A multi-component parallel-plate flow chamber system for studying the effect of exercise-induced wall shear stress on endothelial cells.

PubMed

Wang, Yan-Xia; Xiang, Cheng; Liu, Bo; Zhu, Yong; Luan, Yong; Liu, Shu-Tian; Qin, Kai-Rong

2016-12-28

In vivo studies have demonstrated that reasonable exercise training can improve endothelial function. To confirm the key role of wall shear stress induced by exercise on endothelial cells, and to understand how wall shear stress affects the structure and the function of endothelial cells, it is crucial to design and fabricate an in vitro multi-component parallel-plate flow chamber system which can closely replicate exercise-induced wall shear stress waveforms in artery. The in vivo wall shear stress waveforms from the common carotid artery of a healthy volunteer in resting and immediately after 30 min acute aerobic cycling exercise were first calculated by measuring the inner diameter and the center-line blood flow velocity with a color Doppler ultrasound. According to the above in vivo wall shear stress waveforms, we designed and fabricated a parallel-plate flow chamber system with appropriate components based on a lumped parameter hemodynamics model. To validate the feasibility of this system, human umbilical vein endothelial cells (HUVECs) line were cultured within the parallel-plate flow chamber under abovementioned two types of wall shear stress waveforms and the intracellular actin microfilaments and nitric oxide (NO) production level were evaluated using fluorescence microscope. Our results show that the trends of resting and exercise-induced wall shear stress waveforms, especially the maximal, minimal and mean wall shear stress as well as oscillatory shear index, generated by the parallel-plate flow chamber system are similar to those acquired from the common carotid artery. In addition, the cellular experiments demonstrate that the actin microfilaments and the production of NO within cells exposed to the two different wall shear stress waveforms exhibit different dynamic behaviors; there are larger numbers of actin microfilaments and higher level NO in cells exposed in exercise-induced wall shear stress condition than resting wall shear stress condition. The parallel-plate flow chamber system can well reproduce wall shear stress waveforms acquired from the common carotid artery in resting and immediately after exercise states. Furthermore, it can be used for studying the endothelial cells responses under resting and exercise-induced wall shear stress environments in vitro.

REST Controls Self-Renewal and Tumorigenic Competence of Human Glioblastoma Cells

PubMed Central

Conti, Luciano; Crisafulli, Laura; Brilli, Elisa; Conforti, Paola; Zunino, Franco; Magrassi, Lorenzo; Schiffer, Davide; Cattaneo, Elena

2012-01-01

The Repressor Element 1 Silencing Transcription factor (REST/NRSF) is a master repressor of neuronal programs in non-neuronal lineages shown to function as a central regulator of developmental programs and stem cell physiology. Aberrant REST function has been associated with a number of pathological conditions. In cancer biology, REST has been shown to play a tumor suppressor activity in epithelial cancers but an oncogenic role in brain childhood malignancies such as neuroblastoma and medulloblastoma. Here we examined REST expression in human glioblastoma multiforme (GBM) specimens and its role in GBM cells carrying self-renewal and tumorigenic competence. We found REST to be expressed in GBM specimens, its presence being particularly enriched in tumor cells in the perivascular compartment. Significantly, REST is highly expressed in self-renewing tumorigenic-competent GBM cells and its knock down strongly reduces their self-renewal in vitro and tumor-initiating capacity in vivo and affects levels of miR-124 and its downstream targets. These results indicate that REST contributes to GBM maintenance by affecting its self-renewing and tumorigenic cellular component and that, hence, a better understanding of these circuitries in these cells might lead to new exploitable therapeutic targets. PMID:22701651

Programmatic access to logical models in the Cell Collective modeling environment via a REST API.

PubMed

Kowal, Bryan M; Schreier, Travis R; Dauer, Joseph T; Helikar, Tomáš

2016-01-01

Cell Collective (www.cellcollective.org) is a web-based interactive environment for constructing, simulating and analyzing logical models of biological systems. Herein, we present a Web service to access models, annotations, and simulation data in the Cell Collective platform through the Representational State Transfer (REST) Application Programming Interface (API). The REST API provides a convenient method for obtaining Cell Collective data through almost any programming language. To ensure easy processing of the retrieved data, the request output from the API is available in a standard JSON format. The Cell Collective REST API is freely available at http://thecellcollective.org/tccapi. All public models in Cell Collective are available through the REST API. For users interested in creating and accessing their own models through the REST API first need to create an account in Cell Collective (http://thecellcollective.org). thelikar2@unl.edu. Technical user documentation: https://goo.gl/U52GWo. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Resveratrol via sirtuin-1 downregulates RE1-silencing transcription factor (REST) expression preventing PCB-95-induced neuronal cell death.

PubMed

Guida, Natascia; Laudati, Giusy; Anzilotti, Serenella; Secondo, Agnese; Montuori, Paolo; Di Renzo, Gianfranco; Canzoniero, Lorella M T; Formisano, Luigi

2015-11-01

Resveratrol (3,5,4'-trihydroxystilbene) (RSV), a polyphenol widely present in plants, exerts a neuroprotective function in several neurological conditions; it is an activator of class III histone deacetylase sirtuin1 (SIRT1), a crucial regulator in the pathophysiology of neurodegenerative diseases. By contrast, the RE1-silencing transcription factor (REST) is involved in the neurotoxic effects following exposure to polychlorinated biphenyl (PCB) mixture A1254. The present study investigated the effects of RSV-induced activation of SIRT1 on REST expression in SH-SY5Y cells. Further, we investigated the possible relationship between the non-dioxin-like (NDL) PCB-95 and REST through SIRT1 to regulate neuronal death in rat cortical neurons. Our results revealed that RSV significantly decreased REST gene and protein levels in a dose- and time-dependent manner. Interestingly, overexpression of SIRT1 reduced REST expression, whereas EX-527, an inhibitor of SIRT1, increased REST expression and blocked RSV-induced REST downregulation. These results suggest that RSV downregulates REST through SIRT1. In addition, RSV enhanced activator protein 1 (AP-1) transcription factor c-Jun expression and its binding to the REST promoter gene. Indeed, c-Jun knockdown reverted RSV-induced REST downregulation. Intriguingly, in SH-SY5Y cells and rat cortical neurons the NDL PCB-95 induced necrotic cell death in a concentration-dependent manner by increasing REST mRNA and protein expression. In addition, SIRT1 knockdown blocked RSV-induced neuroprotection in rat cortical neurons treated with PCB-95. Collectively, these results indicate that RSV via SIRT1 activates c-Jun, thereby reducing REST expression in SH-SY5Y cells under physiological conditions and blocks PCB-95-induced neuronal cell death by activating the same SIRT1/c-Jun/REST pathway. Copyright © 2015 Elsevier Inc. All rights reserved.

Transcriptional activation of human mu-opioid receptor gene by insulin-like growth factor-I in neuronal cells is modulated by the transcription factor REST.

PubMed

Bedini, Andrea; Baiula, Monica; Spampinato, Santi

2008-06-01

The human mu-opioid receptor gene (OPRM1) promoter contains a DNA sequence binding the repressor element 1 silencing transcription factor (REST) that is implicated in transcriptional repression. We investigated whether insulin-like growth factor I (IGF-I), which affects various aspects of neuronal induction and maturation, regulates OPRM1 transcription in neuronal cells in the context of the potential influence of REST. A series of OPRM1-luciferase promoter/reporter constructs were transfected into two neuronal cell models, neuroblastoma-derived SH-SY5Y cells and PC12 cells. In the former, endogenous levels of human mu-opioid receptor (hMOPr) mRNA were evaluated by real-time PCR. IGF-I up-regulated OPRM1 transcription in: PC12 cells lacking REST, in SH-SY5Y cells transfected with constructs deficient in the REST DNA binding element, or when REST was down-regulated in retinoic acid-differentiated cells. IGF-I activates the signal transducer and activator of transcription-3 signaling pathway and this transcription factor, binding to the signal transducer and activator of transcription-1/3 DNA element located in the promoter, increases OPRM1 transcription. We propose that a reduction in REST is a critical switch enabling IGF-I to up-regulate hMOPr. These findings help clarify how hMOPr expression is regulated in neuronal cells.

Sweet taste transduction in hamster: sweeteners and cyclic nucleotides depolarize taste cells by reducing a K+ current.

PubMed

Cummings, T A; Daniels, C; Kinnamon, S C

1996-03-01

1. The gigaseal voltage-clamp technique was used to record responses of hamster taste receptor cells to synthetic sweeteners and cyclic nucleotides. Voltage-dependent currents and steady-state currents were monitored during bath exchanges of saccharin, two high-potency sweeteners, 8-chlorophenylthio-adenosine 3',5'-cyclic monophosphate (8cpt-cAMP), and dibutyryl-guanosine 3',5'-cyclic monophosphate (db-cGMP). 2. Of the 237 fungiform taste cells studied, only one in eight was sweet responsive. Outward currents, both voltage-dependent and resting, were reduced by all of the sweeteners tested in sweet-responsive taste cells, whereas these currents were unaffected by sweeteners in sweet-unresponsive taste cells. 3. In every sweet-responsive cell tested, 8cpt-cAMP and db-cGMP mimicked the response to the sweeteners, but neither nucleotide elicited responses in sweet-unresponsive cells. Thus there was a one-to-one correlation between sweet responsivity and cyclic nucleotide responsivity. 4. Sweet responses showed cross adaptation with cyclic nucleotide responses. This indicates that the same ion channel is modulated by sweeteners and cyclic nucleotides. 5. The sweetener- and cyclic nucleotide-blocked current had an apparent reversal potential of -50 mV, which was close to the potassium reversal potential in these experiments. In addition, there was no effect of sweeteners and cyclic nucleotides in the presence of the K+ channel blocker tetraethylammonium bromide (TEA). These data suggest that block of a resting, TEA-sensitive K+ current is the final common step leading to taste cell depolarization during sweet transduction. 6. These data, together with data from a previous study (Cummings et al. 1993), suggest that both synthetic sweeteners and sucrose utilize second-messenger pathways that block a resting K+ conductance to depolarize the taste cell membrane.

What goes on in the resting-state? A qualitative glimpse into resting-state experience in the scanner

PubMed Central

Hurlburt, Russell T.; Alderson-Day, Ben; Fernyhough, Charles; Kühn, Simone

2015-01-01

The brain’s resting-state has attracted considerable interest in recent years, but currently little is known either about typical experience during the resting-state or about whether there are inter-individual differences in resting-state phenomenology. We used descriptive experience sampling (DES) in an attempt to apprehend high fidelity glimpses of the inner experience of five participants in an extended fMRI study. Results showed that the inner experiences and the neural activation patterns (as quantified by amplitude of low frequency fluctuations analysis) of the five participants were largely consistent across time, suggesting that our extended-duration scanner sessions were broadly similar to typical resting-state sessions. However, there were very large individual differences in inner phenomena, suggesting that the resting-state itself may differ substantially from one participant to the next. We describe these individual differences in experiential characteristics and display some typical moments of resting-state experience. We also show that retrospective characterizations of phenomena can often be very different from moment-by-moment reports. We discuss implications for the assessment of inner experience in neuroimaging studies more generally, concluding that it may be possible to use fMRI to investigate neural correlates of phenomena apprehended in high fidelity. PMID:26500590

Leucocytosis, Thrombocytosis, and Plasma Osmolality During Rest and Exercise: A Hypothesis

NASA Technical Reports Server (NTRS)

McKenzie, M. A.; Greenleaf, John E.; Looft-Wilson, R.; Barnes, P. R.

1999-01-01

The mechanism for inducing leucocytosis (increase in white blood cells) and thrombocytosis (increase in platelets) during exercise is unclear. Because plasma osmolality (Osm) may influence T-cell proliferation, Osm and the number of leucocytes (WBC) and platelets in blood were measured periodically during a 90 min rest period, and were compared with those during upright sitting ergometer exercise in six unt.rained, healthy men who cycled for 70 min at 71% of their maximal oxygen uptake (V prime O(sub 2(sub max)). There were 6 experiments in which the subjects drank different fluid formula-t4ilons (10 ml/kg) of various ionic and osmotic concentrations intermittently during 60 min of the rest period and during the exercise period. Osmolality, and WBC and platelet counts increased significantly (p<0.05) within the first 10 min of exercise, but the additional 60 min of exercise did not significantly change the leucocytosis or thrombocytosis. There were low but significant correlations between individual values of total WBC and total Osm during exercise (r(sub 0.001(2),284) = 0.39) and during rest plus exercise (r(sub 0.001(2),499) = 0.43). With combined data from the six experiments, mean Osm correlated highly and significantly with both mean WBC (r(sub 0.001(2),6) = 0.95, p < 0.001) and mean platelets (r(sub 0.001(2),6) = 0.94, p < 0.01) during the exercise phase. These data indicate that increases in leucocytes, thrombocytes, and osmolality occur primarily within the first 10 min of high-intensity exercise, but neither hypovolemia nor hyperthermia during exercise contributed to the leucocytosis, thrombocytosis, or hyperosmolality. The high correlations between plasma Osm and WBC or platelet counts suggest changes in osmolality may contribute to the mechanism of leucocytosis and thrombocytosis induced by exercise.

Transcription factor REST negatively influences the protein kinase C-dependent up-regulation of human mu-opioid receptor gene transcription.

PubMed

Bedini, Andrea; Baiula, Monica; Carbonari, Gioia; Spampinato, Santi

2010-01-01

Mu-opioid receptor expression increases during neurogenesis, regulates the survival of maturing neurons and is implicated in ischemia-induced neuronal death. The repressor element 1 silencing transcription factor (REST), a regulator of a subset of genes in differentiating and post-mitotic neurons, is involved in its transcriptional repression. Extracellular signaling molecules and mechanisms that control the human mu-opioid receptor (hMOR) gene transcription are not clearly understood. We examined the role of protein kinase C (PKC) on hMOR transcription in a model of neuronal cells and in the context of the potential influence of REST. In native SH-SY5Y neuroblastoma cells, PKC activation with phorbol 12-myristate 13-acetate (PMA, 16 nM, 24h) down-regulated hMOR transcription and concomitantly elevated the REST binding activity to repressor element 1 of the hMOR promoter. In contrast, PMA activated hMOR gene transcription when REST expression was knocked down by an antisense strategy or by retinoic acid-induced cell differentiation. PMA acts through a PKC-dependent pathway requiring downstream MAP kinases and the transcription factor AP-1. In a series of hMOR-luciferase promoter/reporter constructs transfected into SH-SY5Y cells and PC12 cells, PMA up-regulated hMOR transcription in PC12 cells lacking REST, and in SH-SY5Y cells either transfected with constructs deficient in the REST DNA binding element or when REST was down-regulated in retinoic acid-differentiated cells. These findings help explain how hMOR transcription is regulated and may clarify its contribution to epigenetic modifications and reprogramming of differentiated neuronal cells exposed to PKC-activating agents. Copyright 2009 Elsevier Ltd. All rights reserved.

Exploring Instructive Physiological Signaling with the Bioelectric Tissue Simulation Engine

PubMed Central

Pietak, Alexis; Levin, Michael

2016-01-01

Bioelectric cell properties have been revealed as powerful targets for modulating stem cell function, regenerative response, developmental patterning, and tumor reprograming. Spatio-temporal distributions of endogenous resting potential, ion flows, and electric fields are influenced not only by the genome and external signals but also by their own intrinsic dynamics. Ion channels and electrical synapses (gap junctions) both determine, and are themselves gated by, cellular resting potential. Thus, the origin and progression of bioelectric patterns in multicellular tissues is complex, which hampers the rational control of voltage distributions for biomedical interventions. To improve understanding of these dynamics and facilitate the development of bioelectric pattern control strategies, we developed the BioElectric Tissue Simulation Engine (BETSE), a finite volume method multiphysics simulator, which predicts bioelectric patterns and their spatio-temporal dynamics by modeling ion channel and gap junction activity and tracking changes to the fundamental property of ion concentration. We validate performance of the simulator by matching experimentally obtained data on membrane permeability, ion concentration and resting potential to simulated values, and by demonstrating the expected outcomes for a range of well-known cases, such as predicting the correct transmembrane voltage changes for perturbation of single cell membrane states and environmental ion concentrations, in addition to the development of realistic transepithelial potentials and bioelectric wounding signals. In silico experiments reveal factors influencing transmembrane potential are significantly different in gap junction-networked cell clusters with tight junctions, and identify non-linear feedback mechanisms capable of generating strong, emergent, cluster-wide resting potential gradients. The BETSE platform will enable a deep understanding of local and long-range bioelectrical dynamics in tissues, and assist the development of specific interventions to achieve greater control of pattern during morphogenesis and remodeling. PMID:27458581

Methodological Caveats in the Detection of Coordinated Replay between Place Cells and Grid Cells

PubMed Central

Trimper, John B.; Trettel, Sean G.; Hwaun, Ernie; Colgin, Laura Lee

2017-01-01

At rest, hippocampal “place cells,” neurons with receptive fields corresponding to specific spatial locations, reactivate in a manner that reflects recently traveled trajectories. These “replay” events have been proposed as a mechanism underlying memory consolidation, or the transfer of a memory representation from the hippocampus to neocortical regions associated with the original sensory experience. Accordingly, it has been hypothesized that hippocampal replay of a particular experience should be accompanied by simultaneous reactivation of corresponding representations in the neocortex and in the entorhinal cortex, the primary interface between the hippocampus and the neocortex. Recent studies have reported that coordinated replay may occur between hippocampal place cells and medial entorhinal cortex grid cells, cells with multiple spatial receptive fields. Assessing replay in grid cells is problematic, however, as the cells exhibit regularly spaced spatial receptive fields in all environments and, therefore, coordinated replay between place cells and grid cells may be detected by chance. In the present report, we adapted analytical approaches utilized in recent studies of grid cell and place cell replay to determine the extent to which coordinated replay is spuriously detected between grid cells and place cells recorded from separate rats. For a subset of the employed analytical methods, coordinated replay was detected spuriously in a significant proportion of cases in which place cell replay events were randomly matched with grid cell firing epochs of equal duration. More rigorous replay evaluation procedures and minimum spike count requirements greatly reduced the amount of spurious findings. These results provide insights into aspects of place cell and grid cell activity during rest that contribute to false detection of coordinated replay. The results further emphasize the need for careful controls and rigorous methods when testing the hypothesis that place cells and grid cells exhibit coordinated replay. PMID:28824388

Proton dynamics of phosphoric acid in HT-PEFCs: Towards "operando" experiments

NASA Astrophysics Data System (ADS)

Khaneft, Marina; Shuai, Liu; Lin, Yu; Janßen, Holger; Lüke, Wiebke; Zorn, Reiner; Ivanova, Oxana; Radulescu, Aurel; Holderer, Olaf; Lehnert, Werner

2018-05-01

High Temperature Polymer Electrolyte Fuel Cells (HT-PEFCs) have been studied with quasielastic neutron scattering, which gives access to the proton diffusion in the fuel cell on local length- and timescales. So far, the different components such as the proton conducting membrane and the electrode layers have been studied separately. Here we show that also operating fuel cells can be investigated and the proton diffusion can be measured under real working conditions. The proton diffusion during power production is compared to that "at rest" but at elevated temperatures.

