the neurophysiological basis of motor rhythms and their behavioral relevance and offer the possibility of developing tACS as a therapeutic tool. PMID:28348136
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Airaki, Morad; Sánchez-Moreno, Lourdes; Leterrier, Marina; Barroso, Juan B; Palma, José M; Corpas, Francisco J
2011-11-01
Glutathione (GSH) is one of the major, soluble, low molecular weight antioxidants, as well as the major non-protein thiol in plant cells. However, the relevance of this molecule could be even greater considering that it can react with nitric oxide (NO) to generate S-nitrosoglutathione (GSNO) which is considered to function as a mobile reservoir of NO bioactivity in plants. Although this NO-derived molecule has an increased physiological and phytopathological relevance in plants cells, its identification and quantification in plant tissues have not be reported so far. Using liquid chromatography-electrospray/mass spectrometry (LC-ES/MS), a method was set up to detect and quantify simultaneously GSNO as well reduced and oxidized glutathione (GSH and GSSG, respectively) in different pepper plant organs including roots, stems and leaves, and in Arabidopsis leaves. The analysis of NO and GSNO reductase (GSNOR) activity in these pepper organs showed that the content of GSNO was directly related to the content of NO in each organ and oppositely related to the GSNOR activity. This approach opens up new analytical possibilities to understand the relevance of GSNO in plant cells under physiological and stress conditions.
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Caloric primary rewards systematically alter time perception.
Fung, Bowen J; Murawski, Carsten; Bode, Stefan
2017-11-01
Human time perception can be influenced by contextual factors, such as the presence of reward. Yet, the exact nature of the relationship between time perception and reward has not been conclusively characterized. We implemented a novel experimental paradigm to measure estimations of time across a range of suprasecond intervals, during the anticipation and after the consumption of fruit juice, a physiologically relevant primary reward. We show that average time estimations were systematically affected by the consumption of reward, but not by the anticipation of reward. Compared with baseline estimations of time, reward consumption was associated with subsequent overproductions of time, and this effect increased for larger magnitudes of reward. Additional experiments demonstrated that the effect of consumption did not extend to a secondary reward (money), a tasteless, noncaloric primary reward (water), or a sweet, noncaloric reward (aspartame). However, a tasteless caloric reward (maltodexrin) did induce overproductions of time, although this effect did not scale with reward magnitude. These results suggest that the consumption of caloric primary rewards can alter time perception, which may be a psychophysiological mechanism by which organisms regulate homeostatic balance. (PsycINFO Database Record (c) 2017 APA, all rights reserved).
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Taghva, Alexander; Song, Dong; Hampson, Robert E.; Deadwyler, Sam A.; Berger, Theodore W.
2013-01-01
BACKGROUND Identification of functional dependence among neurons is a necessary component in both the rational design of neural prostheses as well as in the characterization of network physiology. The objective of this article is to provide a tutorial for neurosurgeons regarding information theory, specifically time-delayed mutual information, and to compare time-delayed mutual information, an information theoretic quantity based on statistical dependence, with cross-correlation, a commonly used metric for this task in a preliminary analysis of rat hippocampal neurons. METHODS Spike trains were recorded from rats performing delayed nonmatch-to-sample task using an array of electrodes surgically implanted into the hippocampus of each hemisphere of the brain. In addition, spike train simulations of positively correlated neurons, negatively correlated neurons, and neurons correlated by nonlinear functions were generated. These were evaluated by time-delayed mutual information (MI) and cross-correlation. RESULTS Application of time-delayed MI to experimental data indicated the optimal bin size for information capture in the CA3-CA1 system was 40 ms, which may provide some insight into the spatiotemporal nature of encoding in the rat hippocampus. On simulated data, time-delayed MI showed peak values at appropriate time lags in positively correlated, negatively correlated, and complexly correlated data. Cross-correlation showed peak and troughs with positively correlated and negatively correlated data, but failed to capture some higher order correlations. CONCLUSIONS Comparison of time-delayed MI to cross-correlation in identification of functionally dependent neurons indicates that the methods are not equivalent. Time-delayed MI appeared to capture some interactions between CA3-CA1 neurons at physiologically plausible time delays missed by cross-correlation. It should be considered as a method for identification of functional dependence between neurons and may be useful in the development of neural prosthetics. PMID:22120279
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Taghva, Alexander; Song, Dong; Hampson, Robert E; Deadwyler, Sam A; Berger, Theodore W
2012-12-01
Identification of functional dependence among neurons is a necessary component in both the rational design of neural prostheses as well as in the characterization of network physiology. The objective of this article is to provide a tutorial for neurosurgeons regarding information theory, specifically time-delayed mutual information, and to compare time-delayed mutual information, an information theoretic quantity based on statistical dependence, with cross-correlation, a commonly used metric for this task in a preliminary analysis of rat hippocampal neurons. Spike trains were recorded from rats performing delayed nonmatch-to-sample task using an array of electrodes surgically implanted into the hippocampus of each hemisphere of the brain. In addition, spike train simulations of positively correlated neurons, negatively correlated neurons, and neurons correlated by nonlinear functions were generated. These were evaluated by time-delayed mutual information (MI) and cross-correlation. Application of time-delayed MI to experimental data indicated the optimal bin size for information capture in the CA3-CA1 system was 40 ms, which may provide some insight into the spatiotemporal nature of encoding in the rat hippocampus. On simulated data, time-delayed MI showed peak values at appropriate time lags in positively correlated, negatively correlated, and complexly correlated data. Cross-correlation showed peak and troughs with positively correlated and negatively correlated data, but failed to capture some higher order correlations. Comparison of time-delayed MI to cross-correlation in identification of functionally dependent neurons indicates that the methods are not equivalent. Time-delayed MI appeared to capture some interactions between CA3-CA1 neurons at physiologically plausible time delays missed by cross-correlation. It should be considered as a method for identification of functional dependence between neurons and may be useful in the development of neural prosthetics. Copyright © 2012 Elsevier Inc. All rights reserved.
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Physiological regulation and metabolic role of browning in white adipose tissue.
Jankovic, Aleksandra; Otasevic, Vesna; Stancic, Ana; Buzadzic, Biljana; Korac, Aleksandra; Korac, Bato
2017-09-01
Great progress has been made in our understanding of the browning process in white adipose tissue (WAT) in rodents. The recognition that i) adult humans have physiologically inducible brown adipose tissue (BAT) that may facilitate resistance to obesity and ii) that adult human BAT molecularly and functionally resembles beige adipose tissue in rodents, reignited optimism that obesity and obesity-related diabetes type 2 can be battled by controlling the browning of WAT. In this review the main cellular mechanisms and molecular mediators of browning of WAT in different physiological states are summarized. The relevance of browning of WAT in metabolic health is considered primarily through a modulation of biological role of fat tissue in overall metabolic homeostasis.
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Lung bioaccessibility of contaminants in particulate matter of geological origin.
Guney, Mert; Chapuis, Robert P; Zagury, Gerald J
2016-12-01
Human exposure to particulate matter (PM) has been associated with adverse health effects. While inhalation exposure to airborne PM is a prominent research subject, exposure to PM of geological origin (i.e., generated from soil/soil-like material) has received less attention. This review discusses the contaminants in PM of geological origin and their relevance for human exposure and then evaluates lung bioaccessibility assessment methods and their use. PM of geological origin can contain toxic elements as well as organic contaminants. Observed/predicted PM lung clearance times are long, which may lead to prolonged contact with lung environment. Thus, certain exposure scenarios warrant the use of in vitro bioaccessibility testing to predict lung bioavailability. Limited research is available on lung bioaccessibility test development and test application to PM of geological origin. For in vitro tests, test parameter variation between different studies and concerns about physiological relevance indicate a crucial need for test method standardization and comparison with relevant animal data. Research is recommended on (1) developing robust in vitro lung bioaccessibility methods, (2) assessing bioaccessibility of various contaminants (especially polycyclic aromatic hydrocarbons (PAHs)) in PM of diverse origin (surface soils, mine tailings, etc.), and (3) risk characterization to determine relative importance of exposure to PM of geological origin.
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Lanius, Ruth A.
2015-01-01
The primary aim of this commentary is to describe trauma-related dissociation and altered states of consciousness in the context of a four-dimensional model that has recently been proposed (Frewen & Lanius, 2015). This model categorizes symptoms of trauma-related psychopathology into (1) those that occur within normal waking consciousness and (2) those that are dissociative and are associated with trauma-related altered states of consciousness (TRASC) along four dimensions: (1) time; (2) thought; (3) body; and (4) emotion. Clinical applications and future research directions relevant to each dimension are discussed. Conceptualizing TRASC across the dimensions of time, thought, body, and emotion has transdiagnostic implications for trauma-related disorders described in both the Diagnostic Statistical Manual and the International Classifications of Diseases. The four-dimensional model provides a framework, guided by existing models of dissociation, for future research examining the phenomenological, neurobiological, and physiological underpinnings of trauma-related dissociation. PMID:25994026
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On-Orbit Prospective Echocardiography on International Space Station
NASA Technical Reports Server (NTRS)
Hamilton, Douglas R.; Sargsyan, Ashot E.; Martin, David; Garcia, Kathleen M.; Melton, Shannon; Feiverson, Alan; Dulchavsky, Scott A.
2010-01-01
A number of echocardiographic research projects and experiments have been flown on almost every space vehicle since 1970, but validation of standard methods and the determination of Space Normal cardiac function has not been reported to date. Advanced Diagnostics in Microgravity (ADUM) -remote guided echocardiographic technique provides a novel and effective approach to on-board assessment of cardiac physiology and structure using a just-in-time training algorithm and real-time remote guidance aboard the International Space Station (ISS). The validation of remotely guided echocardiographic techniques provides the procedures and protocols to perform scientific and clinical echocardiography on the ISS and the Moon. The objectives of this study were: 1.To confirm the ability of non-physician astronaut/cosmonaut crewmembers to perform clinically relevant remotely guided echocardiography using the Human Research Facility on board the ISS. 2.To compare the preflight, postflight and in-flight echocardiographic parameters commonly used in clinical medicine.
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Bioaccessibility of metals in alloys: Evaluation of three surrogate biofluids
Hillwalker, Wendy E.; Anderson, Kim A.
2014-01-01
Bioaccessibility in vitro tests measure the solubility of materials in surrogate biofluids. However, the lack of uniform methods and the effects of variable test parameters on material solubility limit interpretation. One aim of this study was to measure and compare bioaccessibility of selected economically important alloys and metals in surrogate physiologically based biofluids representing oral, inhalation and dermal exposures. A second aim was to experimentally test different biofluid formulations and residence times in vitro. A third aim was evaluation of dissolution behavior of alloys with in vitro lung and dermal biofluid surrogates. This study evaluated the bioaccessibility of sixteen elements in six alloys and 3 elemental/metal powders. We found that the alloys/metals, the chemical properties of the surrogate fluid, and residence time all had major impacts on metal solubility. The large variability of bioaccessibility indicates the relevancy of assessing alloys as toxicologically distinct relative to individual metals. PMID:24212234
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Häcker, Axel; Peters, Kristina; Knoll, Thomas; Marlinghaus, Ernst; Alken, Peter; Jenne, Jürgen W; Michel, Maurice Stephan
2006-11-01
To investigate strategies to achieve confluent kidney-tissue ablation by high-intensity focused ultrasound (HIFU). Our model of the perfused ex-vivo porcine kidney was used. Tissue ablation was performed with an experimental HIFU device (Storz Medical, Kreuzlingen, Switzerland). Lesion-to-lesion interaction was investigated by varying the lesion distance (5 to 2.5 mm), generator power (300, 280, and 260 W), cooling time (10, 20, and 30 seconds), and exposure time (4, 3, and 2 seconds). The lesion rows were analyzed grossly and by histologic examination (hematoxylin-eosin and nicotinamide adenine dinucleotide staining). It was possible to achieve complete homogeneous ablation of a clinically relevant tissue volume but only by meticulous adjustment of the exposure parameters. Minimal changes in these parameters caused changes in lesion formation with holes within the lesions and lesion-to-lesion interaction. Our preliminary results show that when using this new device, HIFU can ablate a large tissue volume homogeneously in perfused ex-vivo porcine tissue under standardized conditions with meticulous adjustment of exposure parameters. Further investigations in vivo are necessary to test whether large tissue volumes can be ablated completely and reliably despite the influence of physiologic tissue and organ movement.
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2015-01-01
Abstract Introduction Understanding the physiology of penile erection is important for all who work in the field of sexual medicine. Aim The aim of this study was to highlight and analyze historical aspects of the scientific understanding of penile erection. Methods (i) Review of the chapters on the physiology of erection out of the author's collection of books dealing with male sexual functioning published in the German, French, Dutch, and English language in between 1780 and 1940. (ii) Review of the topic “physiology of penile erection” of relevant chapters of C lassical writings on erectile dysfunction. A n annotated collection of original texts from three millennia, including the study of all relevant references mentioned in these books. Main Outcome Measure The main outcome measure used for the study was the scientific understanding of the physiology of penile erection. Results In Antiquity, Galen considered penile erection as the result the accumulation of air. His ideas so dominated medieval medicine that nearly everyone then alive was a Galenist. The beginning of the Renaissance shows meaningful examples of experimental scientific work on the penis. Da Vinci correctly concluded that erections were caused by blood, and in the 18th century, Von Haller from Switzerland was the first who explained that erections were under the control of the nervous system. In the 19th century, a mindset that emphasized on experimentation determined a new direction, namely experimental physiology. Animal studies clarified that stimulation of the nervi erigentes‐induced small muscle relaxation in the corpora cavernosa. Nearly all were published in the German language. That may be one of the reasons that the existence of the concept of smooth muscle relaxation remained controversial until the first World Congress on Impotence in 1984 in Paris. Conclusions As the Renaissance's innovative research defined neural and vascular physiologic phenomena responsible for penile erection. The concepts from animal experimentations in Europe in the 19th century significantly contributed to the current understanding of penile erection. van Driel MF. Physiology of penile erection—a brief history of the scientific understanding up till the eighties of the 20th century. Sex Med 2015;3:343–351. PMID:26797073
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Milles, J; van der Geest, R J; Jerosch-Herold, M; Reiber, J H C; Lelieveldt, B P F
2007-01-01
This paper presents a novel method for registration of cardiac perfusion MRI. The presented method successfully corrects for breathing motion without any manual interaction using Independent Component Analysis to extract physiologically relevant features together with their time-intensity behavior. A time-varying reference image mimicking intensity changes in the data of interest is computed based on the results of ICA, and used to compute the displacement caused by breathing for each frame. Qualitative and quantitative validation of the method is carried out using 46 clinical quality, short-axis, perfusion MR datasets comprising 100 images each. Validation experiments showed a reduction of the average LV motion from 1.26+/-0.87 to 0.64+/-0.46 pixels. Time-intensity curves are also improved after registration with an average error reduced from 2.65+/-7.89% to 0.87+/-3.88% between registered data and manual gold standard. We conclude that this fully automatic ICA-based method shows an excellent accuracy, robustness and computation speed, adequate for use in a clinical environment.
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Assessment, management and treatment of acute fingertip injuries.
Kearney, Anthony; Canty, Louise
2016-06-01
Fingertip injuries with nail bed trauma can require specialist hand surgery, depending on severity. However, most of these injuries can be managed in well-equipped emergency departments by emergency nurses with an in-depth knowledge and understanding of the anatomy and physiology of the fingernail and surrounding structures, assessment and examination, pain management and treatment. This article describes the surface and underlying anatomy and physiology of the nail, the most common mechanisms of injury, relevant diagnostic investigations, and initial assessment and management. It also discusses treatment options, referral pathways, and patient discharge advice.
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DiVincenti, Louis; Westcott, Robin; Lee, Candice
2014-01-01
Because of its similarity to humans in important respects, sheep (Ovis aries) are a common animal model for translational research in cardiovascular surgery. However, some unique aspects of sheep anatomy and physiology present challenges to its use in these complicated experiments. In this review, we discuss relevant anatomy and physiology of sheep and discuss management before, during, and after procedures requiring cardiopulmonary bypass to provide a concise source of information for veterinarians, technicians, and researchers developing and implementing protocols with this model. PMID:25255065
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Metabolomics from the Lab to the Field: Lessons Learned Along the Way
Use of metabolomics in laboratory studies for chemical toxicity evaluation is fast becoming an established technique in environmental science, displaying excellent sensitivity, physiological relevance, and providing valuable information regarding toxic mode(s)-of-action. These qu...
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Measuring dynamic kidney function in an undergraduate physiology laboratory.
Medler, Scott; Harrington, Frederick
2013-12-01
Most undergraduate physiology laboratories are very limited in how they treat renal physiology. It is common to find teaching laboratories equipped with the capability for high-resolution digital recordings of physiological functions (muscle twitches, ECG, action potentials, respiratory responses, etc.), but most urinary laboratories still rely on a "dipstick" approach of urinalysis. Although this technique can provide some basic insights into the functioning of the kidneys, it overlooks the dynamic processes of filtration, reabsorption, and secretion. In the present article, we provide a straightforward approach of using renal clearance measurements to estimate glomerular filtration rate, fractional water reabsorption, glucose clearance, and other physiologically relevant parameters. The estimated values from our measurements in laboratory are in close agreement with those anticipated based on textbook parameters. For example, we found glomerular filtration rate to average 124 ± 45 ml/min, serum creatinine to be 1.23 ± 0.4 mg/dl, and fractional water reabsorption to be ∼96.8%. Furthermore, analyses for the class data revealed significant correlations between parameters like fractional water reabsorption and urine concentration, providing opportunities to discuss urine concentrating mechanisms and other physiological processes. The procedures outlined here are general enough that most undergraduate physiology laboratory courses should be able to implement them without difficulty.
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Physiologically relevant organs on chips.
Yum, Kyungsuk; Hong, Soon Gweon; Healy, Kevin E; Lee, Luke P
2014-01-01
Recent advances in integrating microengineering and tissue engineering have generated promising microengineered physiological models for experimental medicine and pharmaceutical research. Here we review the recent development of microengineered physiological systems, or also known as "ogans-on-chips", that reconstitute the physiologically critical features of specific human tissues and organs and their interactions. This technology uses microengineering approaches to construct organ-specific microenvironments, reconstituting tissue structures, tissue-tissue interactions and interfaces, and dynamic mechanical and biochemical stimuli found in specific organs, to direct cells to assemble into functional tissues. We first discuss microengineering approaches to reproduce the key elements of physiologically important, dynamic mechanical microenvironments, biochemical microenvironments, and microarchitectures of specific tissues and organs in microfluidic cell culture systems. This is followed by examples of microengineered individual organ models that incorporate the key elements of physiological microenvironments into single microfluidic cell culture systems to reproduce organ-level functions. Finally, microengineered multiple organ systems that simulate multiple organ interactions to better represent human physiology, including human responses to drugs, is covered in this review. This emerging organs-on-chips technology has the potential to become an alternative to 2D and 3D cell culture and animal models for experimental medicine, human disease modeling, drug development, and toxicology. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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Constantin, Kaytlin; Moline, Rachel L.; Bailey, Heidi N.
2017-01-01
Parents’ ability to regulate their emotions is essential to providing supportive caregiving behaviours when their child is in pain. Extant research focuses on parent self-reported experience or observable behavioural responses. Physiological responding, such as heart rate (HR) and heart rate variability (HRV), is critical to the experience and regulation of emotions and provides a complementary perspective on parent experience; yet, it is scarcely assessed. This pilot study examined parent (n = 25) cardiac response (HR, HRV) at rest (neutral film clip), immediately before the cold pressor task (pre-CPT), and following the CPT (post-CPT). Further, variables that may influence changes in HR and HRV in the context of pediatric pain were investigated, including (1) initial HRV, and (2) parent perception of their child’s typical response to needle procedures. Time-domain (root mean square of successive differences; RMSSD) and frequency-domain (high-frequency heart rate variability; HF-HRV) parameters of HRV were computed. HR and HF-HRV varied as a function of time block. Typical negative responses to needle pain related to higher parental HR and lower HRV at rest. Parents with higher HRV at baseline experienced the greatest decreases in HRV after the CPT. Consequently, considering previous experience with pain and resting HRV levels are relevant to understanding parent physiological responses before and after child pain. PMID:29160828
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Thoma, M V; Scholz, U; Ehlert, U; Nater, U M
2012-01-01
Music listening has been suggested to have short-term beneficial effects. The aim of this study was to investigate the association and potential mediating mechanisms between various aspects of habitual music-listening behaviour and physiological and psychological functioning. An internet-based survey was conducted in university students, measuring habitual music-listening behaviour, emotion regulation, stress reactivity, as well as physiological and psychological functioning. A total of 1230 individuals (mean = 24.89 ± 5.34 years, 55.3% women) completed the questionnaire. Quantitative aspects of habitual music-listening behaviour, i.e. average duration of music listening and subjective relevance of music, were not associated with physiological and psychological functioning. In contrast, qualitative aspects, i.e. reasons for listening (especially 'reducing loneliness and aggression', and 'arousing or intensifying specific emotions') were significantly related to physiological and psychological functioning (all p = 0.001). These direct effects were mediated by distress-augmenting emotion regulation and individual stress reactivity. The habitual music-listening behaviour appears to be a multifaceted behaviour that is further influenced by dispositions that are usually not related to music listening. Consequently, habitual music-listening behaviour is not obviously linked to physiological and psychological functioning.
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[Physiology in the mirror of systematic catalogue of Russian Academy of Sciences Library].
Orlov, I V; Lazurkina, V B
2011-07-01
Representation of general human and animal physiology publications in the systematic catalogue of the Library of the Russian Academy of Sciences is considered. The organization of the catalogue as applied to the problems of physiology, built on the basis of library-bibliographic classification used in the Russian universal scientific libraries is described. The card files of the systematic catalogue of the Library contain about 8 million cards. Topics that reflect the problems of general physiology contain 39 headings. For the full range of sciences including physiology the tables of general types of divisions were developed. They have been marked by indexes using lower-case letters of the Russian alphabet. For further detalizations of these indexes decimal symbols are used. The indexes are attached directly to the field of knowledge index. With the current relatively easy availability of network resources value and relevance of any catalogue are reduced. However it concerns much more journal articles, rather than reference books, proceedings of various conferences, bibliographies, personalities, and especially the monographs contained in the systematic catalogue. The card systematic catalogue of the Library remains an important source of information on general physiology issues, as well as its magistral narrower sections.
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Moss, Darren Michael; Marzolini, Catia; Rajoli, Rajith K R; Siccardi, Marco
2015-01-01
The pharmacokinetic properties of anti-infective drugs are a determinant part of treatment success. Pathogen replication is inhibited if adequate drug levels are achieved in target sites, whereas excessive drug concentrations linked to toxicity are to be avoided. Anti-infective distribution can be predicted by integrating in vitro drug properties and mathematical descriptions of human anatomy in physiologically based pharmacokinetic models. This method reduces the need for animal and human studies and is used increasingly in drug development and simulation of clinical scenario such as, for instance, drug-drug interactions, dose optimization, novel formulations and pharmacokinetics in special populations. We have assessed the relevance of physiologically based pharmacokinetic modeling in the anti-infective research field, giving an overview of mechanisms involved in model design and have suggested strategies for future applications of physiologically based pharmacokinetic models. Physiologically based pharmacokinetic modeling provides a powerful tool in anti-infective optimization, and there is now no doubt that both industry and regulatory bodies have recognized the importance of this technology. It should be acknowledged, however, that major challenges remain to be addressed and that information detailing disease group physiology and anti-infective pharmacodynamics is required if a personalized medicine approach is to be achieved.
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International collaboration on Russian spacecraft and the case for free flyer biosatellites
NASA Technical Reports Server (NTRS)
Grindeland, Richard E.; Ilyin, Eugene A.; Holley, Daniel C.; Skidmore, Michael G.
2005-01-01
Animal research has been critical to the initiation and progress of space exploration. Animals were the original explorers of "space" two centuries ago and have played a crucial role by demonstrating that the space environment, with precautions, is compatible with human survival. Studies of mammals have yielded much of our knowledge of space physiology. As spaceflights to other planets are anticipated, animal research will continue to be essential to further reveal space physiology and to enable the longer missions. Much of the physiology data collected from space was obtained from the Cosmos (Bion) spaceflights, a series of Russian (Soviet)-International collaborative flights, over a 22 year period, which employed unmanned, free flyer biosatellites. Begun as a Soviet-only program, after the second flight the Russians invited American and other foreign scientists to participate. This program filled the 10 year hiatus between the last US biosatellite and the first animal experiments on the shuttles. Of the 11 flights in the Cosmos program nine of them were international; the flights continued over the years regardless of political differences between the Soviet Union and the Western world. The science evolved from sharing tissues to joint international planning and development, and from rat postmortem tissue analysis to in vivo measurements of a host of monkey physiological parameters during flight. Many types of biological specimens were carried on the modified Vostok spacecraft, but only the mammalian studies are discussed herein. The types of studies done encompass the full range of physiology and have begun to answer "critical" questions of space physiology posed by various ad hoc committees. The studies have not only yielded a prodigious and significant body of data, they have also introduced some new perspectives in physiology. A number of the physiological insights gained are relevant to physiology on Earth. The Cosmos flights also added significantly to flight-related technology, some of which also has application on our planet. In summary, the Cosmos biosatellite flights were extremely productive and of low cost. The Bion vehicles are versatile in that they can be placed into a variety of orbits and altitudes, and can carry radiation sources or other hazardous material which cannot be carried on manned vehicles. With recent advances in sensor, robotic, and data processing technology, future free flyers will be even more productive, and will largely preclude the need to fly animal experiments on manned vehicles. Currently, mammalian researchers do not have access to space for an unknown time, seriously impeding the advancement and understanding of space physiology during long duration missions. Initiation of a new, international program of free flyer biosatellites is critical to our further understanding of space physiology, and essential to continued human exploration of space.
