Δευτέρα 14 Αυγούστου 2017
High Prevalence of Extended-Spectrum β-Lactamase-Producing Enterobacteriaceae in Wild Fish from the Mediterranean Sea in Algeria
Microbial Drug Resistance , Vol. 0, No. 0.
from Mary Ann Liebert, Inc. publishers via xlomafota13 on Inoreader http://ift.tt/2uJi064
via IFTTT
Role of Translesion Synthesis DNA Polymerases in DNA Replication in the Presence of a Weak DNA Polymerase {delta} in Saccharomyces cerevisiae
Translesion synthesis (TLS) DNA polymerases (pols) are often mutagenic for lesion bypass due to their low fidelity. Here, we isolated a weak yeast DNA pol mutant that possessed amino acid substitution V592G by genetic selection. The pol3-V592G cells were sensitive to hydroxyurea (HU), which increases the requirement for dNTPs, and their HU sensitivity was suppressed by L612M substitution. We also demonstrated that V592G substitution suppressed the phosphonoacetic acid (PAA) sensitivity of pol3-L612M cells, suggesting a cycle of mutual suppression in the HU- and PAA-sensitive yeast DNA pol mutants as similarly observed in the optA1- and PAA-sensitive T4 DNA pol mutants. However, the HU-sensitive pol3-V592G cells exhibited a mutator phenotype, which is contrast to the optA1-senisitive T4 phages that have an antimutator phenotype. Analysis of mutation spectra demonstrated that DNA pol participated in DNA replication in pol3-V592G cells in the presence of MMR, which extends earlier findings indicating that DNA pol contributes to DNA replication by a weak DNA pol . Importantly, we determined the true replication fidelity of pol3-V592G cells in the absence of MMR for the first time since replication errors could be masked by MMR, and thus demonstrated that DNA pol or a combination of DNA pols and contributed to replication errors in pol3-V592G cells. Overall, our observations suggest that the decreased polymerase activity of pol3-V592G cells resulted in increased TLS and reduced homologous recombination (HR).
from Genetics via xlomafota13 on Inoreader http://ift.tt/2hZYu3d
via IFTTT
Symptoms of Anxiety and Depression are Independently associated with Inflammatory Bowel Disease-related Disability
Inflammatory bowel disease(IBD) frequently results in disability. The relevance of psychological effects in causing disability, and whether disability occurs similarly in non-Western cohorts is as yet unknown.
from Gastroenterology via xlomafota13 on Inoreader http://ift.tt/2w8zYT1
via IFTTT
Combining contrast harmonic and elastography during EUS examination of pancreatic tumors increases diagnostic accuracy
We recently observed an increasing interest for the investigation of endoscopic ultrasound elastography (EUS-E) and contrast harmonic (CH-EUS) in the differential diagnosis of pancreatic masses. In this field, the diagnostic accuracy of EUS-guided tissue acquisition is still sub-optimal (<90%) [1].
from Gastroenterology via xlomafota13 on Inoreader http://ift.tt/2uIQs0D
via IFTTT
Symptoms of Anxiety and Depression are Independently associated with Inflammatory Bowel Disease-related Disability
Inflammatory bowel disease(IBD) frequently results in disability. The relevance of psychological effects in causing disability, and whether disability occurs similarly in non-Western cohorts is as yet unknown.
from Gastroenterology via xlomafota13 on Inoreader http://ift.tt/2w8zYT1
via IFTTT
Combining contrast harmonic and elastography during EUS examination of pancreatic tumors increases diagnostic accuracy
We recently observed an increasing interest for the investigation of endoscopic ultrasound elastography (EUS-E) and contrast harmonic (CH-EUS) in the differential diagnosis of pancreatic masses. In this field, the diagnostic accuracy of EUS-guided tissue acquisition is still sub-optimal (<90%) [1].
from Gastroenterology via xlomafota13 on Inoreader http://ift.tt/2uIQs0D
via IFTTT
Validity of a smartphone protractor to measure sagittal parameters in adult spinal deformity
Smartphones have become an integral tool in the daily life of healthcare professionals (Franko 2011). Their ease of use and wide availability often make smartphones the first tool surgeons use to perform measurements. This technique has been validated for certain orthopaedic pathologies (Shaw 2012, Quek 2014, Milanese 2014, Milani 2014), but never to assess sagittal parameters in adult spinal deformity. This study was designed to assess the validity, reproducibility, precision and efficiency of using a smartphone protractor application to measure sagittal parameters commonly measured in adult spinal deformity assessment and surgical planning.
from Sports Medicine via xlomafota13 on Inoreader http://ift.tt/2vDa1sA
via IFTTT
Androgen receptor is expressed in mouse cardiomyocytes at prenatal and early postnatal developmental stages
Previous studies show that androgens are involved in hypertrophy and excitability of cardiomyocytes and that their effects are mediated through their receptor. The aim of this study was to evaluate the presenc...
from Physiology via xlomafota13 on Inoreader http://ift.tt/2uWA8Za
via IFTTT
Changes in tibialis anterior architecture affect the amplitude of surface electromyograms
Variations in the amplitude of surface electromyograms (EMGs) are typically considered to advance inferences on the timing and degree of muscle activation in different circumstances. Surface EMGs are however a...
from Rehabilitation via xlomafota13 on Inoreader http://ift.tt/2w5b2ww
via IFTTT
Factors influencing outcomes after medial hamstring lengthening with semitendinosus transfer in patients with cerebral palsy
Although several studies have investigated the outcomes after distal hamstring lengthening (DHL), no study has undertaken an approach that included all or most of the important factors that could influence the...
from Rehabilitation via xlomafota13 on Inoreader http://ift.tt/2wYNmpX
via IFTTT
Robot-supported assessment of balance in standing and walking
Clinically useful and efficient assessment of balance during standing and walking is especially challenging in patients with neurological disorders. However, rehabilitation robots could facilitate assessment p...
from Rehabilitation via xlomafota13 on Inoreader http://ift.tt/2w4OPP3
via IFTTT
NLR, MLP, SVM, and LDA: a comparative analysis on EMG data from people with trans-radial amputation
Currently, the typically adopted hand prosthesis surface electromyography (sEMG) control strategies do not provide the users with a natural control feeling and do not exploit all the potential of commercially ...
from Rehabilitation via xlomafota13 on Inoreader http://ift.tt/2wYQTED
via IFTTT
Code 3® announces licensing agreement and partnership with Vital Vio Inc. to bring innovative VioSafe™ White Light Disinfection™ technology into ambulances and other emergency response vehicles
ST. LOUIS, Mo. — Code 3® a leader in engineering and manufacturing of innovative emergency lighting and warning products used in emergency response vehicles, today announced a licensing agreement with Vital Vio, Inc., developer of an innovative, continuous White Light Disinfection™ technology designed to safely and constantly kill germs on indoor surfaces. "We are absolutely thrilled ...
from EMS via xlomafota13 on Inoreader http://ift.tt/2vxD3v0
via IFTTT
Crestline and Oxford County announce Canada’s first hybrid ambulance
New ambulances will reduce Oxford's annual greenhouse gas emissions by 10.7 eCO₂ tons OXFORD COUNTY, Ontario — Oxford County becomes the first municipality in Canada to introduce electric hybrid ambulances as part of its Paramedic Services fleet with the purchase of two Crestline Coach Fleetmax XL3 Hybrid ambulances. Oxford County has been steadily shifting towards cleaner burning fuels ...
from EMS via xlomafota13 on Inoreader http://ift.tt/2wK2W9x
via IFTTT
Air Force medic crews compete in EMT rodeo
By EMS1 Staff CURRY COUNTY, N.M. — EMT teams from across the Air Force came together at the Cannon Air Force Base for the 10th annual EMT Rodeo. Cannon Air Force reported that 21 teams consisting of four EMTs competed for best military EMT honors as well as validate their training and Readiness Skill Verification requirements. Participating medics gained 23 continuing education units, which is ...
from EMS via xlomafota13 on Inoreader http://ift.tt/2vCOIav
via IFTTT
EMS Innovations: #10 Safety sharps to reduce needle sticks
When AIDS, hepatitis and other bloodborne pathogens emerged in the '80s as invisible killers, dirty needles were widely considered EMS providers' greatest risk. Through the mid-'90s, disease prevention consisted mainly of personal protective equipment and annual classes on how not to get infected. The curriculum justifiably portrayed uncapped needles as accidents waiting to happen; ...
from EMS via xlomafota13 on Inoreader http://ift.tt/2vVJDfR
via IFTTT
EMS Innovations: #10 Safety sharps to reduce needle sticks
Counting down the 10 most important EMS-related innovations in the past 25 years
from EMS via xlomafota13 on Inoreader http://ift.tt/2fFluDZ
via IFTTT
Air Force medic crews to compete in EMT rodeo
By EMS1 Staff CURRY COUNTY, N.M. — EMT teams from across the Air Force are coming together at the Cannon Air Force Base for the 10th annual EMT Rodeo. Cannon Air Force reported that 21 teams consisting of four EMTs will compete for best military EMT honors as well as validate their training and Readiness Skill Verification requirements. Participating medics will gain 23 continuing education units ...
from EMS via xlomafota13 on Inoreader http://ift.tt/2vxEPwq
via IFTTT
Diffusion-weighted tractography in the common marmoset monkey at 9.4T
The common marmoset (Callithrix jacchus) is a small New World primate that is becoming increasingly popular in the neurosciences as an animal model of preclinical human disease. With several major disorders characterized by alterations in neural white matter (e.g., multiple sclerosis, Alzheimer's disease, schizophrenia), proposed to be transgenically modeled using marmosets, the ability to isolate and characterize reliably major white matter fiber tracts with MRI will be of use for evaluating structural brain changes related to disease processes and symptomatology. Here, we propose protocols for isolating major white matter fiber tracts in the common marmoset using in vivo ultrahigh-field MRI (9.4T) diffusion-weighted imaging (DWI) data. With the use of a high angular-resolution DWI (256 diffusion-encoding directions) sequence, collected on four anesthetized marmosets, we provide guidelines for manually drawing fiber-tracking regions of interest, based on easily identified anatomical landmarks in DWI native space. These fiber-tract isolation protocols are expected to be experimentally useful for visualization and quantification of individual white matter fiber tracts in both control and experimental groups of marmosets (e.g., transgenic models). As disease models in the marmoset advance, the determination of how macroscopic white matter anatomy is altered as a function of disease state will be relevant in bridging the existing translational gap between preclinical rodent models and human patients.