Role of the epithelial cell rests of Malassez in the development, maintenance and regeneration of periodontal ligament tissues.

PubMed

Xiong, Jimin; Gronthos, Stan; Bartold, P Mark

2013-10-01

Periodontitis is a highly prevalent inflammatory disease that results in damage to the tooth-supporting tissues, potentially leading to tooth loss. Periodontal tissue regeneration is a complex process that involves the collaboration of two hard tissues (cementum and alveolar bone) and two soft tissues (gingiva and periodontal ligament). To date, no periodontal-regenerative procedures provide predictable clinical outcomes. To understand the rational basis of regenerative procedures, a better understanding of the events associated with the formation of periodontal components will help to establish reliable strategies for clinical practice. An important aspect of this is the role of the Hertwig's epithelial root sheath in periodontal development and that of its descendants, the epithelial cell rests of Malassez, in the maintenance of the periodontium. An important structure during tooth root development, the Hertwig's epithelial root sheath is not only a barrier between the dental follicle and dental papilla cells but is also involved in determining the shape, size and number of roots and in the development of dentin and cementum, and may act as a source of mesenchymal progenitor cells for cementoblasts. In adulthood, the epithelial cell rests of Malassez are the only odontogenic epithelial population in the periodontal ligament. Although there is no general agreement on the functions of the epithelial cell rests of Malassez, accumulating evidence suggests that the putative roles of the epithelial cell rests of Malassez in adult periodontal ligament include maintaining periodontal ligament homeostasis to prevent ankylosis and maintain periodontal ligament space, to prevent root resorption, to serve as a target during periodontal ligament innervation and to contribute to cementum repair. Recently, ovine epithelial cell rests of Malassez cells have been shown to harbor clonogenic epithelial stem-cell populations that demonstrate similar properties to mesenchymal stromal/stem cells, both functionally and phenotypically. Therefore, the epithelial cell rests of Malassez, rather than being 'cell rests', as indicated by their name, are an important source of stem cells that might play a pivotal role in periodontal regeneration. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Effect of fluticasone propionate on neutrophil chemotaxis, superoxide generation, and extracellular proteolytic activity in vitro.

PubMed Central

Llewellyn-Jones, C. G.; Hill, S. L.; Stockley, R. A.

1994-01-01

BACKGROUND--Corticosteroids are widely used in the treatment of many inflammatory conditions but the exact mode of action on neutrophil function is uncertain. Fluticasone propionate is a new topically active synthetic steroid which can be measured in body fluids and which undergoes first pass metabolism. METHODS--The effects of fluticasone propionate on the function of neutrophils isolated from normal, healthy control subjects and on the chemotactic activity of sputum sol phase were assessed. RESULTS--Preincubation of neutrophils with fluticasone propionate reduced the chemotactic response to 10(-8) mol/l F-Met-Leu-Phe (FMLP) and to a 1:5 dilution of sputum sol phase in a dose dependent manner. Furthermore, when fluticasone propionate was added to sputum from eight patients with stable chronic obstructive bronchitis the chemotactic activity of a 1:5 dilution of the sol phase fell from a mean (SE) value of 22.2 (1.21) cells/field to 19.6 (0.89), 17.1 (0.74), and 11.9 (0.6) cells field at 1 mumol/l, 10 mumol/l, and 100 mumol/l, respectively. In further experiments fluticasone propionate preincubated with neutrophils inhibited fibronectin degradation by resting cells and by cells stimulated by FMLP (15.2% inhibition of resting cells, 5.1% inhibition of stimulated cells with 1 mumol/l fluticasone propionate, 24% and 18.7% inhibition respectively at 100 mumol/l fluticasone propionate. Fluticasone propionate had no effect on generation of superoxide anion by resting or stimulated cells. CONCLUSIONS--These results indicate that fluticasone propionate has a direct suppressive effect on several aspects of neutrophil function and may suggest a role for this agent in the modulation of neutrophil mediated damage to connective tissue. PMID:8202875

Effect of fluticasone propionate on neutrophil chemotaxis, superoxide generation, and extracellular proteolytic activity in vitro.

PubMed

Llewellyn-Jones, C G; Hill, S L; Stockley, R A

1994-03-01

Corticosteroids are widely used in the treatment of many inflammatory conditions but the exact mode of action on neutrophil function is uncertain. Fluticasone propionate is a new topically active synthetic steroid which can be measured in body fluids and which undergoes first pass metabolism. The effects of fluticasone propionate on the function of neutrophils isolated from normal, healthy control subjects and on the chemotactic activity of sputum sol phase were assessed. Preincubation of neutrophils with fluticasone propionate reduced the chemotactic response to 10(-8) mol/l F-Met-Leu-Phe (FMLP) and to a 1:5 dilution of sputum sol phase in a dose dependent manner. Furthermore, when fluticasone propionate was added to sputum from eight patients with stable chronic obstructive bronchitis the chemotactic activity of a 1:5 dilution of the sol phase fell from a mean (SE) value of 22.2 (1.21) cells/field to 19.6 (0.89), 17.1 (0.74), and 11.9 (0.6) cells field at 1 mumol/l, 10 mumol/l, and 100 mumol/l, respectively. In further experiments fluticasone propionate preincubated with neutrophils inhibited fibronectin degradation by resting cells and by cells stimulated by FMLP (15.2% inhibition of resting cells, 5.1% inhibition of stimulated cells with 1 mumol/l fluticasone propionate, 24% and 18.7% inhibition respectively at 100 mumol/l fluticasone propionate. Fluticasone propionate had no effect on generation of superoxide anion by resting or stimulated cells. These results indicate that fluticasone propionate has a direct suppressive effect on several aspects of neutrophil function and may suggest a role for this agent in the modulation of neutrophil mediated damage to connective tissue.

Single-Molecule Light-Sheet Imaging of Suspended T Cells.

PubMed

Ponjavic, Aleks; McColl, James; Carr, Alexander R; Santos, Ana Mafalda; Kulenkampff, Klara; Lippert, Anna; Davis, Simon J; Klenerman, David; Lee, Steven F

2018-05-08

Adaptive immune responses are initiated by triggering of the T cell receptor. Single-molecule imaging based on total internal reflection fluorescence microscopy at coverslip/basal cell interfaces is commonly used to study this process. These experiments have suggested, unexpectedly, that the diffusional behavior and organization of signaling proteins and receptors may be constrained before activation. However, it is unclear to what extent the molecular behavior and cell state is affected by the imaging conditions, i.e., by the presence of a supporting surface. In this study, we implemented single-molecule light-sheet microscopy, which enables single receptors to be directly visualized at any plane in a cell to study protein dynamics and organization in live, resting T cells. The light sheet enabled the acquisition of high-quality single-molecule fluorescence images that were comparable to those of total internal reflection fluorescence microscopy. By comparing the apical and basal surfaces of surface-contacting T cells using single-molecule light-sheet microscopy, we found that most coated-glass surfaces and supported lipid bilayers profoundly affected the diffusion of membrane proteins (T cell receptor and CD45) and that all the surfaces induced calcium influx to various degrees. Our results suggest that, when studying resting T cells, surfaces are best avoided, which we achieve here by suspending cells in agarose. Copyright © 2018. Published by Elsevier Inc.

REST–Mediated Recruitment of Polycomb Repressor Complexes in Mammalian Cells

PubMed Central

Landt, Eskild; Agrawal-Singh, Shuchi; Bak, Mads; Tommerup, Niels; Rappsilber, Juri; Södersten, Erik; Hansen, Klaus

2012-01-01

Polycomb Repressive Complex (PRC) 1 and PRC2 regulate genes involved in differentiation and development. However, the mechanism for how PRC1 and PRC2 are recruited to genes in mammalian cells is unclear. Here we present evidence for an interaction between the transcription factor REST, PRC1, and PRC2 and show that RNF2 and REST co-regulate a number of neuronal genes in human teratocarcinoma cells (NT2-D1). Using NT2-D1 cells as a model of neuronal differentiation, we furthermore showed that retinoic-acid stimulation led to displacement of PRC1 at REST binding sites, reduced H3K27Me3, and increased gene expression. Genome-wide analysis of Polycomb binding in Rest−/− and Eed−/− mouse embryonic stem (mES) cells showed that Rest was required for PRC1 recruitment to a subset of Polycomb regulated neuronal genes. Furthermore, we found that PRC1 can be recruited to Rest binding sites independently of CpG islands and the H3K27Me3 mark. Surprisingly, PRC2 was frequently increased around Rest binding sites located in CpG-rich regions in the Rest−/− mES cells, indicating a more complex interplay where Rest also can limit PRC2 recruitment. Therefore, we propose that Rest has context-dependent functions for PRC1- and PRC2- recruitment, which allows this transcription factor to act both as a recruiter of Polycomb as well as a limiting factor for PRC2 recruitment at CpG islands. PMID:22396653

Centrosomal Latency of Incoming Foamy Viruses in Resting Cells

PubMed Central

Giron, Marie Lou; Roingeard, Philippe; Clave, Emmanuel; Tobaly-Tapiero, Joelle; Bittoun, Patricia; Toubert, Antoine; de Thé, Hugues; Saïb, Ali

2007-01-01

Completion of early stages of retrovirus infection depends on the cell cycle. While gammaretroviruses require mitosis for proviral integration, lentiviruses are able to replicate in post-mitotic non-dividing cells. Resting cells such as naive resting T lymphocytes from peripheral blood cannot be productively infected by retroviruses, including lentiviruses, but the molecular basis of this restriction remains poorly understood. We demonstrate that in G0 resting cells (primary fibroblasts or peripheral T cells), incoming foamy retroviruses accumulate in close proximity to the centrosome, where they lie as structured and assembled capsids for several weeks. Under these settings, virus uncoating is impaired, but upon cell stimulation, Gag proteolysis and capsid disassembly occur, which allows viral infection to proceed. The data imply that foamy virus uncoating is the rate-limiting step for productive infection of primary G0 cells. Incoming foamy retroviruses can stably persist at the centrosome, awaiting cell stimulation to initiate capsid cleavage, nuclear import, and viral gene expression. PMID:17530924

Regulation of RE1 Protein Silencing Transcription Factor (REST) Expression by HIP1 Protein Interactor (HIPPI)*

PubMed Central

Datta, Moumita; Bhattacharyya, Nitai P.

2011-01-01

Earlier we have shown that the proapoptotic protein HIPPI (huntingtin interacting protein 1 (HIP1) protein interactor) along with its molecular partner HIP1 could regulate transcription of the caspase-1 gene. Here we report that RE1-silencing transcription factor/neuron-restrictive silencer factor (REST/NRSF) is a new transcriptional target of HIPPI. HIPPI could bind to the promoter of REST and increased its expression in neuronal as well as non-neuronal cells. Such activation of REST down-regulated expression of REST target genes, such as brain-derived neurotrophic factor (BDNF) or proenkephalin (PENK). The ability of HIPPI to activate REST gene transcription was dependent on HIP1, the nuclear transporter of HIPPI. Using a Huntington disease cell model, we have demonstrated that feeble interaction of HIP1 with mutant huntingtin protein resulted in increased nuclear accumulation of HIPPI and HIP1, leading to higher occupancy of HIPPI at the REST promoter, triggering its transcriptional activation and consequent repression of REST target genes. This novel transcription regulatory mechanism of REST by HIPPI may contribute to the deregulation of transcription observed in the cell model of Huntington disease. PMID:21832040

Regulation of RE1 protein silencing transcription factor (REST) expression by HIP1 protein interactor (HIPPI).

PubMed

Datta, Moumita; Bhattacharyya, Nitai P

2011-09-30

Earlier we have shown that the proapoptotic protein HIPPI (huntingtin interacting protein 1 (HIP1) protein interactor) along with its molecular partner HIP1 could regulate transcription of the caspase-1 gene. Here we report that RE1-silencing transcription factor/neuron-restrictive silencer factor (REST/NRSF) is a new transcriptional target of HIPPI. HIPPI could bind to the promoter of REST and increased its expression in neuronal as well as non-neuronal cells. Such activation of REST down-regulated expression of REST target genes, such as brain-derived neurotrophic factor (BDNF) or proenkephalin (PENK). The ability of HIPPI to activate REST gene transcription was dependent on HIP1, the nuclear transporter of HIPPI. Using a Huntington disease cell model, we have demonstrated that feeble interaction of HIP1 with mutant huntingtin protein resulted in increased nuclear accumulation of HIPPI and HIP1, leading to higher occupancy of HIPPI at the REST promoter, triggering its transcriptional activation and consequent repression of REST target genes. This novel transcription regulatory mechanism of REST by HIPPI may contribute to the deregulation of transcription observed in the cell model of Huntington disease.

White spotting phenotype induced by targeted REST disruption during neural crest specification to a melanocyte cell lineage.

PubMed

Aoki, Hitomi; Hara, Akira; Kunisada, Takahiro

2015-05-01

Neural crest cells (NCCs) emerge from the dorsal region of the neural tube of vertebrate embryos and have the pluripotency to differentiate into both neuronal and non-neuronal lineages including melanocytes. Rest, also known as NRSF (neuro-restrictive silencer factor), is a regulator of neuronal development and function and suggested to be involved in the lineage specification of NCCs. However, further investigations of Rest gene functions in vivo have been hampered by the fact that Rest null mice show early embryonic lethality. To investigate the function of Rest in NCC development, we recently established NCC-specific Rest conditional knockout (CKO) mice and observed their neonatal death. Here, we have established viable heterozygous NCC-specific Rest CKO mice to analyze the function of Rest in an NCC-derived melanocyte cell lineage and found that the white spotting phenotype was associated with the reduction in the number of melanoblasts in the embryonic skin. The Rest deletion induced after the specification to melanocytes did not reduce the number of melanoblasts; therefore, the expression of REST during the early neural crest specification stage was necessary for the normal development of melanoblasts to cover all of the skin. © 2015 The Molecular Biology Society of Japan and Wiley Publishing Asia Pty Ltd.

Gag-Positive Reservoir Cells Are Susceptible to HIV-Specific Cytotoxic T Lymphocyte Mediated Clearance In Vitro and Can Be Detected In Vivo

PubMed Central

Graf, Erin H.; Pace, Matthew J.; Peterson, Bennett A.; Lynch, Lindsay J.; Chukwulebe, Steve B.; Mexas, Angela M.; Shaheen, Farida; Martin, Jeffrey N.; Deeks, Steven G.; Connors, Mark; Migueles, Stephen A.; O’Doherty, Una

2013-01-01

Resting CD4+ T cells infected with HIV persist in the presence of suppressive anti-viral therapy (ART) and are barriers to a cure. One potential curative approach, therapeutic vaccination, is fueled by recognition of the ability of a subset of elite controllers (EC) to control virus without therapy due to robust anti-HIV immune responses. Controllers have low levels of integrated HIV DNA and low levels of replication competent virus, suggesting a small reservoir. As our recent data indicates some reservoir cells can produce HIV proteins (termed GPR cells for Gag-positive reservoir cells), we hypothesized that a fraction of HIV-expressing resting CD4+ T cells could be efficiently targeted and cleared in individuals who control HIV via anti-HIV cytotoxic T lymphocytes (CTL). To test this we examined if superinfected resting CD4+ T cells from EC express HIV Gag without producing infectious virus and the susceptibility of these cells to CTL. We found that resting CD4+ T cells expressed HIV Gag and were cleared by autologous CD8+ T cells from EC. Importantly, we found the extent of CTL clearance in our in vitro assay correlates with in vivo reservoir size and that a population of Gag expressing resting CD4+ T cells exists in vivo in patients well controlled on therapy. PMID:23951263

Blood volume responses of men and women to bed rest

NASA Technical Reports Server (NTRS)

Fortney, S. M.; Turner, C.; Steinmann, L.; Driscoll, T.; Alfrey, C.

1994-01-01

This paper reviews a series of studies that indicate that estrogens play an important role in blood volume regulation. The first study illustrates that the plasma volume (PV) of ambulatory women fluctuates during the menstrual cycle, increasing during periods of elevated estrogens. In the second study, it was shown that exogenous and endogenous elevations in blood estrogens attenuate the decrease in PV during bed rest. In the third study, the hypothesis was tested that women, who naturally have a higher blood estrogen content compared with men, will have a smaller loss of PV during bed rest. Ten men and ten women underwent a 13-day, 6 degrees head-down bed rest. Plasma volume and red cell mass (RCM) were measured before and after bed rest using 125I and 51Cr labeling, respectively. Before bed rest, the men and women had similar blood volume (BV) and PV (mL/kg body weight), but the women had a smaller (P < .01) RCM (22.2 +/- 0.9 versus 26.2 +/- 0.8 mL/kg, mean +/- SE). During bed rest, the decrease in RCM (mL/kg) was similar in men and women. However, the decrease in BV was greater in men (8.0 +/- 0.8 mL/kg versus 5.8 +/- 0.8 mL/kg), because of a greater reduction in PV (6.3 +/- 0.6 mL/kg versus 4.1 +/- 0.6 mL/kg). Because the decline in BV has been proposed to contribute to the cardiovascular deconditioning after bed rest, it is possible that women may experience less cardiac and circulatory strain on reambulation.