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Applications of minimal physiologically-based pharmacokinetic models
Cao, Yanguang
2012-01-01
Conventional mammillary models are frequently used for pharmacokinetic (PK) analysis when only blood or plasma data are available. Such models depend on the quality of the drug disposition data and have vague biological features. An alternative minimal-physiologically-based PK (minimal-PBPK) modeling approach is proposed which inherits and lumps major physiologic attributes from whole-body PBPK models. The body and model are represented as actual blood and tissue usually total body weight) volumes, fractions (fd) of cardiac output with Fick’s Law of Perfusion, tissue/blood partitioning (Kp), and systemic or intrinsic clearance. Analyzing only blood or plasma concentrations versus time, the minimal-PBPK models parsimoniously generate physiologically-relevant PK parameters which are more easily interpreted than those from mam-millary models. The minimal-PBPK models were applied to four types of therapeutic agents and conditions. The models well captured the human PK profiles of 22 selected beta-lactam antibiotics allowing comparison of fitted and calculated Kp values. Adding a classical hepatic compartment with hepatic blood flow allowed joint fitting of oral and intravenous (IV) data for four hepatic elimination drugs (dihydrocodeine, verapamil, repaglinide, midazolam) providing separate estimates of hepatic intrinsic clearance, non-hepatic clearance, and pre-hepatic bioavailability. The basic model was integrated with allometric scaling principles to simultaneously describe moxifloxacin PK in five species with common Kp and fd values. A basic model assigning clearance to the tissue compartment well characterized plasma concentrations of six monoclonal antibodies in human subjects, providing good concordance of predictions with expected tissue kinetics. The proposed minimal-PBPK modeling approach offers an alternative and more rational basis for assessing PK than compartmental models. PMID:23179857
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Lemarié, Fanny; Beauchamp, Erwan; Legrand, Philippe; Rioux, Vincent
2016-01-01
Caprylic acid (octanoic acid, C8:0) belongs to the class of medium-chain saturated fatty acids (MCFAs). Dairy products and specific oils like coconut oil are natural sources of dietary C8:0 but higher intakes of this fatty acid can be provided with MCT (Medium-Chain Triglycerides) oil that consists in 75% of C8:0. MCFAs have physical and metabolic properties that are distinct from those of long-chain saturated fatty acids (LCFAs ≥ 12 carbons). Beneficial physiological effects of dietary C8:0 have been studied for a long time and MCT oil has been used as a special energy source for patients suffering from pancreatic insufficiency, impaired lymphatic chylomicron transport and fat malabsorption. More recently, caprylic acid was also shown to acylate ghrelin, the only known peptide hormone with an orexigenic effect. Through its covalent binding to the ghrelin peptide, caprylic acid exhibits an emerging and specific role in modulating physiological functions themselves regulated by octanoylated ghrelin. Dietary caprylic acid is therefore now suspected to provide the ghrelin O-acyltransferase (GOAT) enzyme with octanoyl-CoA co-substrates necessary for the acyl modification of ghrelin. This review tries to highlight the discrepancy between the formerly described beneficial effects of dietary MCFAs on body weight loss and the C8:0 newly reported effect on appetite stimulation via ghrelin octanoylation. The subsequent aim of this review is to demonstrate the relevance of carrying out further studies to better understand the physiological functions of this particular fatty acid. Copyright © 2015 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.
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NASA Astrophysics Data System (ADS)
Grassi, Bruno; Quaresima, Valentina
2016-09-01
In most daily activities related to work or leisure, the energy for muscle work substantially comes from oxidative metabolism. Functional limitations or impairments of this metabolism can significantly affect exercise tolerance and performance. As a method for the functional evaluation of skeletal muscle oxidative metabolism, near-infrared spectroscopy (NIRS) has important strengths but also several limitations, some of which have been overcome by recent technological developments. Skeletal muscle fractional O2 extraction, the main variable which can be noninvasively evaluated by NIRS, is the result of the dynamic balance between O2 utilization and O2 delivery; it can yield relevant information on key physiological and pathophysiological mechanisms, relevant in the evaluation of exercise performance and exercise tolerance in healthy subjects (in normal and in altered environmental conditions) and in patients. In the right hands, NIRS can offer insights into the physiological and pathophysiological adaptations to conditions of increased O2 needs that involve, in an integrated manner, different organs and systems of the body. In terms of patient evaluation, NIRS allows determination of the evolution of the functional impairments, to identify their correlations with clinical symptoms, to evaluate the effects of therapeutic or rehabilitative interventions, and to gain pathophysiological and diagnostic insights.
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Grassi, Bruno; Quaresima, Valentina
2016-09-01
In most daily activities related to work or leisure, the energy for muscle work substantially comes from oxidative metabolism. Functional limitations or impairments of this metabolism can significantly affect exercise tolerance and performance. As a method for the functional evaluation of skeletal muscle oxidative metabolism, near-infrared spectroscopy (NIRS) has important strengths but also several limitations, some of which have been overcome by recent technological developments. Skeletal muscle fractional O2 extraction, the main variable which can be noninvasively evaluated by NIRS, is the result of the dynamic balance between O2 utilization and O2 delivery; it can yield relevant information on key physiological and pathophysiological mechanisms, relevant in the evaluation of exercise performance and exercise tolerance in healthy subjects (in normal and in altered environmental conditions) and in patients. In the right hands, NIRS can offer insights into the physiological and pathophysiological adaptations to conditions of increased O2 needs that involve, in an integrated manner, different organs and systems of the body. In terms of patient evaluation, NIRS allows determination of the evolution of the functional impairments, to identify their correlations with clinical symptoms, to evaluate the effects of therapeutic or rehabilitative interventions, and to gain pathophysiological and diagnostic insights.
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Physiological relevance of plant 2-Cys peroxiredoxin overoxidation level and oligomerization status.
Cerveau, Delphine; Ouahrani, Djelloul; Marok, Mohamed Amine; Blanchard, Laurence; Rey, Pascal
2016-01-01
Peroxiredoxins are ubiquitous thioredoxin-dependent peroxidases presumed to display, upon environmental constraints, a chaperone function resulting from a redox-dependent conformational switch. In this work, using biochemical and genetic approaches, we aimed to unravel the factors regulating the redox status and the conformation of the plastidial 2-Cys peroxiredoxin (2-Cys PRX) in plants. In Arabidopsis, we show that in optimal growth conditions, the overoxidation level mainly depends on the availability of thioredoxin-related electron donors, but not on sulfiredoxin, the enzyme reducing the 2-Cys PRX overoxidized form. We also observed that upon various physiological temperature, osmotic and light stress conditions, the overoxidation level and oligomerization status of 2-Cys PRX can moderately vary depending on the constraint type. Further, no major change was noticed regarding protein conformation in water-stressed Arabidopsis, barley and potato plants, whereas species-dependent up- and down-variations in overoxidation were observed. In contrast, both 2-Cys PRX overoxidation and oligomerization were strongly induced during a severe oxidative stress generated by methyl viologen. From these data, revealing that the oligomerization status of plant 2-Cys PRX does not exhibit important variation and is not tightly linked to the protein redox status upon physiologically relevant environmental constraints, the possible in planta functions of 2-Cys PRX are discussed. © 2015 John Wiley & Sons Ltd.
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Red Cell Physiology and Signaling Relevant to the Critical Care Setting
Said, Ahmed; Rogers, Stephen; Doctor, Allan
2015-01-01
Purpose of Review Oxygen (O2) delivery, the maintenance of which is fundamental to supporting those with critical illness, is a function of blood O2 content and flow. Here, we review red blood cell (RBC) physiology relevant to disordered O2 delivery in the critically ill. Recent Findings Flow (rather then content) is the focus of O2 delivery regulation: O2 content is relatively fixed, whereas flow fluctuates by several orders of magnitude. Thus, blood flow volume and distribution vary to maintain coupling between O2 delivery and demand. The trapping, processing and delivery of nitric oxide (NO) by RBCs has emerged as a conserved mechanism through which regional blood flow is linked to biochemical cues of perfusion sufficiency. We will review conventional RBC physiology influencing O2 delivery (O2 affinity & rheology) and introduce a new paradigm for O2 delivery homeostasis based on coordinated gas transport and vascular signaling by RBCs. Summary By coordinating vascular signaling in a fashion that links O2 and NO flux, RBCs couple vessel caliber (and thus blood flow) to O2 need in tissue. Malfunction of this signaling system is implicated in a wide array of pathophysiologies and may be explanatory for the dysoxia frequently encountered in the critical care setting. PMID:25888155
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Red cell physiology and signaling relevant to the critical care setting.
Said, Ahmed; Rogers, Stephen; Doctor, Allan
2015-06-01
Oxygen (O2) delivery, the maintenance of which is fundamental to supporting those with critical illness, is a function of blood O2 content and flow. Here, we review red blood cell (RBC) physiology relevant to disordered O2 delivery in the critically ill. Flow (rather than content) is the focus of O2 delivery regulation. O2 content is relatively fixed, whereas flow fluctuates by several orders of magnitude. Thus, blood flow volume and distribution vary to maintain coupling between O2 delivery and demand. The trapping, processing and delivery of nitric oxide (NO) by RBCs has emerged as a conserved mechanism through which regional blood flow is linked to biochemical cues of perfusion sufficiency. We will review conventional RBC physiology that influences O2 delivery (O2 affinity & rheology) and introduce a new paradigm for O2 delivery homeostasis based on coordinated gas transport and vascular signaling by RBCs. By coordinating vascular signaling in a fashion that links O2 and NO flux, RBCs couple vessel caliber (and thus blood flow) to O2 need in tissue. Malfunction of this signaling system is implicated in a wide array of pathophysiologies and may be explanatory for the dysoxia frequently encountered in the critical care setting.
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Llewelyn, John; Macdonald, Stewart L; Moritz, Craig; Martins, Felipe; Hatcher, Amberlee; Phillips, Ben L
2018-01-09
The impact of climate change may be felt most keenly by tropical ectotherms. In these taxa, it is argued, thermal specialisation means a given shift in temperature will have a larger effect on fitness. For species with limited dispersal ability, the impact of climate change depends on the capacity for their climate-relevant traits to shift. Such shifts can occur through genetic adaptation, various forms of plasticity, or a combination of these processes. Here we assess the extent and causes of shifts in seven physiological traits in a tropical lizard, the rainforest sunskink (Lampropholis coggeri). Two populations were sampled that differ from each other in both climate and physiological traits. We compared trait values in each animal soon after field collection versus following acclimation to laboratory conditions. We also compared trait values between populations in: (1) recently field-collected animals, (2) the same animals following laboratory acclimation, and (3) the laboratory-reared offspring of these animals. Our results reveal high trait lability, driven primarily by acclimation and local adaptation. By contrast, developmental plasticity, resulting from incubation temperature, had little-to-no effect on most traits. These results suggest that, while specialised, tropical ectotherms may be capable of rapid shifts in climate-relevant traits. This article is protected by copyright. All rights reserved.
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Artificial intelligence, physiological genomics, and precision medicine.
Williams, Anna Marie; Liu, Yong; Regner, Kevin R; Jotterand, Fabrice; Liu, Pengyuan; Liang, Mingyu
2018-04-01
Big data are a major driver in the development of precision medicine. Efficient analysis methods are needed to transform big data into clinically-actionable knowledge. To accomplish this, many researchers are turning toward machine learning (ML), an approach of artificial intelligence (AI) that utilizes modern algorithms to give computers the ability to learn. Much of the effort to advance ML for precision medicine has been focused on the development and implementation of algorithms and the generation of ever larger quantities of genomic sequence data and electronic health records. However, relevance and accuracy of the data are as important as quantity of data in the advancement of ML for precision medicine. For common diseases, physiological genomic readouts in disease-applicable tissues may be an effective surrogate to measure the effect of genetic and environmental factors and their interactions that underlie disease development and progression. Disease-applicable tissue may be difficult to obtain, but there are important exceptions such as kidney needle biopsy specimens. As AI continues to advance, new analytical approaches, including those that go beyond data correlation, need to be developed and ethical issues of AI need to be addressed. Physiological genomic readouts in disease-relevant tissues, combined with advanced AI, can be a powerful approach for precision medicine for common diseases.
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Kirilina, Evgeniya; Yu, Na; Jelzow, Alexander; Wabnitz, Heidrun; Jacobs, Arthur M; Tachtsidis, Ilias
2013-01-01
Functional Near-Infrared Spectroscopy (fNIRS) is a promising method to study functional organization of the prefrontal cortex. However, in order to realize the high potential of fNIRS, effective discrimination between physiological noise originating from forehead skin haemodynamic and cerebral signals is required. Main sources of physiological noise are global and local blood flow regulation processes on multiple time scales. The goal of the present study was to identify the main physiological noise contributions in fNIRS forehead signals and to develop a method for physiological de-noising of fNIRS data. To achieve this goal we combined concurrent time-domain fNIRS and peripheral physiology recordings with wavelet coherence analysis (WCA). Depth selectivity was achieved by analyzing moments of photon time-of-flight distributions provided by time-domain fNIRS. Simultaneously, mean arterial blood pressure (MAP), heart rate (HR), and skin blood flow (SBF) on the forehead were recorded. WCA was employed to quantify the impact of physiological processes on fNIRS signals separately for different time scales. We identified three main processes contributing to physiological noise in fNIRS signals on the forehead. The first process with the period of about 3 s is induced by respiration. The second process is highly correlated with time lagged MAP and HR fluctuations with a period of about 10 s often referred as Mayer waves. The third process is local regulation of the facial SBF time locked to the task-evoked fNIRS signals. All processes affect oxygenated haemoglobin concentration more strongly than that of deoxygenated haemoglobin. Based on these results we developed a set of physiological regressors, which were used for physiological de-noising of fNIRS signals. Our results demonstrate that proposed de-noising method can significantly improve the sensitivity of fNIRS to cerebral signals.
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Influence of the Circadian System on Disease Severity
Litinski, Mikhail; Scheer, Frank AJL; Shea, Steven A
2009-01-01
Synopsis The severity of many diseases varies across the day and night. For example, adverse cardiovascular incidents peak in the morning, asthma is often worse at night and temporal lobe epileptic seizures are most prevalent in the afternoon. These patterns may be due to the day/night rhythm in environment and behavior, and/or endogenous circadian rhythms in physiology. Furthermore, chronic misalignment between the endogenous circadian timing system and the behavioral cycles could be a cause of increased risk of diabetes, obesity, cardiovascular disease and certain cancers in shift workers. Here we describe the magnitude, relevance and potential biological basis of such daily changes in disease severity and of circadian/behavioral misalignment, and present how these insights may help in the development of appropriate chronotherapy. PMID:20161149
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Mendoza, Walter; Miranda, J Jaime
2017-02-01
One of the major drivers of change in the practice of cardiology is population change. This article discusses the current debate about epidemiologic transition paired with other ongoing transitions with direct relevance to cardiovascular conditions. Challenges specific to patterns of risk factors over time; readiness for disease surveillance and meeting global targets; health system, prevention, and treatment efforts; and physiologic traits and human-environment interactions are identified. This article concludes that a focus on the most populated regions of the world will contribute substantially to protecting the large gains in global survival and life expectancy accrued over the last decades. Copyright © 2016 Elsevier Inc. All rights reserved.
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Poly(2-oxazoline) hydrogels as next generation three-dimensional cell supports
Dargaville, Tim R; Hollier, Brett G; Shokoohmand, Ali; Hoogenboom, Richard
2014-01-01
Synthetic hydrogels selectively decorated with cell adhesion motifs are rapidly emerging as promising substrates for 3D cell culture. When cells are grown in 3D they experience potentially more physiologically relevant cell–cell interactions and physical cues compared with traditional 2D cell culture on stiff surfaces. A newly developed polymer based on poly(2-oxazoline)s has been used for the first time to control attachment of fibroblast cells and is discussed here for its potential use in 3D cell culture with particular focus on cancer cells toward the ultimate aim of high-throughput screening of anticancer therapies. Advantages and limitations of using poly(2-oxazoline) hydrogels are discussed and compared with more established polymers, especially polyethylene glycol (PEG). PMID:24714592
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Identification of inactivity behavior in smart home.
Poujaud, J; Noury, N; Lundy, J-E
2008-01-01
To help elderly people live independently at home, the TIMC-IMAG laboratory developed Health Smart Homes called 'HIS'. These smart Homes are composed of several sensors to monitor the activities of daily living of the patients. Volunteers have accepted to be monitored during 2 years in their own flats. During one year, we carried out our survey on one elderly patient. Thanks to this experimentation, we will access to relevant information like physiological, environmental and activity. This paper focuses on daily living activity. We will introduce an original data splitting method based on the relationship between the frame of time and the location in the flat. Moreover we will present two different methods to determine a threshold of critical inactivity and eventually we will discuss their possible utilities.
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Immunological responses to semen in the female genital tract.
Schuberth, H J; Taylor, U; Zerbe, H; Waberski, D; Hunter, R; Rath, D
2008-11-01
When spermatozoa, seminal plasma and semen extender reach the uterus and interact with local leukocytes and endometrial cells, several immune mechanisms are initiated which have immediate, mid-term and long-term effects on ovulation, sperm cell selection, fertilization and pregnancy success by assuring the acceptance of fetal tissues. This report gives an overview on relevant key immune mechanisms following roughly the time axis after insemination. Detailed knowledge regarding these mechanisms will aid maximizing reproductive efficiency in livestock production. In the future, the many species involved will require a more comparative approach, since evidence is growing that endometrial physiology and the response to varying amounts and compositions of seminal plasma, various semen extenders, and variable numbers of spermatozoa also provoke different immune responses.
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NASA Astrophysics Data System (ADS)
Ceffa, Nicolo G.; Cesana, Ilaria; Collini, Maddalena; D'Alfonso, Laura; Carra, Silvia; Cotelli, Franco; Sironi, Laura; Chirico, Giuseppe
2017-10-01
Ramification of blood circulation is relevant in a number of physiological and pathological conditions. The oxygen exchange occurs largely in the capillary bed, and the cancer progression is closely linked to the angiogenesis around the tumor mass. Optical microscopy has made impressive improvements in in vivo imaging and dynamic studies based on correlation analysis of time stacks of images. Here, we develop and test advanced methods that allow mapping the flow fields in branched vessel networks at the resolution of 10 to 20 μm. The methods, based on the application of spatiotemporal image correlation spectroscopy and its extension to cross-correlation analysis, are applied here to the case of early stage embryos of zebrafish.
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AFM Structural Characterization of Drinking Water Biofilm under Physiological Conditions
Due to the complexity of mixed culture drinking water biofilm, direct visual observation under in situ conditions has been challenging. In this study, atomic force microscopy (AFM) revealed the three dimensional morphology and arrangement of drinking water relevant biofilm in air...
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SPEECH--MAN'S NATURAL COMMUNICATION.
ERIC Educational Resources Information Center
DUDLEY, HOMER; AND OTHERS
SESSION 63 OF THE 1967 INSTITUTE OF ELECTRICAL AND ELECTRONIC ENGINEERS INTERNATIONAL CONVENTION BROUGHT TOGETHER SEVEN DISTINGUISHED MEN WORKING IN FIELDS RELEVANT TO LANGUAGE. THEIR TOPICS INCLUDED ORIGIN AND EVOLUTION OF SPEECH AND LANGUAGE, LANGUAGE AND CULTURE, MAN'S PHYSIOLOGICAL MECHANISMS FOR SPEECH, LINGUISTICS, AND TECHNOLOGY AND…
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Biomarkers and Environmental Stress: Relevance of Cellular Responses in Determining Adverse Outcomes
Biomarkers are measurable changes in a biological system indicative of an interaction with a chemical, physical, or biological agent. Such changes can be molecular, biochemical, physiological, or histological and can be reflective of either xenobiotic exposures or effects. Molecu...
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Yeast‐insect associations: It takes guts
2018-01-01
Abstract Insects interact with microorganisms in several situations, ranging from the accidental interaction to locate attractive food or the acquisition of essential nutrients missing in the main food source. Despite a wealth of studies recently focused on bacteria, the interactions between insects and yeasts have relevant implications for both of the parties involved. The insect intestine shows several structural and physiological differences among species, but it is generally a hostile environment for many microorganisms, selecting against the most sensitive and at the same time guaranteeing a less competitive environment to resistant ones. An intensive characterization of the interactions between yeasts and insects has highlighted their relevance not only for attraction to food but also for the insect's development and behaviour. Conversely, some yeasts have been shown to benefit from interactions with insects, in some cases by being carried among different environments. In addition, the insect intestine may provide a place to reside for prolonged periods and possibly mate or generate sexual forms able to mate once back in the external environments. YEA‐May‐17‐0084.R3 PMID:29363168
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Clarifying the Roles of Homeostasis and Allostasis in Physiological Regulation
Ramsay, Douglas S.; Woods, Stephen C.
2014-01-01
Homeostasis, the dominant explanatory framework for physiological regulation, has undergone significant revision in recent years, with contemporary models differing significantly from the original formulation. Allostasis, an alternative view of physiological regulation, goes beyond its homeostatic roots, offering novel insights relevant to our understanding and treatment of several chronic health conditions. Despite growing enthusiasm for allostasis, the concept remains diffuse, due in part to ambiguity as to how the term is understood and used, impeding meaningful translational and clinical research on allostasis. Here we provide a more focused understanding of homeostasis and allostasis by explaining how both play a role in physiological regulation, and a critical analysis of regulation suggests how homeostasis and allostasis can be distinguished. Rather than focusing on changes in the value of a regulated variable (e.g., body temperature, body adiposity, or reward), research investigating the activity and relationship among the multiple regulatory loops that influence the value of these regulated variables may be the key to distinguishing homeostasis and allostasis. The mechanisms underlying physiological regulation and dysregulation are likely to have important implications for health and disease. PMID:24730599
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Effects of Hatching Time on Behavior and Weight Development of Chickens
Løtvedt, Pia; Jensen, Per
2014-01-01
The length of the embryonic period varies both among and within species and can affect the individual phenotype in many ways, both physiologically and behaviorally. In chickens, the hatch window may last 24–48 hours (up to 10% of the incubation time), and studies have shown that incubation length may affect post-hatch growth and physiology. However, little is known about effects on behavior. We therefore investigated how behavior variation correlates with hatching time in the early life of chickens. We also measured egg weight and egg weight loss in relation to hatching time, as well as post-hatch growth. For females, there was a negative correlation between hatch time and body weight from day 4 and throughout the experiment. For males, such a correlation was only observed when testing all hatched males up until day 10. The birds were exposed to a number of behavioral tests, and a principal components analysis was performed on the variables, resulting in four components. For the largest component, termed “Passivity”, a tendency of a difference was found between early and middle male hatchers. Furthermore, a significant difference between early and middle male hatchers was found in the second component, termed “Response to novelty”. In a spatial learning test, late hatchers tended to learn slower. The behavior of females was not significantly affected by hatching time in any of these tests. This study is among the first to demonstrate a link between time of hatching and early behavior in a precocial species like the chicken, and may help shedding light on the evolutionary trade-offs between incubation length and post-hatch traits. The results may also be relevant from a perspective of stress coping and therefore also for animal welfare and productivity in the chicken industry. The mechanisms linking hatching time with post-hatch phenotype remain to be investigated. PMID:25058654
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Lätt, Evelin; Jürimäe, Jaak; Mäestu, Jarek; Purge, Priit; Rämson, Raul; Haljaste, Kaja; Keskinen, Kari L; Rodriguez, Ferran A; Jürimäe, Toivo
2010-01-01
The purpose of this study was to analyze the relationships between 100-m front crawl swimming performance and relevant biomechanical, anthropometrical and physiological parameters in male adolescent swimmers. Twenty five male swimmers (mean ± SD: age 15. 2 ± 1.9 years; height 1.76 ± 0.09 m; body mass 63.3 ± 10.9 kg) performed an all-out 100-m front crawl swimming test in a 25-m pool. A respiratory snorkel and valve system with low hydrodynamic resistance was used to collect expired air. Oxygen uptake was measured breath-by-breath by a portable metabolic cart. Swimming velocity, stroke rate (SR), stroke length and stroke index (SI) were assessed during the test by time video analysis. Blood samples for lactate measurement were taken from the fingertip pre exercise and at the third and fifth minute of recovery to estimate net blood lactate accumulation (ΔLa). The energy cost of swimming was estimated from oxygen uptake and blood lactate energy equivalent values. Basic anthropometry included body height, body mass and arm span. Body composition parameters were measured using dual-energy X-ray absorptiometry (DXA). Results indicate that biomechanical factors (90.3%) explained most of 100-m front crawl swimming performance variability in these adolescent male swimmers, followed by anthropometrical (45.8%) and physiological (45.2%) parameters. SI was the best single predictor of performance, while arm span and ∆La were the best anthropometrical and physiological indicators, respectively. SI and SR alone explained 92.6% of the variance in competitive performance. These results confirm the importance of considering specific stroke technical parameters when predicting success in young swimmers. Key pointsThis study investigated the influence of different anthropometrical, physiological and biomechanical parameters on 100-m swimming performance in adolescent boys.Biomechanical factors contributed most to sprint swimming performance in these young male swimmers (90.3% of variability in performance), followed by anthropometrical (45.8%) and physiological (45.2%) parameters.Two selected variables (stroke index and stroke rate) explained 92.6% of the variance in competitive performance in these adolescent swimmers.