NEW & NOTEWORTHY Although significant progress has been made in mapping white matter connections in the marmoset brain using ex vivo tracing techniques, the application of in vivo virtual dissection of major white matter fiber tracts has been established by few studies in the marmoset literature. Here, we demonstrate the feasibility of whole-brain diffusion-weighted tractography in anesthetized marmosets at ultrahigh-field MRI (9.4T) and propose protocols for isolating nine major white matter fiber tracts in the marmoset brain.
from Physiology via xlomafota13 on Inoreader http://ift.tt/2vVr4IZ
via IFTTT
Contribution of blood oxygen and carbon dioxide sensing to the energetic optimization of human walking
People can adapt their gait to minimize energetic cost, indicating that walking's neural control has access to ongoing measurements of the body's energy use. In this study we tested the hypothesis that an important source of energetic cost measurements arises from blood gas receptors that are sensitive to O2 and CO2 concentrations. These receptors are known to play a role in regulating other physiological processes related to energy consumption, such as ventilation rate. Given the role of O2 and CO2 in oxidative metabolism, sensing their levels can provide an accurate estimate of the body's total energy use. To test our hypothesis, we simulated an added energetic cost for blood gas receptors that depended on a subject's step frequency and determined if subjects changed their behavior in response to this simulated cost. These energetic costs were simulated by controlling inspired gas concentrations to decrease the circulating levels of O2 and increase CO2. We found this blood gas control to be effective at shifting the step frequency that minimized the ventilation rate and perceived exertion away from the normally preferred frequency, indicating that these receptors provide the nervous system with strong physiological and psychological signals. However, rather than adapt their preferred step frequency toward these lower simulated costs, subjects persevered at their normally preferred frequency even after extensive experience with the new simulated costs. These results suggest that blood gas receptors play a negligible role in sensing energetic cost for the purpose of optimizing gait.
NEW & NOTEWORTHY Human gait adaptation implies that the nervous system senses energetic cost, yet this signal is unknown. We tested the hypothesis that the blood gas receptors sense cost for gait optimization by controlling blood O2 and CO2 with step frequency as people walked. At the simulated energetic minimum, ventilation and perceived exertion were lowest, yet subjects preferred walking at their original frequency. This suggests that blood gas receptors are not critical for sensing cost during gait.
from Physiology via xlomafota13 on Inoreader http://ift.tt/2vCjrnR
via IFTTT
Activity of primate V1 neurons during the gap saccade task
When a saccadic eye movement is made toward a visual stimulus, the variability in accompanying primary visual cortex (V1) activity is related to saccade latency in both humans and simians. To understand the nature of this relationship, we examined the functional link between V1 activity and the initiation of visually guided saccades during the gap saccade task, in which a brief temporal gap is inserted between the turning off of a fixation stimulus and the appearance of a saccadic target. The insertion of such a gap robustly reduces saccade latency and facilitates the occurrence of extremely short-latency (express) saccades. Here we recorded single-cell activity from macaque V1 while monkeys performed the gap saccade task. In parallel with the gap effect on saccade latency the neural latency (time of first spike) of V1 response elicited by the saccade target became shorter, and the firing rate increased as the gap duration increased. Similarly, neural latency was shorter and firing rate was higher before express saccades relative to regular-latency saccades. In addition to these posttarget changes, the level of spontaneous spike activity during the pretarget period was negatively correlated with both neural and saccade latencies. These results demonstrate that V1 activity correlates with the gap effect and indicate that trial-to-trial variability in the state of V1 accompanies the variability of neural and behavioral latencies.
NEW & NOTEWORTHY The link between neural activity in monkey primary visual cortex (V1) and visually guided behavioral response is confirmed with the gap saccade paradigm. Results indicated that the variability in neural latency of V1 spike activity correlates with the gap effect on saccade latency and that the trial-to-trial variability in the state of V1 before the onset of saccade target correlates with the variability in neural and behavioral latencies.
from Physiology via xlomafota13 on Inoreader http://ift.tt/2vVliXN
via IFTTT
Validation of electrical stimulation models: intracellular calcium measurement in three-dimensional scaffolds
Peripheral nerve injury can be disabling. Regeneration is limited by the rate of axonal extension, and proximal injury to peripheral nerves can take over a year to reach target organs. Electrical stimulation (ES) has been shown to increase the rate of neurite growth, though the mechanism is not yet well understood. In our prior manuscript, we developed a computational model that demonstrates how ES can functionally elevate intracellular calcium concentration ([Ca2+]i) based on ES intensity and duration. In this article, we validate the computation model for the [Ca2+]i changes in neuron soma. Embryonic chicken dorsal root ganglion cells were suspended in 3-dimensional collagen scaffolds. Fura-2 was used to measure [Ca2+]i in response to biphasic ES pulses ranging from 70 to 60,000 V/m in intensity and from 10 µs to 100 ms in duration. The computational model most closely matched the experimental data of the neurons with the highest [Ca2+]i elevation for ES pulses 100 µs or greater in duration. Nickel (200 µM) and cadmium (200 µM) blocked 98–99% of the [Ca2+]i rise, indicating that the rise in [Ca2+]i in response to ES is via voltage-dependent calcium channels. The average [Ca2+]i rise in response to ES was about one-tenth of the peak rise. Therefore, the computational model is validated for elevating [Ca2+]i of neurons and can be used as a tool for designing efficacious ES protocols for improving neuronal regeneration.
NEW & NOTEWORTHY Electrical stimulation is used to enhance neuron growth, and the role of neuronal intracellular calcium concentration ([Ca2+]i) is an area of research interest. Widely varying stimulation parameters in the literature make it difficult to compare stimulation protocols. The results in this manuscript are the first to show neuronal [Ca2+]i in response to a broad and defined range of electrical pulse durations and intensities. These results validate our previously published novel computational model of [Ca2+]i.
from Physiology via xlomafota13 on Inoreader http://ift.tt/2vCCfDu
via IFTTT
Accumulation of methylglyoxal increases the advanced glycation end-product levels in DRG and contributes to lumbar disk herniation-induced persistent pain
Lumbar disk herniation (LDH) with discogenic low back pain and sciatica is a common and complicated musculoskeletal disorder. The underlying mechanisms are poorly understood, and there are no effective therapies for LDH-induced pain. In the present study, we found that the patients who suffered from LDH-induced pain had elevated plasma methylglyoxal (MG) levels. In rats, implantation of autologous nucleus pulposus (NP) to the left lumbar 5 spinal nerve root, which mimicked LDH, induced mechanical allodynia, increased MG level in plasma and dorsal root ganglion (DRG), and enhanced the excitability of small DRG neurons (<30 μm in diameter). Intrathecal injection of MG also induced mechanical allodynia, and its application to DRG neurons ex vivo increased the number of action potentials evoked by depolarizing current pulses. Furthermore, inhibition of MG accumulation by aminoguanidine attenuated the enhanced excitability of small DRG neurons and the mechanical allodynia induced by NP implantation. In addition, NP implantation increased levels of advanced glycation end products (AGEs) in DRG, and intrathecal injection of MG-derived AGEs induced the mechanical allodynia and DRG neuronal hyperactivity. Intrathecal injection of MG also significantly increased the expression of AGEs in DRG. Importantly, scavenging of MG by aminoguanidine also attenuated the increase in AGEs induced by NP implantation. These results suggested that LDH-induced MG accumulation contributed to persistent pain by increasing AGE levels. Thus generation of AGEs from MG may represent a target for treatment of LDH-induced pain.
NEW & NOTEWORTHY Our study demonstrates that methylglyoxal accumulation via increasing advanced glycation end-product levels in dorsal root ganglion contributes to the persistent pain induced by lumbar disk herniation, which proposed potential targets for the treatment of lumbar disk herniation-induced persistent pain.
from Physiology via xlomafota13 on Inoreader http://ift.tt/2vV17sY
via IFTTT
The stochastic nature of action potential backpropagation in apical tuft dendrites
In cortical pyramidal neurons, backpropagating action potentials (bAPs) supply Ca2+ to synaptic contacts on dendrites. To determine whether the efficacy of AP backpropagation into apical tuft dendrites is stable over time, we performed dendritic Ca2+ and voltage imaging in rat brain slices. We found that the amplitude of bAP-Ca2+ in apical tuft branches was unstable, given that it varied from trial to trial (termed "bAP-Ca2+ flickering"). Small perturbations in dendritic physiology, such as spontaneous synaptic inputs, channel inactivation, or temperature-induced changes in channel kinetics, can cause bAP flickering. In the tuft branches, the density of Na+ and K+ channels was sufficient to support local initiation of fast spikelets by glutamate iontophoresis. We quantified the time delay between the somatic AP burst and the peak of dendritic Ca2+ transient in the apical tuft, because this delay is important for induction of spike-timing dependent plasticity. Depending on the frequency of the somatic AP triplets, Ca2+ signals peaked in the apical tuft 20–50 ms after the 1st AP in the soma. Interestingly, at low frequency (<20 Hz), the Ca2+ peaked sooner than at high frequency, because only the 1st AP invaded tuft. Activation of dendritic voltage-gated Ca2+ channels is sensitive to the duration of the dendritic voltage transient. In apical tuft branches, small changes in the duration of bAP voltage waveforms cause disproportionately large increases in dendritic Ca2+ influx (bAP-Ca2+ flickering). The stochastic nature of bAP-Ca2+ adds a new perspective on the mechanisms by which pyramidal neurons combine inputs arriving at different cortical layers.