Activated but not resting T cells or thymocytes express colony-stimulating factor 1 mRNA without co-expressing c-fms mRNA.

PubMed

Cerdan, C; Courcoul, M; Razanajaona, D; Pierrès, A; Maroc, N; Lopez, M; Mannoni, P; Mawas, C; Olive, D; Birg, F

1990-02-01

Following the observation that, besides acute myeloid leukemia cells, acute lymphoid leukemia cells of either B or T phenotype could express the transcript for the colony-stimulating factor 1 (CSF-1), a growth factor known to be restricted to the monocytic-macrophage lineage, various sources of resting and/or activated T cells and thymocytes were screened for expression of this hemopoietic growth factor. We report here that the CSF-1 transcript was rapidly (7 h) induced in T cells by a variety of stimuli, but was not detectable in either resting T cells or thymocytes. In addition, secretion of CSF-1 was detectable in the supernatants of activated T cells by 72 h, with a peak around 92-120 h. In contrast to activated monocytes, the transcript of the c-fms proto-oncogene, the product of which is the receptor for CSF-1, was not detectable in either resting or activated T cells. This observation could be relevant to the intimate relationships between T cells and antigen-presenting cells during immune responses.

Epoxidation of Short-Chain Alkenes by Resting-Cell Suspensions of Propane-Grown Bacteria

PubMed Central

Hou, Ching T.; Patel, Ramesh; Laskin, Allen I.; Barnabe, Nancy; Barist, Irene

1983-01-01

Sixteen new cultures of propane-utilizing bacteria were isolated from lake water from Warinanco Park, Linden, N.J. and from lake and soil samples from Bayway Refinery, Linden, N.J. In addition, 19 known cultures obtained from culture collections were also found to be able to grow on propane as the sole carbon and energy source. In addition to their ability to oxidize n-alkanes, resting-cell suspensions of both new cultures and known cultures grown on propane oxidize short-chain alkenes to their corresponding 1,2-epoxides. Among the substrate alkenes, propylene was oxidized at the highest rate. In contrast to the case with methylotrophic bacteria, the product epoxides are further metabolized. Propane and other gaseous n-alkanes inhibit the epoxidation of propylene. The optimum conditions for in vivo epoxidation are described. Results from inhibition studies indicate that a propane monooxygenase system catalyzes both the epoxidation and hydroxylation reactions. Experiments with cell-free extracts show that both hydroxylation and epoxidation activities are located in the soluble fraction obtained after 80,000 × g centrifugation. PMID:16346338

CellBase, a comprehensive collection of RESTful web services for retrieving relevant biological information from heterogeneous sources.

PubMed

Bleda, Marta; Tarraga, Joaquin; de Maria, Alejandro; Salavert, Francisco; Garcia-Alonso, Luz; Celma, Matilde; Martin, Ainoha; Dopazo, Joaquin; Medina, Ignacio

2012-07-01

During the past years, the advances in high-throughput technologies have produced an unprecedented growth in the number and size of repositories and databases storing relevant biological data. Today, there is more biological information than ever but, unfortunately, the current status of many of these repositories is far from being optimal. Some of the most common problems are that the information is spread out in many small databases; frequently there are different standards among repositories and some databases are no longer supported or they contain too specific and unconnected information. In addition, data size is increasingly becoming an obstacle when accessing or storing biological data. All these issues make very difficult to extract and integrate information from different sources, to analyze experiments or to access and query this information in a programmatic way. CellBase provides a solution to the growing necessity of integration by easing the access to biological data. CellBase implements a set of RESTful web services that query a centralized database containing the most relevant biological data sources. The database is hosted in our servers and is regularly updated. CellBase documentation can be found at http://docs.bioinfo.cipf.es/projects/cellbase.

Exercise intensity modulates the appearance of circulating microvesicles with proangiogenic potential upon endothelial cells.

PubMed

Wilhelm, Eurico N; González-Alonso, José; Parris, Christopher; Rakobowchuk, Mark

2016-11-01

The effect of endurance exercise on circulating microvesicle dynamics and their impact on surrounding endothelial cells is unclear. Here we tested the hypothesis that exercise intensity modulates the time course of platelet (PMV) and endothelial-derived (EMV) microvesicle appearance in the circulation through hemodynamic and biochemical-related mechanisms, and that microvesicles formed during exercise would stimulate endothelial angiogenesis in vitro. Nine healthy young men had venous blood samples taken before, during, and throughout the recovery period after 1 h of moderate [46 ± 2% maximal oxygen uptake (V̇o 2max )] or heavy (67 ± 2% V̇o 2max ) intensity semirecumbent cycling and a time-matched resting control trial. In vitro experiments were performed by incubating endothelial cells with rest and exercise-derived microvesicles to examine their effects on cell angiogenic capacities. PMVs (CD41 + ) increased from baseline only during heavy exercise (from 21 ± 1 × 10 3 to 55 ± 8 × 10 3 and 48 ± 6 × 10 3 PMV/μl at 30 and 60 min, respectively; P < 0.05), returning to baseline early in postexercise recovery (P > 0.05), whereas EMVs (CD62E + ) were unchanged (P > 0.05). PMVs were related to brachial artery shear rate (r 2 = 0.43) and plasma norepinephrine concentrations (r 2 = 0.21) during exercise (P < 0.05). Exercise-derived microvesicles enhanced endothelial proliferation, migration, and tubule formation compared with rest microvesicles (P < 0.05). These results demonstrate substantial increases in circulating PMVs during heavy exercise and that exercise-derived microvesicles stimulate human endothelial cells by enhancing angiogenesis and proliferation. This involvement of microvesicles may be considered a novel mechanism through which exercise mediates vascular healing and adaptation. Copyright © 2016 the American Physiological Society.

The quest for tissue stem cells in the pancreas and other organs, and their application in beta-cell replacement.

PubMed

Houbracken, Isabelle; Bouwens, Luc

2010-01-01

Adult stem cell research has drawn a lot of attention by many researchers, due to its medical hope of cell replacement or regenerative therapy for diabetes patients. Despite the many research efforts to date, there is no consensus on the existence of stem cells in adult pancreas. Genetic lineage tracing experiments have put into serious doubt whether β-cell neogenesis from stem/progenitor cells takes place postnatally. Different in vitro experiments have suggested centroacinar, ductal, acinar, stellate, or yet unidentified clonigenic cells as candidate β-cell progenitors. As in the rest of the adult stem cell field, sound and promising observations have been made. However, these observations still need to be replicated. As an alternative to committed stem/progenitor cells in the pancreas, transdifferentiation or lineage reprogramming of exocrine acinar and endocrine α-cells may be used to generate new β-cells. At present, it is unclear which approach is most medically promising. This article highlights the progress being made in knowledge about tissue stem cells, their existence and availability for therapy in diabetes. Particular attention is given to the assessment of methods to verify the existence of tissue stem cells.

Ralstonia eutropha as a biocatalyst for desulfurization of dibenzothiophene.

PubMed

Dejaloud, Azita; Vahabzadeh, Farzaneh; Habibi, Alireza

2017-07-01

The potential of Ralstonia eutropha as a biocatalyst for desulfurization of dibenzothiophene (DBT) was studied in growing and resting cell conditions. The results of both conditions showed that sulfur was removed from DBT which accompanied by the formation of 2-hydroxybiphenyl (2-HBP). In growing cell experiments, glucose was used as an energy supplying substrate in initial concentrations of 55 mM (energy-limited) and 111 mM (energy-sufficient). The growing cell behaviors were quantitatively described using the logistic equation and maintenance concept. The results indicated that 2-HBP production was higher for the energy-sufficient cultures, while the values of the specific growth rate and the maintenance coefficient for these media were lower than those of the energy-limited cultures. Additionally, the kinetic studies showed that the half-saturation constant for the energy-limited cultures was 2 times higher than the energy-sufficient ones where the inhibition constant (0.08 mM) and the maximum specific DBT desulfurization rate (0.002 mmol g cell -1  h -1 ) were almost constant. By defining desulfurizing capacity (D DBT ) including both the biomass concentration and time to reach a particular percentage of DBT conversion, the best condition for desulfurizing cell was determined at 23% g cell L -1  h -1 which corresponded with the resting cells that were harvested at the mid-exponential growth phase.

Puerarin Suppresses the Self-Renewal of Murine Embryonic Stem Cells by Inhibition of REST-MiR-21 Regulatory Pathway.

PubMed

Yin, Mengmeng; Yuan, Yin; Cui, Yurong; Hong, Xian; Luo, Hongyan; Hu, Xinwu; Tang, Ming; Hescheler, Jurgen; Xi, Jiaoya

2015-01-01

Puerarin shows a wide range of biological activities, including affecting the cardiac differentiation from murine embryonic stem (mES) cells. However, little is known about its effect and mechanism of action on the self-renewal of mES cells. This study aimed to determine the effect of puerarin on the self-renewal and pluripotency of mES cells and its underlying mechanisms. RT-PCR and real-time PCR were used to detect the transcripts of core transcription factors, specific markers for multiple lineages, REST and microRNA-21 (miR-21). Colony-forming assay was performed to estimate the self-renewal capacity of mES cells. Western blotting and wortmannin were employed to explore the role of PI3K/Akt signaling pathway in the inhibitory action of puerarin on REST transcript. Transfected mES cells with antagomir21 were used to confirm the role of miR-21 in the action of puerarin on cell self-renewal. Puerarin significantly decreased the percentage of the self-renewal colonies, and suppressed the transcripts of Oct4, Nanog, Sox2, c-Myc and REST. Besides, PECAM, NCAM and miR-21 were up-regulated both under the self-renewal conditions and at day 4 of differentiation. The PI3K inhibitor wortmannin successfully reversed the mRNA expression changes of REST, Nanog and Sox2. Transfection of antagomir21 efficiently reversed the effects of puerarin on mES cells self-renewal. Inhibition of REST-miR-21 regulatory pathway may be the key mechanism of puerarin-induced suppression of mES cells self-renewal.

T-dependent activation of resting B cells mediated by concanavalin A.

PubMed

Ratcliffe, M J; Julius, M H

1984-03-01

In cultures containing long-term cultured lines of antigen-specific helper T (Th) cells, normal unprimed B cells and concanavalin A (Con A), induction of B cells to immunoglobulin secretion and DNA synthesis was observed. The plaque-forming cell (PFC) response was large (frequently greater than 75 000 PFC/10(6) input B cells) demonstrating the polyspecific nature of the response. Con A-mediated maturation and induction to DNA synthesis of responding B cells was completely Th cell dependent and inhibited with methyl-alpha-D-mannoside. Both resting and blasted B cells, separated by Percoll density centrifugation, were induced to DNA synthesis and immunoglobulin secretion. Responses were completely unrestricted by the B cell major histocompatibility complex, even at the level of the resting B cell. The polyclonal nature of the response taken together with the Con A-mediated bypassing of T cell specificity and restricting haplotype indicates that this response is analogous to lectin-mediated cytotoxicity.

Proliferation of epithelial cell rests, formation of apical cysts, and regression of apical cysts after periapical wound healing.

PubMed

Lin, Louis M; Huang, George T-J; Rosenberg, Paul A

2007-08-01

There is continuing controversy regarding the potential for inflammatory apical cysts to heal after nonsurgical endodontic therapy. Molecular cell biology may provide answers to a series of related questions. How are the epithelial cell rests of Malassez stimulated to proliferate? How are the apical cysts formed? How does the lining epithelium of apical cysts regress after endodontic therapy? Epithelial cell rests are induced to divide and proliferate by inflammatory mediators, proinflammatory cytokines, and growth factors released from host cells during periradicular inflammation. Quiescent epithelial cell rests can behave like restricted-potential stem cells if stimulated to proliferate. Formation of apical cysts is most likely caused by the merging of proliferating epithelial strands from all directions to form a three-dimensional ball mass. After endodontic therapy, epithelial cells in epithelial strands of periapical granulomas and the lining epithelium of apical cysts may stop proliferating because of a reduction in inflammatory mediators, proinflammatory cytokines, and growth factors. Epithelial cells will also regress because of activation of apoptosis or programmed cell death through deprivation of survival factors or by receiving death signals during periapical wound healing.

Formation of resting cells by non-spore-forming microorganisms as a strategy of long-term survival in the environment

NASA Astrophysics Data System (ADS)

Mulyukin, Andrei L.; Soina, Vera S.; Demkina, Elena V.; Kozlova, Alla N.; Suzina, Natalia E.; Dmitriev, Vladimir V.; Duda, Vitalii I.; El'-Registan, Galina I.

2003-01-01

Non-spore-forming bacteria of the genera Micrococcus and Arthrobacter, including the isolates from permafrost sediments, were found to be able to form cystlike cells under special conditions. Cystlike cells maintained the viability during long-term storage (for up to several years), had undetectable respiratory activity and the elevated resistance to heating and other unfavorable conditions, possessed the specific fine structure and morphology, and were formed in the life cycles of the microorganism. These properties allow cystlike cells to be attributed to a new type of resting microbial forms. Furthermore, the distinctive feature of resting cystlike cells was their low P/S ratios and high Ca/K ratios in comparison to vegetative cells as shown by X-ray microanalysis. The experimentally obtained bacterial cystlike cells with thickened and laminated cell walls and altered texture of the cytoplasm were similar to the cells abundant in native microbial populations isolated from permafrost sediments and ancient soils of the Kolyma lowland (Siberia, Russia). Due to the inherent elevated resistance to adverse conditions and maintenance of viability for prolonged periods, resting cystlike cells are likely to ensure long-term survival of non-spore-forming bacteria in cold environments.

Product toxicity and cometabolic competitive inhibition modeling of chloroform and trichloroethylene transformation by methanotrophic resting cells.

PubMed Central

Alvarez-Cohen, L; McCarty, P L

1991-01-01

The rate and capacity for chloroform (CF) and trichloroethylene (TCE) transformation by a mixed methanotrophic culture of resting cells (no exogenous energy source) and formate-fed cells were measured. As reported previously for TCE, formate addition resulted in an increased CF transformation rate (0.35 day-1 for resting cells and 1.5 day-1 for formate-fed cells) and transformation capacity (0.0065 mg of CF per mg of cells for resting cells and 0.015 mg of CF per mg of cells for formate-fed cells), suggesting that depletion of energy stores affects transformation behavior. The observed finite transformation capacity, even with an exogenous energy source, suggests that toxicity was also a factor. CF transformation capacity was significantly lower than that for TCE, suggesting a greater toxicity from CF transformation. The toxicity of CF, TCE, and their transformation products to whole cells was evaluated by comparing the formate oxidation activity of acetylene-treated cells to that of non-acetylene-treated cells with and without prior exposure to CF or TCE. Acetylene arrests the activity of methane monooxygenase in CF and TCE oxidation without halting cell activity toward formate. Significantly diminished formate oxidation by cells exposed to either CR or TCE without acetylene compared with that with acetylene suggests that the solvents themselves were not toxic under the experimental conditions but their transformation products were. The concurrent transformation of CF and TCE by resting cells was measured, and results were compared with predictions from a competitive-inhibition cometabolic transformation model. The reasonable fit between model predictions and experimental observations was supportive of model assumptions. PMID:1905516

Vpx overcomes a SAMHD1-independent block to HIV reverse transcription that is specific to resting CD4 T cells.

PubMed

Baldauf, Hanna-Mari; Stegmann, Lena; Schwarz, Sarah-Marie; Ambiel, Ina; Trotard, Maud; Martin, Margarethe; Burggraf, Manja; Lenzi, Gina M; Lejk, Helena; Pan, Xiaoyu; Fregoso, Oliver I; Lim, Efrem S; Abraham, Libin; Nguyen, Laura A; Rutsch, Frank; König, Renate; Kim, Baek; Emerman, Michael; Fackler, Oliver T; Keppler, Oliver T

2017-03-07

Early after entry into monocytes, macrophages, dendritic cells, and resting CD4 T cells, HIV encounters a block, limiting reverse transcription (RT) of the incoming viral RNA genome. In this context, dNTP triphosphohydrolase SAM domain and HD domain-containing protein 1 (SAMHD1) has been identified as a restriction factor, lowering the concentration of dNTP substrates to limit RT. The accessory lentiviral protein X (Vpx) proteins from the major simian immunodeficiency virus of rhesus macaque, sooty mangabey, and HIV-2 (SIVsmm/SIVmac/HIV-2) lineage packaged into virions target SAMHD1 for proteasomal degradation, increase intracellular dNTP pools, and facilitate HIV cDNA synthesis. We find that virion-packaged Vpx proteins from a second SIV lineage, SIV of red-capped mangabeys or mandrills (SIVrcm/mnd-2), increased HIV infection in resting CD4 T cells, but not in macrophages, and, unexpectedly, acted in the absence of SAMHD1 degradation, dNTP pool elevation, or changes in SAMHD1 phosphorylation. Vpx rcm/mnd-2 virion incorporation resulted in a dramatic increase of HIV-1 RT intermediates and viral cDNA in infected resting CD4 T cells. These analyses also revealed a barrier limiting HIV-1 infection of resting CD4 T cells at the level of nuclear import. Single amino acid changes in the SAMHD1-degrading Vpx mac239 allowed it to enhance early postentry steps in a Vpx rcm/mnd-2-like fashion. Moreover, Vpx enhanced HIV-1 infection of SAMHD1-deficient resting CD4 T cells of a patient with Aicardi-Goutières syndrome. These results indicate that Vpx, in addition to SAMHD1, overcomes a previously unappreciated restriction for lentiviruses at the level of RT that acts independently of dNTP concentrations and is specific to resting CD4 T cells.

Dormant state in bacteria: Conceptions and implications for terrestrial biogeoscience and astrobiology

NASA Astrophysics Data System (ADS)

Mulyukin, A.