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Lätt, Evelin; Jürimäe, Jaak; Mäestu, Jarek; Purge, Priit; Rämson, Raul; Haljaste, Kaja; Keskinen, Kari L.; Rodriguez, Ferran A.; Jürimäe, Toivo
2010-01-01
The purpose of this study was to analyze the relationships between 100-m front crawl swimming performance and relevant biomechanical, anthropometrical and physiological parameters in male adolescent swimmers. Twenty five male swimmers (mean ± SD: age 15. 2 ± 1.9 years; height 1.76 ± 0.09 m; body mass 63.3 ± 10.9 kg) performed an all-out 100-m front crawl swimming test in a 25-m pool. A respiratory snorkel and valve system with low hydrodynamic resistance was used to collect expired air. Oxygen uptake was measured breath-by-breath by a portable metabolic cart. Swimming velocity, stroke rate (SR), stroke length and stroke index (SI) were assessed during the test by time video analysis. Blood samples for lactate measurement were taken from the fingertip pre exercise and at the third and fifth minute of recovery to estimate net blood lactate accumulation (ΔLa). The energy cost of swimming was estimated from oxygen uptake and blood lactate energy equivalent values. Basic anthropometry included body height, body mass and arm span. Body composition parameters were measured using dual-energy X-ray absorptiometry (DXA). Results indicate that biomechanical factors (90.3%) explained most of 100-m front crawl swimming performance variability in these adolescent male swimmers, followed by anthropometrical (45.8%) and physiological (45.2%) parameters. SI was the best single predictor of performance, while arm span and ∆La were the best anthropometrical and physiological indicators, respectively. SI and SR alone explained 92.6% of the variance in competitive performance. These results confirm the importance of considering specific stroke technical parameters when predicting success in young swimmers. Key points This study investigated the influence of different anthropometrical, physiological and biomechanical parameters on 100-m swimming performance in adolescent boys. Biomechanical factors contributed most to sprint swimming performance in these young male swimmers (90.3% of variability in performance), followed by anthropometrical (45.8%) and physiological (45.2%) parameters. Two selected variables (stroke index and stroke rate) explained 92.6% of the variance in competitive performance in these adolescent swimmers. PMID:24149633
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Moraska, Albert F.; Hickner, Robert C.; Kohrt, Wendy M.; Brewer, Alan
2012-01-01
Objective To demonstrate proof-of-principle measurement for physiological change within an active myofascial trigger point (MTrP) undergoing trigger point release (ischemic compression). Design Interstitial fluid was sampled continuously at a trigger point before and after intervention. Setting A biomedical research clinic at a university hospital. Participants Two subjects from a pain clinic presenting with chronic headache pain. Interventions A single microdialysis catheter was inserted into an active MTrP of the upper trapezius to allow for continuous sampling of interstitial fluid before and after application of trigger point therapy by a massage therapist. Main Outcome Measures Procedural success, pain tolerance, feasibility of intervention during sample collection, determination of physiologically relevant values for local blood flow, as well as glucose and lactate concentrations. Results Both patients tolerated the microdialysis probe insertion into the MTrP and treatment intervention without complication. Glucose and lactate concentrations were measured in the physiological range. Following intervention, a sustained increase in lactate was noted for both subjects. Conclusions Identifying physiological constituents of MTrP’s following intervention is an important step toward understanding pathophysiology and resolution of myofascial pain. The present study forwards that aim by showing proof-of-concept for collection of interstitial fluid from an MTrP before and after intervention can be accomplished using microdialysis, thus providing methodological insight toward treatment mechanism and pain resolution. Of the biomarkers measured in this study, lactate may be the most relevant for detection and treatment of abnormalities in the MTrP. PMID:22975226
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Poquet, Laure; Wooster, Tim J
2016-08-01
Lipids play an important role in the diet of preterm and term infants providing a key energy source and essential lipid components for development. While a lot is known about adult lipid digestion, our understanding of infant digestion physiology is still incomplete, the greatest gap being on the biochemistry of the small intestine, particularly the activity and relative importance of the various lipases active in the intestine. The literature has been reviewed to identify the characteristics of lipid digestion of preterm and term infants, but also to better understand the physiology of the infant gastrointestinal tract compared to adults that impacts the absorption of lipids. The main differences are a higher gastric pH, submicellar bile salt concentration, a far more important role of gastric lipases as well as differences at the level of the intestinal barrier. Importantly, the consequences of improper in vitro replication of gastric digestions conditions (pH and lipase specificity) are demonstrated using examples from the most recent of studies. It is true that some animal models could be adapted to study infant lipid digestion physiology, however the ethical relevance of such models is questionable, hence the development of accurate in vitro models is a must. In vitro models that combine up to date knowledge of digestion biochemistry with intestinal cells in culture are the best choice to replicate digestion and absorption in infant population, this would allow the adaptation of infant formula for a better digestion and absorption of dietary lipids by preterm and term infants. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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Kaufman, Milissa L; Kimble, Matthew O; Kaloupek, Danny G; McTeague, Lisa M; Bachrach, Peter; Forti, Allison M; Keane, Terence M
2002-03-01
A recent study found that female rape victims with acute posttraumatic stress disorder (PTSD) who received a high score on the Peritraumatic Dissociative Experiences Questionnaire exhibited suppression of physiological responses during exposure to trauma-related stimuli. The goal of our present study was to test whether the same relationship holds true for male Vietnam combat veterans with chronic PTSD, using secondary analyses applied to data derived from a Veteran's Affairs Cooperative Study. Vietnam combat veterans (N = 1238) completed measures to establish combat-related PTSD diagnostic status, extent of PTSD-related symptomatic distress, and presence of dissociative symptoms during their most stressful combat-related experiences. Extreme subgroups of veterans with current PTSD were classified as either low dissociators (N = 118) or high dissociators (N = 256) based on an abbreviated version of the Peritraumatic Dissociative Experiences Questionnaire. Dependent variables reflected subjective distress along with heart rate, skin conductance, electromyographic, and blood pressure data when responding to neutral and trauma-related audiovisual and imagery presentations. Veterans in the current PTSD group had significantly higher dissociation scores than did veterans in the lifetime and never PTSD groups. Among veterans with current PTSD, high dissociators reported greater PTSD-related symptomatic distress than did low dissociators, but the groups did not differ with respect to physiological reactivity to the trauma-related laboratory presentations. Our results replicate the previously reported relationship between peritraumatic dissociation and PTSD status in Vietnam combat veterans. However, we found no association between peritraumatic dissociation and the extent of physiological responding to trauma-relevant cues in male veterans with chronic combat-related PTSD.
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The therapeutic use of the relaxation response in stress-related diseases.
Esch, Tobias; Fricchione, Gregory L; Stefano, George B
2003-02-01
The objective of this work was to investigate a possible (therapeutic) connection between the relaxation response (RR) and stress-related diseases. Further, common underlying molecular mechanisms and autoregulatory pathways were examined. For the question of (patho)physiology and significance of RR techniques in the treatment of stress-related diseases, we analyzed peer-reviewed references only. The RR has been shown to be an appropriate and relevant therapeutic tool to counteract several stress-related disease processes and certain health-restrictions, particularly in certain immunological, cardiovascular, and neurodegenerative diseases/mental disorders. Further, common underlying molecular mechanisms may exist that represent a connection between the stress response, pathophysiological findings in stress-related diseases, and physiological changes/autoregulatory pathways described in the RR. Here, constitutive or low-output nitric oxide (NO) production may be involved in a protective or ameliorating context, whereas inducible, high-output NO release may facilitate detrimental disease processes. In mild or early disease states, a high degree of biological and physiological flexibility may still be possible (dynamic balance). Here, the therapeutic use of RR techniques may be considered particularly relevant, and the observable (beneficial) effects may be exerted via activation of constitutive NO pathways. RR techniques, regularly part of professional stress management or mind/body medical settings, represent an important tool to be added to therapeutic strategies dealing with stress-related diseases. Moreover, as part of 'healthy' life-style modifications, they may serve primary (or secondary) prevention. Further studies are necessary to elucidate the complex physiology underlying the RR and its impact upon stress-related disease states.
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Kratochwill, Klaus; Boehm, Michael; Herzog, Rebecca; Lichtenauer, Anton Michael; Salzer, Elisabeth; Lechner, Michael; Kuster, Lilian; Bergmeister, Konstantin; Rizzi, Andreas; Mayer, Bernd; Aufricht, Christoph
2012-03-01
Exposure of mesothelial cells to peritoneal dialysis fluids (PDF) results in cytoprotective cellular stress responses (CSR) that counteract PDF-induced damage. In this study, we tested the hypothesis that the CSR may be inadequate in relevant models of peritoneal dialysis (PD) due to insufficient levels of glutamine, resulting in increased vulnerability against PDF cytotoxicity. We particularly investigated the role of alanyl-glutamine (Ala-Gln) dipeptide on the cytoprotective PDF stress proteome. Adequacy of CSR was investigated in two human in vitro models (immortalized cell line MeT-5A and mesothelial cells derived from peritoneal effluent of uraemic patients) following exposure to heat-sterilized glucose-based PDF (PD4-Dianeal, Baxter) diluted with medium and, in a comparative proteomics approach, at different levels of glutamine ranging from depletion (0 mM) via physiological (0.7 mM) to pharmacological levels (8 mM administered as Ala-Gln). Despite severe cellular injury, expression of cytoprotective proteins was dampened upon PDF exposure at physiological glutamine levels, indicating an inadequate CSR. Depletion of glutamine aggravated cell injury and further reduced the CSR, whereas addition of Ala-Gln at pharmacological level restored an adequate CSR, decreasing cellular damage in both PDF exposure systems. Ala-Gln specifically stimulated chaperoning activity, and cytoprotective processes were markedly enhanced in the PDF stress proteome. Taken together, this study demonstrates an inadequate CSR of mesothelial cells following PDF exposure associated with low and physiological levels of glutamine, indicating a new and potentially relevant pathomechanism. Supplementation of PDF with pharmacological doses of Ala-Gln restored the cytoprotective stress proteome, resulting in improved resistance of mesothelial cells to exposure to PDF. Future work will study the clinical relevance of CSR-mediated cytoprotection.
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Pirfenidone for Idiopathic Pulmonary Fibrosis: A Systematic Review and Meta-Analysis
Venegas, Carmen; Arenas, Alex; Rada, Gabriel
2015-01-01
Idiopathic pulmonary fibrosis (IPF) is a progressive disease with poor prognosis. In the last decades pirfenidone an anti-inflammatory and anti-fibrotic agent has shown benefit in inhibit collagen production and has also demonstrated benefit in decline progression in IPF in physiological outcomes as Forced vital capacity (FVC), in clinical outcomes such as progression free survival (PFS) and a benefit in mortality but no in clinically relevant outcomes as exacerbations or worsening of IPF. Methods: We conducted a systematic review to evaluate the effectiveness of physiological and clinical outcomes of pirfenidone compared to placebo in IPF. We performed a search with no language restriction. Two researchers performed literature search, quality assessment, data extraction and analysis. And was performed a summary of findings table following the GRADE approach. Results: We included 5 RCTs (Randomized controlled trials) in analysis. The meta-analysis resulted in a decrease in all cause-mortality (RR 0.52 IC 0.32–0.88) and IPF related mortality (RR 0.32 IC 0.14–0.75); other outcomes evaluated were worsening of IPF (RR 0.64 IC 0.50–0.83) and acute exacerbation (RR: 0.72 IC 0.30–1.66 respectively). Also there was a decrease in progression free survival (PFS) (RR 0.83 IC 0.74–0.92) compared to placebo. Conclusions: We observed significant differences in physiologic and clinically relevant outcomes such as reduction in all-cause mortality, IPF related mortality, worsening and exacerbation of IPF and PFS. So pirfenidone treatment should be considered not only for its benefits in pulmonary function tests but also by its clinically relevant outcomes. PMID:26308723
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Mori, Tomohisa; Hayashi, Teruo
2012-01-01
The endoplasmic reticulum (ER) chaperone σ-1 receptor (Sig-1R) is cytoprotective against ER stress-induced apoptosis. The level of Sig-1Rs in the brain was reported to be lower in early parkinsonian patients. Because dopamine (DA) toxicity is well known to be involved in the etiology of Parkinson's disease, we tested in this study whether a relationship might exist between Sig-1Rs and DA-induced cytotoxicity in a cellular model by using Chinese hamster ovary (CHO) cells. DA in physiological concentrations (e.g., lower than 10 μM) does not cause apoptosis. However, the same concentrations of DA cause apoptosis in Sig-1R knockdown CHO cells. In search of a mechanistic explanation, we found that unfolded protein response is not involved. Rather, the level of protective protein Bcl-2 is critically involved in this DA/Sig-1R knockdown-induced apoptosis. Specifically, the DA/Sig-1R knockdown causes a synergistic proteasomal conversion of nuclear factor κB (NF-κB) p105 to the active form of p50, which is known to down-regulate the transcription of Bcl-2. It is noteworthy that the DA/Sig-1R knockdown-induced apoptosis is blocked by the overexpression of Bcl-2. Our results therefore indicate that DA is involved in the activation of NF-κB and suggest that endogenous Sig-1Rs are tonically inhibiting the proteasomal conversion/activation of NF-κB caused by physiologically relevant concentrations of DA that would otherwise cause apoptosis. Thus, Sig-1Rs and associated ligands may represent new therapeutic targets for the treatment of parkinsonism. PMID:22399814
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Su, Dian; Shukla, Anil K.; Chen, Baowei
2013-04-01
S-nitrosylation (SNO) is an important reversible thiol oxidation event that has been increasingly recognized for its role in cell signaling. While many proteins susceptible to S-nitrosylation have been reported, site-specific identification of physiologically relevant SNO modifications remains an analytical challenge due to the low-abundance and labile nature of the modification. Herein we present further improvement and optimization of the recently reported, resin-assisted cysteinyl peptide enrichment protocol for SNO identification and the extension of this application to mouse skeletal muscle to identify specific sites sensitive to S-nitrosylation by quantitative reactivity profiling. The results of our data indicate that the protein- andmore » peptide-level enrichment protocols provide comparable specificity and coverage of SNO-peptide identifications. S-nitrosylation reactivity profiling was performed by quantitatively comparing the site-specific SNO modification levels in samples treated with S-nitrosoglutathione (GSNO), an NO donor, at two different physiologically relevant concentrations (i.e., 10 μM and 100 μM). The reactivity profiling experiments overall identified 489 SNO-modified cysteine sites from 197 proteins with the specificity of 95.2% at the unique-peptide-level based on the percentage of Cys-peptides. Among these sites, 260 sites from 135 proteins were observed with relatively high reactivity to S-nitrosylation; such SNO-sensitive sites are more likely to be physiologically relevant. Many of the SNO-sensitive proteins are preferentially localized in mitochondria, contractile fiber and actin cytoskeleton, suggesting the susceptibility of these subcellular compartments to redox regulation. Moreover, the SNO-sensitive proteins seem to be primarily involved in metabolic pathways, including TCA cycle, glycolysis/gluconeogenesis, glutathione metabolism, and fatty acid metabolism, suggesting the importance of redox regulation in muscle metabolism and insulin action.« less
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Meléndez, D M; Marti, S; Pajor, E A; Moya, D; Heuston, C E M; Gellatly, D; Janzen, E D; Schwartzkopf-Genswein, K S
2017-10-01
Three experiments evaluated the effect of band and knife castration on acute pain for the first 7 d after the procedure on 1-wk-, 2-mo-, and 4-mo-old calves. All calves were blocked by age and weight and randomly assigned to 1 of 3 treatments: sham castration (control, CT), band castration (BA), and knife castration (KN). Experiment 1 evaluated 1-wk-old Angus bull calves ( = 34; 43.0 ± 6.61 kg BW), Exp. 2 evaluated 2-mo-old Angus bull calves ( = 34; 91.5 ± 11.93 kg BW), and Exp. 3 evaluated 4-mo-old Angus bull calves ( = 35; 157.6 ± 22.52 kg BW). For all experiments, physiological and behavioral parameters were collected before (d -1 and immediately before castration [T0]) and after (60 and 120 min and on d 7) castration to assess acute pain. Physiological measures included complete blood cell count, cortisol, substance P, and scrotal temperature. Behavioral measures consisted of a visual analog scale, stride length, and time and frequency budgets for walking, standing, lying, tail flicking, foot stamping, and head turning. Performance parameters included initial and final BW and ADG. In Exp. 1, tail flicking was greater ( = 0.02) in KN calves compared to BA calves 2 to 4 h after castration, although no differences were seen between BA and KN compared to CT calves. In Exp. 2, a treatment × time interaction ( = 0.02) was observed for cortisol, where KN calves had greater cortisol concentrations 120 min after castration compared to BA and CT calves; KN calves also lay down and ate less ( < 0.01; = 0.02) and stood and walked more ( < 0.01; = 0.05) compared to BA and CT calves 2 to 4 h after castration. In Exp. 3, a treatment × time interaction ( < 0.01) was observed for cortisol concentrations in which all treatments were different from one another at 60 and 120 min, with BA calves having the greatest concentrations, KN calves being intermediate, and CT having the lowest concentrations. Overall, KN and BA castrated calves presented physiological and behavioral changes associated with acute pain; however, 2-mo-old BA calves presented the fewest behavioral changes and no physiological changes associated with acute pain compared to CT calves.
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Levin, Roy J; Both, Stephanie; Georgiadis, Janniko; Kukkonen, Tuuli; Park, Kwangsung; Yang, Claire C
2016-05-01
The article consists of six sections written by separate authors that review female genital anatomy, the physiology of female sexual function, and the pathophysiology of female sexual dysfunction but excluding hormonal aspects. To review the physiology of female sexual function and the pathophysiology of female sexual dysfunction especially since 2010 and to make specific recommendations according to the Oxford Centre for evidence based medicine (2009) "levels of evidence" wherever relevant. Recommendations were made for particular studies to be undertaken especially in controversial aspects in all six sections of the reviewed topics. Despite numerous laboratory assessments of female sexual function, genital assessments alone appear insufficient to characterise fully the complete sexual response. Copyright © 2016 International Society for Sexual Medicine. Published by Elsevier Inc. All rights reserved.
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[Development of opened instrument for generating and measuring physiological signal].
Chen, Longcong; Hu, Guohu; Gao, Bin
2004-12-01
An opened instrument with liquid crystal display (LCD) for generating and measuring physiological signal is introduced in this paper. Based on a single-chip microcomputer. the instrument uses the technique of LCD screen to display signal wave and information, and it realizes man-machine interaction by keyboard. This instrument can produce not only defined signal in common use by utilizing important saved data and relevant arithmetic, but also user-defined signal. Therefore, it is open to produce signal. In addition, this instrument has strong extension because of its modularized design as computer, which has much function such as displaying, measuring and saving physiological signal, and many features such as low power consumption, small volume, low cost and portability. Hence this instrument is convenient for experiment teaching, clinic examining, maintaining of medical instrument.
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Ouedraogo, Zangbéwendé Guy; Fouache, Allan; Trousson, Amalia; Baron, Silvère; Lobaccaro, Jean-Marc A
2017-10-01
Liver X receptors (LXRs) are members of the nuclear receptor superfamily that have been shown to regulate various physiological functions such as lipid metabolism and cholesterol homeostasis. Concordant reports have elicited the possibility to target them to cure many human diseases including arteriosclerosis, cancer, arthritis, and diabetes. The high relevance of modulating LXR activities to treat numerous skin diseases, mainly those with exacerbated inflammation processes, contrasts with the lack of approved therapeutic use. This review makes an assessment to sum up the findings regarding the physiological roles of LXRs in skin and help progress towards the therapeutic and safe management of their activities. It focuses on the possible pharmacological targeting of LXRs to cure or prevent selected skin diseases. Copyright © 2017 Elsevier B.V. All rights reserved.
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A Review on Ubiquitination of Neurotrophin Receptors: Facts and Perspectives
Sánchez-Sánchez, Julia; Arévalo, Juan Carlos
2017-01-01
Ubiquitination is a reversible post-translational modification involved in a plethora of different physiological functions. Among the substrates that are ubiquitinated, neurotrophin receptors (TrkA, TrkB, TrkC, and p75NTR) have been studied recently. TrkA is the most studied receptor in terms of its ubiquitination, and different E3 ubiquitin ligases and deubiquitinases have been implicated in its ubiquitination, whereas not much is known about the other neurotrophin receptors aside from their ubiquitination. Additional studies are needed that focus on the ubiquitination of TrkB, TrkC, and p75NTR in order to further understand the role of ubiquitination in their physiological and pathological functions. Here we review what is currently known regarding the ubiquitination of neurotrophin receptors and its physiological and pathological relevance. PMID:28335430
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Physiological and Anthropometrical Predictors of 15-Kilometer Time Trial Cycling Performance Time.
ERIC Educational Resources Information Center
Miller, Frank R.; Manfredi, Thomas G.
1987-01-01
A study assessing the relationship between physiological and anthropometrical variables and cycling performance time found that anaerobic threshhold and body circumference ratio correlated highly with cycling performance time. (Author/CB)
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We describe the development and implementation of a Physiological and Anatomical Visual Analytics tool (PAVA), a web browser-based application, used to visualize experimental/simulated chemical time-course data (dosimetry), epidemiological data and Physiologically-Annotated Data ...
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Rehder, Dieter
2015-06-01
Four decades of research carried out by Lage Pettersson, his group and his coworkers are reviewed, research that has been directed predominantly towards the speciation of vanadate and systems containing, along with vanadate and co-reactants such as phosphate and peroxide, biologically relevant organics. In particular, those organics have been addressed that either are (potential) ligands for vanadate-derived coordination compounds generated at physiological conditions and/or function as constituents in medicinally interesting oxidovanadium compounds. Examples for molecules introduced in the context of the physiological vanadate-ligand interaction include the dipeptides Pro-Ala, Ala-Gly, Ala-His and Ala-Ser, the serum constituents lactate and citrate, and the nucleobases adenosine and uridine. The speciation in the vanadate-picolinate and vanadate-maltol systems is geared towards insulin-enhancing vanadium drugs. The speciation as a function of pH, ionic strength and the concentration of vanadate and the ligand(s) is based on potentiometric and (51)V NMR investigations, a methodical combination that allows reliable access to composition, formation constants and, to some extent, also structural details for the manifold of species present in aqueous media at physiological pH and beyond. The time frame 1971 to 2014 is reviewed, emphasizing the interval 1985 to 2006, and thus focusing on biologically interesting vanadium systems. Figurative representations from the original literature have been included. Copyright © 2015 Elsevier Inc. All rights reserved.
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Arthurs, Christopher J; Lau, Kevin D; Asrress, Kaleab N; Redwood, Simon R; Figueroa, C Alberto
2016-05-01
This work presents a mathematical model of the metabolic feedback and adrenergic feedforward control of coronary blood flow that occur during variations in the cardiac workload. It is based on the physiological observations that coronary blood flow closely follows myocardial oxygen demand, that myocardial oxygen debts are repaid, and that control oscillations occur when the system is perturbed and so are phenomenological in nature. Using clinical data, we demonstrate that the model can provide patient-specific estimates of coronary blood flow changes between rest and exercise, requiring only the patient's heart rate and peak aortic pressure as input. The model can be used in zero-dimensional lumped parameter network studies or as a boundary condition for three-dimensional multidomain Navier-Stokes blood flow simulations. For the first time, this model provides feedback control of the coronary vascular resistance, which can be used to enhance the physiological accuracy of any hemodynamic simulation, which includes both a heart model and coronary arteries. This has particular relevance to patient-specific simulation for which heart rate and aortic pressure recordings are available. In addition to providing a simulation tool, under our assumptions, the derivation of our model shows that β-feedforward control of the coronary microvascular resistance is a mathematical necessity and that the metabolic feedback control must be dependent on two error signals: the historical myocardial oxygen debt, and the instantaneous myocardial oxygen deficit. Copyright © 2016 the American Physiological Society.
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Mitra, A; Fadda, H M
2014-08-04
The purpose of this study was to investigate the influence of gastric emptying patterns, surfactants, and dosage form on the supersaturation of a poorly soluble weakly basic drug, dipyridamole, using an in vitro model mimicking the dynamic environment of the upper gastrointestinal tract, and, furthermore, to evaluate the usefulness of this model in establishing correlations to in vivo bioavailability for drugs with solubility/dissolution limited absorption. A simulated stomach duodenum model comprising four compartments was used to assess supersaturation and precipitation kinetics as a function of time. It integrates physiologically relevant fluid volumes, fluid transfer rates, and pH changes of the upper GI tract. Monoexponential gastric emptying patterns simulating the fasted state were compared to linear gastric emptying patterns simulating the fed state. The effect of different surfactants commonly used in oral preparations, specifically, sodium lauryl sulfate (SLS), poloxamer-188, and polysorbate-80, on dipyridamole supersaturation was investigated while maintaining surface tension of the simulated gastric fluids at physiological levels and without obtaining artificial micellar solubilization of the drug. The supersaturation behavior of different dose strengths of dipyridamole was explored. Significant levels of dipyridamole supersaturation were observed in the duodenal compartment under all the different in vivo relevant conditions explored. Dipyridamole supersaturation ratios of up to 11-fold have been observed, and supersaturation has been maintained for up to 120 min. Lower duodenal concentrations of dipyridamole were observed under linear gastric emptying patterns compared to mononexponential gastric emptying. The mean duodenal area under concentration-time curves (AUC60min) for the dipyridamole concentration profile in the duodenal compartment is significantly different for all the surfactants explored (P < 0.05). Our investigations with the different surfactants and comparison of dosage form (solution versus suspension) on the precipitation of dipyridamole revealed that crystal growth, rather than nucleation, is the rate-limiting step for the precipitation of dipyridamole. A linear dose-response relationship was found for the mean in vitro duodenal area under concentration-time curves (AUC∞) in the dose range of 25 mg to 100 mg (R(2) = 0.886). This is in agreement with the pharmacokinetic data of dipyridamole reported in the literature. The simulated stomach duodenum model can provide a reliable and discriminative screening tool for exploring the effect of different physiological variables or formulations on the supersaturation/precipitation kinetics of weakly basic drugs with solubility limited absorption. The amount of drug in solution in the duodenal compartment of the SSD correlates to bioavailability for the weakly basic drug, dipyridamole, which has solubility limited absorption and undergoes supersaturation/precipitation.
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Relevance of trichothecenes in fungal physiology: Disruption of tri5 in Trichoderma arundinaceum
USDA-ARS?s Scientific Manuscript database
Trichothecenes are sesquiterpenoid mycotoxins produced mainly by Fusarium species. Harzianum A (HA), a non-phytotoxic trichothecene produced by Trichoderma arundinaceum, has recently been found to have antagonistic activity against fungal plant pathogens and to induce plant genes involved in defense...
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Allergenic properties and differential response of walnut subjected to processing treatments
USDA-ARS?s Scientific Manuscript database
Walnut is one of the most frequently involved foods in anaphylactic reactions. We investigated changes in walnut allergenicity after physical treatments by in vitro techniques and physiologically relevant assays. Changes in the allergenicity of walnut subjected to high pressure and thermal/pressur...