NEW & NOTEWORTHY The bAP-Ca2+ signal amplitudes in some apical tuft branches randomly vary from moment to moment. In repetitive measurements, successful AP invasions are followed by complete failures. Passive spread of voltage from the apical trunk into the tuft occasionally reaches the threshold for local Na+ spike, resulting in stronger Ca2+ influx. During a burst of three somatic APs, the peak of dendritic Ca2+ in the apical tuft occurs with a delay of 20-50 ms depending on AP frequency.
from Physiology via xlomafota13 on Inoreader http://ift.tt/2vCjsYX
via IFTTT
Excitability and firing behavior of single slow motor axons transmitting natural repetitive firing of human motoneurons
Excitability of motor axons is critically important for realizing their main function, i.e., transmitting motoneuron firing to muscle fibers. The present study was designed to explore excitability recovery and firing behavior in single slow axons transmitting human motoneuron firing during voluntary muscle contractions. The abductor digiti minimi, flexor carpi ulnaris, and tibialis anterior were investigated during threshold stimulation of corresponding motor nerves. Motor unit (MU) firing index in response to testing volleys evoking M-responses was used as a physiological measure of axonal excitability and its changes throughout a target interspike interval (ISI) were explored. It was shown that axons displayed an early irresponsive period (within the first ~2–5 ms of a target ISI) that was followed by a responsive period (for the next 5–17 ms of the ISI), in which MUs fired axonal doublets, and a later irresponsive period. At the beginning of the responsive period, M-responses showed small latency delays. However, since at that ISI moment, MUs displayed excitability recovery with high firing index, slight latency changes may be considered as a functionally insignificant phenomenon. The duration of axonal doublet ISIs did not depend on motoneuron firing frequencies (range 4.3–14.6 imp/s). The question of whether or not traditionally described axonal recovery excitability cycle is realistic in natural motor control is discussed. In conclusion, the present approach, exploring, for the first time, excitability recovery in single slow axons during motoneuron natural activation, can provide further insight into axonal firing behavior in normal states and diseases.
NEW & NOTEWORTHY Excitability of single slow axons was estimated by motor unit firing index in response to motor nerve stimulation, and its changes throughout a target interspike interval were explored during transmitting human motoneuron natural firing. It was found that axons exhibited early irresponsive, responsive, and later irresponsive periods. Findings question whether the traditionally described axonal excitability recovery cycle is realistic in natural motor control.
from Physiology via xlomafota13 on Inoreader http://ift.tt/2vVwy6u
via IFTTT
Diverse effects of stimulus history in waking mouse auditory cortex
Responses to auditory stimuli are often strongly influenced by recent stimulus history. For example, in a paradigm called forward suppression, brief sounds can suppress the perception of, and the neural responses to, a subsequent sound, with the magnitude of this suppression depending on both the spectral and temporal distances between the sounds. As a step towards understanding the mechanisms that generate these adaptive representations in awake animals, we quantitatively characterize responses to two-tone sequences in the auditory cortex of waking mice. We find that cortical responses in a forward suppression paradigm are more diverse in waking mice than previously appreciated, that these responses vary between cells with different firing characteristics and waveform shapes, but that the variability in these responses is not substantially related to cortical depth or columnar location. Moreover, responses to the first tone in the sequence are often not linearly related to the suppression of the second tone response, suggesting that spike-frequency adaptation of cortical cells is not a large contributor to forward suppression or its variability. Instead, we use a simple multilayered model to show that cell-to-cell differences in the balance of intracortical inhibition and excitation will naturally produce such a diversity of forward interactions. We propose that diverse inhibitory connectivity allows the cortex to encode spectro-temporally fluctuating stimuli in multiple parallel ways.
NEW & NOTEWORTHY Behavioral and neural responses to auditory stimuli are profoundly influenced by recent sounds, yet how this occurs is not known. Here, the authors show in the auditory cortex of awake mice that the quality of history-dependent effects is diverse and related to cell type, response latency, firing rates, and receptive field bandwidth. In a cortical model, differences in excitatory-inhibitory balance can produce this diversity, providing the cortex with multiple ways of representing temporally complex information.
from Physiology via xlomafota13 on Inoreader http://ift.tt/2vCto4U
via IFTTT
Physiological properties of brain-machine interface input signals
Brain-machine interfaces (BMIs), also called brain-computer interfaces (BCIs), decode neural signals and use them to control some type of external device. Despite many experimental successes and terrific demonstrations in animals and humans, a high-performance, clinically viable device has not yet been developed for widespread usage. There are many factors that impact clinical viability and BMI performance. Arguably, the first of these is the selection of brain signals used to control BMIs. In this review, we summarize the physiological characteristics and performance—including movement-related information, longevity, and stability—of multiple types of input signals that have been used in invasive BMIs to date. These include intracortical spikes as well as field potentials obtained inside the cortex, at the surface of the cortex (electrocorticography), and at the surface of the dura mater (epidural signals). We also discuss the potential for future enhancements in input signal performance, both by improving hardware and by leveraging the knowledge of the physiological characteristics of these signals to improve decoding and stability.
from Physiology via xlomafota13 on Inoreader http://ift.tt/2vVlh6b
via IFTTT
Trajectory curvature in saccade sequences: spatiotopic influences vs. residual motor activity
When decisions drive saccadic eye movements, traces of the decision process can be inferred from the movement trajectories. For example, saccades can curve away from distractor stimuli, which was thought to reflect cortical inhibition biasing activity in the superior colliculus. Recent neurophysiological work does not support this theory, and two recent models have replaced top-down inhibition with lateral interactions in the superior colliculus or neural fatigue in the brainstem saccadic burst generator. All current models operate in retinotopic coordinates and are based on single saccade paradigms. To extend these models to sequences of saccades, we assessed whether and how saccade curvature depends on previously fixated locations and the direction of previous saccades. With a two-saccade paradigm, we first demonstrated that second saccades curved away from the initial fixation stimulus. Furthermore, by varying the time from fixation offset and the intersaccadic duration, we distinguished the extent of curvature originating from the spatiotopic representation of the previous fixation location or residual motor activity of the previous saccade. Results suggest that both factors drive curvature, and we discuss how these effects could be implemented in current models. In particular, we propose that the collicular retinotopic maps receive an excitatory spatiotopic update from the lateral interparial region.
NEW & NOTEWORTHY Saccades curve away from locations of previous fixation. Varying stimulus timing demonstrates the effects of both 1) spatiotopic representation and 2) motor residual activity from previous saccades. The spatiotopic effect can be explained if current models are augmented with an excitatory top-down spatiotopic signal.
from Physiology via xlomafota13 on Inoreader http://ift.tt/2vCArdM
via IFTTT
Neurophysiology and neural engineering: a review
Neurophysiology is the branch of physiology concerned with understanding the function of neural systems. Neural engineering (also known as neuroengineering) is a discipline within biomedical engineering that uses engineering techniques to understand, repair, replace, enhance, or otherwise exploit the properties and functions of neural systems. In most cases neural engineering involves the development of an interface between electronic devices and living neural tissue. This review describes the origins of neural engineering, the explosive development of methods and devices commencing in the late 1950s, and the present-day devices that have resulted. The barriers to interfacing electronic devices with living neural tissues are many and varied, and consequently there have been numerous stops and starts along the way. Representative examples are discussed. None of this could have happened without a basic understanding of the relevant neurophysiology. I also consider examples of how neural engineering is repaying the debt to basic neurophysiology with new knowledge and insight.
from Physiology via xlomafota13 on Inoreader http://ift.tt/2vVcMYw
via IFTTT
Mesoscale-duration activated states gate spiking in response to fast rises in membrane voltage in the awake brain
Seconds-scale network states, affecting many neurons within a network, modulate neural activity by complementing fast integration of neuron-specific inputs that arrive in the milliseconds before spiking. Nonrhythmic subthreshold dynamics at intermediate timescales, however, are less well characterized. We found, using automated whole cell patch clamping in vivo, that spikes recorded in CA1 and barrel cortex in awake mice are often preceded not only by monotonic voltage rises lasting milliseconds but also by more gradual (lasting tens to hundreds of milliseconds) depolarizations. The latter exert a gating function on spiking, in a fashion that depends on the gradual rise duration: the probability of spiking was higher for longer gradual rises, even when controlled for the amplitude of the gradual rises. Barrel cortex double-autopatch recordings show that gradual rises are shared across some, but not all, neurons. The gradual rises may represent a new kind of state, intermediate both in timescale and in proportion of neurons participating, which gates a neuron's ability to respond to subsequent inputs.