2003-04-01

Gaining insight into strategies and mechanisms that ensure long term-preservation of microorganisms in various environments, including cold habitats, is a very important issue for terrestrial biogeoscience and astrobiology. This communication has a focus on the analysis of the published and our experimental data regarding the dormant state of different microorganisms, with an emphasis on non-spore-forming bacteria, which are widely spread in numerous ecological niches (e.g. permafrost sediments). Albeit it is recognized that one of the strategies to endure environmental stresses is entering of non-spore-forming bacteria into the viable-but-non-culturable state, a question of whether these microorganisms have the resting stage remains unclear. However, our previous studies showed that non-spore-forming bacteria and yeast could form cyst-like cells that possess many attributes of constitutively resting cells. As applied to the survival strategy of non-spore-forming bacteria in permafrost sediments, recognizing a very important role of the viable-but-nonculturable state in asporogenous bacteria, we however believe that their long-term maintenance in such habitats is due to the formation of cyst-like cells. Interestingly, bacterial isolates from permafrost sediments showed a greater productivity of autoregulatory factors, favoring the transition of cells into the resting state, and a more elevated resistance to some stresses than closely related collection strains. This suggests a greater potentiality of the permafrost isolates to enter the resting stage and thereby to survive for millennia years in natural habitats. However, it is known that only a little part of microorganisms that are present in environmental samples can be enumerated by standard plating on agar media, and a discrepancy between the total number of cells and those capable of forming colonies is a rather common case. Such a discrepancy can be due to either the actual non-culturability of microbial cells and to that the conditions that are most appropriate to wake resting cells to growth are unknown to microbiologists. Furthermore, resting bacterial cells of just the same species differ in their ability to recover the growth and multiplication and profundity of the dormant state, so special 'reanimation' procedures are required. To overcome obstacles due to an expectable underestimation of total cell number in the environmental samples, it is important to find out the criteria, which allow one to distinguish between microbial cells of different physiological state, including the resting cells, by direct methods. Some of such approaches to revealing the specific features of potentially viable resting cells (in laboratory cultures) were developed in our works and used for a primary detection of microbial cells in situ and for appraisal of their physiological state. So, it is worth to discuss what we can propose for a better understanding of the phenomenon of long-term preservation of microorganisms in cold terrestrial ecosystems and whether resting cells of non-spore-forming-bacteria can be regarded as a target in exobiological explorations.

CO Metabolism in the Acetogen Acetobacterium woodii

PubMed Central

Bertsch, Johannes

2015-01-01

The Wood-Ljungdahl pathway allows acetogenic bacteria to grow on a number of one-carbon substrates, such as carbon dioxide, formate, methyl groups, or even carbon monoxide. Since carbon monoxide alone or in combination with hydrogen and carbon dioxide (synthesis gas) is an increasingly important feedstock for third-generation biotechnology, we studied CO metabolism in the model acetogen Acetobacterium woodii. When cells grew on H2-CO2, addition of 5 to 15% CO led to higher final optical densities, indicating the utilization of CO as a cosubstrate. However, the growth rate was decreased by the presence of small amounts of CO, which correlated with an inhibition of H2 consumption. Experiments with resting cells revealed that the degree of inhibition of H2 consumption was a function of the CO concentration. Since the hydrogen-dependent CO2 reductase (HDCR) of A. woodii is known to be very sensitive to CO, we speculated that cells may be more tolerant toward CO when growing on formate, the product of the HDCR reaction. Indeed, addition of up to 25% CO did not influence growth rates on formate, while the final optical densities and the production of acetate increased. Higher concentrations (75 and 100%) led to a slight inhibition of growth and to decreasing rates of formate and CO consumption. Experiments with resting cells revealed that the HDCR is a site of CO inhibition. In contrast, A. woodii was not able to grow on CO as a sole carbon and energy source, and growth on fructose-CO or methanol-CO was not observed. PMID:26092462

Boosting Long-Term Memory via Wakeful Rest: Intentional Rehearsal Is Not Necessary, Consolidation Is Sufficient

PubMed Central

Dewar, Michaela; Alber, Jessica; Cowan, Nelson; Della Sala, Sergio

2014-01-01

People perform better on tests of delayed free recall if learning is followed immediately by a short wakeful rest than by a short period of sensory stimulation. Animal and human work suggests that wakeful resting provides optimal conditions for the consolidation of recently acquired memories. However, an alternative account cannot be ruled out, namely that wakeful resting provides optimal conditions for intentional rehearsal of recently acquired memories, thus driving superior memory. Here we utilised non-recallable words to examine whether wakeful rest boosts long-term memory, even when new memories could not be rehearsed intentionally during the wakeful rest delay. The probing of non-recallable words requires a recognition paradigm. Therefore, we first established, via Experiment 1, that the rest-induced boost in memory observed via free recall can be replicated in a recognition paradigm, using concrete nouns. In Experiment 2, participants heard 30 non-recallable non-words, presented as ‘foreign names in a bridge club abroad’ and then either rested wakefully or played a visual spot-the-difference game for 10 minutes. Retention was probed via recognition at two time points, 15 minutes and 7 days after presentation. As in Experiment 1, wakeful rest boosted recognition significantly, and this boost was maintained for at least 7 days. Our results indicate that the enhancement of memory via wakeful rest is not dependent upon intentional rehearsal of learned material during the rest period. We thus conclude that consolidation is sufficient for this rest-induced memory boost to emerge. We propose that wakeful resting allows for superior memory consolidation, resulting in stronger and/or more veridical representations of experienced events which can be detected via tests of free recall and recognition. PMID:25333957

Boosting long-term memory via wakeful rest: intentional rehearsal is not necessary, consolidation is sufficient.

PubMed

Dewar, Michaela; Alber, Jessica; Cowan, Nelson; Della Sala, Sergio

2014-01-01

People perform better on tests of delayed free recall if learning is followed immediately by a short wakeful rest than by a short period of sensory stimulation. Animal and human work suggests that wakeful resting provides optimal conditions for the consolidation of recently acquired memories. However, an alternative account cannot be ruled out, namely that wakeful resting provides optimal conditions for intentional rehearsal of recently acquired memories, thus driving superior memory. Here we utilised non-recallable words to examine whether wakeful rest boosts long-term memory, even when new memories could not be rehearsed intentionally during the wakeful rest delay. The probing of non-recallable words requires a recognition paradigm. Therefore, we first established, via Experiment 1, that the rest-induced boost in memory observed via free recall can be replicated in a recognition paradigm, using concrete nouns. In Experiment 2, participants heard 30 non-recallable non-words, presented as 'foreign names in a bridge club abroad' and then either rested wakefully or played a visual spot-the-difference game for 10 minutes. Retention was probed via recognition at two time points, 15 minutes and 7 days after presentation. As in Experiment 1, wakeful rest boosted recognition significantly, and this boost was maintained for at least 7 days. Our results indicate that the enhancement of memory via wakeful rest is not dependent upon intentional rehearsal of learned material during the rest period. We thus conclude that consolidation is sufficient for this rest-induced memory boost to emerge. We propose that wakeful resting allows for superior memory consolidation, resulting in stronger and/or more veridical representations of experienced events which can be detected via tests of free recall and recognition.

Resting-State Retinotopic Organization in the Absence of Retinal Input and Visual Experience

PubMed Central

Binda, Paola; Benson, Noah C.; Bridge, Holly; Watkins, Kate E.

2015-01-01

Early visual areas have neuronal receptive fields that form a sampling mosaic of visual space, resulting in a series of retinotopic maps in which the same region of space is represented in multiple visual areas. It is not clear to what extent the development and maintenance of this retinotopic organization in humans depend on retinal waves and/or visual experience. We examined the corticocortical receptive field organization of resting-state BOLD data in normally sighted, early blind, and anophthalmic (in which both eyes fail to develop) individuals and found that resting-state correlations between V1 and V2/V3 were retinotopically organized for all subject groups. These results show that the gross retinotopic pattern of resting-state connectivity across V1-V3 requires neither retinal waves nor visual experience to develop and persist into adulthood. SIGNIFICANCE STATEMENT Evidence from resting-state BOLD data suggests that the connections between early visual areas develop and are maintained even in the absence of retinal waves and visual experience. PMID:26354906

Effect of the metals iron, copper and silver on fluorobenzene biodegradation by Labrys portucalensis.

PubMed

Moreira, Irina S; Amorim, Catarina L; Carvalho, Maria F; Ferreira, António C; Afonso, Carlos M; Castro, Paula M L

2013-04-01

Organic and metallic pollutants are ubiquitous in the environment. Many metals are reported to be toxic to microorganisms and to inhibit biodegradation. The effect of the metals iron, copper and silver on the metabolism of Labrys portucalensis F11 and on fluorobenzene (FB) biodegradation was examined. The results indicate that the addition of 1 mM of Fe(2+) to the culture medium has a positive effect on bacterial growth and has no impact in the biodegradation of 1 and 2 mM of FB. The presence of 1 mM of Cu(2+) was found to strongly inhibit the growth of F11 cultures and to reduce the biodegradation of 1 and 2 mM of FB to ca. 50 %, with 80 % of stoichiometrically expected fluoride released. In the experiments with resting cells, the FB degraded (from 2 mM supplied) was reduced ca. 20 % whereas the fluoride released was reduced to 45 % of that stoichiometrically expected. Ag(+) was the most potent inhibitor of FB degradation. In experiments with growing cells, the addition of 1 mM of Ag(+) to the culture medium containing 1 and 2 mM of FB resulted in no fluoride release, whereas FB degradation was only one third of that observed in control cultures. In the experiments with resting cells, the addition of Ag(+) resulted in 25 % reduction in substrate degradation and fluoride release was only 20 % of that stoichiometrically expected. The accumulation of catechol and 4-fluorocatechol in cultures supplemented with Cu(2+) or Ag(+) suggest inhibition of the key enzyme of FB metabolism-catechol 1,2-dioxygenase.

A Subset of Latency-Reversing Agents Expose HIV-Infected Resting CD4+ T-Cells to Recognition by Cytotoxic T-Lymphocytes

PubMed Central

Jones, R. Brad; Mueller, Stefanie; O’Connor, Rachel; Rimpel, Katherine; Sloan, Derek D.; Karel, Dan; Wong, Hing C.; Jeng, Emily K.; Thomas, Allison S.; Whitney, James B.; Lim, So-Yon; Kovacs, Colin; Benko, Erika; Karandish, Sara; Huang, Szu-Han; Buzon, Maria J.; Lichterfeld, Mathias; Irrinki, Alivelu; Murry, Jeffrey P.; Tsai, Angela; Yu, Helen; Geleziunas, Romas; Trocha, Alicja; Ostrowski, Mario A.; Irvine, Darrell J.; Walker, Bruce D.

2016-01-01

Resting CD4+ T-cells harboring inducible HIV proviruses are a critical reservoir in antiretroviral therapy (ART)-treated subjects. These cells express little to no viral protein, and thus neither die by viral cytopathic effects, nor are efficiently cleared by immune effectors. Elimination of this reservoir is theoretically possible by combining latency-reversing agents (LRAs) with immune effectors, such as CD8+ T-cells. However, the relative efficacy of different LRAs in sensitizing latently-infected cells for recognition by HIV-specific CD8+ T-cells has not been determined. To address this, we developed an assay that utilizes HIV-specific CD8+ T-cell clones as biosensors for HIV antigen expression. By testing multiple CD8+ T-cell clones against a primary cell model of HIV latency, we identified several single agents that primed latently-infected cells for CD8+ T-cell recognition, including IL-2, IL-15, two IL-15 superagonists (IL-15SA and ALT-803), prostratin, and the TLR-2 ligand Pam3CSK4. In contrast, we did not observe CD8+ T-cell recognition of target cells following treatment with histone deacetylase inhibitors or with hexamethylene bisacetamide (HMBA). In further experiments we demonstrate that a clinically achievable concentration of the IL-15 superagonist ‘ALT-803’, an agent presently in clinical trials for solid and hematological tumors, primes the natural ex vivo reservoir for CD8+ T-cell recognition. Thus, our results establish a novel experimental approach for comparative evaluation of LRAs, and highlight ALT-803 as an LRA with the potential to synergize with CD8+ T-cells in HIV eradication strategies. PMID:27082643

A Subset of Latency-Reversing Agents Expose HIV-Infected Resting CD4+ T-Cells to Recognition by Cytotoxic T-Lymphocytes.

PubMed

Jones, R Brad; Mueller, Stefanie; O'Connor, Rachel; Rimpel, Katherine; Sloan, Derek D; Karel, Dan; Wong, Hing C; Jeng, Emily K; Thomas, Allison S; Whitney, James B; Lim, So-Yon; Kovacs, Colin; Benko, Erika; Karandish, Sara; Huang, Szu-Han; Buzon, Maria J; Lichterfeld, Mathias; Irrinki, Alivelu; Murry, Jeffrey P; Tsai, Angela; Yu, Helen; Geleziunas, Romas; Trocha, Alicja; Ostrowski, Mario A; Irvine, Darrell J; Walker, Bruce D

2016-04-01

Resting CD4+ T-cells harboring inducible HIV proviruses are a critical reservoir in antiretroviral therapy (ART)-treated subjects. These cells express little to no viral protein, and thus neither die by viral cytopathic effects, nor are efficiently cleared by immune effectors. Elimination of this reservoir is theoretically possible by combining latency-reversing agents (LRAs) with immune effectors, such as CD8+ T-cells. However, the relative efficacy of different LRAs in sensitizing latently-infected cells for recognition by HIV-specific CD8+ T-cells has not been determined. To address this, we developed an assay that utilizes HIV-specific CD8+ T-cell clones as biosensors for HIV antigen expression. By testing multiple CD8+ T-cell clones against a primary cell model of HIV latency, we identified several single agents that primed latently-infected cells for CD8+ T-cell recognition, including IL-2, IL-15, two IL-15 superagonists (IL-15SA and ALT-803), prostratin, and the TLR-2 ligand Pam3CSK4. In contrast, we did not observe CD8+ T-cell recognition of target cells following treatment with histone deacetylase inhibitors or with hexamethylene bisacetamide (HMBA). In further experiments we demonstrate that a clinically achievable concentration of the IL-15 superagonist 'ALT-803', an agent presently in clinical trials for solid and hematological tumors, primes the natural ex vivo reservoir for CD8+ T-cell recognition. Thus, our results establish a novel experimental approach for comparative evaluation of LRAs, and highlight ALT-803 as an LRA with the potential to synergize with CD8+ T-cells in HIV eradication strategies.

Electricity generation in microbial fuel cells using neutral red as an electronophore

DOE Office of Scientific and Technical Information (OSTI.GOV)

Park, D.H.; Zeikus, J.G.

2000-04-01

Neutral red (NR) was utilized as an electron mediator in microbial fuel cells consuming glucose to study both its efficiency during electricity generation and its role in altering anaerobic growth and metabolism of Escherichia coli and Actinobacillus succinogenes. A study of chemical fuel cells in which NADH, NR, and ferricyanide were the electron donor, the electronophore, and the electron acceptor, respectively, showed that electrical current produced from NADH was proportional to the concentration of NADH. Fourfold more current was produced from NADH in chemical fuel cells when NR was the electron mediator than when thionin was the electron mediator. Inmore » microbial fuel cells in which E. coli resting cells were used the amount of current produced from glucose when NR was the electron mediator was 10-fold more than the amount produced when thionin was the electron mediator. The amount of electrical energy generated and the amount of current produced from glucose in NR-mediated microbial fuel cells containing either E. coli or A. succinogenes were about 10- and 2-fold greater, respectively, when resting cells were used than when growing cells were used. Cell growth was inhibited substantially when these microbial fuel cells were making current, and more oxidized end products were formed under these conditions. When sewage sludge was used in the fuel cell, stable and equivalent levels of current were obtained with glucose, as observed in the pure-culture experiments. These results suggest that NR is better than other electron mediators used in microbial fuel cells and that sludge production can be decreased while electricity is produced in fuel cells. Their results are discussed in relation to factors that may improve the relatively low electrical efficiencies obtained with microbial fuel cells.« less

Human Natural Killer Cells Exhibit Direct Activity Against Aspergillus fumigatus Hyphae, But Not Against Resting Conidia

PubMed Central

Schmidt, Stanislaw; Tramsen, Lars; Hanisch, Mitra; Latgé, Jean-Paul; Huenecke, Sabine; Koehl, Ulrike

2011-01-01

Because natural killer (NK) cells kill tumor cells and combat infections, there is growing interest in adoptively transferring NK cells to hematopoietic stem cell recipients. Unfortunately, in humans, the activity of NK cells against Aspergillus species, the major cause of invasive fungal infection in stem cell recipients, are poorly characterized. Our results show that unstimulated and interleukin-2 prestimulated human NK cells kill Aspergillus fumigatus hyphae but do not affect resting conidia. Killing is also induced by the supernatant of prestimulated NK cells and human perforin. The high levels of interferon-γ and granulocyte macrophage colony-stimulating factor produced by prestimulated NK cells are significantly reduced by Aspergillus, indicating an immunosuppressive effect of the fungus. Whereas Aspergillus hyphae activate NK cells, resting, and germinating, conidia and conidia of ΔrodA mutants lacking the hydrophobic surface layer do not. Our results suggest that adoptively transferred human NK cells may be a potential antifungal tool in the transplantation context. PMID:21208932

REST and stress resistance in ageing and Alzheimer's disease

NASA Astrophysics Data System (ADS)

Lu, Tao; Aron, Liviu; Zullo, Joseph; Pan, Ying; Kim, Haeyoung; Chen, Yiwen; Yang, Tun-Hsiang; Kim, Hyun-Min; Drake, Derek; Liu, X. Shirley; Bennett, David A.; Colaiácovo, Monica P.; Yankner, Bruce A.