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Ding, Bei; Soblosky, Lauren; Nguyen, Khoi; Geng, Junqing; Yu, Xinglong; Ramamoorthy, Ayyalusamy; Chen, Zhan
2013-01-01
Antimicrobial peptides (AMPs) could become the next generation antibiotic compounds which can overcome bacterial resistance by disrupting cell membranes and it is essential to determine the factors underlying its mechanism of action. Although high-resolution NMR and other biological studies have provided valuable insights, it has been a major challenge to follow the AMP-membrane interactions at physiologically-relevant low peptide concentrations. In this study, we demonstrate a novel approach to overcome this major limitation by performing Sum Frequency Generation (SFG) vibrational spectroscopic experiments on lipid bilayers containing an AMP, LL-37. Our results demonstrate the power of SFG to study non-linear helical peptides and also infer that lipid-peptide interaction and the peptide orientation depend on the lipid membrane composition. The observed SFG signal changes capture the aggregating process of LL-37 on membrane. In addition, our SFG results on cholesterol-containing lipid bilayers indicate the inhibition effect of cholesterol on peptide-induced membrane permeation process. PMID:23676762
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NASA Astrophysics Data System (ADS)
Ding, Bei; Soblosky, Lauren; Nguyen, Khoi; Geng, Junqing; Yu, Xinglong; Ramamoorthy, Ayyalusamy; Chen, Zhan
2013-05-01
Antimicrobial peptides (AMPs) could become the next generation antibiotic compounds which can overcome bacterial resistance by disrupting cell membranes and it is essential to determine the factors underlying its mechanism of action. Although high-resolution NMR and other biological studies have provided valuable insights, it has been a major challenge to follow the AMP-membrane interactions at physiologically-relevant low peptide concentrations. In this study, we demonstrate a novel approach to overcome this major limitation by performing Sum Frequency Generation (SFG) vibrational spectroscopic experiments on lipid bilayers containing an AMP, LL-37. Our results demonstrate the power of SFG to study non-linear helical peptides and also infer that lipid-peptide interaction and the peptide orientation depend on the lipid membrane composition. The observed SFG signal changes capture the aggregating process of LL-37 on membrane. In addition, our SFG results on cholesterol-containing lipid bilayers indicate the inhibition effect of cholesterol on peptide-induced membrane permeation process.
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Ding, Bei; Soblosky, Lauren; Nguyen, Khoi; Geng, Junqing; Yu, Xinglong; Ramamoorthy, Ayyalusamy; Chen, Zhan
2013-01-01
Antimicrobial peptides (AMPs) could become the next generation antibiotic compounds which can overcome bacterial resistance by disrupting cell membranes and it is essential to determine the factors underlying its mechanism of action. Although high-resolution NMR and other biological studies have provided valuable insights, it has been a major challenge to follow the AMP-membrane interactions at physiologically-relevant low peptide concentrations. In this study, we demonstrate a novel approach to overcome this major limitation by performing Sum Frequency Generation (SFG) vibrational spectroscopic experiments on lipid bilayers containing an AMP, LL-37. Our results demonstrate the power of SFG to study non-linear helical peptides and also infer that lipid-peptide interaction and the peptide orientation depend on the lipid membrane composition. The observed SFG signal changes capture the aggregating process of LL-37 on membrane. In addition, our SFG results on cholesterol-containing lipid bilayers indicate the inhibition effect of cholesterol on peptide-induced membrane permeation process.
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Benito, Itziar; Casañas, Juan José; Montesinos, María Luz
2018-06-19
Several proteomic analyses have been performed on synaptic fractions isolated from cortex or even total brain, resulting in preparations with a high synaptic heterogeneity and complexity. Synaptoneurosomes (SNs) are subcellular membranous elements that contain sealed pre- and post-synaptic components. They are obtained by subcellular fractionation of brain homogenates and serve as a suitable model to study many aspects of the synapse physiology. Here we report the proteomic content of SNs isolated from hippocampus of adult mice, a brain region involved in memory that presents lower synaptic heterogeneity than cortex. Interestingly, in addition to pre- and post-synaptic proteins, we found that proteins involved in RNA binding and translation were overrepresented in our preparation. These results validate the protocol we previously reported for SNs isolation, and, as reported by other authors, highlight the relevance of local synaptic translation for hippocampal physiology. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.
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A PMMA microfluidic dielectric sensor for blood coagulation monitoring at the point-of-care.
Maji, Debnath; Suster, Michael A; Kucukal, Erdem; Gurkan, Umut A; Stavrou, Evi X; Mohseni, Pedram
2016-08-01
This paper describes the design and construct of a fully biocompatible, microfluidic, dielectric sensor targeted at monitoring human whole blood coagulation at the point-of-care (POC). The sensor assembly procedure involves using sputtered electrodes in a microfluidic channel with a physiologically relevant height of 50μm to create a three-dimensional (3D), parallel-plate, capacitive sensing area. The sensor is constructed with biocompatible materials of polymethyl methacrylate (PMMA) for the substrate and titanium nitride (TiN) for the sensing and floating electrodes. The real part of the complex relative dielectric permittivity of human whole blood is measured from 10kHz to 100MHz using an impedance analyzer and under static conditions. The temporal variation in dielectric permittivity at 1MHz for human whole blood undergoing coagulation shows a peak in permittivity at 5 minutes, which closely matches our previously established results. This sensor can pave the way for monitoring blood coagulation under physiologically relevant shear flow rates in the future.
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Begara-Morales, Juan C.; Sánchez-Calvo, Beatriz; Chaki, Mounira; Valderrama, Raquel; Mata-Pérez, Capilla; Padilla, María N.; Corpas, Francisco J.; Barroso, Juan B.
2016-01-01
Nitric oxide (NO) is a biological messenger that orchestrates a plethora of plant functions, mainly through post-translational modifications (PTMs) such as S-nitrosylation or tyrosine nitration. In plants, hundreds of proteins have been identified as potential targets of these NO-PTMs under physiological and stress conditions indicating the relevance of NO in plant-signaling mechanisms. Among these NO protein targets, there are different antioxidant enzymes involved in the control of reactive oxygen species (ROS), such as H2O2, which is also a signal molecule. This highlights the close relationship between ROS/NO signaling pathways. The major plant antioxidant enzymes, including catalase, superoxide dismutases (SODs) peroxiredoxins (Prx) and all the enzymatic components of the ascorbate-glutathione (Asa-GSH) cycle, have been shown to be modulated to different degrees by NO-PTMs. This mini-review will update the recent knowledge concerning the interaction of NO with these antioxidant enzymes, with a special focus on the components of the Asa-GSH cycle and their physiological relevance. PMID:26909095
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An Overview of Monthly Rhythms and Clocks
Raible, Florian; Takekata, Hiroki; Tessmar-Raible, Kristin
2017-01-01
Organisms have evolved to cope with geophysical cycles of different period lengths. In this review, we focus on the adaptations of animals to the lunar cycle, specifically, on the occurrence of biological rhythms with monthly (circalunar) or semi-monthly (circasemilunar) period lengths. Systematic experimental investigation, starting in the early twentieth century, has allowed scientists to distinguish between mythological belief and scientific facts concerning the influence of the lunar cycle on animals. These studies revealed that marine animals of various taxa exhibit circalunar or circasemilunar reproductive rhythms. Some of these rely on endogenous oscillators (circalunar or circasemilunar clocks), whereas others are directly driven by external cues, such as the changes in nocturnal illuminance. We review current insight in the molecular and cellular mechanisms involved in circalunar rhythms, focusing on recent work in corals, annelid worms, midges, and fishes. In several of these model systems, the transcript levels of some core circadian clock genes are affected by both light and endogenous circalunar oscillations. How these and other molecular changes relate to the changes in physiology or behavior over the lunar cycle remains to be determined. We further review the possible relevance of circalunar rhythms for terrestrial species, with a particular focus on mammalian reproduction. Studies on circalunar rhythms of conception or birth rates extend to humans, where the lunar cycle was suggested to also affect sleep and mental health. While these reports remain controversial, factors like the increase in “light pollution” by artificial light might contribute to discrepancies between studies. We finally discuss the existence of circalunar oscillations in mammalian physiology. We speculate that these oscillations could be the remnant of ancient circalunar oscillators that were secondarily uncoupled from a natural entrainment mechanism, but still maintained relevance for structuring the timing of reproduction or physiology. The analysis and comparison of circalunar rhythms and clocks are currently challenging due to the heterogeneity of samples concerning species diversity, environmental conditions, and chronobiological conditions. We suggest that future research will benefit from the development of standardized experimental paradigms, and common principles for recording and reporting environmental conditions, especially light spectra and intensities. PMID:28553258
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[Isolation of Aspergillus tritici from internal environment (Chile): Ecological and clinical scope].
Vieille Oyarzo, Peggy; Cruz Choappa, Rodrigo; Piontelli Laforet, Eduardo
2018-03-29
Indoor environments provide important protective habitats for humans, who live or work in them most of the time. Many of these environments lack ventilation, which affects the composition of microbial communities, especially that of the fungal community. The aim of this study is to report the isolation of Aspergillus section Candidi from indoor environments of the School of Medicine at Universidad de Valparaiso, Chile, and identification through morpho-physiological and molecular approaches. Their ecological and clinical features were highlighted. An environmental non-volumetric sampling was performed on PDA medium; 2 petri dishes were exposed in 10 different places to select the Aspergillus samples. Subcultures were performed on agar Czapek with yeast extract (CYA), malt extract agar (MEA) and creatin sacarose agar (CREA) media only for the morpho-physiological and later the molecular identification of white spore species. Of the 20 samples analyzed, one Aspergillus belonging to Candidi section was isolated. Based on its morphology and molecular features, it was classified as Aspergillustritici Mehrotra & Basu. Its ecology and medical relevance are reviewed and discussed. Copyright © 2017 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.
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Whitehead, Andrew; Roach, Jennifer L; Zhang, Shujun; Galvez, Fernando
2012-04-15
The killifish Fundulus heteroclitus is abundant in osmotically dynamic estuaries and it can quickly adjust to extremes in environmental salinity. We performed a comparative osmotic challenge experiment to track the transcriptomic and physiological responses to two salinities throughout a time course of acclimation, and to explore the genome regulatory mechanisms that enable extreme osmotic acclimation. One southern and one northern coastal population, known to differ in their tolerance to hypo-osmotic exposure, were used as our comparative model. Both populations could maintain osmotic homeostasis when transferred from 32 to 0.4 p.p.t., but diverged in their compensatory abilities when challenged down to 0.1 p.p.t., in parallel with divergent transformation of gill morphology. Genes involved in cell volume regulation, nucleosome maintenance, ion transport, energetics, mitochondrion function, transcriptional regulation and apoptosis showed population- and salinity-dependent patterns of expression during acclimation. Network analysis confirmed the role of cytokine and kinase signaling pathways in coordinating the genome regulatory response to osmotic challenge, and also posited the importance of signaling coordinated through the transcription factor HNF-4α. These genome responses support hypotheses of which regulatory mechanisms are particularly relevant for enabling extreme physiological flexibility.
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Bobst, Cedric E; Thomas, John J; Salinas, Paul A; Savickas, Philip; Kaltashov, Igor A
2010-01-01
The solution dynamics of an enzyme acid-β-glucocerebrosidase (GCase) probed at a physiologically relevant (lysosomal) pH by hydrogen/deuterium exchange mass spectrometry (HDX-MS) reveals very uneven distribution of backbone amide protection across the polypeptide chain. Highly mobile segments are observed even within the catalytic cavity alongside highly protective segments, highlighting the importance of the balance between conformational stability and flexibility for enzymatic activity. Forced oxidation of GCase that resulted in a 40–60% reduction in in vitro biological activity affects the stability of some key structural elements within the catalytic site. These changes in dynamics occur on a longer time scale that is irrelevant for catalysis, effectively ruling out loss of structure in the catalytic site as a major factor contributing to the reduction of the catalytic activity. Oxidation also leads to noticeable destabilization of conformation in remote protein segments on a much larger scale, which is likely to increase the aggregation propensity of GCase and affect its bioavailability. Therefore, it appears that oxidation exerts its negative impact on the biological activity of GCase indirectly, primarily through accelerated aggregation and impaired trafficking. PMID:20945356
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Association of Enjoyable Leisure Activities With Psychological and Physical Well-Being
Pressman, Sarah D.; Matthews, Karen A.; Cohen, Sheldon; Martire, Lynn M.; Scheier, Michael; Baum, Andrew; Schulz, Richard
2010-01-01
Objective To examine whether engaging in multiple enjoyable activities was associated with better psychological and physiological functioning. Few studies have examined the health benefits of the enjoyable activities that individuals participate in voluntarily in their free time. Method Participants from four different studies (n = 1399 total, 74% female, age = 19–89 years) completed a self-report measure (Pittsburgh Enjoyable Activities Test (PEAT)) assessing their participation in ten different types of leisure activities as well as measures assessing positive and negative psychosocial states. Resting blood pressure, cortisol (over 2 days), body mass index, waist circumference, and perceived physiological functioning were assessed. Results Higher PEAT scores were associated with lower blood pressure, total cortisol, waist circumference, and body mass index, and perceptions of better physical function. These associations withstood controlling for demographic measures. The PEAT was correlated with higher levels of positive psychosocial states and lower levels of depression and negative affect. Conclusion Enjoyable leisure activities, taken in the aggregate, are associated with psychosocial and physical measures relevant for health and well-being. Future studies should determine the extent that these behaviors in the aggregate are useful predictors of disease and other health outcomes. PMID:19592515
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Surface area-volume ratios in insects.
Kühsel, Sara; Brückner, Adrian; Schmelzle, Sebastian; Heethoff, Michael; Blüthgen, Nico
2017-10-01
Body mass, volume and surface area are important for many aspects of the physiology and performance of species. Whereas body mass scaling received a lot of attention in the literature, surface areas of animals have not been measured explicitly in this context. We quantified surface area-volume (SA/V) ratios for the first time using 3D surface models based on a structured light scanning method for 126 species of pollinating insects from 4 orders (Diptera, Hymenoptera, Lepidoptera, and Coleoptera). Water loss of 67 species was measured gravimetrically at very dry conditions for 2 h at 15 and 30 °C to demonstrate the applicability of the new 3D surface measurements and relevance for predicting the performance of insects. Quantified SA/V ratios significantly explained the variation in water loss across species, both directly or after accounting for isometric scaling (residuals of the SA/V ∼ mass 2/3 relationship). Small insects with a proportionally larger surface area had the highest water loss rates. Surface scans of insects to quantify allometric SA/V ratios thus provide a promising method to predict physiological responses, improving the potential of body mass isometry alone that assume geometric similarity. © 2016 Institute of Zoology, Chinese Academy of Sciences.
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Endepols, H; Jungnickel, J; Braun, K
2001-01-01
Cocultures of the learning-relevant forebrain region mediorostral neostriatum and hyperstriatum ventrale (MNH) and its main glutamatergic input area nucleus dorsomedialis anterior thalami/posterior thalami were morphologically and physiologically characterized. Synaptic contacts of thalamic fibers were light- and electron-microscopically detected on MNH neurons by applying the fluorescence tracer DiI-C18(3) into the thalamus part of the coculture. Most thalamic synapses on MNH neurons were symmetric and located on dendritic shafts, but no correlation between Gray-type ultrastructure and dendritic localization was found. Using intracellular current clamp recordings, we found that the electrophysiological properties, such as input resistance, time constant, action potential threshold, amplitude, and duration of MNH neurons, remain stable for over 30 days in vitro. Pharmacological blockade experiments revealed glutamate as the main neurotransmitter of thalamic synapses on MNH neurons, which were also found on inhibitory neurons. High frequency stimulation of thalamic inputs evoked synaptic potentiation in 22% of MNH neurons. The results indicate that DMA/DMP-MNH cocultures, which can be maintained under stable conditions for at least 4 weeks, provide an attractive in vitro model for investigating synaptic plasticity in the avian brain.
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NASA Astrophysics Data System (ADS)
Mariano, Jay
A survey of over 500 science teachers reported that two thirds of their science classes were lecture based lessons where students were required to listen and take notes (Boyle, 2010). In addition to taking notes from lectures, note taking is a necessary skill to possess to record scientific observations and procedures and record information during class. Guided notes is a pedagogical method in which the instructor prepares and provides students with a modified form of lecture information to guide students (Neef, McCord, & Ferreri, 2006). This study examined the extent to which the use of guided notes in a unit of study of the muscular system of anatomy and physiology positively affected the mastery on content-based assessments for 11 th grade students. The data collection methods included quiz and test scores, a 4-point Likert scale survey, and an open-ended questionnaire. Results of the data revealed that guided notes was one factor that led to mastery in learning content. Additionally, students in this study preferred this method as it helped them to distinguish relevant information allowing more time to listen and focus on the teacher.
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Almeida, David M.; McGonagle, Katherine; King, Heather
2010-01-01
This paper presents a research method for assessing stress and mental health in ongoing population-based social surveys that combines self-reports of naturally occurring daily stressors with a primary marker of stress physiology, salivary cortisol. We first discuss the relevance of stress processes to mental health and introduce a model for examining daily stress processes, which highlights multiple components of daily stressor exposure. A primary aim of this approach is to capture variability across stressful situations, between persons of different groups, or within persons over a period of time. Next, we describe how the assessment of diurnal salivary cortisol is a promising approach to examining naturally occurring stress physiology in large social surveys. We then present findings from the National Study of Daily Experiences (a substudy of the Midlife in the United States Study) that document the feasibility and reliability of the collection of daily stressors and salivary diurnal cortisol and provide examples of research findings linking stressor exposure to diurnal cortisol. The final portion of the paper describes ways that this approach can leverage the strengths of various features of longitudinal social surveys to extend research on stress and mental health. PMID:20183906
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Endepols, Heike; Jungnickel, Julia; Braun, Katharina
2001-01-01
Cocultures of the learning-relevant forebrain region mediorostrai neostriatum and hyperstriatum ventrale (MNH) and its main glutamatergic input area nucleus dorsomedialis anterior thalami/posterior thalami were morphologically and physiologically characterized. Synaptic contacts of thalamic fibers were lightand electron-microscopically detected on MNH neurons by applying the fluorescence tracer DiI-C18(3) into the thalamus part of the coculture. Most thalamic synapses on MNH neurons were symmetric and located on dendritic shafts, but no correlation between Gray-type ultrastructure and dendritic localization was found. Using intraceilular current clamp recordings, we found that the electrophysiological properties, such as input resistance, time constant, action potential threshold, amplitude, and duration of MNH neurons, remain stable for over 30 days in vitro. Pharmacological blockade experiments revealed glutamate as the main neurotransmitter of thalamic synapses on MNH neurons, which were also found on inhibitory neurons. High frequency stimulation of thalamic inputs evoked synaptic potentiation in 22% of MNH neurons. The results indicate that DMA/DMP-MNH cocultures, which can be maintained under stable conditions for at least 4 weeks, provide an attractive in vitro model for investigating synaptic plasticity in the avian brain. PMID:12018771
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Zhu, Lingyun; Li, Lianjie; Meng, Chunyan
2014-12-01
There have been problems in the existing multiple physiological parameter real-time monitoring system, such as insufficient server capacity for physiological data storage and analysis so that data consistency can not be guaranteed, poor performance in real-time, and other issues caused by the growing scale of data. We therefore pro posed a new solution which was with multiple physiological parameters and could calculate clustered background data storage and processing based on cloud computing. Through our studies, a batch processing for longitudinal analysis of patients' historical data was introduced. The process included the resource virtualization of IaaS layer for cloud platform, the construction of real-time computing platform of PaaS layer, the reception and analysis of data stream of SaaS layer, and the bottleneck problem of multi-parameter data transmission, etc. The results were to achieve in real-time physiological information transmission, storage and analysis of a large amount of data. The simulation test results showed that the remote multiple physiological parameter monitoring system based on cloud platform had obvious advantages in processing time and load balancing over the traditional server model. This architecture solved the problems including long turnaround time, poor performance of real-time analysis, lack of extensibility and other issues, which exist in the traditional remote medical services. Technical support was provided in order to facilitate a "wearable wireless sensor plus mobile wireless transmission plus cloud computing service" mode moving towards home health monitoring for multiple physiological parameter wireless monitoring.
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Fluid flow and convective transport of solutes within the intervertebral disc.
Ferguson, Stephen J; Ito, Keita; Nolte, Lutz P
2004-02-01
Previous experimental and analytical studies of solute transport in the intervertebral disc have demonstrated that for small molecules diffusive transport alone fulfils the nutritional needs of disc cells. It has been often suggested that fluid flow into and within the disc may enhance the transport of larger molecules. The goal of the study was to predict the influence of load-induced interstitial fluid flow on mass transport in the intervertebral disc. An iterative procedure was used to predict the convective transport of physiologically relevant molecules within the disc. An axisymmetric, poroelastic finite-element structural model of the disc was developed. The diurnal loading was divided into discrete time steps. At each time step, the fluid flow within the disc due to compression or swelling was calculated. A sequentially coupled diffusion/convection model was then employed to calculate solute transport, with a constant concentration of solute being provided at the vascularised endplates and outer annulus. Loading was simulated for a complete diurnal cycle, and the relative convective and diffusive transport was compared for solutes with molecular weights ranging from 400 Da to 40 kDa. Consistent with previous studies, fluid flow did not enhance the transport of low-weight solutes. During swelling, interstitial fluid flow increased the unidirectional penetration of large solutes by approximately 100%. Due to the bi-directional temporal nature of disc loading, however, the net effect of convective transport over a full diurnal cycle was more limited (30% increase). Further study is required to determine the significance of large solutes and the timing of their delivery for disc physiology.
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Improving practices in nanomedicine through near real-time pharmacokinetic analysis
NASA Astrophysics Data System (ADS)
Magafia, Isidro B.
More than a decade into the development of gold nanoparticles, with multiple clinical trials underway, ongoing pre-clinical research continues towards better understanding in vivo interactions. The goal is treatment optimization through improved best practices. In an effort to collect information for healthcare providers enabling informed decisions in a relevant time frame, instrumentation for real-time plasma concentration (multi-wavelength photoplethysmography) and protocols for rapid elemental analysis (energy dispersive X-Ray fluorescence) of biopsied tumor tissue have been developed in a murine model. An initial analysis, designed to demonstrate the robust nature and utility of the techniques, revealed that area under the bioavailability curve (AUC) alone does not currently inform tumor accumulation with a high degree of accuracy (R2=0.56), marginally better than injected dose (R2=0.46). This finding suggests that the control of additional experimental and physiological variables (chosen through modeling efforts) may yield more predictable tumor accumulation. Subject core temperature, blood pressure, and tumor perfusion are evaluated relative to particle uptake in a murine tumor model. New research efforts are also focused on adjuvant therapies that are employed to modify circulation parameters, including the AUC, of nanorods and gold nanoshells. Preliminary studies demonstrated a greater than 300% increase in average AUC using a reticuloendothelial blockade agent versus control groups. Given a better understanding of the relative importance of the physiological factors that influence rates of tumor accumulation, a set of experimental best practices is presented. This dissertation outlines the experimental protocols conducted, and discusses the real-world needs discovered and how these needs became specifications of developed protocols.
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John, Harald; Hierer, Jessica; Haas, Olga; Forssmann, Wolf-Georg
2007-03-01
Chemerin is a chemoattractive protein acting as a ligand for the G-protein-coupled receptor ChemR23/CMKLR1 and plays an important role in the innate and adaptive immunity. Proteolytic processing of its C terminus is essential for receptor binding and physiological activity. Therefore, we investigated the plasma stability of the decapeptide chemerin 145-154 (P(145)-F(154)) corresponding to the C terminus of the physiologically active chemerin variant E(21)-F(154) from human hemofiltrate. For monitoring concentration-time profiles and degradation products we developed a novel matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry procedure using an internal peptide standard (hemorphin LVV-H7) for quantification. The linear range covers 2.5 orders of magnitude in the lower micromolar concentration range (lower limit of quantification 0.312 microg/ml, 0.25 microM) characterized by satisfactory reproducibility (CV < or =9%), accuracy (< or =10%), ruggedness, and recovery (98%). We found that chemerin 145-154 is C-terminally truncated in human citrate plasma by the cleavage of the penultimate dipeptidyl residue. N-terminal truncation was not observed. In contrast to citrate plasma, no degradation was detected in ethylenediammetetraacetate (EDTA) plasma. We identified angiotensin-converting-enzyme (ACE) to be responsible for C-terminal truncation, which could be completely inhibited by EDTA and captopril. These results are relevant to clarify the natural processing of chemerin and the potential involvement of ACE in mediating the immune response.
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Linnenbringer, Erin; Gehlert, Sarah; Geronimus, Arline T.
2017-01-01
Hormone receptor negative (HR−) breast cancer subtypes are etiologically distinct from the more common, less aggressive, and more treatable form of estrogen receptor positive (ER+) breast cancer. Numerous population-based studies have found that, in the United States, Black women are 2 to 3 times more likely to develop HR− breast cancer than White women. Much of the existing research on racial disparities in breast cancer subtype has focused on identifying predisposing genetic factors associated with African ancestry. This approach fails to acknowledge that racial stratification shapes a wide range of environmental and social exposures over the life course. Human stress genomics considers the role of individual stress perceptions on gene expression. Yet, the role of structurally rooted biopsychosocial processes that may be activated by the social patterning of stressors in an historically unequal society, whether perceived by individual black women or not, could also impact cellular physiology and gene expression patterns relevant to HR− breast cancer etiology. Using the weathering hypothesis as our conceptual framework, we develop a structural perspective for examining racial disparities in breast cancer subtypes, integrating important findings from the stress biology, breast cancer epidemiology, and health disparities literatures. After integrating key findings from these largely independent literatures, we develop a theoretically and empirically guided framework for assessing potential multilevel factors relevant to the development of HR− breast cancer disproportionately among Black women in the US. We hypothesize that a dynamic interplay among socially patterned psychosocial stressors, physiological & behavioral responses, and genomic pathways contribute to the increased risk of HR− breast cancer among Black women. This work provides a basis for exploring potential alternative pathways linking the lived experience of race to the risk of HR- breast cancer, and suggests new avenues for research and public health action. PMID:29333472
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Linnenbringer, Erin; Gehlert, Sarah; Geronimus, Arline T
2017-01-01
Hormone receptor negative (HR-) breast cancer subtypes are etiologically distinct from the more common, less aggressive, and more treatable form of estrogen receptor positive (ER+) breast cancer. Numerous population-based studies have found that, in the United States, Black women are 2 to 3 times more likely to develop HR- breast cancer than White women. Much of the existing research on racial disparities in breast cancer subtype has focused on identifying predisposing genetic factors associated with African ancestry. This approach fails to acknowledge that racial stratification shapes a wide range of environmental and social exposures over the life course. Human stress genomics considers the role of individual stress perceptions on gene expression. Yet, the role of structurally rooted biopsychosocial processes that may be activated by the social patterning of stressors in an historically unequal society, whether perceived by individual black women or not, could also impact cellular physiology and gene expression patterns relevant to HR- breast cancer etiology. Using the weathering hypothesis as our conceptual framework, we develop a structural perspective for examining racial disparities in breast cancer subtypes, integrating important findings from the stress biology, breast cancer epidemiology, and health disparities literatures. After integrating key findings from these largely independent literatures, we develop a theoretically and empirically guided framework for assessing potential multilevel factors relevant to the development of HR- breast cancer disproportionately among Black women in the US. We hypothesize that a dynamic interplay among socially patterned psychosocial stressors, physiological & behavioral responses, and genomic pathways contribute to the increased risk of HR- breast cancer among Black women. This work provides a basis for exploring potential alternative pathways linking the lived experience of race to the risk of HR- breast cancer, and suggests new avenues for research and public health action.