NEW & NOTEWORTHY We analyzed subthreshold activity preceding spikes in hippocampus and barrel cortex of awake mice. Aperiodic voltage ramps extending over tens to hundreds of milliseconds consistently precede and facilitate spikes, in a manner dependent on both their amplitude and their duration. These voltage ramps represent a "mesoscale" activated state that gates spike production in vivo.
from Physiology via xlomafota13 on Inoreader http://ift.tt/2vCbyiA
via IFTTT
Genome-wide identification and expression analysis of the BTB domain-containing protein gene family in tomato
Abstract
BTB (broad-complex, tramtrack, and bric-a-brac) family proteins are characterized by the presence of a protein–protein interaction BTB domain. BTB proteins have diverse functions, including transcriptional regulation, protein degradation, chromatin remodeling, and cytoskeletal regulation. However, little is known about this gene family in tomato (Solanum lycopersicum), the most important model plant for crop species. In this study, 38 BTB genes were identified based on tomato whole-genome sequence. Phylogenetic analysis of BTB proteins in tomato revealed that SlBTB proteins could be divided into at least 4 subfamilies. The SlBTB proteins contains 1–3 BTB domains, and several other types of functional domains, including KCTD (Potassium channel tetramerization domain-containing), the MATH (meprin and TRAF homology), ANK (Ankyrin repeats), NPR1 (nonexpressor of pathogenesis-related proteins1), NPH3 (Nonphototropic Hypocotyl 3), TAZ zinc finger, C-terminal Kelch, Skp1 and Arm (Armadillo/beta-catenin-like repeat) domains are also found in some tomato BTB proteins. Moreover, their expression patterns in tissues/stages, in response to different abiotic stress treatments and hormones were also investigated. This study provides the first comprehensive analysis of BTB gene family in the tomato genome. The data will undoubtedly be useful for better understanding the potential functions of BTB genes, and their possible roles in mediating hormone cross-talk and abiotic stress in tomato as well as in some other relative species.
from Genetics via xlomafota13 on Inoreader http://ift.tt/2vx22yE
via IFTTT
Couple charged $1K for ambulance ride that never left hospital
AMR recently charged Paul Smale and Wilma Mullins-Smale $1,087 for a short trip from the heli-pad to the hospital four years ago
from EMS via xlomafota13 on Inoreader http://ift.tt/2uCB1uU
via IFTTT
Top Innovations of Modern EMS: #10 Safety sharps to reduce needle sticks
When AIDS, hepatitis and other bloodborne pathogens emerged in the '80s as invisible killers, dirty needles were widely considered EMS providers' greatest risk. Through the mid-'90s, disease prevention consisted mainly of personal protective equipment and annual classes on how not to get infected. The curriculum justifiably portrayed uncapped needles as accidents waiting to happen; ...
from EMS via xlomafota13 on Inoreader http://ift.tt/2wXrgnE
via IFTTT
Tissue-specific seasonal changes in mitochondrial function of a mammalian hibernator
Mammalian hibernators, such as golden-mantled ground squirrels (Callospermophilus lateralis; GMGS), cease to feed while reducing metabolic rate and body temperature during winter months, surviving exclusively on endogenous fuels stored before hibernation. We hypothesized that mitochondria, the cellular sites of oxidative metabolism, undergo tissue-specific seasonal adjustments in carbohydrate and fatty acid utilization to facilitate or complement this remarkable phenotype. To address this, we performed high-resolution respirometry of mitochondria isolated from GMGS liver, heart, skeletal muscle, and brown adipose tissue (BAT) sampled during summer (active), fall (prehibernation), and winter (hibernation) seasons using multisubstrate titration protocols. Mitochondrial phospholipid composition was examined as a postulated intrinsic modulator of respiratory function across tissues and seasons. Respirometry revealed seasonal variations in mitochondrial oxidative phosphorylation capacity, substrate utilization, and coupling efficiency that reflected the distinct functions and metabolic demands of the tissues they support. A consistent finding across tissues was a greater influence of fatty acids (palmitoylcarnitine) on respiratory parameters during the prehibernation and hibernation seasons. In particular, fatty acids had a greater suppressive effect on pyruvate-supported oxidative phosphorylation in heart, muscle, and liver mitochondria and enhanced uncoupled respiration in BAT and muscle mitochondria in the colder seasons. Seasonal variations in the mitochondrial membrane composition reflected changes in the supply and utilization of polyunsaturated fatty acids but were generally mild and inconsistent with functional variations. In conclusion, mitochondria respond to seasonal variations in physical activity, temperature, and nutrient availability in a tissue-specific manner that complements circannual shifts in the bioenergetic and thermoregulatory demands of mammalian hibernators.
from Physiology via xlomafota13 on Inoreader http://ift.tt/2wIL52O
via IFTTT
Maternal and postnatal high-fat diet consumption programs energy balance and hypothalamic melanocortin signaling in nonhuman primate offspring
Maternal high-fat-diet (HFD) consumption during pregnancy decreased fetal body weight and impacted development of hypothalamic melanocortin neural circuitry in nonhuman primate offspring. We investigated whether these impairments during gestation persisted in juvenile offspring and examined the interaction between maternal and early postnatal HFD consumption. Adult dams consumed either a control diet (CTR; 15% calories from fat) or a high-saturated-fat diet (HFD; 37% calories from fat) during pregnancy. Offspring were weaned onto a CTR or HFD at ~8 mo of age. Offspring from HFD-fed dams displayed early catch-up growth and elevated body weight at 6 and 13 mo of age. Maternal and postnatal HFD exposure reduced the amount of agouti-related peptide fibers in the paraventricular nucleus of the hypothalamus. Postnatal HFD consumption also decreased the amount of agouti-related peptide fibers in the arcuate nucleus of the hypothalamus. Postnatal HFD was associated with decreased food intake and increased activity. These results support and extend our previous findings of maternal diet effects on fetal development and reveal, for the first time in a nonhuman primate model, that maternal HFD-induced disturbances in offspring body weight regulation extended past gestation into the juvenile period. Maternal HFD consumption increases the risk for offspring developing obesity, with the developmental timing of HFD exposure differentially impacting the melanocortin system and energy balance regulation. The present findings provide translational insight into human clinical populations, suggesting that profound health consequences may await individuals later in life following intrauterine and postnatal HFD exposure.
from Physiology via xlomafota13 on Inoreader http://ift.tt/2vx8xl5
via IFTTT
Sedentary conditions and enhanced responses to GABA in the RVLM: role of the contralateral RVLM
A sedentary lifestyle is a major risk factor for cardiovascular disease, and both conditions are associated with overactivity of the sympathetic nervous system. Ongoing discharge of sympathetic nerves is regulated by the rostral ventrolateral medulla (RVLM), which in turn is modulated by the primary excitatory and inhibitory neurotransmitters glutamate and -amino-butyric acid (GABA), respectively. We reported previously that sedentary conditions enhance GABAergic modulation of sympathoexcitation in the RVLM, despite overall increased sympathoexcitation. Thus the purpose of this study was to test the hypothesis that sedentary conditions increase responsiveness to GABA in RVLM. Male Sprague-Dawley rats performed either chronic wheeling running or remained sedentary for 12–15 wk. Animals were instrumented to perform RVLM microinjections under Inactin anesthesia while mean arterial pressure (MAP) and splanchnic sympathetic nerve activity (SSNA) were recorded. Unilateral microinjections of GABA (30 nl, 0.3–600 mM) into the RVLM produced dose-dependent decreases in MAP and SSNA; however, no group differences were observed. Inhibition of the contralateral RVLM (muscimol, 2 mM, 90 nl) caused decreases in MAP and SSNA that were not different between groups but enhanced decreases in SSNA to GABA in sedentary rats only. In sinoaortic denervated rats, GABA microinjections before or after inhibition of the contralateral RVLM caused decreases in MAP and SSNA that were not different between groups. Our results suggest that the contralateral RVLM plays an important role in buffering responses to inhibition of the ipsilateral RVLM under sedentary but not physically active conditions. Based on these studies and others, sedentary conditions appear to enhance both sympathoinhibitory and sympathoexcitatory mechanisms in the RVLM. Enhanced sympathoinhibition may act to reduce already elevated sympathetic nervous system activity following sedentary conditions.
from Physiology via xlomafota13 on Inoreader http://ift.tt/2wIHEJv
via IFTTT
Circulating motilin, ghrelin, and GLP-1 and their correlations with gastric slow waves in patients with chronic kidney disease
Patients with chronic kidney disease (CKD) commonly complain upper gastrointestinal (GI) symptoms, especially anorexia. Hemodialysis (HD) has been noted to improve GI symptoms; however, the underlying mechanisms are unclear. This study was designed 1) to study effects of HD on GI symptoms and gastric slow waves; and 2) to investigate possible roles of ghrelin and glucagon-like peptide-1 (GLP-1): the study recruited 13 healthy controls, 20 CKD patients without HD (CKD group), and 18 CKD patients with HD (HD group). Dyspeptic symptoms, autonomic functions, gastric slow waves, and plasma level of ghrelin and GLP-1 were analyzed. First, the CKD patients with HD showed markedly lower scores of anorexia (0.6 ± 0.2 vs. 3.2 ± 0.4, P < 0.001) compared with patients without HD. Second, the CKD group but not HD group showed a significant reduction (25.6%) in the percentage of normal gastric slow waves, compared with controls. Third, the CKD group exhibited a significantly lower ghrelin level compared with the HD group (26.8 ± 0.9 vs. 34.1 ± 2.3 ng/l, P < 0.02) and a higher GLP-1 level (29.4 ± 2.8 vs. 20.0 ± 2.1 pmol/l, P < 0.05) compared with controls. Moreover, the percentage of normal slow waves was positively correlated with ghrelin (r = 0.385, P = 0.019) but negatively correlated with GLP-1 (r = –0.558, P < 0.001) in all CKD patients. Hemodialysis improves upper GI symptoms and gastric slow waves in CKD patients. An increase in ghrelin and a decrease in GLP-1 might be involved in the HD-induced improvement in gastric slow waves.