2014-03-01

Human neurons are functional over an entire lifetime, yet the mechanisms that preserve function and protect against neurodegeneration during ageing are unknown. Here we show that induction of the repressor element 1-silencing transcription factor (REST; also known as neuron-restrictive silencer factor, NRSF) is a universal feature of normal ageing in human cortical and hippocampal neurons. REST is lost, however, in mild cognitive impairment and Alzheimer's disease. Chromatin immunoprecipitation with deep sequencing and expression analysis show that REST represses genes that promote cell death and Alzheimer's disease pathology, and induces the expression of stress response genes. Moreover, REST potently protects neurons from oxidative stress and amyloid β-protein toxicity, and conditional deletion of REST in the mouse brain leads to age-related neurodegeneration. A functional orthologue of REST, Caenorhabditis elegans SPR-4, also protects against oxidative stress and amyloid β-protein toxicity. During normal ageing, REST is induced in part by cell non-autonomous Wnt signalling. However, in Alzheimer's disease, frontotemporal dementia and dementia with Lewy bodies, REST is lost from the nucleus and appears in autophagosomes together with pathological misfolded proteins. Finally, REST levels during ageing are closely correlated with cognitive preservation and longevity. Thus, the activation state of REST may distinguish neuroprotection from neurodegeneration in the ageing brain.

Specification of skeletal muscle differentiation by repressor element-1 silencing transcription factor (REST)-regulated Kv7.4 potassium channels

PubMed Central

Iannotti, Fabio Arturo; Barrese, Vincenzo; Formisano, Luigi; Miceli, Francesco; Taglialatela, Maurizio

2013-01-01

Changes in the expression of potassium (K+) channels is a pivotal event during skeletal muscle differentiation. In mouse C2C12 cells, similarly to human skeletal muscle cells, myotube formation increased the expression of Kv7.1, Kv7.3, and Kv7.4, the last showing the highest degree of regulation. In C2C12 cells, Kv7.4 silencing by RNA interference reduced the expression levels of differentiation markers (myogenin, myosin heavy chain, troponinT-1, and Pax3) and impaired myotube formation and multinucleation. In Kv7.4-silenced cells, the differentiation-promoting effect of the Kv7 activator N-(2-amino-4-(4-fluorobenzylamino)-phenyl)-carbamic acid ethyl ester (retigabine) was abrogated. Expression levels for the repressor element-1 silencing transcription factor (REST) declined during myotube formation. Transcript levels for Kv7.4, as well as for myogenin, troponinT-1, and Pax3, were reduced by REST overexpression and enhanced upon REST suppression by RNA interference. Four regions containing potential REST-binding sites in the 5′ untranslated region and in the first intron of the Kv7.4 gene were identified by bioinformatic analysis. Chromatin immunoprecipitation assays showed that REST binds to these regions, exhibiting a higher efficiency in myoblasts than in myotubes. These data suggest that Kv7.4 plays a permissive role in skeletal muscle differentiation and highlight REST as a crucial transcriptional regulator for this K+ channel subunit. PMID:23242999

The Fysics of Filopodia (or The Physics of Philopodia)

NASA Astrophysics Data System (ADS)

Schwarz, Jen; Gopinathan, Ajay; Lee, Kun-Chun; Liu, Andrea; Yang, Louise

2006-03-01

Cell motility is driven by the dynamic reorganization of the cellular cytoskeleton which is composed of actin. Monomeric actin assembles into filaments that grow, shrink, branch and bundle. Branching generates new filaments that form a mesh-like structure that protrudes outward allowing the cell to move somewhere. But how does it know where to move? It has been proposed that filopodia serve as scouts for the cell. Filopodia are bundles of actin filaments that extend out ahead of the rest of the cell to probe its upcoming environment. Recent in vitro experiments [Vignjevic et al., J. Ce ll Bio. 160, 951 (2003)] determine the minimal ingredients required for such a process. We model these experiments analytically and via Monte Carlo simulations to estimate the typical bundle size and length. We also estimate the size of the mesh-like structure from which the filopodia emerge and explain the observed nonmonotonicity of this size as a function of capping protein concentration, which inhibits filament growth.

Binding of hnRNP H and U2AF65 to Respective G-codes and a Poly-Uridine Tract Collaborate in the N50-5'ss Selection of the REST N Exon in H69 Cells

PubMed Central

Ortuño-Pineda, Carlos; Galindo-Rosales, José Manuel; Calderón-Salinas, José Victor; Villegas-Sepúlveda, Nicolás; Saucedo-Cárdenas, Odila; De Nova-Ocampo, Mónica; Valdés, Jesús

2012-01-01

The splicing of the N exon in the pre-mRNA coding for the RE1-silencing transcription factor (REST) results in a truncated protein that modifies the expression pattern of some of its target genes. A weak 3'ss, three alternative 5'ss (N4-, N50-, and N62-5'ss) and a variety of putative target sites for splicing regulatory proteins are found around the N exon; two GGGG codes (G2-G3) and a poly-Uridine tract (N-PU) are found in front of the N50-5'ss. In this work we analyzed some of the regulatory factors and elements involved in the preferred selection of the N50-5'ss (N50 activation) in the small cell lung cancer cell line H69. Wild type and mutant N exon/β-globin minigenes recapitulated N50 exon splicing in H69 cells, and showed that the N-PU and the G2-G3 elements are required for N50 exon splicing. Biochemical and knockdown experiments identified these elements as U2AF65 and hnRNP H targets, respectively, and that they are also required for N50 exon activation. Compared to normal MRC5 cells, and in keeping with N50 exon activation, U2AF65, hnRNP H and other splicing factors were highly expressed in H69 cells. CLIP experiments revealed that hnRNP H RNA-binding occurs first and is a prerequisite for U2AF65 RNA binding, and EMSA and CLIP experiments suggest that U2AF65-RNA recognition displaces hnRNP H and helps to recruit other splicing factors (at least U1 70K) to the N50-5'ss. Our results evidenced novel hnRNP H and U2AF65 functions: respectively, U2AF65-recruiting to a 5'ss in humans and the hnRNP H-displacing function from two juxtaposed GGGG codes. PMID:22792276

Biosynthesis of Ergothioneine from Endogenous Hercynine in Mycobacterium smegmatis

PubMed Central

Genghof, Dorothy S.; Van Damme, Olga

1968-01-01

Ergothioneine was synthesized and accumulated in growing cultures of Mycobacterium smegmatis when the medium was adequately supplied with sulfur. In a low sulfur medium, the accumulation was sharply limited although growth of the organism was apparently normal. Synthesis of hercynine, the precursor of ergothioneine, was unaffected by low sulfur levels and was markedly increased by addition of l-histidine, the precursor of hercynine. Resting-cell pellicle experiments, performed with cells grown on the low sulfur high histidine medium, showed that ergothioniene was synthesized from endogenous hercynine, when cysteine or compounds readily converted to cysteine (such as cystine, lanthionine, cystathionine, and thiazolidine carboxylic acid) were added. Homocysteine and djenkolic acid allowed for minimal synthesis of betaine, whereas methionine, S-methylcysteine, sodium sulfate, and sodium thiosulfate were unable to donate sulfur for ergothioniene synthesis under the experimental conditions employed. Addition of cysteine to a resting pellicle preparation caused the formation of 100 to 200 μg of ergothioneine per g of dry cells in 2.5 to 3 hr. A modified procedure for isolating ergothioneine and hercynine, employing a 75% ethyl alcohol extraction of wet organisms, followed by a single alumina column separation of the compounds, is described. PMID:5644441

Dinoflagellate cysts and bloom events at Todos Santos Bay, Baja California, México, 1999 2000

NASA Astrophysics Data System (ADS)

Peña-Manjarrez, José Luis; Helenes, Javier; Gaxiola-Castro, Gilberto; Orellana-Cepeda, Elizabeth

2005-07-01

Forty-two species of dinoflagellate motile cells and 18 species of organic-walled dinoflagellate resting cysts were identified in samples collected at Todos Santos Bay, Baja California, México, from September 1999 to June 2000. These temperate to cool-temperate species belong mainly to the families Gonyaulacaceae and Protoperidiniaceae. Lingulodinium polyedrum (Stein, 1883) Dodge 1989 was the dominant species both in the sediments and water column. During this period we observed planktonic motile cells, temporary cysts with cellulose walls, and resting cysts with resistant dinosporin walls. Two dinoflagellate blooms occurred in the spring to summer of 2000 allowing us to observe the timing of cyst production. The temporary cysts appeared between these blooms and also in the summer, whereas the resting cysts appeared during the preceding fall and winter. Resting cysts appeared in colder conditions, whereas the temporary cysts were produced within a particular thermal window and under nutrient depletion. Resting cysts were concentrated in discrete areas at depths of less than 25 m, and associated with sediments ranging from silt to fine sand. These cysts were abundant in the surface sediments during summer, fall and winter, whereas the motile cells dominated during the spring and summer, when the two L. polyedrum blooms were observed. The abundance of cells in the plankton, comprising motile cells and temporary cysts, appears to be inversely proportional to the concentration of resting cysts of the same species in the surface sediments.

Evidence against a hypothesis of vestibular efferent function

NASA Technical Reports Server (NTRS)

Cochran, S. L.

1994-01-01

Efferent stimulation and nicotinic agonists can either decrease or increase the frequency of occurrence of EPSPs recorded from VIIIth nerve afferents in the frog. It has been hypothesized that the distribution of hair cell resting membrane potentials overlaps the equilibrium potential dictated by the nicotinic-gated channels on the hair cells. Nicotinic mediated increases in EPSP frequency would then be due to depolarization of hair cells that were more hyperpolarized at rest, while decreases in EPSP frequency would be due to hyperpolarization of hair cells more depolarized at rest. In order to test this hypothesis, while recording from afferents which showed an increase in EPSP frequency due to bath application of the nicotinic agonist DMPP (1,1-dimethyl-4-phenylpiperizinium iodide), hair cells were depolarized with 10 mM K+ in the bath, and then the effects of DMPP on EPSP frequency were assessed. In this situation, DMPP still increased EPSP frequency, suggesting that the equilibrium potential for the nicotinic-gated channel was much more positive than the resting potentials of the hair cells. An alternative hypothesis then seems likely, that the nicotinic receptors on hair cells are able to activate different iontophores that result in either hair cell depolarization or hyperpolarization, dependent upon which iontophore predominates in the hair cells innervating a particular afferent.

Immunological characterization of eristostatin and echistatin binding sites on alpha IIb beta 3 and alpha V beta 3 integrins.

PubMed Central

Marcinkiewicz, C; Rosenthal, L A; Mosser, D M; Kunicki, T J; Niewiarowski, S

1996-01-01

Two disintegrins with a high degree of amino acid sequence similarity, echistatin and eristostatin, showed a low level of interaction with Chinese hamster ovary (CHO) cells, but they bound to CHO cells transfected with alpha IIb beta 3 genes (A5 cells) and to CHO cells transfected with alpha v beta 3 genes (VNRC3 cells) in a reversible and saturable manner. Scatchard analysis revealed that eristostatin bound to 816000 sites per A5 cell (Kd 28 nM) and to 200000 sites (Kd 14 nM) per VNRC3 cell respectively. However, VNRC3 cells did not bind to immobilized eristostatin. Echistatin bound to 495000 sites (Kd 53 nM) per A5 cell and to 443000 sites (Kd 20 nM) per VNRC3 cell. As determined by flow cytometry, radiobinding assay and adhesion studies, binding of both disintegrins to A5 cells and resting platelets and binding of echistatin to VNRC3 cells resulted in the expression of ligand-induced binding sites (LIBS) on the beta 3 subunit. Eristostatin inhibited, more strongly than echistatin, the binding of three monoclonal antibodies: OPG2 (RGD motif dependent), A2A9 (alpha IIb beta 3 complex dependent) and 7E3 (alpha IIb beta 3 and alpha v beta 3 complex dependent) to A5 cells, to resting and to activated platelets and to purified alpha IIb beta 3. Experiments in which echistatin and eristostatin were used alone or in combination to inhibit the binding of 7E3 and OPG2 antibodies to resting platelets suggested that these two disintegrins bind to different but overlapping sites on alpha IIb beta 3 integrin. Monoclonal antibody LM 609 and echistatin seemed to bind to different sites on alpha v beta 3 integrin. However, echistatin inhibited binding of 7E3 antibody to VNRC3 cells and to purified alpha v beta 3 suggesting that alpha v beta 3 and alpha IIb beta 3 might share the same epitope to which both echistatin and 7E3 bind. Eristostatin had no effect in these systems, providing further evidence that it binds to a different epitope on alpha v beta 3. PMID:8760368

Fluctuations of Attentional Networks and Default Mode Network during the Resting State Reflect Variations in Cognitive States: Evidence from a Novel Resting-state Experience Sampling Method.

PubMed

Van Calster, Laurens; D'Argembeau, Arnaud; Salmon, Eric; Peters, Frédéric; Majerus, Steve

2017-01-01

Neuroimaging studies have revealed the recruitment of a range of neural networks during the resting state, which might reflect a variety of cognitive experiences and processes occurring in an individual's mind. In this study, we focused on the default mode network (DMN) and attentional networks and investigated their association with distinct mental states when participants are not performing an explicit task. To investigate the range of possible cognitive experiences more directly, this study proposes a novel method of resting-state fMRI experience sampling, informed by a phenomenological investigation of the fluctuation of mental states during the resting state. We hypothesized that DMN activity would increase as a function of internal mentation and that the activity of dorsal and ventral networks would indicate states of top-down versus bottom-up attention at rest. Results showed that dorsal attention network activity fluctuated as a function of subjective reports of attentional control, providing evidence that activity of this network reflects the perceived recruitment of controlled attentional processes during spontaneous cognition. Activity of the DMN increased when participants reported to be in a subjective state of internal mentation, but not when they reported to be in a state of perception. This study provides direct evidence for a link between fluctuations of resting-state neural activity and fluctuations in specific cognitive processes.

Genetic Perturbations Suggest a Role of the Resting Potential in Regulating the Expression of the Ion Channels of the KCNA and HCN families in Octopus Cells of the Ventral Cochlear Nucleus

PubMed Central

Cao, Xiao-Jie; Oertel, Donata

2017-01-01

Low-voltage-activated K+ (gKL) and hyperpolarization-activated mixed cation conductances (gh) mediate currents, IKL and Ih, through channels of the Kv1 (KCNA) and HCN families respectively and give auditory neurons the temporal precision required for signaling information about the onset, fine structure, and time of arrival of sounds. Being partially activated at rest, gKL and gh contribute to the resting potential and shape responses to even small subthreshold synaptic currents. Resting gKL and gh also affect the coupling of somatic depolarization with the generation of action potentials. To learn how these important conductances are regulated we have investigated how genetic perturbations affect their expression in octopus cells of the ventral cochlear nucleus (VCN). We report five new findings: First, the magnitude of gh and gKL varied over more than two-fold between wild type strains of mice. Second, average resting potentials are not different in different strains of mice even in the face of large differences in average gKL and gh. Third, IKL has two components, one being α-dendrotoxin (α-DTX)-sensitive and partially inactivating and the other being α-DTX-insensitive, tetraethylammonium (TEA)-sensitive, and non-inactivating. Fourth, the loss of Kv1.1 results in diminution of the α-DTX-sensitive IKL, and compensatory increased expression of an α-DTX-insensitive, tetraethylammonium (TEA)-sensitive IKL. Fifth, Ih and IKL are balanced at the resting potential in all wild type and mutant octopus cells even when resting potentials vary in individual cells over nearly 10 mV, indicating that the resting potential influences the expression of gh and gKL. The independence of resting potentials on gKL and gh shows that gKL and gh do not, over days or weeks, determine the resting potential but rather that the resting potential plays a role in regulating the magnitude of either or both gKL and gh. PMID:28065805

CD28 and lipid rafts coordinate recruitment of Lck to the immunological synapse of human T lymphocytes.

PubMed

Tavano, Regina; Gri, Giorgia; Molon, Barbara; Marinari, Barbara; Rudd, Christopher E; Tuosto, Loretta; Viola, Antonella

2004-11-01

In T lymphocytes, the Src family kinase Lck associates lipid rafts and accumulates at the immunological synapse (IS) during T cell stimulation by APCs. Using CD4- or CD28-deficient murine T cells, it was suggested that recruitment of Lck to the IS depends on CD4, whereas CD28 sustains Lck activation. However, in human resting T cells, CD28 is responsible for promoting recruitment of lipid rafts to the IS by an unknown mechanism. Thus, we performed a series of experiments to determine 1) whether Lck is recruited to the IS through lipid rafts; and 2) whether Lck recruitment to the IS of human resting T cells depends on CD4 or on CD28 engagement. We found that CD28, but not CD4, stimulation induced recruitment of Lck into detergent-resistant domains as well as its accumulation at the IS. We also found that Lck recruitment to the IS depends on the CD28 COOH-terminal PxxPP motif. Thus, the CD28-3A mutant, generated by substituting the prolines in positions 208, 211, and 212 with alanines, failed to induce Lck and lipid raft accumulation at the synapse. These results indicate that CD28 signaling orchestrates both Lck and lipid raft recruitment to the IS to amplify T cell activation.

Model of bicarbonate secretion by resting frog stomach fundus mucosa. II. Role of the oxyntopeptic cells.