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West, Adrian R; Zaman, Nishat; Cole, Darren J; Walker, Matthew J; Legant, Wesley R; Boudou, Thomas; Chen, Christopher S; Favreau, John T; Gaudette, Glenn R; Cowley, Elizabeth A; Maksym, Geoffrey N
2013-01-01
Airway smooth muscle (ASM) cellular and molecular biology is typically studied with single-cell cultures grown on flat 2D substrates. However, cells in vivo exist as part of complex 3D structures, and it is well established in other cell types that altering substrate geometry exerts potent effects on phenotype and function. These factors may be especially relevant to asthma, a disease characterized by structural remodeling of the airway wall, and highlights a need for more physiologically relevant models of ASM function. We utilized a tissue engineering platform known as microfabricated tissue gauges to develop a 3D culture model of ASM featuring arrays of ∼0.4 mm long, ∼350 cell "microtissues" capable of simultaneous contractile force measurement and cell-level microscopy. ASM-only microtissues generated baseline tension, exhibited strong cellular organization, and developed actin stress fibers, but lost structural integrity and dissociated from the cantilevers within 3 days. Addition of 3T3-fibroblasts dramatically improved survival times without affecting tension development or morphology. ASM-3T3 microtissues contracted similarly to ex vivo ASM, exhibiting reproducible responses to a range of contractile and relaxant agents. Compared with 2D cultures, microtissues demonstrated identical responses to acetylcholine and KCl, but not histamine, forskolin, or cytochalasin D, suggesting that contractility is regulated by substrate geometry. Microtissues represent a novel model for studying ASM, incorporating a physiological 3D structure, realistic mechanical environment, coculture of multiple cells types, and comparable contractile properties to existing models. This new model allows for rapid screening of biochemical and mechanical factors to provide insight into ASM dysfunction in asthma.
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Louis, Fiona; Pannetier, Pauline; Souguir, Zied; Le Cerf, Didier; Valet, Philippe; Vannier, Jean-Pierre; Vidal, Guillaume; Demange, Elise
2017-08-01
The lack of relevant in vitro models for adipose tissue makes necessary the development of a more physiological environment providing spatial and chemical cues for the effective maturation of adipocytes. We developed a biofunctionalized hydrogel with components of adipose extracellular matrix: collagen I, collagen VI, and the cell binding domain of fibronectin and we compared it to usual 2D cultures on plastic plates. This scaffold allowed 3D culture of mature adipocytes from the preadipocytes cell lines 3T3-L1 and 3T3-F442A, as well as primary Human White Preadipocytes (HWP), acquiring in vivo-like organization, with spheroid shaped adipocytes forming multicellular aggregates. The size of these aggregates increased with time up to 120 μm in diameter after 4 weeks of maturation, with good viability. Significantly higher lipogenic activity (up to 20-fold at day 28 for HWP cultures) and differentiation rates were also observed compared to 2D. Gene expression analyses highlighted earlier differentiation and complete maturation of 3D HWP compared to 2D, reinforced by the expression of Perilipin protein after 21 days of nutrition. This increase in adipocytes phenotypic and genotypic markers made this scaffold-driven culture as a robust adipose 3D model. Retinoic acid inhibition of lipogenesis in HWP or isoprenalin and caffeine induction of lipolysis performed on mouse 3T3-F442A cells, showed higher doses of molecules than typically used in 2D, underlying the physiologic relevance of this 3D culture system. Biotechnol. Bioeng. 2017;114: 1813-1824. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.
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Structural Asymmetry of the Terminal Catalytic Complex in Selenocysteine Synthesis*
French, Rachel L.; Gupta, Nirupama; Copeland, Paul R.; Simonović, Miljan
2014-01-01
Selenocysteine (Sec), the 21st amino acid, is synthesized from a serine precursor in a series of reactions that require selenocysteine tRNA (tRNASec). In archaea and eukaryotes, O-phosphoseryl-tRNASec:selenocysteinyl-tRNASec synthase (SepSecS) catalyzes the terminal synthetic reaction during which the phosphoseryl intermediate is converted into the selenocysteinyl moiety while being attached to tRNASec. We have previously shown that only the SepSecS tetramer is capable of binding to and recognizing the distinct fold of tRNASec. Because only two of the four tRNA-binding sites were occupied in the crystal form, a question was raised regarding whether the observed arrangement and architecture faithfully recapitulated the physiologically relevant ribonucleoprotein complex important for selenoprotein formation. Herein, we determined the stoichiometry of the human terminal synthetic complex of selenocysteine by using small angle x-ray scattering, multi-angle light scattering, and analytical ultracentrifugation. In addition, we provided the first estimate of the ratio between SepSecS and tRNASec in vivo. We show that SepSecS preferentially binds one or two tRNASec molecules at a time and that the enzyme is present in large molar excess over the substrate tRNA in vivo. Moreover, we show that in a complex between SepSecS and two tRNAs, one enzyme homodimer plays a role of the noncatalytic unit that positions CCA ends of two tRNASec molecules into the active site grooves of the other, catalytic, homodimer. Finally, our results demonstrate that the previously determined crystal structure represents the physiologically and catalytically relevant complex and suggest that allosteric regulation of SepSecS might play an important role in regulation of selenocysteine and selenoprotein synthesis. PMID:25190812
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Ballesteros, Daniel; Walters, Christina
2011-11-01
Slow movement of molecules in glassy matrices controls the kinetics of chemical and physical reactions in dry seeds. Variation in physiological activity among seeds suggests that there are differences in mobility among seed glasses. Testing this hypothesis is difficult because few tools are available to measure molecular mobility within dry seeds. Here, motional properties within dry pea cotyledons were assessed using dynamic mechanical analysis. The technique detected several molecular relaxations between -80 and +80°C and gave a more detailed description of water content-temperature effects on molecular motion than previously understood from studies of glass formation in seeds at glass transition (Tg). Diffusive movement is delimited by the α relaxation, which appears to be analogous to Tg. β and γ relaxations were also detected at temperatures lower than α relaxations, clearly demonstrating intramolecular motion within the glassy matrix of the pea cotyledon. Glass transitions, or the mechanical counterpart α relaxation, appear to be less relevant to seed aging during dry storage than previously thought. On the other hand, β relaxation occurs at temperature and moisture conditions typically used for seed storage and has established importance for physical aging of synthetic polymer glasses. Our data show that the nature and extent of molecular motion varies considerably with moisture and temperature, and that the hydrated conditions used for accelerated aging experiments and ultra-dry conditions sometimes recommended for seed storage give greater molecular mobility than more standard seed storage practices. We believe characterization of molecular mobility is critical for evaluating how dry seeds respond to the environment and persist through time. Published 2011. This article is a US Government work and is in the public domain in the USA.
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Prymaczok, Natalia C; Pasqualino, Valeria M; Viau, Verónica E; Rodríguez, Enrique M; Medesani, Daniel A
2016-02-01
This study was aimed at determining the role of the crustacean hyperglycemic hormone (CHH) in the physiological compensation to both saline and thermal stress, in the freshwater crayfish Cherax quadricarinatus. By determining the expression of the CHH gene in the eyestalk of juvenile crayfish, we found that maximal induction of CHH was induced at high salinity (10 g/L) and low temperature (20 °C). In order to investigate the role of CHH in the physiological compensation to such stressful conditions, recombinant CHH was supplied to stressed animals. CHH-injected crayfish showed increased hemolymphatic levels of glucose, in accordance with a significant utilization of glycogen reserves from the hepatopancreas. Furthermore, CHH administration allowed stressed animals to regulate hemolymphatic sodium and potassium at more constant levels than controls. Taken together, these results suggest a relevant role of CHH in increasing the energy available intended for processes involved in the physiological compensation of C. quadricarinatus to both saline and thermal stress.
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A Database as a Service for the Healthcare System to Store Physiological Signal Data.
Chang, Hsien-Tsung; Lin, Tsai-Huei
2016-01-01
Wearable devices that measure physiological signals to help develop self-health management habits have become increasingly popular in recent years. These records are conducive for follow-up health and medical care. In this study, based on the characteristics of the observed physiological signal records- 1) a large number of users, 2) a large amount of data, 3) low information variability, 4) data privacy authorization, and 5) data access by designated users-we wish to resolve physiological signal record-relevant issues utilizing the advantages of the Database as a Service (DaaS) model. Storing a large amount of data using file patterns can reduce database load, allowing users to access data efficiently; the privacy control settings allow users to store data securely. The results of the experiment show that the proposed system has better database access performance than a traditional relational database, with a small difference in database volume, thus proving that the proposed system can improve data storage performance.
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NASA Astrophysics Data System (ADS)
Huber, Martin; Braun, Hans; Krieg, J.\\:Urgen-Christian
2004-03-01
Sensitization is discussed as an important phenomenon playing a role in normal physiology but also with respect to the initiation and progression of a variety of neuropsychiatric disorders such as epilepsia, substance-related disorders or recurrent affective disorders. The relevance to understand the dynamics of sensitization phenomena is emphasized by recent findings that even single stimulations can induce longlasting changes in biological systems. To address specific questions associated with the sensitization dynamics, we use a computational approach and develop simple but physiologically-plausible models. In the present study we examine the effect of noisy stimulation on sensitization development in the model. We consider sub- and suprathresold stimulations with varying noise intensities and determine as response measures the (i) absolute number of stimulus-induced sensitzations and (ii) the temporal relsation of stimulus-sensitization coupling. The findings indicate that stochastic effects including stochastic resonance might well contribute to the physiology of sensitization mechanisms under both nomal and pathological conditions.
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Gururani, Mayank Anand; Venkatesh, Jelli; Ganesan, Markkandan; Strasser, Reto Jörg; Han, Yunjeong; Kim, Jeong-Il; Lee, Hyo-Yeon; Song, Pill-Soon
2015-01-01
Chlorophyll-a fluorescence analysis provides relevant information about the physiology of plants growing under abiotic stress. In this study, we evaluated the influence of cold stress on the photosynthetic machinery of transgenic turfgrass, Zoysia japonica, expressing oat phytochrome A (PhyA) or a hyperactive mutant phytochrome A (S599A) with post-translational phosphorylation blocked. Biochemical analysis of zoysiagrass subjected to cold stress revealed reduced levels of hydrogen peroxide, increased proline accumulation, and enhanced specific activities of antioxidant enzymes compared to those of control plants. Detailed analyses of the chlorophyll-a fluorescence data through the so-called OJIP test exhibited a marked difference in the physiological status among transgenic and control plants. Overall, these findings suggest an enhanced level of cold tolerance in S599A zoysiagrass cultivars as reflected in the biochemical and physiological analyses. Further, we propose that chlorophyll-a fluorescence analysis using OJIP test is an efficient tool in determining the physiological status of plants under cold stress conditions. PMID:26010864
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A Database as a Service for the Healthcare System to Store Physiological Signal Data
Lin, Tsai-Huei
2016-01-01
Wearable devices that measure physiological signals to help develop self-health management habits have become increasingly popular in recent years. These records are conducive for follow-up health and medical care. In this study, based on the characteristics of the observed physiological signal records– 1) a large number of users, 2) a large amount of data, 3) low information variability, 4) data privacy authorization, and 5) data access by designated users—we wish to resolve physiological signal record-relevant issues utilizing the advantages of the Database as a Service (DaaS) model. Storing a large amount of data using file patterns can reduce database load, allowing users to access data efficiently; the privacy control settings allow users to store data securely. The results of the experiment show that the proposed system has better database access performance than a traditional relational database, with a small difference in database volume, thus proving that the proposed system can improve data storage performance. PMID:28033415
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NASA Johnson Space Center Biomedical Research Resources
NASA Technical Reports Server (NTRS)
Paloski, W. H.
1999-01-01
Johnson Space Center (JSC) medical sciences laboratories constitute a national resource for support of medical operations and life sciences research enabling a human presence in space. They play a critical role in evaluating, defining, and mitigation the untoward effect of human adaption to space flight. Over the years they have developed the unique facilities and expertise required to perform: biomedical sample analysis and physiological performance tests supporting medical evaluations of space flight crew members and scientific investigations of the operationally relevant medical, physiological, cellular, and biochemical issues associated with human space flight. A general overview of these laboratories is presented in viewgraph form.
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Mechanics of the Unusual Basilar Membrane in Gerbil
NASA Astrophysics Data System (ADS)
Kapuria, Santosh; Steele, Charles R.; Puria, Sunil
2011-11-01
The basilar membrane in gerbil differs from most other mammals, since its width and thickness show little variation from base to apex, and tympanic fiber layer in the pectinate zone forms a pronounced arch. Measurements indicate a quadratically increasing stiffness under point loading, which is contrary to the expected behavior of an arch. The plateau value has been considered to be the physiologically relevant stiffness, but it only occurs after 10-25 μm of deflection, whereas the normal physiological deflection is in the submicron range. The present work aims to resolve these contradictions by considering the mechanics of the geometric configuration.
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The energy expenditure of normal and pathologic gait.
Waters, R L; Mulroy, S
1999-07-01
Physiological energy expenditure measurement has proven to be a reliable method of quantitatively assessing the penalties imposed by gait disability. The purpose of this review is to outline the basic principles of exercise physiology relevant to human locomotion; detail the energy expenditure of normal walking; and summarize the results of energy expenditure studies performed in patients with specific neurologic and orthopedic disabilities. The magnitude of the disabilities and the patients' capacity to tolerate the increased energy requirements are compared. This paper also will examine the effectiveness of rehabilitation interventions at mitigating the energetic penalties of disability during ambulation.
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Coutant, Thomas; Vergneau-Grosset, Claire; Langlois, Isabelle
2018-05-01
Drug delivery to exotic animals may be extrapolated from domestic animals, but some physiologic and anatomic differences complicate treatment administration. Knowing these differences enables one to choose optimal routes for drug delivery. This review provides practitioners with a detailed review of the currently reported methods used for drug delivery of various medications in the most common exotic animal species. Exotic animal peculiarities that are relevant for drug administration are discussed in the text and outlined in tables and boxes to help the reader easily find targeted information. Copyright © 2018 Elsevier Inc. All rights reserved.
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Physiological Correlations with Short, Medium, and Long Cycling Time-Trial Performance
ERIC Educational Resources Information Center
Borszcz, Fernando K.; Tramontin, Artur F.; de Souza, Kristopher M.; Carminatti, Lorival J.; Costa, Vitor P.
2018-01-01
Purpose: Several studies have demonstrated that physiological variables predict cycling endurance performance. However, it is still unclear whether the predictors will change over different performance durations. The aim of this study was to assess the correlations between physiological variables and cycling time trials with different durations.…
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Roberts, John K; Hargett, Charles W; Nagler, Alisa; Jakoi, Emma; Lehrich, Ruediger W
2015-09-01
Medical education reform is underway, but the optimal course for change has yet to be seen. While planning for the redesign of a renal physiology course at the Duke School of Medicine, the authors used a Q-sort survey to assess students' attitudes and learning preferences to inform curricular change. The authors invited first-year medical students at the Duke School of Medicine to take a Q-sort survey on the first day of renal physiology. Students prioritized statements related to their understanding of renal physiology, learning preferences, preferred course characteristics, perceived clinical relevance of renal physiology, and interest in nephrology as a career. By-person factor analysis was performed using the centroid method. Three dominant factors were strongly defined by learning preferences: "readers" prefer using notes, a textbook, and avoid lectures; "social-auditory learners" prefer attending lectures, interactivity, and working with peers; and "visual learners" prefer studying images, diagrams, and viewing materials online. A smaller, fourth factor represented a small group of students with a strong predisposition against renal physiology and nephrology. In conclusion, the Q-sort survey identified and then described in detail the dominant viewpoints of our students. Learning style preferences better classified first-year students rather than any of the other domains. A more individualized curriculum would simultaneously cater to the different types of learners in the classroom. Copyright © 2015 The American Physiological Society.
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Allometric Scaling and Cell Ratios in Multi-Organ in vitro Models of Human Metabolism
DOE Office of Scientific and Technical Information (OSTI.GOV)
Ucciferri, Nadia; Interdepartmental Research Center “E. Piaggio”, University of Pisa, Pisa; Sbrana, Tommaso
2014-12-17
Intelligent in vitro models able to recapitulate the physiological interactions between tissues in the body have enormous potential as they enable detailed studies on specific two-way or higher order tissue communication. These models are the first step toward building an integrated picture of systemic metabolism and signaling in physiological or pathological conditions. However, the rational design of in vitro models of cell–cell or cell–tissue interaction is difficult as quite often cell culture experiments are driven by the device used, rather than by design considerations. Indeed, very little research has been carried out on in vitro models of metabolism connecting differentmore » cell or tissue types in a physiologically and metabolically relevant manner. Here, we analyze the physiological relationship between cells, cell metabolism, and exchange in the human body using allometric rules, downscaling them to an organ-on-a-plate device. In particular, in order to establish appropriate cell ratios in the system in a rational manner, two different allometric scaling models (cell number scaling model and metabolic and surface scaling model) are proposed and applied to a two compartment model of hepatic-vascular metabolic cross-talk. The theoretical scaling studies illustrate that the design and hence relevance of multi-organ models is principally determined by experimental constraints. Two experimentally feasible model configurations are then implemented in a multi-compartment organ-on-a-plate device. An analysis of the metabolic response of the two configurations demonstrates that their glucose and lipid balance is quite different, with only one of the two models recapitulating physiological-like homeostasis. In conclusion, not only do cross-talk and physical stimuli play an important role in in vitro models, but the numeric relationship between cells is also crucial to recreate in vitro interactions, which can be extrapolated to the in vivo reality.« less
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Allometric Scaling and Cell Ratios in Multi-Organ in vitro Models of Human Metabolism.
Ucciferri, Nadia; Sbrana, Tommaso; Ahluwalia, Arti
2014-01-01
Intelligent in vitro models able to recapitulate the physiological interactions between tissues in the body have enormous potential as they enable detailed studies on specific two-way or higher order tissue communication. These models are the first step toward building an integrated picture of systemic metabolism and signaling in physiological or pathological conditions. However, the rational design of in vitro models of cell-cell or cell-tissue interaction is difficult as quite often cell culture experiments are driven by the device used, rather than by design considerations. Indeed, very little research has been carried out on in vitro models of metabolism connecting different cell or tissue types in a physiologically and metabolically relevant manner. Here, we analyze the physiological relationship between cells, cell metabolism, and exchange in the human body using allometric rules, downscaling them to an organ-on-a-plate device. In particular, in order to establish appropriate cell ratios in the system in a rational manner, two different allometric scaling models (cell number scaling model and metabolic and surface scaling model) are proposed and applied to a two compartment model of hepatic-vascular metabolic cross-talk. The theoretical scaling studies illustrate that the design and hence relevance of multi-organ models is principally determined by experimental constraints. Two experimentally feasible model configurations are then implemented in a multi-compartment organ-on-a-plate device. An analysis of the metabolic response of the two configurations demonstrates that their glucose and lipid balance is quite different, with only one of the two models recapitulating physiological-like homeostasis. In conclusion, not only do cross-talk and physical stimuli play an important role in in vitro models, but the numeric relationship between cells is also crucial to recreate in vitro interactions, which can be extrapolated to the in vivo reality.
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The emerging relevance of the gut microbiome in cardiometabolic health
USDA-ARS?s Scientific Manuscript database
Host metabolic pathways and physiological responses are regulated by signals linking the host to the gut microbial community or microbiome. Here, we draw a spotlight on lipid and bile acid metabolism and inflammatory response as they pertain to cardiometabolic dysfunction. Gut microbial dysbiosis al...
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META-ANALYSIS OF THE LIFE STYLE FACTORS RELEVANT TO ENVIRONMENTAL HAZARDS FOR THE AGING POPULATION
The goal of this U.S. Environmental Protection Agency (EPA) study is to characterize activity patterns, physiological changes, and environmental exposures for the aging population. Meta analysis was performed on more than 2000 reviewed articles to evaluate the lifestyle factors ...
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Research Update: Sport and Physical Activity for People with Physical Disabilities.
ERIC Educational Resources Information Center
Smith, Ralph W.
1993-01-01
Examines research on sport and physical activity for individuals with physical disabilities, focusing on psychosocial characteristics of participants, physiological impacts of participation, and performance enhancement. With the advent of the Americans with Disabilities Act (1990), such research has relevance for all recreation professionals. (SM)
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Nowak, Magdalena; Hinson, Emily; van Ede, Freek; Pogosyan, Alek; Guerra, Andrea; Quinn, Andrew; Brown, Peter; Stagg, Charlotte J
2017-04-26
Beta and gamma oscillations are the dominant oscillatory activity in the human motor cortex (M1). However, their physiological basis and precise functional significance remain poorly understood. Here, we used transcranial magnetic stimulation (TMS) to examine the physiological basis and behavioral relevance of driving beta and gamma oscillatory activity in the human M1 using transcranial alternating current stimulation (tACS). tACS was applied using a sham-controlled crossover design at individualized intensity for 20 min and TMS was performed at rest (before, during, and after tACS) and during movement preparation (before and after tACS). We demonstrated that driving gamma frequency oscillations using tACS led to a significant, duration-dependent decrease in local resting-state GABA A inhibition, as quantified by short interval intracortical inhibition. The magnitude of this effect was positively correlated with the magnitude of GABA A decrease during movement preparation, when gamma activity in motor circuitry is known to increase. In addition, gamma tACS-induced change in GABA A inhibition was closely related to performance in a motor learning task such that subjects who demonstrated a greater increase in GABA A inhibition also showed faster short-term learning. The findings presented here contribute to our understanding of the neurophysiological basis of motor rhythms and suggest that tACS may have similar physiological effects to endogenously driven local oscillatory activity. Moreover, the ability to modulate local interneuronal circuits by tACS in a behaviorally relevant manner provides a basis for tACS as a putative therapeutic intervention. SIGNIFICANCE STATEMENT Gamma oscillations have a vital role in motor control. Using a combined tACS-TMS approach, we demonstrate that driving gamma frequency oscillations modulates GABA A inhibition in the human motor cortex. Moreover, there is a clear relationship between the change in magnitude of GABA A inhibition induced by tACS and the magnitude of GABA A inhibition observed during task-related synchronization of oscillations in inhibitory interneuronal circuits, supporting the hypothesis that tACS engages endogenous oscillatory circuits. We also show that an individual's physiological response to tACS is closely related to their ability to learn a motor task. These findings contribute to our understanding of the neurophysiological basis of motor rhythms and their behavioral relevance and offer the possibility of developing tACS as a therapeutic tool. Copyright © 2017 Nowak et al.
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Identification of resilient individuals and those at risk for performance deficits under stress.
Winslow, Brent D; Carroll, Meredith B; Martin, Jonathan W; Surpris, Glenn; Chadderdon, George L
2015-01-01
Human task performance is affected by exposure to physiological and psychological stress. The ability to measure the physiological response to stressors and correlate that to task performance could be used to identify resilient individuals or those at risk for stress-related performance decrements. Accomplishing this prior to performance under severe stress or the development of clinical stress disorders could facilitate focused preparation such as tailoring training to individual needs. Here we measure the effects of stress on physiological response and performance through behavior, physiological sensors, and subjective ratings, and identify which individuals are at risk for stress-related performance decrements. Participants performed military-relevant training tasks under stress in a virtual environment, with autonomic and hypothalamic-pituitary-adrenal axis (HPA) reactivity analyzed. Self-reported stress, as well as physiological indices of stress, increased in the group pre-exposed to socioevaluative stress. Stress response was effectively captured via electrodermal and cardiovascular measures of heart rate and skin conductance level. A resilience classification algorithm was developed based upon physiological reactivity, which correlated with baseline unstressed physiological and self-reported stress values. Outliers were identified in the experimental group that had a significant mismatch between self-reported stress and salivary cortisol. Baseline stress measurements were predictive of individual resilience to stress, including the impact stress had on physiological reactivity and performance. Such an approach may have utility in identifying individuals at risk for problems performing under severe stress. Continuing work has focused on adapting this method for military personnel, and assessing the utility of various coping and decision-making strategies on performance and physiological stress.
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Identification of resilient individuals and those at risk for performance deficits under stress
Winslow, Brent D.; Carroll, Meredith B.; Martin, Jonathan W.; Surpris, Glenn; Chadderdon, George L.
2015-01-01
Human task performance is affected by exposure to physiological and psychological stress. The ability to measure the physiological response to stressors and correlate that to task performance could be used to identify resilient individuals or those at risk for stress-related performance decrements. Accomplishing this prior to performance under severe stress or the development of clinical stress disorders could facilitate focused preparation such as tailoring training to individual needs. Here we measure the effects of stress on physiological response and performance through behavior, physiological sensors, and subjective ratings, and identify which individuals are at risk for stress-related performance decrements. Participants performed military-relevant training tasks under stress in a virtual environment, with autonomic and hypothalamic-pituitary-adrenal axis (HPA) reactivity analyzed. Self-reported stress, as well as physiological indices of stress, increased in the group pre-exposed to socioevaluative stress. Stress response was effectively captured via electrodermal and cardiovascular measures of heart rate and skin conductance level. A resilience classification algorithm was developed based upon physiological reactivity, which correlated with baseline unstressed physiological and self-reported stress values. Outliers were identified in the experimental group that had a significant mismatch between self-reported stress and salivary cortisol. Baseline stress measurements were predictive of individual resilience to stress, including the impact stress had on physiological reactivity and performance. Such an approach may have utility in identifying individuals at risk for problems performing under severe stress. Continuing work has focused on adapting this method for military personnel, and assessing the utility of various coping and decision-making strategies on performance and physiological stress. PMID:26441503
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Andrews, Russel D; Enstipp, Manfred R
2016-12-01
To fully understand how diving seabirds and marine mammals balance the potentially conflicting demands of holding their breath while living their lives underwater (and maintaining physiological homeostasis during exercise, feeding, growth, and reproduction), physiological studies must be conducted with animals in their natural environments. The purpose of this article is to review the importance of making physiological measurements on diving animals in field settings, while acknowledging the challenges and highlighting some solutions. The most extreme divers are great candidates for study, especially in a comparative and mechanistic context. However, physiological data are also required of a wide range of species for problems relating to other disciplines, in particular ecology and conservation biology. Physiological data help with understanding and predicting the outcomes of environmental change, and the direct impacts of anthropogenic activities. Methodological approaches that have facilitated the development of field-based diving physiology include the isolated diving hole protocol and the translocation paradigm, and while there are many techniques for remote observation, animal-borne biotelemetry, or "biologging", has been critical. We discuss issues related to the attachment of instruments, the retrieval of data and sensing of physiological variables, while also considering negative impacts of tagging. This is illustrated with examples from a variety of species, and an in-depth look at one of the best studied and most extreme divers, the emperor penguin (Aptenodytes forsteri). With a variety of approaches and high demand for data on the physiology of diving seabirds and marine mammals, the future of field studies is bright. Copyright © 2016 Elsevier Inc. All rights reserved.