from Physiology via xlomafota13 on Inoreader http://ift.tt/2vwXf0c
via IFTTT
Sustained increases in skin blood flow are not a prerequisite to initiate sweating during passive heat exposure
Some studies have observed a functional relationship between sweating and skin blood flow. However, the implications of this relationship during physiologically relevant conditions remain unclear. We manipulated sudomotor activity through changes in sweating efficiency to determine if parallel changes in vasomotor activity are observed. Eight young men completed two trials at 36°C and two trials at 42°C. During these trials, air temperature remained constant while ambient vapor pressure increased from 1.6 to 5.6 kPa over 2 h. Forced airflow across the skin was used to create conditions of high (HiSeff) or low (LoSeff) sweating efficiency. Local sweat rate (LSR), local skin blood flow (SkBF), as well as mean skin and esophageal temperatures were measured continuously. It took longer for LSR to increase during HiSeff at 36°C (HiSeff: 99 ± 11 vs. LoSeff: 77 ± 11 min, P < 0.01) and 42°C (HiSeff: 72 ± 16 vs. LoSeff: 51 ± 15 min, P < 0.01). In general, an increase in LSR preceded the increase in SkBF when expressed as ambient vapor pressure and time for all conditions (P < 0.05). However, both responses were activated at a similar change in mean body temperature (average across all trials, LSR: 0.26 ± 0.15 vs. SkBF: 0.30 ± 0.18°C, P = 0.26). These results demonstrate that altering the point at which LSR is initiated during heat exposure is paralleled by similar shifts for the increase in SkBF. However, local sweat production occurs before an increase in SkBF, suggesting that SkBF is not necessarily a prerequisite for sweating.
from Physiology via xlomafota13 on Inoreader http://ift.tt/2wJkwKL
via IFTTT
Examining the Roles of Technology in Aging and Quality of Life
Technology surrounds us, from the mobile phones that most of us carry to the televisions that we watch to the ways that we find information about a restaurant or vacation destination. Older adults are no exception; they are increasingly incorporating diverse types of technologies into their lives.
from Health via xlomafota13 on Inoreader http://ift.tt/2w5RFT7
via IFTTT
from Health via xlomafota13 on Inoreader http://ift.tt/2w5RFT7
via IFTTT
Aging in Activity Space: Results From Smartphone-Based GPS-Tracking of Urban Seniors
Abstract
Objectives
Prior research emphasizes the importance of the residential neighborhood context during later life but little attention has been afforded to other areas that older adults encounter as they move beyond their residential environments for daily activities and social interactions. This study examines the predominance of the residential context within older adults' everyday lives. Method
We provided 60 older adults in four New York City neighborhoods with iPhones, which captured Global Positioning Systems (GPS) locations at 5-min intervals over 1 week (n = 55,561) and 17 ecological momentary assessments (EMAs) over 4 days (n = 757) to assess real-time activities. Results
Older adults in our sample spent nearly 40% of their time outside of their residential tracts and they visited 28 other tracts, on average. Exercising, shopping, socializing, and social activities were especially likely to take place outside of residential tracts. Differences in residential and nonresidential poverty exposure vary across gender, race/ethnicity, education, car ownership, and residential areas. Discussion
Measuring activity space, rather than relying on residential tracts, allows examination of the social environments that are relevant for older adults' everyday lives. Variation in characteristics of activity spaces may be an underexplored source of differences in health and well-being during later life.from Health via xlomafota13 on Inoreader http://ift.tt/2uGDMr1
via IFTTT
Machine Learning, Sentiment Analysis, and Tweets: An Examination of Alzheimer’s Disease Stigma on Twitter
Abstract
Objectives
Social scientists need practical methods for harnessing large, publicly available datasets that inform the social context of aging. We describe our development of a semi-automated text coding method and use a content analysis of Alzheimer's disease (AD) and dementia portrayal on Twitter to demonstrate its use. The approach improves feasibility of examining large publicly available datasets. Method
Machine learning techniques modeled stigmatization expressed in 31,150 AD-related tweets collected via Twitter's search API based on 9 AD-related keywords. Two researchers manually coded 311 random tweets on 6 dimensions. This input from 1% of the dataset was used to train a classifier against the tweet text and code the remaining 99% of the dataset. Results
Our automated process identified that 21.13% of the AD-related tweets used AD-related keywords to perpetuate public stigma, which could impact stereotypes and negative expectations for individuals with the disease and increase "excess disability". Discussion
This technique could be applied to questions in social gerontology related to how social media outlets reflect and shape attitudes bearing on other developmental outcomes. Recommendations for the collection and analysis of large Twitter datasets are discussed.from Health via xlomafota13 on Inoreader http://ift.tt/2w5NLtA
via IFTTT
Using a Smartphone-Based Ecological Momentary Assessment Protocol With Community Dwelling Older African Americans
Abstract
Objectives
Little is known about the feasibility of smartphone-based Ecological Momentary Assessment (EMA) approaches to collect psychosocial data from older populations, especially disadvantaged older populations. In response to this gap, this report provides evidence of the feasibility and utility of a smartphone-based EMA approach for real-time assessment with older African Americans. In addition, we share lessons learned about how to improve utility. Methods
Ninety-seven older African Americans ages 55 and older (range: 55–95 years) used an Android smartphone loaded with an EMA application to provide data about their everyday activities and stress four times per day for seven consecutive days. Results
Exit interviews early in the study suggested enhancements to the EMA interface. Adherence was demonstrated with response completion rates of 92–98% on EMA measures and no participant attrition based on the EMA protocol. Discussion
Our findings suggest using a smartphone-based EMA approach for data collection is feasible and has utility with older African Americans. We most likely enhanced adherence by testing, training, monitoring, and adapting the EMA protocol using input from older adults early in the EMA design process.from Health via xlomafota13 on Inoreader http://ift.tt/2uGgfq7
via IFTTT
What Accounts for the Relationship Between Internet Use and Suicidal Ideation of Korean Older Adults? A Mediation Analysis
Abstract
Objectives
This study sought to examine the relationship between Internet use and suicidal ideation in Korean older adults and the mediating roles of social relationships and depressive symptoms. Method
A nationally representative sample of older adults aged 50 or older (N = 6,306), from four waves of the Korean Welfare Panel Study, was used in the analyses. All analyses were conducted using generalized estimation equations, and the mediation effects of social relationship satisfaction and depression in the relationship between Internet use and suicidal ideation were calculated using the product-of-coefficients approach. Results
Internet use was linked with lower levels of suicidal ideation directly and indirectly via the protective effects of Internet use on lowering depression, which was partially mediated by the positive influence Internet use has on older adults' social relationship satisfaction. Discussion
The results support previous theories about the relationship between social relationships, depression, and suicidal behavior and prior results about how the Internet might confer mental and social health benefits to older adults. This suggests that the Internet is an important social and health activity that contributes to lowering suicidal ideation in older adults.from Health via xlomafota13 on Inoreader http://ift.tt/2w5RGXb
via IFTTT
Technology Access and Use, and Their Associations With Social Engagement Among Older Adults: Do Women and Men Differ?