PubMed

Debellis, L; Iacovelli, C; Frömter, E; Curci, S

1994-10-01

In the present publication we report mainly electrophysiological studies on oxyntopeptic cells of frog gastric mucosa which aim at clarifying a possible involvement of these cells in the process of resting gastric alkali (HCO3-) secretion, described in the preceding publication. The experiments were performed on intact gastric fundus mucosa of Rana esculenta mounted in Ussing chambers. After removal of the muscle and connective tissue layer oxyntopeptic cells were punctured from the serosal surface with conventional or pH-sensitive microelectrodes to measure, besides transepithelial voltage and resistance, the basolateral cell membrane potential, the voltage divider ratio, and the cell pH in response to secretagogues and/or changes in serosal ion concentration. Carbachol (10(-4) mol/l), which transiently stimulated HCO3- secretion by 0.22 mumol.cm-2.h-1, transiently acidified the cells by 0.09 +/- SEM 0.03 pH units (n = 6) and transiently induced an apical cell membrane anion conductance. According to the model of gastric HCO3- secretion presented in the preceding publication, this anion conductance could be involved in gastric HCO3- secretion, mediating, besides Cl- efflux, also apical HCO3- efflux. In addition carbachol stimulated basolateral Na+(HCO3-)n-cotransport, which according to the results from the preceding publication mediates basolateral HCO3- uptake for secretion. By contrast, cAMP-mediated secretagogues, such as histamine or others, which stimulate HCl secretion and transiently alkalinize the oxyntopeptic cells, were found to down-regulate the basolateral Na+(HCO3-)n-cotransporter.(ABSTRACT TRUNCATED AT 250 WORDS)

Increased Resting Intracellular Calcium Modulates NF-κB-dependent Inducible Nitric-oxide Synthase Gene Expression in Dystrophic mdx Skeletal Myotubes*

PubMed Central

Altamirano, Francisco; López, Jose R.; Henríquez, Carlos; Molinski, Tadeusz; Allen, Paul D.; Jaimovich, Enrique

2012-01-01

Duchenne muscular dystrophy (DMD) is a genetic disorder caused by dystrophin mutations, characterized by chronic inflammation and severe muscle wasting. Dystrophic muscles exhibit activated immune cell infiltrates, up-regulated inflammatory gene expression, and increased NF-κB activity, but the contribution of the skeletal muscle cell to this process has been unclear. The aim of this work was to study the pathways that contribute to the increased resting calcium ([Ca2+]rest) observed in mdx myotubes and its possible link with up-regulation of NF-κB and pro-inflammatory gene expression in dystrophic muscle cells. [Ca2+]rest was higher in mdx than in WT myotubes (308 ± 6 versus 113 ± 2 nm, p < 0.001). In mdx myotubes, both the inhibition of Ca2+ entry (low Ca2+ solution, Ca2+-free solution, and Gd3+) and blockade of either ryanodine receptors or inositol 1,4,5-trisphosphate receptors reduced [Ca2+]rest. Basal activity of NF-κB was significantly up-regulated in mdx versus WT myotubes. There was an increased transcriptional activity and p65 nuclear localization, which could be reversed when [Ca2+]rest was reduced. Levels of mRNA for TNFα, IL-1β, and IL-6 were similar in WT and mdx myotubes, whereas inducible nitric-oxide synthase (iNOS) expression was increased 5-fold. Reducing [Ca2+]rest using different strategies reduced iNOS gene expression presumably as a result of decreased activation of NF-κB. We propose that NF-κB, modulated by increased [Ca2+]rest, is constitutively active in mdx myotubes, and this mechanism can account for iNOS overexpression and the increase in reactive nitrogen species that promote damage in dystrophic skeletal muscle cells. PMID:22549782

B-cell subset alterations and correlated factors in HIV-1 infection.

PubMed

Pensieroso, Simone; Galli, Laura; Nozza, Silvia; Ruffin, Nicolas; Castagna, Antonella; Tambussi, Giuseppe; Hejdeman, Bo; Misciagna, Donatella; Riva, Agostino; Malnati, Mauro; Chiodi, Francesca; Scarlatti, Gabriella

2013-05-15

During HIV-1 infection, the development, phenotype, and functionality of B cells are impaired. Transitional B cells and aberrant B-cell populations arise in blood, whereas a declined percentage of resting memory B cells is detected. Our study aimed at pinpointing the demographic, immunological, and viral factors driving these pathological findings, and the role of antiretroviral therapy in reverting these alterations. B-cell phenotype and correlating factors were evaluated. Variations in B-cell subsets were evaluated by flow cytometry in HIV-1-infected individuals naive to therapy, elite controllers, and patients treated with antiretroviral drugs (virological control or failure). Multivariable analysis was performed to identify variables independently associated with the B-cell alterations. Significant differences were observed among patients' groups in relation to all B-cell subsets. Resting memory B cells were preserved in patients naive to therapy and elite controllers, but reduced in treated patients. Individuals naive to therapy and experiencing multidrug failure, as well as elite controllers, had significantly higher levels of activated memory B cells compared to healthy controls. In the multivariate analysis, plasma viral load and nadir CD4 T cells independently correlated with major B-cell alterations. Coinfection with hepatitis C but not hepatitis B virus also showed an impact on specific B-cell subsets. Successful protracted antiretroviral treatment led to normalization of all B-cell subsets with exception of resting memory B cells. Our results indicate that viremia and nadir CD4 T cells are important prognostic markers of B-cell perturbations and provide evidence that resting memory B-cell depletion during chronic infection is not reverted upon successful antiretroviral therapy.

Effects Of Exercise During Bed Rest

NASA Technical Reports Server (NTRS)

Greenleaf, John E.; Bernauer, Edmund M.

1993-01-01

Pair of reports adds to growing body of knowledge of physical deconditioning caused by prolonged bed rest and effectiveness of various exercise regimens in preserving or restoring fitness. Major objective to determine what regimens to prescribe to astronauts before flight, during prolonged weightlessness, and immediately before returning to Earth. Knowledge also benefits patients confined by illness or injury. First report discusses experiment on effects of two types of periodic, intense, short-duration exercise during bed rest. Experiment also discussed in documents "Effects Of Exercise During Prolonged Bed Rest" (ARC-12190), and "Isotonic And Isokinetic Exercise During Bed Rest" (ARC-12180). Second report reviews knowledge acquired with view toward development of protocols for exercise regimens.

Elucidation of conditions allowing conversion of penicillin G and other penicillins to deacetoxycephalosporins by resting cells and extracts of Streptomyces clavuligerus NP1

PubMed Central

Cho, Hiroshi; Adrio, José L.; Luengo, José M.; Wolfe, Saul; Ocran, Simeon; Hintermann, Gilberto; Piret, Jacqueline M.; Demain, Arnold L.

1998-01-01

Using resting cells and extracts of Streptomyces clavuligerus NP1, we have been able to convert penicillin G (benzylpenicillin) to deacetoxycephalosporin G. Conversion was achieved by increasing by 45× the concentration of FeSO4 (1.8 mM) and doubling the concentration of α-ketoglutarate (1.28 mM) as compared with standard conditions used for the normal cell-free conversion of penicillin N to deacetoxycephalosporin C. ATP, MgSO4, KCl, and DTT, important in cell-free expansion of penicillin N, did not play a significant role in the ring expansion of penicillin G by resting cells or cell-free extracts. When these conditions were used with 14 other penicillins, ring expansion was achieved in all cases. PMID:9751702

The Neural Mechanisms Underlying the Decision to Rest in the Presence of Fatigue: A Magnetoencephalography Study

PubMed Central

Ishii, Akira; Tanaka, Masaaki; Watanabe, Yasuyoshi

2014-01-01

Adequate rest is essential to avoid fatigue and disruption of homeostasis. However, the neural mechanisms underlying the decision to rest are not well understood. In the present study, we aimed to clarify the neural mechanisms of this decision-making process using magnetoencephalography. Fifteen healthy volunteers participated in decision and control experiments performed in a cross-over fashion. In the decision experiment, participants performed 1,200 reverse Stroop test trials and were intermittently asked to decide whether they wanted to take a rest or continue. In the control experiments, participants performed 1,200 reverse Stroop test trials and were instructed to press a response button intermittently without making any decision. Changes in oscillatory brain activity were assessed using a narrow-band adaptive spatial filtering method. The levels of decrease in theta (4–8 Hz) band power in left Brodmann's area (BA) 31, alpha (8–13 Hz) band power in left BA 10 and BA 9, and beta (13–25 Hz) band power in right BA 46 and left BA 10 were greater in trials when the participant opted to rest (rest trials) than those in control trials. The decrease in theta band power in BA 31 in the rest trials was positively correlated with the subjective level of fatigue after the decision experiment. These results demonstrated that the dorsolateral prefrontal cortex, frontal pole, and posterior cingulate cortex play a role in the decision to rest in the presence of fatigue. These findings may help clarify the neural mechanisms underlying fatigue and fatigue-related problems. PMID:25303465

Application of Taguchi Design and Response Surface Methodology for Improving Conversion of Isoeugenol into Vanillin by Resting Cells of Psychrobacter sp. CSW4.

PubMed

Ashengroph, Morahem; Nahvi, Iraj; Amini, Jahanshir

2013-01-01

For all industrial processes, modelling, optimisation and control are the keys to enhance productivity and ensure product quality. In the current study, the optimization of process parameters for improving the conversion of isoeugenol to vanillin by Psychrobacter sp. CSW4 was investigated by means of Taguchi approach and Box-Behnken statistical design under resting cell conditions. Taguchi design was employed for screening the significant variables in the bioconversion medium. Sequentially, Box-Behnken design experiments under Response Surface Methodology (RSM) was used for further optimization. Four factors (isoeugenol, NaCl, biomass and tween 80 initial concentrations), which have significant effects on vanillin yield, were selected from ten variables by Taguchi experimental design. With the regression coefficient analysis in the Box-Behnken design, a relationship between vanillin production and four significant variables was obtained, and the optimum levels of the four variables were as follows: initial isoeugenol concentration 6.5 g/L, initial tween 80 concentration 0.89 g/L, initial NaCl concentration 113.2 g/L and initial biomass concentration 6.27 g/L. Under these optimized conditions, the maximum predicted concentration of vanillin was 2.25 g/L. These optimized values of the factors were validated in a triplicate shaking flask study and an average of 2.19 g/L for vanillin, which corresponded to a molar yield 36.3%, after a 24 h bioconversion was obtained. The present work is the first one reporting the application of Taguchi design and Response surface methodology for optimizing bioconversion of isoeugenol into vanillin under resting cell conditions.

Survival of akinetes (resting-state cells of cyanobacteria) in low earth orbit and simulated extraterrestrial conditions.

PubMed

Olsson-Francis, Karen; de la Torre, Rosa; Towner, Martin C; Cockell, Charles S

2009-12-01

Cyanobacteria are photosynthetic organisms that have been considered for space applications, such as oxygen production in bioregenerative life support systems, and can be used as a model organism for understanding microbial survival in space. Akinetes are resting-state cells of cyanobacteria that are produced by certain genera of heterocystous cyanobacteria to survive extreme environmental conditions. Although they are similar in nature to endospores, there have been no investigations into the survival of akinetes in extraterrestrial environments. The aim of this work was to examine the survival of akinetes from Anabaena cylindrica in simulated extraterrestrial conditions and in Low Earth Orbit (LEO). Akinetes were dried onto limestone rocks and sent into LEO for 10 days on the ESA Biopan VI. In ground-based experiments, the rocks were exposed to periods of desiccation, vacuum (0.7×10(-3) kPa), temperature extremes (-80 to 80°C), Mars conditions (-27°C, 0.8 kPa, CO(2)) and UV radiation (325-400 nm). A proportion of the akinete population was able to survive a period of 10 days in LEO and 28 days in Mars simulated conditions, when the rocks were not subjected to UV radiation. Furthermore, the akinetes were able to survive 28 days of exposure to desiccation and low temperature with high viability remaining. Yet long periods of vacuum and high temperature were lethal to the akinetes. This work shows that akinetes are extreme-tolerating states of cyanobacteria that have a practical use in space applications and yield new insight into the survival of microbial resting-state cells in space conditions.

Radiation effects on the resting and proliferating cells in normal tissue of mouse (in Japanese)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hayashi, S.

1972-10-01

The investigation was planned to compare the radiosensitivity of callus- forming cells in resting phase with that in proliferating phase and to compare the recovery of sublethal damage of callusforming cells in resting phase with that in proliferating phase. Experimental animals were 8-week-old female I.C.R./ J.C.L. mice. The maximum sizes of callus were nearly constant among control mice without irradiation after fracture. They, however, were inhibited with administered doses and seemed to be reflected by the Proliferating ability of callus-forming cells after irradiation. The analysis was performed by C.I.D. 50 (callus inhibition dose 50) or dose that produced a specifiedmore » inhibition of callus size in half of the subjects. The callus-forming cells in adult mice were in resting phase without any stimulations, but they extensively entered into proliferating phase after fracture. The labeling index rose around 6 hrs after fracture and reached 9% of the maximum value at 72 are after fracture. Mice were followed by x-ray projection until 60 days after irradiation to observe the callus sizes, and the maximum sizes of callus for each mouse were examined by planimetry to calculate the C.I.D. 50. The callus-forming cell was more radioresistant in resting phase by a factor of 1.5 to 2.0 than in proliferating phase. The cell in resting phase demonstrated a marked recovery of sublethal damage in 4 hrs after administration of 1.000 rads, and it showed essentially no more changes in recovery with the increased time interval to 24 hrs, while the cell in proliferating phase demonstrated almost full recovery of sublethal damage is 2 hrs after administration of 300 rads and showed a fluctuated pattern of recovery with a dip at 4 hrs of the time interval in two fractions. (auth)« less

Effect of minerals on accumulation of Cs by fungus Saccaromyces cerevisiae.

PubMed

Ohnuki, Toshihiko; Sakamoto, Fuminori; Yamasaki, Shinya; Kozai, Naofumi; Shiotsu, Hiroyuki; Utsunomiya, Satoshi; Watanabe, Naoko; Kozaki, Tamotsu

2015-06-01

The accumulation of Cs by unicellular fungus of Saccharomyces cerevisiae in the presence of minerals has been studied to elucidate the role of microorganisms in the migration of radioactive Cs in the environment. Two different types of experiments were employed: experiments using stable Cs to examine the effect of a carbon source on the accumulation of Cs, and accumulation experiments of radioactive Cs from agar medium containing (137)Cs and zeolite, vermiculite, phlogopite, smectite, mica, or illite as mineral supplements. In the former type of experiments, the Cs-accumulated cells were analyzed by scanning electron microscopy equipped with energy dispersive X-ray analysis (SEM-EDS). In the latter type, the radioactivity in the yeast cells was measured by an autoradiography technique. When a carbon source was present, higher amounts of Cs accumulated in the cells than in the resting condition without a carbon source. Analyses with SEM-EDS showed that no mineral formed on the cell surface. These results indicate that the yeast cells accumulate Cs by adsorption on the cell surface and intracellular accumulation. In the presence of minerals in the agar medium, the radioactivity in the yeast cells was in the order of mica > smectite, illite > vermiculite, phlogopite, zeolite. This order is inversely correlated to the ratio of the concentration of radioactive Cs between the minerals and the medium solution. These results strongly suggest that the yeast accumulates radioactive Cs competitively with minerals. Copyright © 2015 Elsevier Ltd. All rights reserved.

Regulation of intracellular pH in LLC-PK1 cells by Na+/H+ exchange.

PubMed

Montrose, M H; Murer, H

1986-01-01

Suspensions of LLC-PK1 cells (a continuous epitheliod cell line with renal characteristics) are examined for mechanisms of intracellular pH regulation using the fluorescent probe BCECF. Initial experiments determine suitable calibration procedures for use of the BCECF fluorescent signal. They also determine that the cell suspension contains cells which (after 4 hr in suspension) have Na+ and K+ gradients comparable to those of cells in monolayer culture. The steady-state intracellular pH (7.05 +/- 0.01, n = 5) of cells which have recovered in (pH 7.4) Na+-containing medium is not affected over several minutes by addition of 100 microM amiloride or removal of extracellular Na+ (Na+o less than 1 mM). In contrast, when the cells recover from an acid load (caused by NH4 preincubation and removal), the recovery is largely Na+ dependent and is sensitive to 100 microM amiloride. These results suggest that with resting pH near neutrality, both Na+o/H+i and Na+i/H+o exchange reactions are functionally inactive (compared to cellular buffering capacity). In contrast, Na+o/H+i exchange is activated by an increased cellular acid load. This activation may be observed directly either as a stimulation of net H+ efflux or net Na+ influx with decreasing intracellular pH. The extrapolation of this latter data suggests a "set point" of Na+/H+ exchange of approximately pH 7.0, consistent with the observed resting intracellular pH of approximately 7.05.

Interleukin-induced increase in Ia expression by normal mouse B cells.

PubMed

Roehm, N W; Leibson, H J; Zlotnik, A; Kappler, J; Marrack, P; Cambier, J C

1984-09-01

The constitutive culture supernatant (SN) of the macrophage tumor line P388D1 (P388 SN) and the concanavalin A (Con A)-induced culture supernatant of the T cell hybridoma FS6-14.13 (FS6 Con A SN) were shown to contain nonspecific factors capable of inducing increased Ia expression by normal resting B cells in a dose-dependent manner. In six consecutive experiments the relative increase in Ia expression induced by P388 SN was 4.9 +/- 0.9, with FS6 Con A SN 10.7 +/- 1.5, and with a combination of both preparations 13.0 +/- 1.7. This increase in Ia expression was observed to occur in virtually all the B cells, reaching maximum levels within 24 h of culture. The interleukin-induced increase in B cell Ia expression occurred in the absence of ancillary signals provided by ligand-receptor Ig cross-linking and despite the fact that virtually all the control B cells, cultured in the absence of factors, remained in G0. These results suggest that functional receptors for at least some interleukins are expressed on normal resting B cells and their effects can be manifest in the absence of additional activating signals. The increased Ia expression induced by the nonspecific factor preparations was shown to be correlated with enhanced antigen-presenting capacity by the B cells to T cell hybridomas. The nature of the interleukins responsible for these effects remains to be definitively determined, however, the activity of FS6 Con A SN was shown to correlate with B cell growth factor activity and increased B cell Ia expression was not observed using interleukin 2 (IL-2) or interferon-gamma, prepared by recombinant DNA technology.

Simian virus 40 small t antigen is not required for the maintenance of transformation but may act as a promoter (cocarcinogen) during establishment of transformation in resting rat cells.

PubMed Central

Seif, R; Martin, R G

1979-01-01

Simian virus 40 deletion mutants affecting the 20,000-dalton (20K) t antigen and tsA mutants rendering the 90K T antigen temperature sensitive, as well as double mutants containing both mutations, induced host DNA synthesis in resting rat cells at the restrictive temperature. Nonetheless, the deletion mutants and double mutants did not induce transformation in resting cells even at the permissive temperature. On the other hand, the deletion mutants did induce full transformants when actively growing rat cells were infected; the transformants grew efficiently in agar and to high saturation densities on platic. The double mutants did not induce T-antigen-independent (temperature-insensitive) transformants which were shown previously to arise preferentially from resting cells. Thus, small t antigen was dispensable for the maintenance of the transformed phenotype in T-antigen-dependent rat transformants (transformants derived from growing cells) and may play a role in the establishment of T-antigen-independent transformants. We attempt to establish a parallel between transformation induced by chemical carcinogens and simian virus 40-induced transformation. Images PMID:229274

Simian virus 40 small t antigen is not required for the maintenance of transformation but may act as a promoter (cocarcinogen) during establishment of transformation in resting rat cells.