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All half-lives are wrong, but some half-lives are useful.
Wright, J G; Boddy, A V
2001-01-01
The half-life of a drug, which expresses a change in concentration in units of time, is perhaps the most easily understood pharmacokinetic parameter and provides a succinct description of many concentration-time profiles. The calculation of a half-life implies a linear, first-order, time-invariant process. No drug perfectly obeys such assumptions, although in practise this is often a valid approximation and provides invaluable quantitative information. Nevertheless, the physiological processes underlying half-life should not be forgotten. The concept of clearance facilitates the interpretation of factors affecting drug elimination, such as enzyme inhibition or renal impairment. Relating clearance to the observed concentration-time profile is not as naturally intuitive as is the case with half-life. As such, these 2 approaches to parameterising a linear pharmacokinetic model should be viewed as complementary rather than alternatives. The interpretation of pharmacokinetic parameters when there are multiple disposition phases is more challenging. Indeed, in any pharmacokinetic model, the half-lives are only one component of the parameters required to specify the concentration-time profile. Furthermore, pharmacokinetic parameters are of little use without a dose history. Other factors influencing the relevance of each disposition phase to clinical end-points must also be considered. In summarising the pharmacokinetics of a drug, statistical aspects of the estimation of a half-life are often overlooked. Half-lives are rarely reported with confidence intervals or measures of variability in the population, and some approaches to this problem are suggested. Half-life is an important summary statistic in pharmacokinetics, but care must be taken to employ it appropriately in the context of dose history and clinically relevant pharmacodynamic end-points.
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Decision fatigue: A conceptual analysis.
Pignatiello, Grant A; Martin, Richard J; Hickman, Ronald L
2018-03-01
Decision fatigue is an applicable concept to healthcare psychology. Due to a lack of conceptual clarity, we present a concept analysis of decision fatigue. A search of the term "decision fatigue" was conducted across seven research databases, which yielded 17 relevant articles. The authors identified three antecedent themes (decisional, self-regulatory, and situational) and three attributional themes (behavioral, cognitive, and physiological) of decision fatigue. However, the extant literature failed to adequately describe consequences of decision fatigue. This concept analysis provides needed conceptual clarity for decision fatigue, a concept possessing relevance to nursing and allied health sciences.
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Bacterial adhesion force quantification by fluidic force microscopy
NASA Astrophysics Data System (ADS)
Potthoff, Eva; Ossola, Dario; Zambelli, Tomaso; Vorholt, Julia A.
2015-02-01
Quantification of detachment forces between bacteria and substrates facilitates the understanding of the bacterial adhesion process that affects cell physiology and survival. Here, we present a method that allows for serial, single bacterial cell force spectroscopy by combining the force control of atomic force microscopy with microfluidics. Reversible bacterial cell immobilization under physiological conditions on the pyramidal tip of a microchanneled cantilever is achieved by underpressure. Using the fluidic force microscopy technology (FluidFM), we achieve immobilization forces greater than those of state-of-the-art cell-cantilever binding as demonstrated by the detachment of Escherichia coli from polydopamine with recorded forces between 4 and 8 nN for many cells. The contact time and setpoint dependence of the adhesion forces of E. coli and Streptococcus pyogenes, as well as the sequential detachment of bacteria out of a chain, are shown, revealing distinct force patterns in the detachment curves. This study demonstrates the potential of the FluidFM technology for quantitative bacterial adhesion measurements of cell-substrate and cell-cell interactions that are relevant in biofilms and infection biology.Quantification of detachment forces between bacteria and substrates facilitates the understanding of the bacterial adhesion process that affects cell physiology and survival. Here, we present a method that allows for serial, single bacterial cell force spectroscopy by combining the force control of atomic force microscopy with microfluidics. Reversible bacterial cell immobilization under physiological conditions on the pyramidal tip of a microchanneled cantilever is achieved by underpressure. Using the fluidic force microscopy technology (FluidFM), we achieve immobilization forces greater than those of state-of-the-art cell-cantilever binding as demonstrated by the detachment of Escherichia coli from polydopamine with recorded forces between 4 and 8 nN for many cells. The contact time and setpoint dependence of the adhesion forces of E. coli and Streptococcus pyogenes, as well as the sequential detachment of bacteria out of a chain, are shown, revealing distinct force patterns in the detachment curves. This study demonstrates the potential of the FluidFM technology for quantitative bacterial adhesion measurements of cell-substrate and cell-cell interactions that are relevant in biofilms and infection biology. Electronic supplementary information (ESI) available: Video S1. Detachment of a S. pyogenes cell chain from glass substrate. The cantilever is approached on the outermost adherent cell of a chain and four bacteria were then sequentially detached. The sequential cell detachment suddenly stopped after four bacteria. This possibly occurred because bacteria-glass interactions became too strong or the maximal probe retraction was reached. The cells spontaneously detached from the cantilever flipping back on the surface. Fig. S1. (A) Adhesion force-distance and (B) adhesion force-detaching work correlation of E.coli on PLL for setpoints of 1 and 10 nN. Circle: 1 nN setpoint, square: 10 nN. See DOI: 10.1039/c4nr06495j
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Drug-induced cholestasis: mechanisms, models, and markers.
Chatterjee, Sagnik; Annaert, Pieter
2018-04-27
Drug-induced cholestasis is a risk factor in progression of drug candidates, and poses serious health hazard if not detected before going into human. Intrahepatic accumulation of bile acids (BAs) represents a characteristic phenomenon associated with drug-induced cholestasis. The major challenges in obtaining a complete understanding of drug-induced cholestasis lies in the complexity of BA-mediated toxicity mechanisms and the impact of bile acids at different 'targets' such as transporters, enzymes and nuclear receptors. At the same time, it is not trivial to have a relevant in vitro system that recapitulates these features. In addition, lack of sensitive and early preclinical biomarkers, relevant to the clinical situation, complicates proper detection of drug-induced cholestasis. Significant overlap in biomarker signatures between different mechanisms of drug-induced liver injury (DILI) precludes identification of specific mechanisms. Over the last decade the knowledge gaps in drug-induced cholestasis are closing due to growing mechanistic understanding of BA-mediated toxicity at (patho)physiologically relevant BA concentrations. Significant progress has been made in the mechanistic understanding of drug-induced cholestasis and associated toxicity, biomarkers and susceptibility factors. In addition, novel in vitro models are evolving which provide a holistic understanding of processes underlying drug-induced cholestasis. This review summarizes the challenges and recent understandings about drug-induced cholestasis with a potential path forward. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.
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McClusky, Leon Mendel
2012-01-01
The traditional presentation of the Reproductive Physiology component in an Anatomy and Physiology course to nursing undergraduates focuses on the broad aspects of hormonal regulation of reproduction and gonadal anatomy, with the role of the higher centres of the brain omitted. An introductory discussion is proposed which could precede the lectures on the reproductive organs. The discussion gives an overview of the biological significance of human pleasure, the involvement of the neurotransmitter dopamine, and the role of pleasure in the survival of the individual and even species. Pleasure stimuli (positive and negative) and the biological significance of naturally-induced pleasurable experiences are briefly discussed in the context of reproduction and the preservation of genetic material with an aim to foster relevancy between subject material and human behaviour in any type of society. The tenderness of this aspect of the human existence is well-understood because of its invariable association with soul-revealing human expressions such as love, infatuation, sexual flirtations, all of which are underpinned by arousal, desire and/or pleasure. Assuming that increased knowledge correlates with increased confidence, the proposed approach may provide the nurse with an adequate knowledge base to overcome well-known barriers in communicating with their patients about matters of sexual health and intimacy. Copyright © 2011 Elsevier Ltd. All rights reserved.
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Characterization of dynamic physiology of the bladder by optical coherence tomography
NASA Astrophysics Data System (ADS)
Yuan, Zhijia; Keng, Kerri; Pan, Rubin; Ren, Hugang; Du, Congwu; Kim, Jason; Pan, Yingtian
2012-03-01
Because of its high spatial resolution and noninvasive imaging capabilities, optical coherence tomography has been used to characterize the morphological details of various biological tissues including urinary bladder and to diagnose their alternations (e.g., cancers). In addition to static morphology, the dynamic features of tissue morphology can provide important information that can be used to diagnose the physiological and functional characteristics of biological tissues. Here, we present the imaging studies based on optical coherence tomography to characterize motion related physiology and functions of rat bladder detrusor muscles and compared the results with traditional biomechanical measurements. Our results suggest that optical coherence tomography is capable of providing quantitative evaluation of contractile functions of intact bladder (without removing bladder epithelium and connective tissue), which is potentially of more clinical relevance for future clinical diagnosis - if incorporated with cystoscopic optical coherence tomography.
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Scaling up our understanding of non-consumptive effects in insect systems
Hermann, Sara L.; Landis, Douglas A.
2017-04-06
Here, non-consumptive effects (NCEs) of predators on prey is an important topic in insect ecology with potential applications for pest management. NCEs are changes in prey behavior and physiology that aid in predation avoidance. While NCEs can have positive outcomes for prey survival there may also be negative consequences including increased stress and reduced growth. These effects can cascade through trophic systems influencing ecosystem function. Most NCEs have been studied at small spatial and temporal scales. However, recent studies show promise for the potential to manipulate NCEs for pest management. We suggest the next frontier for NCE studies includes manipulatingmore » the landscape of fear to improve pest control, which requires scaling-up to field and landscape levels, over ecologically relevant time frames.« less
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Scaling up our understanding of non-consumptive effects in insect systems
DOE Office of Scientific and Technical Information (OSTI.GOV)
Hermann, Sara L.; Landis, Douglas A.
Here, non-consumptive effects (NCEs) of predators on prey is an important topic in insect ecology with potential applications for pest management. NCEs are changes in prey behavior and physiology that aid in predation avoidance. While NCEs can have positive outcomes for prey survival there may also be negative consequences including increased stress and reduced growth. These effects can cascade through trophic systems influencing ecosystem function. Most NCEs have been studied at small spatial and temporal scales. However, recent studies show promise for the potential to manipulate NCEs for pest management. We suggest the next frontier for NCE studies includes manipulatingmore » the landscape of fear to improve pest control, which requires scaling-up to field and landscape levels, over ecologically relevant time frames.« less
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Kim, Sung Bong; Zhang, Yi; Won, Sang Min; Bandodkar, Amay J; Sekine, Yurina; Xue, Yeguang; Koo, Jahyun; Harshman, Sean W; Martin, Jennifer A; Park, Jeong Min; Ray, Tyler R; Crawford, Kaitlyn E; Lee, Kyu-Tae; Choi, Jungil; Pitsch, Rhonda L; Grigsby, Claude C; Strang, Adam J; Chen, Yu-Yu; Xu, Shuai; Kim, Jeonghyun; Koh, Ahyeon; Ha, Jeong Sook; Huang, Yonggang; Kim, Seung Wook; Rogers, John A
2018-03-01
This paper introduces super absorbent polymer valves and colorimetric sensing reagents as enabling components of soft, skin-mounted microfluidic devices designed to capture, store, and chemically analyze sweat released from eccrine glands. The valving technology enables robust means for guiding the flow of sweat from an inlet location into a collection of isolated reservoirs, in a well-defined sequence. Analysis in these reservoirs involves a color responsive indicator of chloride concentration with a formulation tailored to offer stable operation with sensitivity optimized for the relevant physiological range. Evaluations on human subjects with comparisons against ex situ analysis illustrate the practical utility of these advances. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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Volumetric Deformation of Live Cells Induced by Pressure-Activated Cross-Membrane Ion Transport
NASA Astrophysics Data System (ADS)
Hui, T. H.; Zhou, Z. L.; Qian, J.; Lin, Y.; Ngan, A. H. W.; Gao, H.
2014-09-01
In this work, we developed a method that allows precise control over changes in the size of a cell via hydrostatic pressure changes in the medium. Specifically, we show that a sudden increase, or reduction, in the surrounding pressure, in the physiologically relevant range, triggers cross-membrane fluxes of sodium and potassium ions in leukemia cell lines K562 and HL60, resulting in reversible volumetric deformation with a characteristic time of around 30 min. Interestingly, healthy leukocytes do not respond to pressure shocks, suggesting that the cancer cells may have evolved the ability to adapt to pressure changes in their microenvironment. A model is also proposed to explain the observed cell deformation, which highlights how the apparent viscoelastic response of cells is governed by the microscopic cross-membrane transport.
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Antimalarials inhibit hematin crystallization by unique drug–surface site interactions
Olafson, Katy N.; Nguyen, Tam Q.; Rimer, Jeffrey D.; Vekilov, Peter G.
2017-01-01
In malaria pathophysiology, divergent hypotheses on the inhibition of hematin crystallization posit that drugs act either by the sequestration of soluble hematin or their interaction with crystal surfaces. We use physiologically relevant, time-resolved in situ surface observations and show that quinoline antimalarials inhibit β-hematin crystal surfaces by three distinct modes of action: step pinning, kink blocking, and step bunch induction. Detailed experimental evidence of kink blocking validates classical theory and demonstrates that this mechanism is not the most effective inhibition pathway. Quinolines also form various complexes with soluble hematin, but complexation is insufficient to suppress heme detoxification and is a poor indicator of drug specificity. Collectively, our findings reveal the significance of drug–crystal interactions and open avenues for rationally designing antimalarial compounds. PMID:28559329
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The place of human psychophysics in modern neuroscience.
Read, J C A
2015-06-18
Human psychophysics is the quantitative measurement of our own perceptions. In essence, it is simply a more sophisticated version of what humans have done since time immemorial: noticed and reflected upon what we can see, hear, and feel. In the 21st century, when hugely powerful techniques are available that enable us to probe the innermost structure and function of nervous systems, is human psychophysics still relevant? I argue that it is, and that in combination with other techniques, it will continue to be a key part of neuroscience for the foreseeable future. I discuss these points in detail using the example of binocular stereopsis, where human psychophysics in combination with physiology and computational vision, has made a substantial contribution. Copyright © 2014 The Author. Published by Elsevier Ltd.. All rights reserved.
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Linking Biological and Cognitive Aging: Toward Improving Characterizations of Developmental Time
DeCarlo, Correne A.; Dixon, Roger A.
2011-01-01
Objectives. Chronological age is the most frequently employed predictor in life-span developmental research, despite repeated assertions that it is best conceived as a proxy for true mechanistic changes that influence cognition across time. The present investigation explores the potential that selected functional biomarkers may contribute to the more effective conceptual and operational definitions of developmental time. Methods. We used data from the Victoria Longitudinal Study to explore both static and dynamic biological or physiological markers that arguably influence process-specific mechanisms underlying cognitive changes in late life. Multilevel models were fit to test the dynamic coupling between change in theoretically relevant biomarkers (e.g., grip strength, pulmonary function) and change in select cognitive measures (e.g., executive function, episodic and semantic memory). Results. Results showed that, independent of the passage of developmental time (indexed as years in study), significant time-varying covariation was observed linking corresponding declines for select cognitive outcomes and biological markers. Discussion. Our findings support the interpretation that cognitive decline is not due to chronological aging per se but rather reflects multiple causal factors from a broad range of biological and physical health domains that operate along the age continuum. PMID:21743053
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A platform for real-time online health analytics during spaceflight
NASA Astrophysics Data System (ADS)
McGregor, Carolyn
Monitoring the health and wellbeing of astronauts during spaceflight is an important aspect of any manned mission. To date the monitoring has been based on a sequential set of discontinuous samplings of physiological data to support initial studies on aspects such as weightlessness, and its impact on the cardiovascular system and to perform proactive monitoring for health status. The research performed and the real-time monitoring has been hampered by the lack of a platform to enable a more continuous approach to real-time monitoring. While any spaceflight is monitored heavily by Mission Control, an important requirement within the context of any spaceflight setting and in particular where there are extended periods with a lack of communication with Mission Control, is the ability for the mission to operate in an autonomous manner. This paper presents a platform to enable real-time astronaut monitoring for prognostics and health management within space medicine using online health analytics. The platform is based on extending previous online health analytics research known as the Artemis and Artemis Cloud platforms which have demonstrated their relevance for multi-patient, multi-diagnosis and multi-stream temporal analysis in real-time for clinical management and research within Neonatal Intensive Care. Artemis and Artemis Cloud source data from a range of medical devices capable of transmission of the signal via wired or wireless connectivity and hence are well suited to process real-time data acquired from astronauts. A key benefit of this platform is its ability to monitor their health and wellbeing onboard the mission as well as enabling the astronaut's physiological data, and other clinical data, to be sent to the platform components at Mission Control at each stage when that communication is available. As a result, researchers at Mission Control would be able to simulate, deploy and tailor predictive analytics and diagnostics during the same spaceflight for - reater medical support.
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Biotransformation rates (Vmax) extrapolated from in vitro data are used increasingly in human physiologically based pharmacokinetic (PBPK) models. Extrapolation of Vmax from in vitro data requires use of scaling factors, including mg of microsomal protein/g liver (MPPGL), nmol of...
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77 FR 72975 - Zeta Cypermethrin; Pesticide Tolerances
Federal Register 2010, 2011, 2012, 2013, 2014
2012-12-07
... confidential pursuant to 40 CFR part 2 may be disclosed publicly by EPA without prior notice. Submit the non... physiological differences between abraded and non-abraded animals, further undermining the relevance of these... classified as a Group C ``Possible human carcinogen,'' based on an increased incidence of lung adenomas and...
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H+-PPase AVP1 is necessary for phloem development in Arabidopsis
USDA-ARS?s Scientific Manuscript database
The presence of a plasma membrane (PM) localized type I H+-PPase in sieve elements of Ricinus communis was documented years ago. Unfortunately, the physiological and developmental relevance of these findings remained obscure due to the lack of genetic and molecular reagents to study Ricinus communis...
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Studying Biology to Understand Risk: Dosimetry Models and Quantitative Adverse Outcome Pathways
Confidence in the quantitative prediction of risk is increased when the prediction is based to as great an extent as possible on the relevant biological factors that constitute the pathway from exposure to adverse outcome. With the first examples now over 40 years old, physiologi...
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Rationale: Historically, single cell culture models have been limited in pathological and physiological relevance. A co-culture model of dendritic cells (DCs) and differentiated human airway epithelial cells was developed to examine potential interactions between these two cell t...
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Early-life effects on adult physical activity: Concepts, relevance, and experimental approaches
USDA-ARS?s Scientific Manuscript database
Locomotion is a defining characteristic of animal life and plays a crucial role in most behaviors. Locomotion involves physical activity, which can have far-reaching effects on physiology and neurobiology, both acutely and chronically. In human populations and in laboratory rodents, higher levels of...
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Making Theory Relevant: The Gender Attitude and Belief Inventory
ERIC Educational Resources Information Center
McCabe, Janice
2013-01-01
This article describes and evaluates the Gender Attitude and Belief Inventory (GABI), a teaching tool designed to aid students in (a) realizing how sociological theory links to their personal beliefs and (b) exploring any combination of 11 frequently used theoretical perspectives on gender, including both conservative theories (physiological,…
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Abstract: In toxicology, as in pharmacology, the fundamental paradigm used to describe chemical interactions with biological systems is the dose-response relationship. Depending on the chemical mode of action, however, the relevant expression of dose may any one of several metri...
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The goal of this U.S. Environmental Protection Agency (EPA) Aging Initiative study is to characterize activity patterns, physiological changes, and environmental exposures for the aging population. Meta-analysis was performed on more than 2000 reviewed articles to evaluate the l...
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Obesity, a Disease of Adaptation to Environmental & Physiological Stressors
ERIC Educational Resources Information Center
Bijaoui, Nadia Judith
2012-01-01
Background: The educational intervention of this Applied Dissertation consisted of a presentation during which self-selected volunteers were introduced to relevant literature focusing on less known factors causing the disease of obesity and contrasting from behavior. Purpose: The workshop was structured to address the problem statement:…
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ERIC Educational Resources Information Center
La Place, John
This book examines comprehensively all the major health topics covered in an introductory health course and may be used in courses with a science orientation as well as in those oriented toward behavioral and social issues. The book is designed so that each chapter is a complete, independent unit. Relevant physiological facts are presented in the…
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Children and Exercise: Appropriate Practices for Grades K-6
ERIC Educational Resources Information Center
Fisher, Michele
2009-01-01
Growth and development have a profound effect on physical fitness, response to exercise, and exercise programming in children. This article reviews the essential pediatric exercise physiology concepts relevant to physical education programs for K-6 children. Indices of physical fitness such as cardiorespiratory endurance, muscular strength, and…
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A Physiological Approach to the Study of Human Information Processing.
ERIC Educational Resources Information Center
Fletcher, James E.
Soviet neuropsychologist Sokolov's notions of tonic and phasic orienting responses and of defense responses are examined for relevance to individual information processing. The phasic orienting response provides an index to attention and to information demands generated by the cerebral cortex. The sum of orienting responses elicted by a message…
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Wu, James T.; Kral, John G.
2004-01-01
Objective: Ghrelin is a novel gastric hormone recognized in 1999 as a mediator of growth hormone release. Since growth hormone is anabolic, an important function of ghrelin may be to coordinate energy needs with the growth process. Newly discovered biologic roles of ghrelin imply that it may have other important physiological functions as well. This is a review of recent clinically relevant, yet less well-known, physiologic actions of ghrelin. Summary Background Data: Ghrelin has profound orexigenic, adipogenic, and somatotrophic properties, increasing food intake and body weight. Secreted predominantly from the stomach, ghrelin is the natural ligand for the growth hormone secretagogue receptor in the pituitary gland, thus fulfilling criteria of a brain-gut peptide. The brain-gut axis is the effector of anabolism by regulating growth, feeding, and metabolism via vagal afferents mediating ghrelin signaling. However, the wide tissue distribution of ghrelin suggests that it may have other functions as well. Methods: Systematic literature review of all PubMed citations between 1999 and August 2003 focusing on clinically relevant biochemical and physiological characteristics of ghrelin. Results: Ghrelin is an important component of an integrated regulatory system of growth and metabolism acting via the vagus nerve, and is implicated in a variety of altered energy states such as obesity, eating disorders, neoplasia, and cachexia. It also enhances immune responses and potentially down-regulates anti-inflammatory molecules. Ghrelin's role as a brain-gut peptide emphasizes the significance of afferent vagal fibers as a major pathway to the brain, serving the purpose of maintaining physiologic homeostasis. Conclusions: The discovery of ghrelin has increased our understanding of feeding regulation, nutritional homeostasis, and metabolic processes. Further characterization of ghrelin's functions will likely generate new pharmacological approaches to diagnose and treat different disease entities including those related to the over-nutrition of obesity and the catabolic response to surgical trauma. PMID:15024307
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Alternative functional in vitro models of human intestinal epithelia
Kauffman, Amanda L.; Gyurdieva, Alexandra V.; Mabus, John R.; Ferguson, Chrissa; Yan, Zhengyin; Hornby, Pamela J.
2013-01-01
Physiologically relevant sources of absorptive intestinal epithelial cells are crucial for human drug transport studies. Human adenocarcinoma-derived intestinal cell lines, such as Caco-2, offer conveniences of easy culture maintenance and scalability, but do not fully recapitulate in vivo intestinal phenotypes. Additional sources of renewable physiologically relevant human intestinal cells would provide a much needed tool for drug discovery and intestinal physiology. We compared two alternative sources of human intestinal cells, commercially available primary human intestinal epithelial cells (hInEpCs) and induced pluripotent stem cell (iPSC)-derived intestinal cells to Caco-2, for use in in vitro transwell monolayer intestinal transport assays. To achieve this for iPSC-derived cells, intestinal organogenesis was adapted to transwell differentiation. Intestinal cells were assessed by marker expression through immunocytochemical and mRNA expression analyses, monolayer integrity through Transepithelial Electrical Resistance (TEER) measurements and molecule permeability, and functionality by taking advantage the well-characterized intestinal transport mechanisms. In most cases, marker expression for primary hInEpCs and iPSC-derived cells appeared to be as good as or better than Caco-2. Furthermore, transwell monolayers exhibited high TEER with low permeability. Primary hInEpCs showed molecule efflux indicative of P-glycoprotein (Pgp) transport. Primary hInEpCs and iPSC-derived cells also showed neonatal Fc receptor-dependent binding of immunoglobulin G variants. Primary hInEpCs and iPSC-derived intestinal cells exhibit expected marker expression and demonstrate basic functional monolayer formation, similar to or better than Caco-2. These cells could offer an alternative source of human intestinal cells for understanding normal intestinal epithelial physiology and drug transport. PMID:23847534
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Alternative functional in vitro models of human intestinal epithelia.
Kauffman, Amanda L; Gyurdieva, Alexandra V; Mabus, John R; Ferguson, Chrissa; Yan, Zhengyin; Hornby, Pamela J
2013-01-01
Physiologically relevant sources of absorptive intestinal epithelial cells are crucial for human drug transport studies. Human adenocarcinoma-derived intestinal cell lines, such as Caco-2, offer conveniences of easy culture maintenance and scalability, but do not fully recapitulate in vivo intestinal phenotypes. Additional sources of renewable physiologically relevant human intestinal cells would provide a much needed tool for drug discovery and intestinal physiology. We compared two alternative sources of human intestinal cells, commercially available primary human intestinal epithelial cells (hInEpCs) and induced pluripotent stem cell (iPSC)-derived intestinal cells to Caco-2, for use in in vitro transwell monolayer intestinal transport assays. To achieve this for iPSC-derived cells, intestinal organogenesis was adapted to transwell differentiation. Intestinal cells were assessed by marker expression through immunocytochemical and mRNA expression analyses, monolayer integrity through Transepithelial Electrical Resistance (TEER) measurements and molecule permeability, and functionality by taking advantage the well-characterized intestinal transport mechanisms. In most cases, marker expression for primary hInEpCs and iPSC-derived cells appeared to be as good as or better than Caco-2. Furthermore, transwell monolayers exhibited high TEER with low permeability. Primary hInEpCs showed molecule efflux indicative of P-glycoprotein (Pgp) transport. Primary hInEpCs and iPSC-derived cells also showed neonatal Fc receptor-dependent binding of immunoglobulin G variants. Primary hInEpCs and iPSC-derived intestinal cells exhibit expected marker expression and demonstrate basic functional monolayer formation, similar to or better than Caco-2. These cells could offer an alternative source of human intestinal cells for understanding normal intestinal epithelial physiology and drug transport.