Abstract
Objectives
To examine how information and communication technology (ICT) access and use are conceptually incorporated in the Successful Aging 2.0 framework. Method
Using data from the 2011 National Health and Aging Trends Study (N = 6,476), we examined how ICT access and use for different purposes are associated with social engagement (i.e., informal and formal social participation) by gender. Weighted logistic regression analyses were performed. Results
Findings revealed that men were more likely to access and use ICT than women. ICT access was positively associated with all types of women's social engagement, but only with men's informal social participation. Information technology (IT) use for health matters was positively associated with formal social participation for women and with informal social participation for men. IT use for personal tasks was negatively associated with formal social participation for older adults. Communication technology use was positively associated with formal and informal social participation for women and men. Discussion
This study supports the expansion of the successful aging model by incorporating ICT access and use. Further, it assists in the identification of specific technologies that promote active engagement in later life for women and men.from Health via xlomafota13 on Inoreader http://ift.tt/2uGmsm0
via IFTTT
Information and Communication Technology Use Is Related to Higher Well-Being Among the Oldest-Old
Abstract
Objectives
Older adults often prioritize socially meaningful goals over informational goals. Thus, we predicted that using information and communication technology (ICT) in service of socially meaningful versus informational goals relates to higher well-being among the oldest-old. Method
We surveyed 445 adults aged 80+ (mean = 84, range = 80–93; 64% female; 26% non-White) online or via telephone. Participants reported motivations for ICT use (connect with others, learn new information) and rated their psychological and physical well-being (i.e., life satisfaction, loneliness, goal attainment, subjective health, functional limitations). We conducted regression and mediation analyses to test our hypothesis. Results
Participants used ICT more to connect with friends/family (M = 3.66, SD = 1.28) than to learn information (M = 2.61, SD = 1.44), p < .001. Overall, ICT use predicted higher well-being across outcomes, ps ≤ .008. Motivations for use differentially mediated these effects: Social motivations mediated the relationships between ICT use and psychological well-being, whereas informational motivations mediated the relationships between ICT use and physical well-being. Discussion
Older adults aged 80+ use ICT less than other generations, but may have much to gain. Using social versus informational technologies may enhance multiple aspects of well-being in different ways during very late life. Highlighting such benefits may increase ICT adoption among the oldest-old.from Health via xlomafota13 on Inoreader http://ift.tt/2w5SP0Z
via IFTTT
Has the Digital Health Divide Widened? Trends of Health-Related Internet Use Among Older Adults From 2003 to 2011
Abstract
Objectives
To examine the trend of health-related Internet use (HRIU) among older adults. Methods
We analyzed data from the 2003, 2005, and 2011–2012 iterations of the National Cancer Institute (NCI)-sponsored Health Information National Trends Survey (HINTS). HRIU was measured by 4 online behaviors: seeking health information, buying medicine, connecting with people with similar health problems, and communicating with doctors. Results
Internet use and HRIU among older adults increased substantially from 2003 to 2011 with more significant increases in seeking health information and communicating with doctors online. Overall, the digital health divide between different demographic groups has narrowed, especially in terms of gender, racial/ethnic group, rural/urban residence, and various health statuses; however, age, education, and household income remain persistent predictors of the digital divide. Those in the oldest group (75 or older), those with less than a high school education, and those with very low income (<$25,000/year) continuously lagged behind their counterparts in all aspects of HRIU. Conclusions
Despite an overall increase in HRIU and a narrowed digital divide, significant variations in HRIU in different demographic groups persisted; therefore, we call for more senior-friendly online resources and culturally appropriate interventions to bridge the digital health divide for vulnerable older adults.from Health via xlomafota13 on Inoreader http://ift.tt/2uGejhk
via IFTTT
Gender Differences in Mobility Device Use Among U.S. Older Adults
Abstract
Objectives
Research has shown greater mobility limitations among women than men. We aimed to examine (a) gender differences in the use of canes for mobility and (b) what factors contribute to these differences under the frameworks of the disablement model and the Theory of Planned Behavior. Method
Using National Health and Aging Trends Study data, we estimated hierarchical logistic regression models to predict the likelihood of cane use among older adults who completed performance-based measures (n = 5,503). We tested the interactions between gender and selected variables to further understand gender difference. Results
In unadjusted analysis, 22% of women and 16% of men used canes. In models adjusted in steps for sociodemographics, health, physical impairments, capacity, psychosocial, and social environment factors, women were progressively less likely to use canes, significantly so at the last step. Suppression effect analyses showed the influence of living alone and receiving mobility help variables. Interaction analyses showed that women reporting poor health or balance were less likely to use canes; obese women were more likely. Discussion
Significant gender differences exist in cane use among older community-living adults. Findings suggest that health and function partly account for these differences. Future research is needed to understand social/cultural factors involved.from Health via xlomafota13 on Inoreader http://ift.tt/2w65C3t
via IFTTT
Cognitive Benefits of Online Social Networking for Healthy Older Adults
Abstract
Objectives
Research suggests that older adults who remain socially active and cognitively engaged have better cognitive function than those who are isolated and disengaged. This study examined the efficacy of learning and using an online social networking website, Facebook.com, as an intervention to maintain or enhance cognitive function in older adults. Method
Forty-one older adults were assigned to learn and use Facebook (n = 14) or an online diary website (active control, n = 13) for 8 weeks or placed on a waitlist (n = 14). Outcome measures included neuropsychological tests of executive functions, memory, and processing speed and self-report questionnaires about social engagement. Results
The Facebook group showed a significant increase in a composite measure of updating, an executive function factor associated with complex working memory tasks, compared to no significant change in the control groups. Other measures of cognitive function and social support showed no differential improvement in the Facebook group. Discussion
Learning and using an online social networking site may provide specific benefits for complex working memory in a group of healthy older adults. This may reflect the particular cognitive demands associated with online social networking and/or the benefits of social engagement more generally.from Health via xlomafota13 on Inoreader http://ift.tt/2uGej0O
via IFTTT
Positive Expectations Regarding Aging Linked to More New Friends in Later Life
Abstract
Objectives
Negative perceptions of aging can be self-fulfilling prophecies, predicting worse cognitive and physical outcomes. Although older adults are portrayed as either lonely curmudgeons or perfect grandparents, little research addresses how perceptions of aging relate to social outcomes. We considered whether more positive expectations about aging encourage older adults to maintain or bolster their social network connections and support. Method
This study examined baseline, 12-, and 24-month questionnaire data from the Baltimore Experience Corps Trial, a longitudinal randomized volunteer intervention for adults aged 60 years and older. The associations between expectations regarding aging and different types of social support were tested using negative binomial and multiple regression models controlling for relevant covariates such as baseline levels of perceived support availability. Results
Participants with more positive expectations at baseline made more new friends 2 years later and had greater overall perceived support availability 12 months later. Notably, only participants with at least average perceived support availability at baseline showed an association between expectations and later support availability. Discussion
These results are the first to link overall expectations regarding aging to the social domain and suggest that the influence of perceptions of aging is not limited to physical or cognitive function.from Health via xlomafota13 on Inoreader http://ift.tt/2w6mqY0
via IFTTT
The Association Between Anxiety and Falls: A Meta-Analysis
Abstract
Objectives
Falls occur frequently among older adults and can lead to a range of adverse and debilitating outcomes. Although symptoms of clinical anxiety have been implicated as risk factors for falls, there is no current consensus on the empirical association between anxiety and falls. The current study aimed to address this gap in the literature by conducting a quantitative, meta-analytic review of findings from previous studies. Method
A systematic literature search of bibliographic databases was conducted, yielding 18 studies that fit the criteria for inclusion in the meta-analysis. Results
A random-effects model of all 18 studies showed a significant overall odds ratio of 1.53 (95% CI 1.28–1.83, p < .001), indicating that elevated levels of anxiety were associated with a 53% increased likelihood of falls. A high amount of variance among effect sizes was observed. Only age was identified as a moderator of this relationship in a subgroup of the samples. Conclusions
Clinical anxiety is associated with falls, however, further research is required to elucidate the factors that might moderate or mediate this relationship, the casual pathways through which they are related, and the associations between different types of anxiety and falls.from Health via xlomafota13 on Inoreader http://ift.tt/2uGiHgt
via IFTTT
Self-Perception of Aging and Satisfaction With Children’s Support
Abstract
Objectives
Those with self-beliefs in negative aging may desire a stronger support network to buffer against potential threats and may hence see their current network as less than adequate. This study investigated whether negative self-perception of aging is associated with increased dissatisfaction with children's support. Method
Six hundred and forty Chinese older adults with at least one child and a total of 2,108 adult children rated the degree of support received from each child individually and the degree to which it met their expectation. Additionally, the participants responded to measures of self-perception of aging (both positive and negative), neuroticism, instrumental activities of daily living, chronic illnesses, financial strain, and living status. The multilevel dataset was analyzed using mixed-effects regression. Results
Individuals who had a more negative self-perception of aging, who were younger, who lived alone, and who had fewer children provided lower support satisfaction ratings after support received from children was controlled for. Positive self-perception of aging was unrelated to support satisfaction. Neuroticism did not account for the relationship between negative self-perception of aging and support satisfaction. Discussion
A negative self-perception of aging may create vulnerability to intergenerational tension that puts older people at risk of adverse psychological and physical health outcomes.from Health via xlomafota13 on Inoreader http://ift.tt/2w5YyE7
via IFTTT
Age-related Decline in Case-Marker Processing and its Relation to Working Memory Capacity
Abstract
Objectives
Purposes of the current study were to investigate whether age-related decline emerged in a case-marker assignment task (CMAT) and to explore the relationship between working-memory (WM) capacity and case-marker processing. Method
A total of 121 individuals participated in the study with 62 younger adults and 59 elderly adults. All were administered a CMAT that consisted of active and passive constructions with canonical and noncanonical word-order conditions. A composite measure of WM tasks served as an index of participants' WM capacity. Results
The older group performed worse than the younger group, and the noncanonical word order elicited worse performance than the canonical condition. The older group demonstrated greater difficulty in case-marker processing under the canonical condition and passive construction. Regression results revealed that age, education, and sentence type were the best predictors to account for performance on the CMAT. Discussion
The canonicity of word order and passive construction were critical factors related to decline in abilities in a case-marker assignment. The combination of age, education, and sentence type factors accounted for overall performance on case-marker processing. Results indicated the crucial necessity to find a cognitively and linguistically demanding condition that elicits aging effects most efficiently, considering language-specific syntactic features.from Health via xlomafota13 on Inoreader http://ift.tt/2uGDhxg
via IFTTT
Mandibular complete denture versus single-implant overdenture: a systematic review of patient-reported outcomes
Abstract
The single-implant mandibular overdenture (SIMO) has been proposed as an alternative for edentulous patients who are poorly adapted to their dentures due to low retention and stability of the conventional mandibular complete denture (CD). However, there is a lack of evidence regarding the effectiveness of SIMO, which can be measured by examining patient perception of treatment effects. The aim of this systematic review was to assess the comparative results of CD and SIMO treatments by using patient-reported outcome measures. A literature search was carried out in PubMed, Scopus and Cochrane Central databases. The search included studies published up to July 2017. The focus question was: "Do single-implant mandibular overdentures improve patient-reported outcomes compared to conventional complete dentures in edentulous patients?" Eligible studies were randomized clinical trials (RCT) and prospective studies. After initial screening for eligibility and full-text analysis, 11 studies were included for data extraction and quality assessment (five parallel-group RCTs, two crossover RCTs, and four prospective studies). All studies reported marked improvement in satisfaction with the dentures and quality-of-life measures after SIMO treatment, irrespective of variations in implant-treatment protocols and retention systems. Methodological considerations revealed a lack of evidence from RCTs on the comparative effectiveness of the two treatment strategies. Hence, although available evidence suggests considerable improvement in patient-reported outcomes following the insertion of a single implant to retain a mandibular denture, further well-designed comparative studies between SIMO and CD are required to improve the level of evidence and to support the indication of SIMO treatment in routine practice.
This article is protected by copyright. All rights reserved.
from Rehabilitation via xlomafota13 on Inoreader http://ift.tt/2wWCJDV
via IFTTT
Effect of rest-pause vs. traditional bench press training on muscle strength, electromyography, and lifting volume in randomized trial protocols
Abstract
Purpose
Rest-pause (4-s unloaded rest between repetitions) training effects on one repetition maximum (1 RM), lifting volume, and neural activation via electromyography (EMG) are currently vague in the literature and can benefit strength and conditioning professionals for resistance training programme design. Therefore, this study compared 1 RM, neural activation via (EMG), and volume differences between rest-pause vs. traditional resistance training.