PubMed

Seif, R; Martin, R G

1979-12-01

Simian virus 40 deletion mutants affecting the 20,000-dalton (20K) t antigen and tsA mutants rendering the 90K T antigen temperature sensitive, as well as double mutants containing both mutations, induced host DNA synthesis in resting rat cells at the restrictive temperature. Nonetheless, the deletion mutants and double mutants did not induce transformation in resting cells even at the permissive temperature. On the other hand, the deletion mutants did induce full transformants when actively growing rat cells were infected; the transformants grew efficiently in agar and to high saturation densities on platic. The double mutants did not induce T-antigen-independent (temperature-insensitive) transformants which were shown previously to arise preferentially from resting cells. Thus, small t antigen was dispensable for the maintenance of the transformed phenotype in T-antigen-dependent rat transformants (transformants derived from growing cells) and may play a role in the establishment of T-antigen-independent transformants. We attempt to establish a parallel between transformation induced by chemical carcinogens and simian virus 40-induced transformation.

Evidence for Direct Electron Transfer by a Gram-Positive Bacterium Isolated from a Microbial Fuel Cell▿†

PubMed Central

Wrighton, K. C.; Thrash, J. C.; Melnyk, R. A.; Bigi, J. P.; Byrne-Bailey, K. G.; Remis, J. P.; Schichnes, D.; Auer, M.; Chang, C. J.; Coates, J. D.

2011-01-01

Despite their importance in iron redox cycles and bioenergy production, the underlying physiological, genetic, and biochemical mechanisms of extracellular electron transfer by Gram-positive bacteria remain insufficiently understood. In this work, we investigated respiration by Thermincola potens strain JR, a Gram-positive isolate obtained from the anode surface of a microbial fuel cell, using insoluble electron acceptors. We found no evidence that soluble redox-active components were secreted into the surrounding medium on the basis of physiological experiments and cyclic voltammetry measurements. Confocal microscopy revealed highly stratified biofilms in which cells contacting the electrode surface were disproportionately viable relative to the rest of the biofilm. Furthermore, there was no correlation between biofilm thickness and power production, suggesting that cells in contact with the electrode were primarily responsible for current generation. These data, along with cryo-electron microscopy experiments, support contact-dependent electron transfer by T. potens strain JR from the cell membrane across the 37-nm cell envelope to the cell surface. Furthermore, we present physiological and genomic evidence that c-type cytochromes play a role in charge transfer across the Gram-positive bacterial cell envelope during metal reduction. PMID:21908627

Heterotrophic Bioleaching of Sulfur, Iron, and Silicon Impurities from Coal by Fusarium oxysporum FE and Exophiala spinifera FM with Growing and Resting Cells.

PubMed

Etemadzadeh, Shekoofeh Sadat; Emtiazi, Giti; Etemadifar, Zahra

2016-06-01

Coal is the most abundant fossil fuel containing sulfur and other elements which promote environmental pollution after burning. Also the silicon impurities make the transportation of coal expensive. In this research, two isolated fungi from oil contaminated soil with accessory number KF554100 (Fusarium oxysporum FE) and KC925672 (Exophiala spinifera FM) were used for heterotrophic biological leaching of coal. The leaching were detected by FTIR, CHNS, XRF analyzer and compared with iron and sulfate released in the supernatant. The results showed that E. spinifera FM produced more acidic metabolites in growing cells, promoting the iron and sulfate ions removal while resting cells of F. oxysporum FE enhanced the removal of aromatic sulfur. XRF analysis showed that the resting cells of E. spinifera FM proceeded maximum leaching for iron and silicon (48.8, 43.2 %, respectively). CHNS analysis demonstrated that 34.21 % of sulfur leaching was due to the activities of resting cells of F. oxysporum FE. Also F. oxysporum FE removed organic sulfur more than E. spinifera FM in both growing and resting cells. FTIR data showed that both fungi had the ability to remove pyrite and quartz from coal. These data indicated that inoculations of these fungi to the coal are cheap and impurity removals were faster than autotrophic bacteria. Also due to the removal of dibenzothiophene, pyrite, and quartz, we speculated that they are excellent candidates for bioleaching of coal, oil, and gas.

Behavioral and Physiological Changes during Benthic-Pelagic Transition in the Harmful Alga, Heterosigma akashiwo: Potential for Rapid Bloom Formation

PubMed Central

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

Behavioral and physiological significance of minimum resting metabolic rate in king penguins.

PubMed

Halsey, L G; Butler, P J; Fahlman, A; Woakes, A J; Handrich, Y

2008-01-01

Because fasting king penguins (Aptenodytes patagonicus) need to conserve energy, it is possible that they exhibit particularly low metabolic rates during periods of rest. We investigated the behavioral and physiological aspects of periods of minimum metabolic rate in king penguins under different circumstances. Heart rate (f(H)) measurements were recorded to estimate rate of oxygen consumption during periods of rest. Furthermore, apparent respiratory sinus arrhythmia (RSA) was calculated from the f(H) data to determine probable breathing frequency in resting penguins. The most pertinent results were that minimum f(H) achieved (over 5 min) was higher during respirometry experiments in air than during periods ashore in the field; that minimum f(H) during respirometry experiments on water was similar to that while at sea; and that RSA was apparent in many of the f(H) traces during periods of minimum f(H) and provides accurate estimates of breathing rates of king penguins resting in specific situations in the field. Inferences made from the results include that king penguins do not have the capacity to reduce their metabolism to a particularly low level on land; that they can, however, achieve surprisingly low metabolic rates at sea while resting in cold water; and that during respirometry experiments king penguins are stressed to some degree, exhibiting an elevated metabolism even when resting.

Microbial degradation of parathion. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Gibson, W. L.

1972-01-01

An organism capable of utilizing parathion as the sole carbon and energy source was isolated by enrichment culture techniques. The bacterium was characterized and tentatively classified as Pseudomonas aeruginosa. A pH of 7.0 - 7.5 and temperature of 30 C were found to be optimum for the consumption of parathion. Virtually no oxygen utilization was observed with resting cell suspensions when nonsolubilized parathion was employed. The use of ethanol as solvent for parathion in resting cell studies or preincubation of cells in ethanol obviated this problem and rapid parathion oxidation was demonstrable. Approximately 80% of the parathion consumed by resting cells was present terminally as carbon dioxide. Permeability of the cell to parathion or its metabolites was contingent upon the use of ethanol as either solvent or denaturant. Metabolites were tentatively identified by thin layer chromatography.

Biomarkers of Dose and Effect of Inhaled Ozone in Resting versus Exercising Human Subjects: Comparison with Resting Rats

PubMed Central

Hatch, Gary E.; McKee, John; Brown, James; McDonnell, William; Seal, Elston; Soukup, Joleen; Slade, Ralph; Crissman, Kay; Devlin, Robert

2013-01-01

To determine the influence of exercise on pulmonary dose of inhaled pollutants, we compared biomarkers of inhaled ozone (O3) dose and toxic effect between exercise levels in humans, and between humans and rats. Resting human subjects were exposed to labeled O3 (18O3, 0.4 ppm, for 2 hours) and alveolar O3 dose measured as the concentration of excess 18O in cells and extracellular material of nasal, bronchial, and bronchoalveolar lavage fluid (BALF). We related O3 dose to effects (changes in BALF protein, LDH, IL-6, and antioxidant substances) measurable in the BALF. A parallel study of resting subjects examined lung function (FEV1) changes following O3. Subjects exposed while resting had 18O concentrations in BALF cells that were 1/5th of those of exercising subjects and directly proportional to the amount of O3 breathed during exposure. Quantitative measures of alveolar O3 dose and toxicity that were observed previously in exercising subjects were greatly reduced or non-observable in O3 exposed resting subjects. Resting rats and resting humans were found to have a similar alveolar O3 dose. PMID:23761957

Pulmonary atelectasis during low stretch ventilation: "open lung" versus "lung rest" strategy.

PubMed

Fanelli, Vito; Mascia, Luciana; Puntorieri, Valeria; Assenzio, Barbara; Elia, Vincenzo; Fornaro, Giancarlo; Martin, Erica L; Bosco, Martino; Delsedime, Luisa; Fiore, Tommaso; Grasso, Salvatore; Ranieri, V Marco

2009-03-01

Limiting tidal volume (VT) may minimize ventilator-induced lung injury (VILI). However, atelectasis induced by low VT ventilation may cause ultrastructural evidence of cell disruption. Apoptosis seems to be involved as protective mechanisms from VILI through the involvement of mitogen-activated protein kinases (MAPKs). We examined the hypothesis that atelectasis may influence the response to protective ventilation through MAPKs. Prospective randomized study. University animal laboratory. Adult male 129/Sv mice. Isolated, nonperfused lungs were randomized to VILI: VT of 20 mL/kg and positive end-expiratory pressure (PEEP) zero; low stretch/lung rest: VT of 6 mL/kg and 8-10 cm H2O of PEEP; low stretch/open lung: VT of 6 mL/kg, two recruitment maneuvers and 14-16 cm H2O of PEEP. Ventilator settings were adjusted using the stress index. Both low stretch strategies equally blunted the VILI-induced derangement of respiratory mechanics (static volume-pressure curve), lung histology (hematoxylin and eosin), and inflammatory mediators (interleukin-6, macrophage inflammatory protein-2 [enzyme-linked immunosorbent assay], and inhibitor of nuclear factor-kB[Western blot]). VILI caused nuclear swelling and membrane disruption of pulmonary cells (electron microscopy). Few pulmonary cells with chromatin condensation and fragmentation were seen during both low stretch strategies. However, although cell thickness during low stretch/open lung was uniform, low stretch/lung rest demonstrated thickening of epithelial cells and plasma membrane bleb formation. Compared with the low stretch/open lung, low stretch/lung rest caused a significant decrease in apoptotic cells (terminal deoxynucleotidyl transferase mediated deoxyuridine-triphosphatase nick end-labeling) and tissue expression of caspase-3 (Western blot). Both low stretch strategies attenuated the activation of MAPKs. Such reduction was larger during low stretch/open lung than during low stretch/lung rest (p < 0.001). Low stretch strategies provide similar attenuation of VILI. However, low stretch/lung rest strategy is associated to less apoptosis and more ultrastructural evidence of cell damage possibly through MAPKs-mediated pathway.

Erythrocyte 2,3-diphosphoglycerate and serum enzyme concentrations in trained and sedentary men.

PubMed

Lijnen, P; Hespel, P; Van Oppens, S; Fiocchi, R; Goossens, W; Vanden Eynde, E; Amery, A

1986-04-01

The acute effect of exercise on the intraerythrocyte 2,3-diphosphoglycerate concentration and on various serum enzymes and some related variables was investigated in 14 male athletes before and after a 50-min cross-country run and compared at rest to 15 sedentary subjects. Compared to the sedentary subjects, the athletes had higher resting levels of serum creatine phosphokinase, plasma myoglobin, and renin substrate but had a lower plasma renin activity. The red blood cell 2,3-diphosphoglycerate concentration increased after exercise in the runners and was not different at rest between the athletes and the sedentary subjects. Our data therefore suggest that the resting plasma renin activity is reduced in athletes when compared to sedentary subjects. Training seems however not to alter the resting level of 2,3-diphosphoglycerate in the red blood cells.

Radioprotective activity of Gentiana lutea extract and mangiferin.

PubMed

Menkovic, Nebojsa; Juranic, Zorica; Stanojkovic, Tatjana; Raonic-Stevanovic, Tatjana; Savikin, Katarina; Zdunić, Gordana; Borojevic, Nenad

2010-11-01

Radioprotective/sensitizing actions of Gentiana lutea aqueous-ethanol extract and mangiferin on radiation-induced effects on different types of cells were investigated. The study focused on the decreasing survival of normal human immunocompetent cells, the survival of the malignant cells in vitro, and the survival of ex vivo irradiated cells before and after consumption of the extract by healthy volunteers. The in vitro experiments showed that mangiferin could inhibit cytotoxic action of ionizing irradiation (doses of 6 and 8 Gy) only on normal resting human PBMC, not stimulated for proliferation. Orally consumed G. lutea extract showed the potential to reduce the cytotoxic effect of x-ray irradiation on normal human immunocompetent cells PBMC of some healthy people, without changing the susceptibility of malignant cells to be destroyed by irradiation. Since the radioprotective effect was individually dependent, further clinical studies are needed. Copyright © 2010 John Wiley & Sons, Ltd.

The Development of a Cell-Assembly for the Treatment of Irradiated Fuels on a Semi-Industrial Scale; ETUDE CONCERNANT LA REALISATION D'UN ENSEMBLE DE CELLULES DESTINEES A DES TRAITEMENTS DE COMBUSTIBLES IRRADIES A L'ECHELLE SEMI-INDUSTRIELLE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Faugeras, P.; Couture, J.; Lefort, G.

1961-01-01

The main studies and experiments involved in the development of a cell- assembly for the treatment of irradiated fuels on a semi-industrial scale are described. It must be possible to modify or transform each of these cells without interrupting the rest of the pilot. A full-scale prototype cell ( 3 x 4 x 6 m) was built with an alpha k-protection independent of the gamma - protection. It features all the main characteristics: tightness to gamma losses, dense glass lighting, and ventilation. This cell has made possible trials on transfer, remote-controls and teledismantling, as well as the development of newmore » methods of rapidly connecting hydraulic circuits. The final form is given of the cells selected for the pilot. (auth)« less

Commercial truck parking detection technology evaluation for Columbia County rest areas.

DOT National Transportation Integrated Search

2016-11-01

Rest areas along Floridas interstate routes are heavily utilized by commercial trucks for overnight parking. : Many of the rest areas regularly experience 100% utilization of the commercial truck parking spaces : during the evening and early morni...

[Membrane model of the regulation of proliferation: the theory and interpretation of an experiment].

PubMed

Volkov, E I

1983-04-01

The role of cell surface physical organization in the cell cycle regulation is analyzed within the framework of the earlier proposed theory (Chernavskii et al., 1982). Two models of cell surface are considered: hard-frame fluid-mosaic model (latticemosaic) and the fluid-mosaic one. The former deals with normal cells. The existence of integral carcasse or "frame" which is formed by the essential part of cross-linked membrane components and may have at least two different conformational states is hypothesized. The second model describes membranes of tumour cells. With the latter theory any mitogen (excluding the restoration of nutrient depletion) reduces the mechanical tensile strength of the frame and stimulates the general structural rearrangement of the plasma membrane. There are only two conformational transitions during the cell cycle which serve as signals for the beginning of S and M phases. If the values of tensile strength are great enough and therefore the conformational transitions are impossible, the cells pass into the resting (prereplicative--G01, or premitotical--G02) state. Three types of experiments are interpreted in the proposed theory: a) on differences in the action of growth factors on normal and tumour cell cycle, b) on the necessary condition for mitogenicity of lectins, c) on the stimulation of proliferation by mechanical deformation of cells.

The many faces of REST oversee epigenetic programming of neuronal genes.

PubMed

Ballas, Nurit; Mandel, Gail

2005-10-01

Nervous system development relies on a complex signaling network to engineer the orderly transitions that lead to the acquisition of a neural cell fate. Progression from the non-neuronal pluripotent stem cell to a restricted neural lineage is characterized by distinct patterns of gene expression, particularly the restriction of neuronal gene expression to neurons. Concurrently, cells outside the nervous system acquire and maintain a non-neuronal fate that permanently excludes expression of neuronal genes. Studies of the transcriptional repressor REST, which regulates a large network of neuronal genes, provide a paradigm for elucidating the link between epigenetic mechanisms and neurogenesis. REST orchestrates a set of epigenetic modifications that are distinct between non-neuronal cells that give rise to neurons and those that are destined to remain as nervous system outsiders.

Two-Step Production of Phenylpyruvic Acid from L-Phenylalanine by Growing and Resting Cells of Engineered Escherichia coli: Process Optimization and Kinetics Modeling.

PubMed

Hou, Ying; Hossain, Gazi Sakir; Li, Jianghua; Shin, Hyun-Dong; Liu, Long; Du, Guocheng; Chen, Jian

2016-01-01

Phenylpyruvic acid (PPA) is widely used in the pharmaceutical, food, and chemical industries. Here, a two-step bioconversion process, involving growing and resting cells, was established to produce PPA from l-phenylalanine using the engineered Escherichia coli constructed previously. First, the biotransformation conditions for growing cells were optimized (l-phenylalanine concentration 20.0 g·L-1, temperature 35°C) and a two-stage temperature control strategy (keep 20°C for 12 h and increase the temperature to 35°C until the end of biotransformation) was performed. The biotransformation conditions for resting cells were then optimized in 3-L bioreactor and the optimized conditions were as follows: agitation speed 500 rpm, aeration rate 1.5 vvm, and l-phenylalanine concentration 30 g·L-1. The total maximal production (mass conversion rate) reached 29.8 ± 2.1 g·L-1 (99.3%) and 75.1 ± 2.5 g·L-1 (93.9%) in the flask and 3-L bioreactor, respectively. Finally, a kinetic model was established, and it was revealed that the substrate and product inhibition were the main limiting factors for resting cell biotransformation.

Commercial truck parking detection technology evaluation for Columbia County rest areas [summary].

DOT National Transportation Integrated Search

2016-12-01

Rest areas along Floridas interstate highways are heavily used by commercial trucks for overnight parking. Many rest areas regularly experience 100% utilization of the commercial truck parking spaces during the evening and early morning hours. Dri...

Control of resting membrane potential by delayed rectifier potassium currents in ferret airway smooth muscle cells.