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2016-01-01
The invasion and range expansion of Aedes albopictus (Skuse) in North America represents an outstanding opportunity to study processes of invasion, range expansion, and climatic adaptation. Furthermore, knowledge obtained from such research is relevant to developing novel strategies to control this important vector species. Substantial evidence indicates that the photoperiodic diapause response is an important adaptation to climatic variation across the range of Ae. albopictus in North America. Photoperiodic diapause is a key determinant of abundance in both space and time, and the timing of entry into and exit out of diapause strongly affects seasonal population dynamics and thus the potential for arbovirus transmission. Emerging genomic technologies are making it possible to develop high-resolution, genome-wide genetic markers that can be used for genetic mapping of traits relevant to disease transmission and phylogeographic studies to elucidate invasion history. Recent work using next-generation sequencing technologies (e.g., RNA-seq), combined with physiological experiments, has provided extensive insight into the transcriptional basis of the diapause response in Ae. albopictus. Applying this knowledge to identify novel targets for vector control represents an important future challenge. Finally, recent studies have begun to identify traits other than diapause that are affected by photoperiodism. Extending this work to identify additional traits influenced by photoperiod should produce important insights into the seasonal biology of Ae. albopictus. PMID:27354438
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Fast X-Ray Fluorescence Microtomography of Hydrated Biological Samples
Lombi, Enzo; de Jonge, Martin D.; Donner, Erica; Kopittke, Peter M.; Howard, Daryl L.; Kirkham, Robin; Ryan, Chris G.; Paterson, David
2011-01-01
Metals and metalloids play a key role in plant and other biological systems as some of them are essential to living organisms and all can be toxic at high concentrations. It is therefore important to understand how they are accumulated, complexed and transported within plants. In situ imaging of metal distribution at physiological relevant concentrations in highly hydrated biological systems is technically challenging. In the case of roots, this is mainly due to the possibility of artifacts arising during sample preparation such as cross sectioning. Synchrotron x-ray fluorescence microtomography has been used to obtain virtual cross sections of elemental distributions. However, traditionally this technique requires long data acquisition times. This has prohibited its application to highly hydrated biological samples which suffer both radiation damage and dehydration during extended analysis. However, recent advances in fast detectors coupled with powerful data acquisition approaches and suitable sample preparation methods can circumvent this problem. We demonstrate the heightened potential of this technique by imaging the distribution of nickel and zinc in hydrated plant roots. Although 3D tomography was still impeded by radiation damage, we successfully collected 2D tomograms of hydrated plant roots exposed to environmentally relevant metal concentrations for short periods of time. To our knowledge, this is the first published example of the possibilities offered by a new generation of fast fluorescence detectors to investigate metal and metalloid distribution in radiation-sensitive, biological samples. PMID:21674049
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Biological properties of extracellular vesicles and their physiological functions
Yáñez-Mó, María; Siljander, Pia R.-M.; Andreu, Zoraida; Zavec, Apolonija Bedina; Borràs, Francesc E.; Buzas, Edit I.; Buzas, Krisztina; Casal, Enriqueta; Cappello, Francesco; Carvalho, Joana; Colás, Eva; Silva, Anabela Cordeiro-da; Fais, Stefano; Falcon-Perez, Juan M.; Ghobrial, Irene M.; Giebel, Bernd; Gimona, Mario; Graner, Michael; Gursel, Ihsan; Gursel, Mayda; Heegaard, Niels H. H.; Hendrix, An; Kierulf, Peter; Kokubun, Katsutoshi; Kosanovic, Maja; Kralj-Iglic, Veronika; Krämer-Albers, Eva-Maria; Laitinen, Saara; Lässer, Cecilia; Lener, Thomas; Ligeti, Erzsébet; Linē, Aija; Lipps, Georg; Llorente, Alicia; Lötvall, Jan; Manček-Keber, Mateja; Marcilla, Antonio; Mittelbrunn, Maria; Nazarenko, Irina; Hoen, Esther N.M. Nolte-‘t; Nyman, Tuula A.; O'Driscoll, Lorraine; Olivan, Mireia; Oliveira, Carla; Pállinger, Éva; del Portillo, Hernando A.; Reventós, Jaume; Rigau, Marina; Rohde, Eva; Sammar, Marei; Sánchez-Madrid, Francisco; Santarém, N.; Schallmoser, Katharina; Ostenfeld, Marie Stampe; Stoorvogel, Willem; Stukelj, Roman; Van der Grein, Susanne G.; Vasconcelos, M. Helena; Wauben, Marca H. M.; De Wever, Olivier
2015-01-01
In the past decade, extracellular vesicles (EVs) have been recognized as potent vehicles of intercellular communication, both in prokaryotes and eukaryotes. This is due to their capacity to transfer proteins, lipids and nucleic acids, thereby influencing various physiological and pathological functions of both recipient and parent cells. While intensive investigation has targeted the role of EVs in different pathological processes, for example, in cancer and autoimmune diseases, the EV-mediated maintenance of homeostasis and the regulation of physiological functions have remained less explored. Here, we provide a comprehensive overview of the current understanding of the physiological roles of EVs, which has been written by crowd-sourcing, drawing on the unique EV expertise of academia-based scientists, clinicians and industry based in 27 European countries, the United States and Australia. This review is intended to be of relevance to both researchers already working on EV biology and to newcomers who will encounter this universal cell biological system. Therefore, here we address the molecular contents and functions of EVs in various tissues and body fluids from cell systems to organs. We also review the physiological mechanisms of EVs in bacteria, lower eukaryotes and plants to highlight the functional uniformity of this emerging communication system. PMID:25979354
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Biological properties of extracellular vesicles and their physiological functions.
Yáñez-Mó, María; Siljander, Pia R-M; Andreu, Zoraida; Zavec, Apolonija Bedina; Borràs, Francesc E; Buzas, Edit I; Buzas, Krisztina; Casal, Enriqueta; Cappello, Francesco; Carvalho, Joana; Colás, Eva; Cordeiro-da Silva, Anabela; Fais, Stefano; Falcon-Perez, Juan M; Ghobrial, Irene M; Giebel, Bernd; Gimona, Mario; Graner, Michael; Gursel, Ihsan; Gursel, Mayda; Heegaard, Niels H H; Hendrix, An; Kierulf, Peter; Kokubun, Katsutoshi; Kosanovic, Maja; Kralj-Iglic, Veronika; Krämer-Albers, Eva-Maria; Laitinen, Saara; Lässer, Cecilia; Lener, Thomas; Ligeti, Erzsébet; Linē, Aija; Lipps, Georg; Llorente, Alicia; Lötvall, Jan; Manček-Keber, Mateja; Marcilla, Antonio; Mittelbrunn, Maria; Nazarenko, Irina; Nolte-'t Hoen, Esther N M; Nyman, Tuula A; O'Driscoll, Lorraine; Olivan, Mireia; Oliveira, Carla; Pállinger, Éva; Del Portillo, Hernando A; Reventós, Jaume; Rigau, Marina; Rohde, Eva; Sammar, Marei; Sánchez-Madrid, Francisco; Santarém, N; Schallmoser, Katharina; Ostenfeld, Marie Stampe; Stoorvogel, Willem; Stukelj, Roman; Van der Grein, Susanne G; Vasconcelos, M Helena; Wauben, Marca H M; De Wever, Olivier
2015-01-01
In the past decade, extracellular vesicles (EVs) have been recognized as potent vehicles of intercellular communication, both in prokaryotes and eukaryotes. This is due to their capacity to transfer proteins, lipids and nucleic acids, thereby influencing various physiological and pathological functions of both recipient and parent cells. While intensive investigation has targeted the role of EVs in different pathological processes, for example, in cancer and autoimmune diseases, the EV-mediated maintenance of homeostasis and the regulation of physiological functions have remained less explored. Here, we provide a comprehensive overview of the current understanding of the physiological roles of EVs, which has been written by crowd-sourcing, drawing on the unique EV expertise of academia-based scientists, clinicians and industry based in 27 European countries, the United States and Australia. This review is intended to be of relevance to both researchers already working on EV biology and to newcomers who will encounter this universal cell biological system. Therefore, here we address the molecular contents and functions of EVs in various tissues and body fluids from cell systems to organs. We also review the physiological mechanisms of EVs in bacteria, lower eukaryotes and plants to highlight the functional uniformity of this emerging communication system.
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AMP Is an Adenosine A1 Receptor Agonist*
Rittiner, Joseph E.; Korboukh, Ilia; Hull-Ryde, Emily A.; Jin, Jian; Janzen, William P.; Frye, Stephen V.; Zylka, Mark J.
2012-01-01
Numerous receptors for ATP, ADP, and adenosine exist; however, it is currently unknown whether a receptor for the related nucleotide adenosine 5′-monophosphate (AMP) exists. Using a novel cell-based assay to visualize adenosine receptor activation in real time, we found that AMP and a non-hydrolyzable AMP analog (deoxyadenosine 5′-monophosphonate, ACP) directly activated the adenosine A1 receptor (A1R). In contrast, AMP only activated the adenosine A2B receptor (A2BR) after hydrolysis to adenosine by ecto-5′-nucleotidase (NT5E, CD73) or prostatic acid phosphatase (PAP, ACPP). Adenosine and AMP were equipotent human A1R agonists in our real-time assay and in a cAMP accumulation assay. ACP also depressed cAMP levels in mouse cortical neurons through activation of endogenous A1R. Non-selective purinergic receptor antagonists (pyridoxalphosphate-6-azophenyl-2′,4′-disulfonic acid and suramin) did not block adenosine- or AMP-evoked activation. Moreover, mutation of His-251 in the human A1R ligand binding pocket reduced AMP potency without affecting adenosine potency. In contrast, mutation of a different binding pocket residue (His-278) eliminated responses to AMP and to adenosine. Taken together, our study indicates that the physiologically relevant nucleotide AMP is a full agonist of A1R. In addition, our study suggests that some of the physiological effects of AMP may be direct, and not indirect through ectonucleotidases that hydrolyze this nucleotide to adenosine. PMID:22215671
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AMP is an adenosine A1 receptor agonist.
Rittiner, Joseph E; Korboukh, Ilia; Hull-Ryde, Emily A; Jin, Jian; Janzen, William P; Frye, Stephen V; Zylka, Mark J
2012-02-17
Numerous receptors for ATP, ADP, and adenosine exist; however, it is currently unknown whether a receptor for the related nucleotide adenosine 5'-monophosphate (AMP) exists. Using a novel cell-based assay to visualize adenosine receptor activation in real time, we found that AMP and a non-hydrolyzable AMP analog (deoxyadenosine 5'-monophosphonate, ACP) directly activated the adenosine A(1) receptor (A(1)R). In contrast, AMP only activated the adenosine A(2B) receptor (A(2B)R) after hydrolysis to adenosine by ecto-5'-nucleotidase (NT5E, CD73) or prostatic acid phosphatase (PAP, ACPP). Adenosine and AMP were equipotent human A(1)R agonists in our real-time assay and in a cAMP accumulation assay. ACP also depressed cAMP levels in mouse cortical neurons through activation of endogenous A(1)R. Non-selective purinergic receptor antagonists (pyridoxalphosphate-6-azophenyl-2',4'-disulfonic acid and suramin) did not block adenosine- or AMP-evoked activation. Moreover, mutation of His-251 in the human A(1)R ligand binding pocket reduced AMP potency without affecting adenosine potency. In contrast, mutation of a different binding pocket residue (His-278) eliminated responses to AMP and to adenosine. Taken together, our study indicates that the physiologically relevant nucleotide AMP is a full agonist of A(1)R. In addition, our study suggests that some of the physiological effects of AMP may be direct, and not indirect through ectonucleotidases that hydrolyze this nucleotide to adenosine.
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Leiding, Thom; Górecki, Kamil; Kjellman, Tomas; Vinogradov, Sergei A; Hägerhäll, Cecilia; Arsköld, Sindra Peterson
2009-05-15
Accurate real-time measurements of proton concentration gradients are pivotal to mechanistic studies of proton translocation by membrane-bound enzymes. Here we report a detailed characterization of the pH-sensitive fluorescent nanoprobe Glu(3), which is well suited for pH measurements in microcompartmentalized biological systems. The probe is a polyglutamic porphyrin dendrimer in which multiple carboxylate termini ensure its high water solubility and prevent its diffusion across phospholipid membranes. The probe's pK is in the physiological pH range, and its protonation can be followed ratiometrically by absorbance or fluorescence in the ultraviolet-visible spectral region. The usefulness of the probe was enhanced by using a semiautomatic titration system coupled to a charge-coupled device (CCD) spectrometer, enabling fast and accurate titrations and full spectral coverage of the system at millisecond time resolution. The probe's pK was measured in bulk solutions as well as inside large unilamellar vesicles in the presence of physiologically relevant ions. Glu(3) was found to be completely membrane impermeable, and its distinct spectroscopic features permit pH measurements inside closed membrane vesicles, enabling quantitative mechanistic studies of membrane-spanning proteins. Performance of the probe was demonstrated by monitoring the rate of proton leakage through the phospholipid bilayer in large vesicles with and without the uncoupler gramicidin present. Overall, as a probe for biological proton translocation measurements, Glu(3) was found to be superior to the commercially available pH indicators.
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NASA Astrophysics Data System (ADS)
Walpitagama, Milanga; Kaslin, Jan; Nugegoda, Dayanthi; Wlodkowic, Donald
2016-12-01
The fish embryo toxicity (FET) biotest performed on embryos of zebrafish (Danio rerio) has gained significant popularity as a rapid and inexpensive alternative approach in chemical hazard and risk assessment. The FET was designed to evaluate acute toxicity on embryonic stages of fish exposed to the test chemical. The current standard, similar to most traditional methods for evaluating aquatic toxicity provides, however, little understanding of effects of environmentally relevant concentrations of chemical stressors. We postulate that significant environmental effects such as altered motor functions, physiological alterations reflected in heart rate, effects on development and reproduction can occur at sub-lethal concentrations well below than LC10. Behavioral studies can, therefore, provide a valuable integrative link between physiological and ecological effects. Despite the advantages of behavioral analysis development of behavioral toxicity, biotests is greatly hampered by the lack of dedicated laboratory automation, in particular, user-friendly and automated video microscopy systems. In this work we present a proof-of-concept development of an optical system capable of tracking embryonic vertebrates behavioral responses using automated and vastly miniaturized time-resolved video-microscopy. We have employed miniaturized CMOS cameras to perform high definition video recording and analysis of earliest vertebrate behavioral responses. The main objective was to develop a biocompatible embryo positioning structures that were suitable for high-throughput imaging as well as video capture and video analysis algorithms. This system should support the development of sub-lethal and behavioral markers for accelerated environmental monitoring.
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Metabolism of psilocybin and psilocin: clinical and forensic toxicological relevance.
Dinis-Oliveira, Ricardo Jorge
2017-02-01
Psilocybin and psilocin are controlled substances in many countries. These are the two main hallucinogenic compounds of the "magic mushrooms" and both act as agonists or partial agonists at 5-hydroxytryptamine (5-HT) 2A subtype receptors. During the last few years, psilocybin and psilocin have gained therapeutic relevance but considerable physiological variability between individuals that can influence dose-response and toxicological profile has been reported. This review aims to discuss metabolism of psilocybin and psilocin, by presenting all major and minor psychoactive metabolites. Psilocybin is primarily a pro-drug that is dephosphorylated by alkaline phosphatase to active metabolite psilocin. This last is then further metabolized, psilocin-O-glucuronide being the main urinary metabolite with clinical and forensic relevance in diagnosis.
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Ferner, Robin E; Aronson, Jeffrey K
2016-01-01
We have traced the historical link between the Law of Mass Action and clinical pharmacology. The Law evolved from the work of the French chemist Claude Louis Berthollet, was first formulated by Cato Guldberg and Peter Waage in 1864 and later clarified by the Dutch chemist Jacobus van 't Hoff in 1877. It has profoundly influenced our qualitative and quantitative understanding of a number of physiological and pharmacological phenomena. According to the Law of Mass Action, the velocity of a chemical reaction depends on the concentrations of the reactants. At equilibrium the concentrations of the chemicals involved bear a constant relation to each other, described by the equilibrium constant, K. The Law of Mass Action is relevant to various physiological and pharmacological concepts, including concentration-effect curves, dose-response curves, and ligand-receptor binding curves, all of which are important in describing the pharmacological actions of medications, the Langmuir adsorption isotherm, which describes the binding of medications to proteins, activation curves for transmembrane ion transport, enzyme inhibition and the Henderson-Hasselbalch equation, which describes the relation between pH, as a measure of acidity and the concentrations of the contributory acids and bases. Guldberg and Waage recognized the importance of dynamic equilibrium, while others failed to do so. Their ideas, over 150 years old, are embedded in and still relevant to clinical pharmacology. Here we explain the ideas and in a subsequent paper show how they are relevant to understanding adverse drug reactions. © 2015 The British Pharmacological Society.
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Mintram, Kate S; Brown, A Ross; Maynard, Samuel K; Thorbek, Pernille; Tyler, Charles R
2018-02-01
Endocrine active chemicals (EACs) are widespread in freshwater environments and both laboratory and field based studies have shown reproductive effects in fish at environmentally relevant exposures. Environmental risk assessment (ERA) seeks to protect wildlife populations and prospective assessments rely on extrapolation from individual-level effects established for laboratory fish species to populations of wild fish using arbitrary safety factors. Population susceptibility to chemical effects, however, depends on exposure risk, physiological susceptibility, and population resilience, each of which can differ widely between fish species. Population models have significant potential to address these shortfalls and to include individual variability relating to life-history traits, demographic and density-dependent vital rates, and behaviors which arise from inter-organism and organism-environment interactions. Confidence in population models has recently resulted in the EU Commission stating that results derived from reliable models may be considered when assessing the relevance of adverse effects of EACs at the population level. This review critically assesses the potential risks posed by EACs for fish populations, considers the ecological factors influencing these risks and explores the benefits and challenges of applying population modeling (including individual-based modeling) in ERA for EACs in fish. We conclude that population modeling offers a way forward for incorporating greater environmental relevance in assessing the risks of EACs for fishes and for identifying key risk factors through sensitivity analysis. Individual-based models (IBMs) allow for the incorporation of physiological and behavioral endpoints relevant to EAC exposure effects, thus capturing both direct and indirect population-level effects.
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Synchrosqueezing an effective method for analyzing Doppler radar physiological signals.
Yavari, Ehsan; Rahman, Ashikur; Jia Xu; Mandic, Danilo P; Boric-Lubecke, Olga
2016-08-01
Doppler radar can monitor vital sign wirelessly. Respiratory and heart rate have time-varying behavior. Capturing the rate variability provides crucial physiological information. However, the common time-frequency methods fail to detect key information. We investigate Synchrosqueezing method to extract oscillatory components of the signal with time varying spectrum. Simulation and experimental result shows the potential of the proposed method for analyzing signals with complex time-frequency behavior like physiological signals. Respiration and heart signals and their components are extracted with higher resolution and without any pre-filtering and signal conditioning.
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Biological tissue imaging with a position and time sensitive pixelated detector.
Jungmann, Julia H; Smith, Donald F; MacAleese, Luke; Klinkert, Ivo; Visser, Jan; Heeren, Ron M A
2012-10-01
We demonstrate the capabilities of a highly parallel, active pixel detector for large-area, mass spectrometric imaging of biological tissue sections. A bare Timepix assembly (512 × 512 pixels) is combined with chevron microchannel plates on an ion microscope matrix-assisted laser desorption time-of-flight mass spectrometer (MALDI TOF-MS). The detector assembly registers position- and time-resolved images of multiple m/z species in every measurement frame. We prove the applicability of the detection system to biomolecular mass spectrometry imaging on biologically relevant samples by mass-resolved images from Timepix measurements of a peptide-grid benchmark sample and mouse testis tissue slices. Mass-spectral and localization information of analytes at physiologic concentrations are measured in MALDI-TOF-MS imaging experiments. We show a high spatial resolution (pixel size down to 740 × 740 nm(2) on the sample surface) and a spatial resolving power of 6 μm with a microscope mode laser field of view of 100-335 μm. Automated, large-area imaging is demonstrated and the Timepix' potential for fast, large-area image acquisition is highlighted.
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The Transition Period in Soccer: A Window of Opportunity.
Silva, Joao Renato; Brito, Joao; Akenhead, Richard; Nassis, George P
2016-03-01
The aim of this paper is to describe the physiological changes that occur during the transition period in soccer players. A secondary aim is to address the issue of utilizing the transition period to lay the foundation for the succeeding season. We reviewed published peer-reviewed studies if they met the following three selection criteria: (1) the studied population comprised adult soccer players (aged >18 years), (2) time points of physiological and performance assessments were provided, and (3) appropriate statistics for the calculation of effect sizes were reported. Following two selection phases, 12 scientific publications were considered, involving a total sample of 252 players. The transition period elicits small to moderate negative changes in body composition, a moderate decline in sprint performance with and without changes of direction, and small to moderate decrements in muscle power. Detraining effects are also evident for endurance-related physiological and performance outcomes: large decrements in maximal oxygen consumption V̇O2max) and time to exhaustion, and moderate to very large impairments have been observed in intermittent-running performance. Off-season programs should be characterized by clear training objectives, a low frequency of training sessions, and simple training tools in order to facilitate compliance. The program suggested here may constitute the 'minimum effective dose' to maintain or at least attenuate the decay of endurance- and neuromuscular-related performance parameters, as well as restore an adequate strength profile (reduce muscle strength imbalances). This periodization strategy may improve the ability of players to cope with the elevated training demands of pre-season training and therefore reduce the risk of injury. Moreover, this strategy will favor a more efficient development of other relevant facets of performance during the pre-competition phase (e.g., tactical organization). We contend that the transition period needs to be perceived as a 'window of opportunity' for players to both recover and 'rebuild' for the following season.
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Individual styles of professional operator's performance for the needs of interplanetary mission.
NASA Astrophysics Data System (ADS)
Boritko, Yaroslav; Gushin, Vadim; Zavalko, Irina; Smoleevskiy, Alexandr; Dudukin, Alexandr
Maintenance of the cosmonaut’s professional performance reliability is one of the priorities of long-term space flights safety. Cosmonaut’s performance during long-term space flight decreases due to combination of the microgravity effects and inevitable degradation of skills during prolonged breaks in training. Therefore, the objective of the elaboration of countermeasures against skill decrement is very relevant. During the experiment with prolonged isolation "Mars-500" in IMBP two virtual models of professional operator’s activities were used to investigate the influence of extended isolation, monotony and confinement on professional skills degradation. One is well-known “PILOT-1” (docking to the space station), another - "VIRTU" (manned operations of planet exploration). Individual resistance to the artificial sensory conflict was estimated using computerized version of “Mirror koordinograf” with GSR registration. Two different individual performance styles, referring to the different types of response to stress, have been identified. Individual performance style, called "conservative control", manifested in permanent control of parameters, conditions and results of the operator’s activity. Operators with this performance style demonstrate high reliability in performing tasks. The drawback of the style is intensive resource expenditure - both the operator (physiological "cost") and the technical system operated (fuel, time). This style is more efficient while executing tasks that require long work with high reliability required according to a detailed protocol, such as orbital flight. Individual style, called "exploratory ", manifested in the search of new ways of task fulfillment. This style is accompanied by partial, periodic lack of control of the conditions and result of operator’s activity due to flexible approach to the tasks perfect implementation. Operators spent less resource (fuel, time, lower physiological "cost") due to high self-regulation in tasks not requiring high reliability. "Exploratory" style is more effective when working in nonregulated and off-nominal situations, such as interplanetary mission, due to possibility to use nonstandard innovative solutions, save physiological resources and rapidly mobilize to demonstrate high reliability at key moments.
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Diamantopoulou, Anastasia; Oitzl, Melly S; Grauer, Ettie
2012-07-23
Highly emotional, stress reactive BALB/c mice secrete more corticosterone in response to fear conditioning than the low stress reactive C57BL/6J mice. Fear memory to cue and context differs between the strains. We injected corticosterone at physiological concentrations (250 μg/kg i.p.) 30 min before fear conditioning. Fear memory was tested 48 and 72 h later. Although corticosterone had little effect on acquisition, it differentially affected fear memories in strain dependent manner: while BALB/c mice decreased freezing during cue and context episodes, C57BL/6J mice showed an overall increase in freezing. BALB/c mice showed extinction over days while no such extinction was seen in C57BL/6J mice. Evaluation of these data in the perspective of previous studies using the same fear conditioning paradigm with corticosterone injections 5 min before or immediately after acquisition, revealed the impact of corticosterone during conditioning on the strength of fear memories. In C57BL/6J mice the overall increase in fear memories was higher if corticosterone was injected 30 min pre acquisition than if injected 5 min pre. In contrast, BALB/c mice showed reduced fear memories when injected 30 min pre compared to that seen 5 min pre acquisition. Both strains showed decreased fear memories compared to vehicle if corticosterone was administered immediately after acquisition. We conclude that the timing of physiologically relevant, stress levels increase in corticosterone is essential for the processing of aversive events and the formation of fear memories. However, the quality of the effect depends on the genetic background. These findings contribute to the understanding of the etiology of stress-related disorders. Copyright © 2012 Elsevier B.V. All rights reserved.
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Monitoring dynamic interactions of tumor cells with tissue and immune cells in a lab-on-a-chip.