Methods
Trained males (N = 20) were randomly assigned to either a rest-pause or a traditional training group. Pre- and post-1 RM testing was recorded. Training sessions were completed twice a week for 4 weeks and consisted of four sets of bench press to volitional fatigue at 80% of pre-test 1 RM with a 2-min rest between sets. Total volume completed was recorded on each training day. Neural activation of the pectoralis major was measured on the first and last training days.
Results
A two-way repeated-measures ANOVA indicated both groups significantly increased their 1 RMs following the 4-week training protocol (p < .05). However, no significant differences were found in 1 RM and neural activation between the two groups (p > .05). An independent samples t test indicated that total volume lifted was significantly higher for the rest-pause group (56,778 vs. 38,315 lbs; p < .05) throughout the protocol and independently during weeks 2, 3, and 4.
Conclusions
While strength and neural activation changes did not differ between groups, both increased 1 RMs and the rest-pause group achieved greater increases in volume than the traditional group. If volume is the focus of training, the rest-pause method should be utilized.
from Physiology via xlomafota13 on Inoreader http://ift.tt/2uGgLEE
via IFTTT
Changes in appetite, energy intake, body composition, and circulating ghrelin constituents during an incremental trekking ascent to high altitude
Abstract
Purpose
Circulating acylated ghrelin concentrations are associated with altitude-induced anorexia in laboratory environments, but have never been measured at terrestrial altitude. This study examined time course changes in appetite, energy intake, body composition, and ghrelin constituents during a high-altitude trek.
Methods
Twelve participants [age: 28(4) years, BMI 23.0(2.1) kg m−2] completed a 14-day trek in the Himalayas. Energy intake, appetite perceptions, body composition, and circulating acylated, des-acylated, and total ghrelin concentrations were assessed at baseline (113 m, 12 days prior to departure) and at three fixed research camps during the trek (3619 m, day 7; 4600 m, day 10; 5140 m, day 12).
Results
Relative to baseline, energy intake was lower at 3619 m (P = 0.038) and 5140 m (P = 0.016) and tended to be lower at 4600 m (P = 0.056). Appetite perceptions were lower at 5140 m (P = 0.027) compared with baseline. Acylated ghrelin concentrations were lower at 3619 m (P = 0.046) and 4600 m (P = 0.038), and tended to be lower at 5140 m (P = 0.070), compared with baseline. Des-acylated ghrelin concentrations did not significantly change during the trek (P = 0.177). Total ghrelin concentrations decreased from baseline to 4600 m (P = 0.045). Skinfold thickness was lower at all points during the trek compared with baseline (P ≤ 0.001) and calf girth decreased incrementally during the trek (P = 0.010).
Conclusions
Changes in plasma acylated and total ghrelin concentrations may contribute to the suppression of appetite and energy intake at altitude, but differences in the time course of these responses suggest that additional factors are also involved. Interventions are required to maintain appetite and energy balance during trekking at terrestrial altitudes.
from Physiology via xlomafota13 on Inoreader http://ift.tt/2w5rqvY
via IFTTT
Beta 2 -adrenergic stimulation increases energy expenditure at rest, but not during submaximal exercise in active overweight men
Abstract
Purpose
β2-Agonists have been proposed as weight-loss treatment, because they elevate energy expenditure. However, it is unknown what effect β2-agonists have on energy expenditure in overweight individuals. Furthermore, the influence of β2-agonist R- and S-enantiomer ratio for the increased energy expenditure is insufficiently explored.
Methods
Nineteen males were included in the study of which 14 completed. Subjects were 31.6 (±3.5) years [mean (±95% CI)] and had a fat percentage of 22.7 (±2.1)%. On separate days, subjects received either placebo or inhaled racemic (rac-) formoterol (2 × 27 µg). After an overnight fast, energy expenditure and substrate oxidation were estimated by indirect calorimetry at rest and during submaximal exercise. Plasma (R,R)- and (S,S)-formoterol enantiomer levels were measured by ultra-performance liquid chromatograph–mass spectrometry.
Results
At rest, energy expenditure and fat oxidation were 12% (P ≤ 0.001) and 38% (P = 0.006) higher for rac-formoterol than placebo. Systemic (R,R):(S,S) formoterol ratio was correlated with change in energy expenditure at rest in response to rac-formoterol (r = 0.63, P = 0.028), whereas no association was observed between fat percentage and rac-formoterol-induced change in energy expenditure. During exercise, energy expenditure was not different between treatments, although carbohydrate oxidation was 15% higher (P = 0.021) for rac-formoterol than placebo. Rac-formoterol-induced shift in substrate choice from rest to exercise was related to plasma ln-rac-formoterol concentrations (r = 0.75, P = 0.005).
Conclusion
Selective β2-adrenoceptor agonism effectively increases metabolic rate and fat oxidation in overweight individuals. The potential for weight loss induced by β2-agonists may be greater for R-enantiopure formulations.
from Physiology via xlomafota13 on Inoreader http://ift.tt/2uG6QPj
via IFTTT
Longer exercise duration delays post-exercise recovery of cardiac parasympathetic but not sympathetic indices
Abstract
Purpose
This study investigated non-invasive indices of post-exercise parasympathetic reactivation (using heart rate variability, HRV) and sympathetic withdrawal (using systolic time intervals, STI) following different exercise durations.
Methods
13 healthy males (age 26.4 ± 4.7 years) cycled at 70% heart rate (HR) reserve for two durations—8 min (SHORT) and 32 min (LONG)—on separate occasions: HRV (including natural logarithm of root mean square of successive differences, Ln-RMSSD) and STI (including pre-ejection period, PEP) were assessed throughout 10 min seated recovery.
Results
Exercise HR was similar between SHORT and LONG (146 ± 7 and 147 ± 6 b min−1, respectively; p = 0.173), as was HR deceleration during 10 min recovery (p = 0.199). HR remained elevated above baseline (p < 0.001) throughout recovery for both trials (SHORT 82 ± 13 b min−1; LONG 86 ± 10 b min−1, at 10 min post-exercise). Ln-RMSSD was similar at end-exercise between trials (SHORT 1.10 ± 0.30 ms; LONG 1.05 ± 0.73 ms; p = 0.656), though it recovered more rapidly following SHORT (p = 0.010), with differences apparent from 1 min (SHORT 2.29 ± 1.08 ms; LONG 1.85 ± 0.82 ms; p = 0.005) to 10 min post-exercise (SHORT 2.89 ± 0.80 ms; LONG 2.46 ± 0.70 ms; p = 0.007). Ln-RMSSD remained suppressed below baseline throughout recovery following both trials (p < 0.001). PEP was the same at end exercise for both trials (70 ± 6 ms), with exercise duration having no effect on recovery (p = 0.659). By 10 min post-exercise, PEP increased to 130 ± 21 ms (SHORT) and 131 ± 20 ms (LONG), which was similar to baseline (p ≥ 0.143).
Conclusions
Prolonged exercise duration attenuated the recovery of HRV indices of parasympathetic reactivation, but did not influence STI indices of sympathetic withdrawal. Therefore, duration must be considered when investigating post-exercise HRV. Monitoring these measures simultaneously can provide insights not revealed by underlying HR or either measure alone.
from Physiology via xlomafota13 on Inoreader http://ift.tt/2w5CIR6
via IFTTT
Sociodemographic and Lifestyle Factors, and Health Conditions of Dominican Adults Living in Puerto Rico
Abstract
Dominicans are the largest migrant community in Puerto Rico, yet understudied. We compared risk factors and health conditions of Dominicans versus Puerto Ricans (PRs). Cross-sectional survey of Dominicans (n = 55) and PRs (n = 310) aged 30–75 years, assessed with validated questionnaires and standardized anthropometric measurements. Significantly, more Dominicans than PRs had attained <8th grade education (37.7 vs. 8.0%), reported household income ≤$10,000 (76.1 vs. 56.9%), lacked health insurance (19.6 vs. 5.5%), and reported food insecurity (24.5 vs. 12.1%). They spent fewer hours/day watching television (2.9 vs. 3.8), and were less likely to smoke (7.6 vs. 19.6%). Medically-diagnosed depression was lower among Dominicans than PRs (9.6 vs. 23.0%); questionnaire-based high depressive symptomatology was similar (47.9 vs. 52.8%). Dominicans living in Puerto Rico had more socioeconomic risk factors but healthier lifestyle behaviors and lower prevalence of medically-diagnosed depression than PRs. Tailored approaches are needed to ameliorate disparities in each ethnic group.
from Health via xlomafota13 on Inoreader http://ift.tt/2uG2S9j
via IFTTT
Audiogram of the mallard duck ( Anas platyrhynchos ) from 16 Hz to 9 kHz
Abstract
The pure-tone thresholds of three mallard ducks were determined from 16 Hz to 9 kHz. The purpose was to determine whether the mallard duck hears infrasound, which then may potentially be used for navigation, similar to how it is proposed that pigeons use it for homing. At a level of 60 dB sound pressure level (re 20 μN/m2), their hearing range extends 6.85 octaves from 66 Hz to 7.6 kHz, with a best sensitivity of 12.5 dB at 2 kHz. However, at no frequency, including the lowest tested, were the ducks' thresholds lower than those of humans. Therefore, unlike pigeons and chickens, but like budgerigars, mallard ducks do not hear infrasound. Thus, the fact that a bird may fly long distances does not necessarily indicate that it hears infrasound.
from Physiology via xlomafota13 on Inoreader http://ift.tt/2w2LO1y
via IFTTT
Clinical phenotype of South–East Asian Temporomandibular Disorder patients with Upper Airway Resistance Syndrome
Abstract
Objective
To document the clinical phenotype of temporomandibular disorder (TMD) patients with concomitant upper airway resistance syndrome (UARS) in a South East Asian population.
Study Design
A multi-center prospective series of 86 TMD patients (26 men and 60 women / mean age 35.7 years) with UARS. All had excessive daytime sleepiness, high arousal index and apnea-hypopnea index (AHI)<5
Results
The mean body mass index was 20.1, mean arousal index 16.2, mean respiratory disturbance index 19.6, mean AHI 3.9 while the mean Epworth Sleepiness Scale was 14.8. Many had functional somatic complaints; 66.3% headaches, 41.9% neck aches, 53.5% masticatory muscle myalgia, 68.6% temporomandibular joint (TMJ) arthralgia while 90.7% reported sleep bruxism (SB). Unlike patients with obstructive sleep apnea (OSA), hypertension was uncommon (4.7%) whilst depression was prevalent at 68.6% with short REM latency of <90mins and an increased REM composition >25% documented in 79.6% and 57.6% of these depressed patients, respectively. 65.1% displayed a posteriorly displaced condyle at maximum intercuspation with or without TMJ clicking. Most exhibited a forward head posture (FHP) characterized by loss of normal cervical lordosis (80.2%), C0-C1 narrowing (38.4%) or an elevated hyoid position (50%), and 91.9% had nasal congestion.
Conclusion
The TMD-UARS phenotype may have originally developed as an adaptive response to 'awake' disordered breathing during growth. Patients with persistent TMD and/or reporting SB should be screened for UARS and chronic nasal obstruction, especially when they also present with FHP. The lateral cephalogram is a useful tool in the differentiation of UARS from other OSA phenotypes.
This article is protected by copyright. All rights reserved.
from Rehabilitation via xlomafota13 on Inoreader http://ift.tt/2wIAEfs
via IFTTT
Vertebrate sex determination: evolutionary plasticity of a fundamental switch
Nature Reviews Genetics. doi:10.1038/nrg.2017.60
Author: Blanche Capel
from Genetics via xlomafota13 on Inoreader http://ift.tt/2wW79GH
via IFTTT
The interplay of epigenetic marks during stem cell differentiation and development
Nature Reviews Genetics. doi:10.1038/nrg.2017.57
Authors: Yaser Atlasi & Hendrik G. Stunnenberg
from Genetics via xlomafota13 on Inoreader http://ift.tt/2wW7adJ
via IFTTT
Settling the score: variant prioritization and Mendelian disease
Nature Reviews Genetics. doi:10.1038/nrg.2017.52
Authors: Karen Eilbeck, Aaron Quinlan & Mark Yandell
from Genetics via xlomafota13 on Inoreader http://ift.tt/2wW9S2H
via IFTTT
Pathogen genetics: Evolutionary dynamics driving drug resistance
Nature Reviews Genetics. doi:10.1038/nrg.2017.68
Author: Linda Koch
from Genetics via xlomafota13 on Inoreader http://ift.tt/2wWrWtk
via IFTTT
Fibrinogen promotes malignant biological tumor behavior involving epithelial–mesenchymal transition via the p-AKT/p-mTOR pathway in esophageal squamous cell carcinoma
Journal of Cancer Research & Clinical Oncology
from Gastroenterology via xlomafota13 on Inoreader http://ift.tt/2fEdx1J
via IFTTT
Cancer survivors may seek unneeded tests for reassurance
Reuters Health News
from Gastroenterology via xlomafota13 on Inoreader http://ift.tt/2hYK6Z9
via IFTTT
Randomized sham-controlled trials in endoscopy: A systematic review and meta-analysis of adverse events
Gastrointestinal Endoscopy
from Gastroenterology via xlomafota13 on Inoreader http://ift.tt/2fE2DZZ
via IFTTT
Glucosamine supplements don’t help knee or hip arthritis pain
Reuters Health News
from Gastroenterology via xlomafota13 on Inoreader http://ift.tt/2hYPZFN
via IFTTT
A prospective evaluation of radiation-free direct solitary cholangioscopy for the management of choledocholithiasis
Gastrointestinal Endoscopy
from Gastroenterology via xlomafota13 on Inoreader http://ift.tt/2fEXqBe
via IFTTT
Vitamin D deficiency is a risk factor for infections in patients affected by HCV-related liver cirrhosis
International Journal of Infectious Diseases
from Gastroenterology via xlomafota13 on Inoreader http://ift.tt/2hY2Ck4
via IFTTT
Physical therapy for fecal incontinence in children with pelvic floor dyssynergia
The Journal of Pediatrics
from Gastroenterology via xlomafota13 on Inoreader http://ift.tt/2fDA5j4
via IFTTT
Disease severity and treatment requirements in familial inflammatory bowel disease
International Journal of Colorectal Disease
from Gastroenterology via xlomafota13 on Inoreader http://ift.tt/2hXfrv7
via IFTTT
Prognostic value of programmed death ligand 1, p53 and Ki-67 in patients with advanced stage colorectal cancer
Human Pathology
from Gastroenterology via xlomafota13 on Inoreader http://ift.tt/2fEtswV
via IFTTT
A qualitative investigation among men who have sex with men on the acceptability of performing a self- or partner anal exam to screen for anal cancer
Cancer Causes and Control
from Gastroenterology via xlomafota13 on Inoreader http://ift.tt/2hYhbUR
via IFTTT
A randomized controlled trial of postoperative thoracic epidural analgesia versus intravenous patient-controlled analgesia after major hepatopancreatobiliary surgery
Annals of Surgery
from Gastroenterology via xlomafota13 on Inoreader http://ift.tt/2fEtwwF
via IFTTT
Efficacy of glutathione for the treatment of nonalcoholic fatty liver disease: An open-label, single-arm, multicenter, pilot study
BMC Gastroenterology
from Gastroenterology via xlomafota13 on Inoreader http://ift.tt/2hYDdXL
via IFTTT
Should older doctors be examined, tested or forced to retire?
Reuters Health News
from Gastroenterology via xlomafota13 on Inoreader http://ift.tt/2fEtfd7
via IFTTT
Value of oral proton pump inhibitors in acute, nonvariceal upper gastrointestinal bleeding: A network meta-analysis
Journal of Clinical Gastroenterology
from Gastroenterology via xlomafota13 on Inoreader http://ift.tt/2hWQLCW
via IFTTT
Assessment of the duplicate notifiable reporting of hepatitis B infection in Zhejiang province, China, 2005–2015
Vaccine
from Gastroenterology via xlomafota13 on Inoreader http://ift.tt/2fDYBk0
via IFTTT
Risk of pancreatitis following treatment of irritable bowel syndrome with eluxadoline
Clinical Gastroenterology and Hepatology
from Gastroenterology via xlomafota13 on Inoreader http://ift.tt/2hZ7l50
via IFTTT
Impact of caloric intake in critically ill patients with, and without, refeeding syndrome: A retrospective study
Clinical Nutrition
from Gastroenterology via xlomafota13 on Inoreader http://ift.tt/2fEwUaU
via IFTTT
Study protocol on comparative effectiveness of mindfulness meditation and qigong on psychophysiological outcomes for patients with colorectal cancer: A randomized controlled trial
BMC Complementary and Alternative Medicine
from Gastroenterology via xlomafota13 on Inoreader http://ift.tt/2hXtr8b
via IFTTT
Development and validation of trigger algorithms to identify delays in diagnostic evaluation of gastroenterological cancer
Clinical Gastroenterology and Hepatology
from Gastroenterology via xlomafota13 on Inoreader http://ift.tt/2fEwSQk
via IFTTT
Predictors of long-term outcomes in patients with acute severe colitis: A Northern Indian cohort study
Journal of Gastroenterology and Hepatology
from Gastroenterology via xlomafota13 on Inoreader http://ift.tt/2hY2zVq
via IFTTT
Arrhythmogenic gene remodelling in elderly patients with type 2 diabetes with aortic stenosis and normal left ventricular ejection fraction
Abstract
Type 2 diabetes is associated with higher rate of ventricular arrhythmias and this is hypothesised to be independent of coronary artery disease or hypertension. To investigate further we compared changes in left ventricular myocardial gene expression in Type 2 diabetes to patients in a control group with left ventricular hypertrophy. 9 control patients and 7 patients with type 2 diabetes with aortic stenosis undergoing aortic valve replacement had standard ECGs, signal averaged ECGs and echocardiograms prior to surgery. During surgery, a left ventricular biopsy was taken and mRNA expression for genes relevant to the cardiac action potential were estimated by RT-PCR. Mathematical modelling of the action potential and calcium transient was undertaken using the O'Hara-Rudy model using scaled changes in gene expression. Echocardiography revealed similar values for left ventricular size, filling pressures and ejection fraction between groups. No difference was seen in positive signal averaged electrocardiograms between groups but the standard ECG demonstrated a prolonged QT interval in the diabetes group. Gene expression of ERG and Kir 3.1 were lower in the diabetes group, whereas Kir 2.1, Kir3.4 and NCX1 expression were higher. Modelling suggested these changes would lead to prolongation of the action potential duration with generation of early after-depolarisations secondary to a reduction in density of the IK, r current (rapid delayed rectifier K+ current) and increased INa/Ca current (Na+-Ca2+ calcium exchange current). This data suggest that diabetes leads to pro-arrythmogenic changes in myocardial gene expression independently of left ventricular hypertrophy or fibrosis in an elderly population.
This article is protected by copyright. All rights reserved
from Physiology via xlomafota13 on Inoreader http://ift.tt/2vAJrjF
via IFTTT
Εγγραφή σε:
Αναρτήσεις (Atom)