Charwat, Verena; Rothbauer, Mario; Tedde, Sandro F; Hayden, Oliver; Bosch, Jacobus J; Muellner, Paul; Hainberger, Rainer; Ertl, Peter
2013-12-03
A complementary cell analysis method has been developed to assess the dynamic interactions of tumor cells with resident tissue and immune cells using optical light scattering and impedance sensing to shed light on tumor cell behavior. The combination of electroanalytical and optical biosensing technologies integrated in a lab-on-a-chip allows for continuous, label-free, and noninvasive probing of dynamic cell-to-cell interactions between adherent and nonadherent cocultures, thus providing real-time insights into tumor cell responses under physiologically relevant conditions. While the study of adherent cocultures is important for the understanding and suppression of metastatic invasion, the analysis of tumor cell interactions with nonadherent immune cells plays a vital role in cancer immunotherapy research. For the first time, the direct cell-to-cell interactions of tumor cells with bead-activated primary T cells were continuously assessed using an effector cell to target a cell ratio of 10:1.
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EPR-based distance measurements at ambient temperature.
Krumkacheva, Olesya; Bagryanskaya, Elena
2017-07-01
Pulsed dipolar (PD) EPR spectroscopy is a powerful technique allowing for distance measurements between spin labels in the range of 2.5-10.0nm. It was proposed more than 30years ago, and nowadays is widely used in biophysics and materials science. Until recently, PD EPR experiments were limited to cryogenic temperatures (T<80K). Recently, application of spin labels with long electron spin dephasing time at room temperature such as triarylmethyl radicals and nitroxides with bulky substituents at a position close to radical centers enabled measurements at room temperature and even at physiologically relevant temperatures by PD EPR as well as other approaches based on EPR (e.g., relaxation enhancement; RE). In this paper, we review the features of PD EPR and RE at ambient temperatures, in particular, requirements on electron spin phase memory time, ways of immobilization of biomolecules, the influence of a linker between the spin probe and biomolecule, and future opportunities. Copyright © 2017 Elsevier Inc. All rights reserved.
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Three-dimensional bioprinting of thick vascularized tissues
NASA Astrophysics Data System (ADS)
Kolesky, David B.; Homan, Kimberly A.; Skylar-Scott, Mark A.; Lewis, Jennifer A.
2016-03-01
The advancement of tissue and, ultimately, organ engineering requires the ability to pattern human tissues composed of cells, extracellular matrix, and vasculature with controlled microenvironments that can be sustained over prolonged time periods. To date, bioprinting methods have yielded thin tissues that only survive for short durations. To improve their physiological relevance, we report a method for bioprinting 3D cell-laden, vascularized tissues that exceed 1 cm in thickness and can be perfused on chip for long time periods (>6 wk). Specifically, we integrate parenchyma, stroma, and endothelium into a single thick tissue by coprinting multiple inks composed of human mesenchymal stem cells (hMSCs) and human neonatal dermal fibroblasts (hNDFs) within a customized extracellular matrix alongside embedded vasculature, which is subsequently lined with human umbilical vein endothelial cells (HUVECs). These thick vascularized tissues are actively perfused with growth factors to differentiate hMSCs toward an osteogenic lineage in situ. This longitudinal study of emergent biological phenomena in complex microenvironments represents a foundational step in human tissue generation.
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Frixione, Eugenio
2017-01-01
Neuron, a Greek term with a rustic background, made much of its way to its current significance since antiquity, when full recognition was achieved that sensory and motor signals travel through the animal body along nerves (neura, plural). Drawing from classic and recent historical scholarship, this study identifies the successive steps toward such a major breakthrough, starting from the usage of the expression in archaic times and continuing up to the much later transference of a mature theory into the modern world. It is shown that four main consecutive stages may be distinguished in the process: (a) incorporation of the word into early anatomical terminology; (b) theorizing on material composition, origin, properties, and role of the neura in animal bodies; (c) functional association of the neura with a transmitting vehicle; (d) identification of true anatomical and physiological correspondences. Upon this over 2000-year-old foundation is still being built one of the most relevant and fascinating scientific adventures of all time.
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Synthesis, characterization and bioimaging of fluorescent labeled polyoxometalates.
Geisberger, Georg; Gyenge, Emina Besic; Hinger, Doris; Bösiger, Peter; Maake, Caroline; Patzke, Greta R
2013-07-21
A fluorescent labeled Wells-Dawson type POM ({P2W17O61Fluo}) was newly synthesized and characterized by a wide range of analytical methods. {P2W17O61Fluo} was functionalized with fluorescein amine through a stable amide bond, and its long time stability was verified by UV/vis spectroscopic techniques at physiologically relevant pH values. No significant impact on the cell viability or morphology of HeLa cells was observed for POM concentrations up to 100 μg mL(-1). Cellular uptake of fluorescent {P2W17O61Fluo} was monitored by confocal laser scanning microscopy. POM uptake occurs mainly after prolonged incubation times of 24 h resulting in different intracellular patterns, i.e. randomly distributed over the entire cytoplasm, or aggregated in larger clusters. This direct monitoring strategy for the interaction of POMs with cells opens up new pathways for elucidating their unknown mode of action on the way to POM-based drug development.
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Antoine, Thomas; Ott, David; Ebell, Katharina; Hansen, Kerrin; Henry, Luc; Becker, Frank; Hannus, Stefan
2016-06-01
G protein-coupled receptors (GPCRs) mediate many important physiological functions and are considered as one of the most successful therapeutic target classes for a wide spectrum of diseases. Drug discovery projects generally benefit from a broad range of experimental approaches for screening compound libraries and for the characterization of binding modes of drug candidates. Owing to the difficulties in solubilizing and purifying GPCRs, assay formats have been so far mainly limited to cell-based functional assays and radioligand binding assays. In this study, we used fluorescence cross-correlation spectroscopy (FCCS) to analyze the interaction of detergent-solubilized receptors to various types of GPCR ligands: endogenous peptides, small molecules, and a large surrogate antagonist represented by a blocking monoclonal antibody. Our work demonstrates the suitability of the homogeneous and time-resolved FCCS assay format for a robust, high-throughput determination of receptor-ligand binding affinities and kinetic rate constants for various therapeutically relevant GPCRs. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.
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Jeng, Yow-Jiun; Watson, Cheryl S.
2011-01-01
Background Estrogens are potent nongenomic phospho-activators of extracellular-signal–regulated kinases (ERKs). A major concern about the toxicity of xenoestrogens (XEs) is potential alteration of responses to physiologic estrogens when XEs are present simultaneously. Objectives We examined estrogen-induced ERK activation, comparing the abilities of structurally related XEs (alkylphenols and bisphenol A) to alter ERK responses induced by physiologic concentrations (1 nM) of estradiol (E2), estrone (E1), and estriol (E3). Methods We quantified hormone/mimetic-induced ERK phosphorylations in the GH3/B6/F10 rat pituitary cell line using a plate immunoassay, comparing effects with those on cell proliferation and by estrogen receptor subtype-selective ligands. Results Alone, these structurally related XEs activate ERKs in an oscillating temporal pattern similar (but not identical) to that with physiologic estrogens. The potency of all estrogens was similar (active between femtomolar and nanomolar concentrations). XEs potently disrupted physiologic estrogen signaling at low, environmentally relevant concentrations. Generally, XEs potentiated (at the lowest, subpicomolar concentrations) and attenuated (at the highest, picomolar to 100 nM concentrations) the actions of the physiologic estrogens. Some XEs showed pronounced nonmonotonic responses/inhibitions. The phosphorylated ERK and proliferative responses to receptor-selective ligands were only partially correlated. Conclusions XEs are both imperfect potent estrogens and endocrine disruptors; the more efficacious an XE, the more it disrupts actions of physiologic estrogens. This ability to disrupt physiologic estrogen signaling suggests that XEs may disturb normal functioning at life stages where actions of particular estrogens are important (e.g., development, reproductive cycling, pregnancy, menopause). PMID:20870566
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NASA Astrophysics Data System (ADS)
Miao, Changyun; Shi, Boya; Li, Hongqiang
2008-12-01
A human physiological parameters intelligent clothing is researched with FBG sensor technology. In this paper, the principles and methods of measuring human physiological parameters including body temperature and heart rate in intelligent clothing with distributed FBG are studied, the mathematical models of human physiological parameters measurement are built; the processing method of body temperature and heart rate detection signals is presented; human physiological parameters detection module is designed, the interference signals are filtered out, and the measurement accuracy is improved; the integration of the intelligent clothing is given. The intelligent clothing can implement real-time measurement, processing, storage and output of body temperature and heart rate. It has accurate measurement, portability, low cost, real-time monitoring, and other advantages. The intelligent clothing can realize the non-contact monitoring between doctors and patients, timely find the diseases such as cancer and infectious diseases, and make patients get timely treatment. It has great significance and value for ensuring the health of the elders and the children with language dysfunction.
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The human cerebellum: a review of physiologic neuroanatomy.
Roostaei, Tina; Nazeri, Arash; Sahraian, Mohammad Ali; Minagar, Alireza
2014-11-01
The cerebellum resides in the posterior cranial fossa dorsal to the brainstem and has diverse connections to the cerebrum, brain stem, and spinal cord. It is anatomically and physiologically divided into distinct functional compartments and is composed of highly regular arrays of neuronal units, each sharing the same basic cerebellar microcircuitry. Its circuitry is critically involved in motor control and motor learning, and its role in nonmotor cognitive and affective functions is becoming increasingly recognized. This article describes the cerebellar gross and histologic neuroanatomy in relation to its function, and the relevance of cerebellar circuitry and firing patterns to motor learning. Copyright © 2014 Elsevier Inc. All rights reserved.
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Armstrong, James; Forrest, Helen; Crawford, Mark W
2015-10-01
Discharge criteria based on physiological scoring systems can be used in the postanesthesia care unit (PACU) to fast-track patients after ambulatory surgery; however, studies comparing physiological scoring systems with traditional time-based discharge criteria are lacking. The purpose of this study was to compare PACU discharge readiness times using physiological vs time-based discharge criteria in pediatric ambulatory surgical patients. We recorded physiological observations from consecutive American Society of Anesthesiologists physical status I-III patients aged 1-18 yr who were admitted to the PACU after undergoing ambulatory surgery in a tertiary academic pediatric hospital. The physiological score was a combination of the Aldrete and Chung systems. Scores were recorded every 15 min starting upon arrival in the PACU. Patients were considered fit for discharge once they attained a score ≥12 (maximum score, 14), provided no score was zero, with the time to achieve a score ≥12 defining the criteria-based discharge (CBD) time. Patients were discharged from the PACU when both the CBD and the existing time-based discharge (TBD) criteria were met. The CBD and TBD data were compared using Kaplan-Meier and log-rank analysis. Observations from 506 children are presented. Median (interquartile range [IQR]) age was 5.5 [2.8-9.9] yr. Median [IQR] CBD and TBD PACU discharge readiness times were 30 [15-45] min and 60 [45-60] min, respectively. Analysis of Kaplan-Meier curves indicated a significant difference in discharge times using the different criteria (hazard ratio, 5.43; 95% confidence interval, 4.51 to 6.53; P < 0.001). All patients were discharged home without incident. This prospective study suggests that discharge decisions based on physiological criteria have the potential for significantly speeding the transit of children through the PACU, thereby enhancing PACU efficiency and resource utilization.
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Effects of experiment start time and duration on measurement of standard physiological variables.
Page, Amanda J; Cooper, Christine E; Withers, Philip C
2011-07-01
Duration and start time of respirometry experiments have significant effects on the measurement of basal values for several commonly measured physiological variables (metabolic rate, evaporative water loss and body temperature). A longer measurement duration reduced values for all variables for all start times, and this was an effect of reduced animal activity rather than random sampling. However, there was also an effect of circadian rhythm on the timing of minimal physiological values. Experiment start time had a significant effect on time taken to reach minimal values for all variables, ranging from 0400 hours ± 38 min (body temperature, start time 2300 hours) to 0854 hours ± 52 min (evaporative water loss, start time 1700 hours). It also influenced the time of day that minimal values were obtained, ranging from 2224 hours ± 40 min (carbon dioxide production, start time 1500 hours) to 0600 hours ± 57 min (oxygen consumption, start time 2300 hours), and the minimum values measured. Consequently, both the measurement duration and the experiment start time should be considered in experimental design to account for both a handling and a circadian effect on the animal's physiology. We suggest that experiments to measure standard physiological variables for small diurnal birds should commence between 1700 and 2100 hours, and measurement duration should be at least 9 h.
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Growth and adhesion properties of monosodium urate monohydrate (MSU) crystals
NASA Astrophysics Data System (ADS)
Perrin, Clare M.
The presence of monosodium urate monohydrate (MSU) crystals in the synovial fluid has long been associated with the joint disease gout. To elucidate the molecular level growth mechanism and adhesive properties of MSU crystals, atomic force microscopy (AFM), scanning electron microscopy, and dynamic light scattering (DLS) techniques were employed in the characterization of the (010) and (1-10) faces of MSU, as well as physiologically relevant solutions supersaturated with urate. Topographical AFM imaging of both MSU (010) and (1-10) revealed the presence of crystalline layers of urate arranged into v-shaped features of varying height. Growth rates were measured for both monolayers (elementary steps) and multiple layers (macrosteps) on both crystal faces under a wide range of urate supersaturation in physiologically relevant solutions. Step velocities for monolayers and multiple layers displayed a second order polynomial dependence on urate supersaturation on MSU (010) and (1-10), with step velocities on (1-10) generally half of those measured on MSU (010) in corresponding growth conditions. Perpendicular step velocities on MSU (010) were obtained and also showed a second order polynomial dependence of step velocity with respect to urate supersaturation, which implies a 2D-island nucleation growth mechanism for MSU (010). Extensive topographical imaging of MSU (010) showed island adsorption from urate growth solutions under all urate solution concentrations investigated, lending further support for the determined growth mechanism. Island sizes derived from DLS experiments on growth solutions were in agreement with those measured on MSU (010) topographical images. Chemical force microscopy (CFM) was utilized to characterize the adhesive properties of MSU (010) and (1-10). AFM probes functionalized with amino acid derivatives and bio-macromolecules found in the synovial fluid were brought into contact with both crystal faces and adhesion forces were tabulated into histograms for comparison. AFM probes functionalized with -COO-, -CH3, and -OH functionalities displayed similar adhesion force with both crystal surfaces of MSU, while adhesion force on (1-10) was three times greater than (010) for -NH2+ probes. For AFM probes functionalized with bovine serum albumin, adhesion force was three times greater on MSU (1-10) than (010), most likely due to the more ionic nature of (1-10).
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The concept of function in modern physiology.
Roux, Etienne
2014-06-01
An overview of the scientific literature shows that the concept of function is central in physiology. However, the concept itself is not defined by physiologists. On the other hand, the teleological, namely, the 'goal-directed' dimension of function, and its subsequent explanatory relevance, is a philosophical problem. Intuitively, the function of a trait in a system explains why this trait is present, but, in the early 1960s, Ernest Nagel and Carl Hempel have shown that this inference cannot be logically founded. However, they showed that self-regulated systems are teleological. According to the selectionist theories, the function of an item is its effect that has been selected by natural selection, a process that explains its presence. As they restrict the functional attribution of a trait to its past selective value and not its current properties, these theories are inconsistent with the concept of function in physiology. A more adequate one is the causal role theory, for which a function of a trait in a system is its causal contribution to the functional capacity of the system. However, this leaves unsolved the question of the 'surplus meaning' of the teleological dimension of function. The significance of considering organisms as 'purpose-like' (teleological) systems may reside not in its explanatory power but in its methodological fruitfulness in physiology. In this view, the teleological dimension of physiological functions is convergent to but not imported from, the teleological dimension of evolutionary biology. © 2014 The Authors. The Journal of Physiology © 2014 The Physiological Society.
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Miller, Mark S; Bedrin, Nicholas G; Ades, Philip A; Palmer, Bradley M; Toth, Michael J
2015-03-15
Skeletal muscle contractile performance is governed by the properties of its constituent fibers, which are, in turn, determined by the molecular interactions of the myofilament proteins. To define the molecular determinants of contractile function in humans, we measured myofilament mechanics during maximal Ca(2+)-activated and passive isometric conditions in single muscle fibers with homogenous (I and IIA) and mixed (I/IIA and IIA/X) myosin heavy chain (MHC) isoforms from healthy, young adult male (n = 5) and female (n = 7) volunteers. Fibers containing only MHC II isoforms (IIA and IIA/X) produced higher maximal Ca(2+)-activated forces over the range of cross-sectional areas (CSAs) examined than MHC I fibers, resulting in higher (24-42%) specific forces. The number and/or stiffness of the strongly bound myosin-actin cross bridges increased in the higher force-producing MHC II isoforms and, in all isoforms, better predicted force than CSA. In men and women, cross-bridge kinetics, in terms of myosin attachment time and rate of myosin force production, were independent of CSA, although women had faster (7-15%) kinetics. The relative proportion of cross bridges and/or their stiffness was reduced as fiber size increased, causing a decline in specific force. Results from our examination of molecular mechanisms across the range of physiological CSAs explain the variation in specific force among the different fiber types in human skeletal muscle, which may have relevance to understanding how various physiological and pathophysiological conditions modulate single-fiber and whole muscle contractility. Copyright © 2015 the American Physiological Society.
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Interactive computer-assisted instruction in acid-base physiology for mobile computer platforms.
Longmuir, Kenneth J
2014-03-01
In this project, the traditional lecture hall presentation of acid-base physiology in the first-year medical school curriculum was replaced by interactive, computer-assisted instruction designed primarily for the iPad and other mobile computer platforms. Three learning modules were developed, each with ∼20 screens of information, on the subjects of the CO2-bicarbonate buffer system, other body buffer systems, and acid-base disorders. Five clinical case modules were also developed. For the learning modules, the interactive, active learning activities were primarily step-by-step learner control of explanations of complex physiological concepts, usually presented graphically. For the clinical cases, the active learning activities were primarily question-and-answer exercises that related clinical findings to the relevant basic science concepts. The student response was remarkably positive, with the interactive, active learning aspect of the instruction cited as the most important feature. Also, students cited the self-paced instruction, extensive use of interactive graphics, and side-by-side presentation of text and graphics as positive features. Most students reported that it took less time to study the subject matter with this online instruction compared with subject matter presented in the lecture hall. However, the approach to learning was highly examination driven, with most students delaying the study of the subject matter until a few days before the scheduled examination. Wider implementation of active learning computer-assisted instruction will require that instructors present subject matter interactively, that students fully embrace the responsibilities of independent learning, and that institutional administrations measure instructional effort by criteria other than scheduled hours of instruction.
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NASA Astrophysics Data System (ADS)
Schimmel, A.; Rammer, W.; Lexer, M. J.
2012-04-01
The PICUS model is a hybrid ecosystem model which is based on a 3D patch model and a physiological stand level production model. The model includes, among others, a submodel of bark beetle disturbances in Norway spruce and a management module allowing any silvicultural treatment to be mimicked realistically. It has been tested intensively for its ability to realistically reproduce tree growth and stand dynamics in complex structured mixed and mono-species temperate forest ecosystems. In several applications the models capacity to generate relevant forest related attributes which were subsequently fed into indicator systems to assess sustainable forest management under current and future climatic conditions has been proven. However, the relatively coarse monthly temporal resolution of the driving climate data as well as the process resolution of the major water relations within the simulated ecosystem hampered the inclusion of more detailed physiologically based assessments of drought conditions and water provisioning ecosystem services. In this contribution we present the improved model version PICUS v1.6 focusing on the newly implemented logic for the water cycle calculations. Transpiration, evaporation from leave surfaces and the forest floor, snow cover and snow melt as well as soil water dynamics in several soil horizons are covered. In enhancing the model overarching goal was to retain the large-scale applicability by keeping the input requirements to a minimum while improving the physiological foundation of water related ecosystem processes. The new model version is tested against empirical time series data. Future model applications are outlined.
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Crystal Structure of Thrombin Bound to the Uncleaved Extracellular Fragment of PAR1
DOE Office of Scientific and Technical Information (OSTI.GOV)
Gandhi, Prafull S.; Chen, Zhiwei; Di Cera, Enrico
2010-05-11
Abundant structural information exists on how thrombin recognizes ligands at the active site or at exosites separate from the active site region, but remarkably little is known about how thrombin recognizes substrates that bridge both the active site and exosite I. The case of the protease-activated receptor PAR1 is particularly relevant in view of the plethora of biological effects associated with its activation by thrombin. Here, we present the 1.8 {angstrom} resolution structure of thrombin S195A in complex with a 30-residue long uncleaved extracellular fragment of PAR1 that documents for the first time a productive binding mode bridging the activemore » site and exosite I. The structure reveals two unexpected features of the thrombin-PAR1 interaction. The acidic P3 residue of PAR1, Asp{sup 39}, does not hinder binding to the active site and actually makes favorable interactions with Gly{sup 219} of thrombin. The tethered ligand domain shows a considerable degree of disorder even when bound to thrombin. The results fill a significant gap in our understanding of the molecular mechanisms of recognition by thrombin in ways that are relevant to other physiological substrates.« less
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Atomic force microscopy as an advanced tool in neuroscience
Jembrek, Maja Jazvinšćak; Šimić, Goran; Hof, Patrick R.; Šegota, Suzana
2015-01-01
This review highlights relevant issues about applications and improvements of atomic force microscopy (AFM) toward a better understanding of neurodegenerative changes at the molecular level with the hope of contributing to the development of effective therapeutic strategies for neurodegenerative illnesses. The basic principles of AFM are briefly discussed in terms of evaluation of experimental data, including the newest PeakForce Quantitative Nanomechanical Mapping (QNM) and the evaluation of Young’s modulus as the crucial elasticity parameter. AFM topography, revealed in imaging mode, can be used to monitor changes in live neurons over time, representing a valuable tool for high-resolution detection and monitoring of neuronal morphology. The mechanical properties of living cells can be quantified by force spectroscopy as well as by new AFM. A variety of applications are described, and their relevance for specific research areas discussed. In addition, imaging as well as non-imaging modes can provide specific information, not only about the structural and mechanical properties of neuronal membranes, but also on the cytoplasm, cell nucleus, and particularly cytoskeletal components. Moreover, new AFM is able to provide detailed insight into physical structure and biochemical interactions in both physiological and pathophysiological conditions. PMID:28123795
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Kankeu, Cynthia; Clarke, Kylie; Van Haver, Delphi; Gevaert, Kris; Impens, Francis; Dittrich, Anna; Roderick, H Llewelyn; Passante, Egle; Huber, Heinrich J
2018-05-17
The rat cardiomyoblast cell line H9C2 has emerged as a valuable tool for studying cardiac development, mechanisms of disease and toxicology. We present here a rigorous proteomic analysis that monitored the changes in protein expression during differentiation of H9C2 cells into cardiomyocyte-like cells over time. Quantitative mass spectrometry followed by gene ontology (GO) enrichment analysis revealed that early changes in H9C2 differentiation are related to protein pathways of cardiac muscle morphogenesis and sphingolipid synthesis. These changes in the proteome were followed later in the differentiation time-course by alterations in the expression of proteins involved in cation transport and beta-oxidation. Studying the temporal profile of the H9C2 proteome during differentiation in further detail revealed eight clusters of co-regulated proteins that can be associated with early, late, continuous and transient up- and downregulation. Subsequent reactome pathway analysis based on these eight clusters further corroborated and detailed the results of the GO analysis. Specifically, this analysis confirmed that proteins related to pathways in muscle contraction are upregulated early and transiently, and proteins relevant to extracellular matrix organization are downregulated early. In contrast, upregulation of proteins related to cardiac metabolism occurs at later time points. Finally, independent validation of the proteomics results by immunoblotting confirmed hereto unknown regulators of cardiac structure and ionic metabolism. Our results are consistent with a 'function follows form' model of differentiation, whereby early and transient alterations of structural proteins enable subsequent changes that are relevant to the characteristic physiology of cardiomyocytes.
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A model for the solution structure of the rod arrestin tetramer.
Hanson, Susan M; Dawson, Eric S; Francis, Derek J; Van Eps, Ned; Klug, Candice S; Hubbell, Wayne L; Meiler, Jens; Gurevich, Vsevolod V
2008-06-01
Visual rod arrestin has the ability to self-associate at physiological concentrations. We previously demonstrated that only monomeric arrestin can bind the receptor and that the arrestin tetramer in solution differs from that in the crystal. We employed the Rosetta docking software to generate molecular models of the physiologically relevant solution tetramer based on the monomeric arrestin crystal structure. The resulting models were filtered using the Rosetta energy function, experimental intersubunit distances measured with DEER spectroscopy, and intersubunit contact sites identified by mutagenesis and site-directed spin labeling. This resulted in a unique model for subsequent evaluation. The validity of the model is strongly supported by model-directed crosslinking and targeted mutagenesis that yields arrestin variants deficient in self-association. The structure of the solution tetramer explains its inability to bind rhodopsin and paves the way for experimental studies of the physiological role of rod arrestin self-association.
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Long-term urethral catheterisation.
Turner, Bruce; Dickens, Nicola
This article discusses long-term urethral catheterisation, focusing on the relevant anatomy and physiology, indications for the procedure, catheter selection and catheter care. It is important that nurses have a good working knowledge of long-term catheterisation as the need for this intervention will increase with the rise in chronic health conditions and the ageing population.
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ERIC Educational Resources Information Center
Hurtt, Barbekka; Bryant, Jennifer
2016-01-01
We describe changes in an undergraduate anatomy and physiology (A&P) curriculum designed to address educational goals at a private, comprehensive university. Educational goals included making course material more relevant to students' future career interests, exposing students to professionals in their careers of interest, and incorporating…
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Leydig cells (LCs) are the cells of the testis that have as their primary function the production of testosterone. LCs are a common target of compounds tested in rodent carcinogenicity bioassays. The number of reviews on Leydig cell tumors (LCTs) has increased in recent years bec...
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ERIC Educational Resources Information Center
Lovell, B.; Moss, M.; Wetherell, M. A.
2015-01-01
Background: The positive relationship between problem behaviours of children with additional complex needs and psychological distress in their caregivers has been widely evidenced. Fewer studies, however, have assessed the relationship between care recipients' problem behaviours and key physiological processes, relevant for the physical…
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Brief Report: A Pilot Study of Parent-Child Biobehavioral Synchrony in Autism Spectrum Disorder
ERIC Educational Resources Information Center
Baker, Jason K.; Fenning, Rachel M.; Howland, Mariann A.; Baucom, Brian R.; Moffitt, Jacquelyn; Erath, Stephen A.
2015-01-01
The theory of biobehavioral synchrony proposes that the predictive power of parent-child attunement likely lies in the manner with which behaviors are aligned with relevant biological processes. Symptoms of autism spectrum disorder (ASD) may challenge the formation of behavioral and physiological synchrony, but maintenance of such parent-child…