PubMed Central

Fleischmann, B K; Washabau, R J; Kotlikoff, M I

1993-01-01

1. In order to determine the physiological role of specific potassium currents in airway smooth muscle, potassium currents were measured in freshly dissociated ferret trachealis cells using the nystatin-permeabilized, whole-cell method, at 35 degrees C. 2. The magnitude of the outward currents was markedly increased as bath temperature was increased from 22 to 35 degrees C. This increase was primarily due to the increase in maximum potassium conductance (gK,max), although there was also a small leftward shift in the relationship between gK and voltage at higher temperatures. The maximum conductance and the kinetics of current activation and inactivation were also temperature dependent. At 35 degrees C, gating of the current was steeply voltage dependent between -40 and 0 mV. Current activation was well fitted by fourth-order kinetics; the mean time constants of activation (30 mV clamp step) were 1.09 +/- 0.17 and 1.96 +/- 0.27 ms at 35 and 22 degrees C, respectively. 3. Outward currents using the nystatin method were qualitatively similar to delayed rectifier currents recorded in dialysed cells with high calcium buffering capacity solutions. 4-Aminopyridine (4-AP; 2 mM), a specific blocker of delayed rectifier potassium channels in this tissue, inhibited over 80% of the outward current evoked by voltage-clamp steps to between -10 and +20 mV (n = 6). Less than 5% of the outward current was blocked over the same voltage range by charybdotoxin (100 nM; n = 15), a specific antagonist of large-conductance, calcium-activated potassium channels in this tissue. 4. The degree to which delayed rectifier and calcium-activated potassium conductances control resting membrane potential was examined in current-clamp experiments. The resting membrane potential of current clamped cells was -33.6 +/- 1.0 mV (n = 62). Application of 4-AP (2 mM) resulted in a 14.4 +/- 1.0 mV depolarization (n = 8) and an increase in input resistance. Charybdotoxin (100 nM) had no effect on resting membrane potential (n = 6). 5. Force measurements were made in isolated strips of trachealis muscle to determine the effect of pharmacological blockade of individual potassium conductances on resting tone. In the presence of tetrodotoxin (1 microM) and atropine (1 microM), 4-AP increased baseline tension in a dose-dependent manner, with an EC50 of 1.8 mM (n = 13); application of 5 mM 4-AP increased tone to 86.8 +/- 8.1% of that produced by 1 microM methacholine, and this tone was almost completely inhibited by nifedipine (1 microM).(ABSTRACT TRUNCATED AT 400 WORDS) PMID:8271220

Engineering of a synthetic quadrastable gene network to approach Waddington landscape and cell fate determination.

PubMed

Wu, Fuqing; Su, Ri-Qi; Lai, Ying-Cheng; Wang, Xiao

2017-04-11

The process of cell fate determination has been depicted intuitively as cells travelling and resting on a rugged landscape, which has been probed by various theoretical studies. However, few studies have experimentally demonstrated how underlying gene regulatory networks shape the landscape and hence orchestrate cellular decision-making in the presence of both signal and noise. Here we tested different topologies and verified a synthetic gene circuit with mutual inhibition and auto-activations to be quadrastable, which enables direct study of quadruple cell fate determination on an engineered landscape. We show that cells indeed gravitate towards local minima and signal inductions dictate cell fates through modulating the shape of the multistable landscape. Experiments, guided by model predictions, reveal that sequential inductions generate distinct cell fates by changing landscape in sequence and hence navigating cells to different final states. This work provides a synthetic biology framework to approach cell fate determination and suggests a landscape-based explanation of fixed induction sequences for targeted differentiation.

Persistence of Only a Minute Viable Population in Chlorotic Microcystis aeruginosa PCC 7806 Cultures Obtained by Nutrient Limitation.

PubMed

Meireles, Diogo de Abreu; Schripsema, Jan; Arnholdt, Andrea Cristina Vetö; Dagnino, Denise

2015-01-01

Cultures from the cyanobacterial strain Microcystis aeruginosa PCC 7806 submitted to nutrient limitation become chlorotic. When returned to nutrient rich conditions these cultures regain their green colour. The aim of this study was to verify whether the cells in these cultures could be considered resting stages allowing the survival of periods of nutrient starvation as has been reported for Synechococcus PCC 7942. The experiments with Microcystis were carried out in parallel with Synechococcus cultures to rule out the possibility that any results obtained with Microcystis were due to our particular experimental conditions. The results of the experiments with Synechococcus PCC 7942 cultures were comparable to the reported in the literature. For Microcystis PCC 7806 a different response was observed. Analysis of chlorotic Microcystis cultures by flow cytometry showed that the phenotype of the cells in the population was not homogenous: the amount of nucleic acids was about the same in all cells but only around one percent of the population emitted red autofluorescence indicating the presence of chlorophyll. Monitoring of the reversion of chlorosis by flow cytometry showed that the re-greening was most likely the result of the division of the small population of red autofluorescent cells originally present in the chlorotic cultures. This assumption was confirmed by analysing the integrity of the DNA and the membrane permeability of the cells of chlorotic cultures. Most of the DNA of these cultures was degraded and only the autofluorescent population of the chlorotic cultures showed membrane integrity. Thus, contrary to what has been reported for other cyanobacterial genera, most of the cells in chlorotic Microcystis cultures are not resting stages but dead. It is interesting to note that the red autofluorescent cells of green and chlorotic cultures obtained in double strength ASM-1 medium differ with respect to metabolism: levels of emission of red autofluorescence are higher in the cells of green cultures and the ability to convert fluorescein diacetate of these cells are heterogeneous when compared to the autofluorescent cells of chlorotic cultures. Thus, the small population of the red autofluorescent cells of chlorotic cultures are in a differentiated metabolic state that allow them to persist in conditions in which most of the population loses viability; persistent cells can be detected in chlorotic cultures maintained for more than a year.

Persistence of Only a Minute Viable Population in Chlorotic Microcystis aeruginosa PCC 7806 Cultures Obtained by Nutrient Limitation

PubMed Central

de Abreu Meireles, Diogo; Schripsema, Jan; Vetö Arnholdt, Andrea Cristina; Dagnino, Denise

2015-01-01

Cultures from the cyanobacterial strain Microcystis aeruginosa PCC 7806 submitted to nutrient limitation become chlorotic. When returned to nutrient rich conditions these cultures regain their green colour. The aim of this study was to verify whether the cells in these cultures could be considered resting stages allowing the survival of periods of nutrient starvation as has been reported for Synechococcus PCC 7942. The experiments with Microcystis were carried out in parallel with Synechococcus cultures to rule out the possibility that any results obtained with Microcystis were due to our particular experimental conditions. The results of the experiments with Synechococcus PCC 7942 cultures were comparable to the reported in the literature. For Microcystis PCC 7806 a different response was observed. Analysis of chlorotic Microcystis cultures by flow cytometry showed that the phenotype of the cells in the population was not homogenous: the amount of nucleic acids was about the same in all cells but only around one percent of the population emitted red autofluorescence indicating the presence of chlorophyll. Monitoring of the reversion of chlorosis by flow cytometry showed that the re-greening was most likely the result of the division of the small population of red autofluorescent cells originally present in the chlorotic cultures. This assumption was confirmed by analysing the integrity of the DNA and the membrane permeability of the cells of chlorotic cultures. Most of the DNA of these cultures was degraded and only the autofluorescent population of the chlorotic cultures showed membrane integrity. Thus, contrary to what has been reported for other cyanobacterial genera, most of the cells in chlorotic Microcystis cultures are not resting stages but dead. It is interesting to note that the red autofluorescent cells of green and chlorotic cultures obtained in double strength ASM-1 medium differ with respect to metabolism: levels of emission of red autofluorescence are higher in the cells of green cultures and the ability to convert fluorescein diacetate of these cells are heterogeneous when compared to the autofluorescent cells of chlorotic cultures. Thus, the small population of the red autofluorescent cells of chlorotic cultures are in a differentiated metabolic state that allow them to persist in conditions in which most of the population loses viability; persistent cells can be detected in chlorotic cultures maintained for more than a year. PMID:26181753

[Study of the effect of JNK signal transduction pathway in intense noise-induced apoptosis in cochlea of guinea pig].

PubMed

Xue, Qiuhong; Chen, Jia; Gong, Shusheng; Xie, Jing; He, Jian; Chen, Xiaolin

2009-12-01

To investigate the mechanism of intense noise-induced cochlea cells death in guinea pig, and the effect of JNK signal transduction pathway in the procedure of cochlea cells apoptosis by intense noise-induced. Thirty-two guinea pigs were randomly divided into 4 groups. The guinea pigs in the experiment groups were exposed to 4 kHz narrow band noise at 120 dB SPL for 4 h. After the noise expose for 1, 4, 14 days of the experiment guinea pigs, ABR of the guinea pigs on experiment and control groups were tested before put them to death. Four guinea pig's cochleas of every group were taken to paraffin section, and the rest was extracted the total cochlear's protein. Apoptosis was tested by terminal deoxynucleotidyl Transferase (TdT)-mediated deoxyuridine triphosphate (d-UTP) nick and labeling method (TUNEL). The phosphorylation of JNK and c-Jun were tested by immunohistochemistry and western blot methods. Tunel-Positive cells in the Corti's, SGC and SV of experiment groups, and there have significant differences compared with the control group (P<0.01) and Tunel-Positive cells are most in 1 d experiment group. The positive cells of P-JNK and P-c-Jun could be detected in guinea pig's cochleas after noise exposed, but no positive cells were found in the control. Protein levels of P-JNK and P-c-Jun were risen up and activated quickly after noise exposed, and achieved peak in 1 d, 4 d and then fallen-offs, but still maintained higher levels within 14 d. Intense noise causes cochlea cell lesion by inducing apoptosis to result in and JNK signal transduction pathway plays an important role in the procedure of apoptosis.

Less head motion during MRI under task than resting-state conditions.

PubMed

Huijbers, Willem; Van Dijk, Koene R A; Boenniger, Meta M; Stirnberg, Rüdiger; Breteler, Monique M B

2017-02-15

Head motion reduces data quality of neuroimaging data. In three functional magnetic resonance imaging (MRI) experiments we demonstrate that people make less head movements under task than resting-state conditions. In Experiment 1, we observed less head motion during a memory encoding task than during the resting-state condition. In Experiment 2, using publicly shared data from the UCLA Consortium for Neuropsychiatric Phenomics LA5c Study, we again found less head motion during several active task conditions than during a resting-state condition, although some task conditions also showed comparable motion. In the healthy controls, we found more head motion in men than in women and more motion with increasing age. When comparing clinical groups, we found that patients with a clinical diagnosis of bipolar disorder, or schizophrenia, move more compared to healthy controls or patients with ADHD. Both these experiments had a fixed acquisition order across participants, and we could not rule out that a first or last scan during a session might be particularly prone to more head motion. Therefore, we conducted Experiment 3, in which we collected several task and resting-state fMRI runs with an acquisition order counter-balanced. The results of Experiment 3 show again less head motion during several task conditions than during rest. Together these experiments demonstrate that small head motions occur during MRI even with careful instruction to remain still and fixation with foam pillows, but that head motion is lower when participants are engaged in a cognitive task. These finding may inform the choice of functional runs when studying difficult-to-scan populations, such as children or certain patient populations. Our findings also indicate that differences in head motion complicate direct comparisons of measures of functional neuronal networks between task and resting-state fMRI because of potential differences in data quality. In practice, a task to reduce head motion might be especially useful when acquiring structural MRI data such as T1/T2-weighted and diffusion MRI in research and clinical settings. Copyright © 2016 Elsevier Inc. All rights reserved.

Determination of Rest Mass Energy of the Electron by a Compton Scattering Experiment

ERIC Educational Resources Information Center

Prasannakumar, S.; Krishnaveni, S.; Umesh, T. K.

2012-01-01

We report here a simple Compton scattering experiment which may be carried out in graduate and undergraduate laboratories to determine the rest mass energy of the electron. In the present experiment, we have measured the energies of the Compton scattered gamma rays with a NaI(Tl) gamma ray spectrometer coupled to a 1 K multichannel analyzer at…

HuB/C/D, nPTB, REST4, and miR-124 regulators of neuronal cell identity are also utilized in the lens.

PubMed

Bitel, Claudine L; Perrone-Bizzozero, Nora I; Frederikse, Peter H

2010-11-04

An interlocking network of transcription factors, RNA binding proteins, and miRNAs globally regulates gene expression and alternative splicing throughout development, and ensures the coordinated mutually exclusive expression of non-neural and neuronal forms of these factors during neurogenesis. Striking similarities between lens fiber cell and neuron cell morphology led us to determine if these factors are also used in the lens. HuR and polypyrimidine tract binding protein (PTB) have been described as 'global regulators' of RNA alternative splicing, stability, and translation in non-neuronal (including ectodermal) tissues examined to date in diverse species, and REST/NRSF (RE-1 Silencing Transcription Factor/Neuron Restrictive Silencing Factor) represses>2,000 neuronal genes in all non-neuronal tissues examined to date, but has not included the lens. During neurogenesis these factors are replaced by what has been considered neuron-specific HuB/C/D, nPTB, and alternatively spliced REST (REST4), which work with miR-124 to activate this battery of genes, comprehensively reprogram neuronal alternative splicing, and maintain their exclusive expression in post-mitotic neurons. Immunoprecipitation, western blot, immunofluorescence, and immunohistochemistry were used to determine the expression and distribution of proteins in mouse and rat lenses. Mobility shift assays were used to examine lenses for REST/NRSF DNA binding activity, and RT-PCR, DNA sequencing, and northern blots were used to identify RNA expression and alternative splicing events in lenses from mouse, rat, and goldfish (N. crassa). We demonstrated that REST, HuR, and PTB proteins are expressed predominantly in epithelial cells in mouse and rat lenses, and showed these factors are also replaced by the predominant expression of REST4, HuB/C/D and nPTB in post-mitotic fiber cells, together with miR-124 expression in vertebrate lenses. REST-regulated gene products were found to be restricted to fiber cells where REST is decreased. These findings predicted nPTB- and HuB/C/D-dependent splicing reactions can also occur in lenses, and we showed Neuronal C-src and Type 1 Neurofibromatosis 1 splicing as well as calcitonin gene related peptide (CGRP) and neural cell adhesion molecule (NCAM-180) alternative transcripts in lenses. Transgenic mice with increased HuD in lens also showed increased growth associated protein 43 (GAP43) and Ca++/Calmodulin dependent kinase IIα (CamKIIα) HuD target gene expression in the lens, similar to brain. The present study provides the first evidence this fundamental set of regulatory factors, previously considered to have a unique role in governing neurogenesis are also used in the lens, and raises questions about the origins of these developmental factors and mechanisms in lens and neuronal cells that also have a basic role in determining the neuronal phenotype.

HuB/C/D, nPTB, REST4, and miR-124 regulators of neuronal cell identity are also utilized in the lens

PubMed Central

Bitel, Claudine L.; Perrone-Bizzozero, Nora I.

2010-01-01

Purpose An interlocking network of transcription factors, RNA binding proteins, and miRNAs globally regulates gene expression and alternative splicing throughout development, and ensures the coordinated mutually exclusive expression of non-neural and neuronal forms of these factors during neurogenesis. Striking similarities between lens fiber cell and neuron cell morphology led us to determine if these factors are also used in the lens. HuR and polypyrimidine tract binding protein (PTB) have been described as ‘global regulators’ of RNA alternative splicing, stability, and translation in non-neuronal (including ectodermal) tissues examined to date in diverse species, and REST/NRSF (RE-1 Silencing Transcription Factor/Neuron Restrictive Silencing Factor) represses >2,000 neuronal genes in all non-neuronal tissues examined to date, but has not included the lens. During neurogenesis these factors are replaced by what has been considered neuron-specific HuB/C/D, nPTB, and alternatively spliced REST (REST4), which work with miR-124 to activate this battery of genes, comprehensively reprogram neuronal alternative splicing, and maintain their exclusive expression in post-mitotic neurons. Methods Immunoprecipitation, western blot, immunofluorescence, and immunohistochemistry were used to determine the expression and distribution of proteins in mouse and rat lenses. Mobility shift assays were used to examine lenses for REST/NRSF DNA binding activity, and RT–PCR, DNA sequencing, and northern blots were used to identify RNA expression and alternative splicing events in lenses from mouse, rat, and goldfish (N. crassa). Results We demonstrated that REST, HuR, and PTB proteins are expressed predominantly in epithelial cells in mouse and rat lenses, and showed these factors are also replaced by the predominant expression of REST4, HuB/C/D and nPTB in post-mitotic fiber cells, together with miR-124 expression in vertebrate lenses. REST-regulated gene products were found to be restricted to fiber cells where REST is decreased. These findings predicted nPTB- and HuB/C/D-dependent splicing reactions can also occur in lenses, and we showed Neuronal C-src and Type 1 Neurofibromatosis 1 splicing as well as calcitonin gene related peptide (CGRP) and neural cell adhesion molecule (NCAM-180) alternative transcripts in lenses. Transgenic mice with increased HuD in lens also showed increased growth associated protein 43 (GAP43) and Ca++/Calmodulin dependent kinase IIα (CamKIIα) HuD target gene expression in the lens, similar to brain. Conclusions The present study provides the first evidence this fundamental set of regulatory factors, previously considered to have a unique role in governing neurogenesis are also used in the lens, and raises questions about the origins of these developmental factors and mechanisms in lens and neuronal cells that also have a basic role in determining the neuronal phenotype. PMID:21139978

Immune surveillance properties of human NK cell-derived exosomes.

PubMed

Lugini, Luana; Cecchetti, Serena; Huber, Veronica; Luciani, Francesca; Macchia, Gianfranco; Spadaro, Francesca; Paris, Luisa; Abalsamo, Laura; Colone, Marisa; Molinari, Agnese; Podo, Franca; Rivoltini, Licia; Ramoni, Carlo; Fais, Stefano

2012-09-15

Exosomes are nanovesicles released by normal and tumor cells, which are detectable in cell culture supernatant and human biological fluids, such as plasma. Functions of exosomes released by "normal" cells are not well understood. In fact, several studies have been carried out on exosomes derived from hematopoietic cells, but very little is known about NK cell exosomes, despite the importance of these cells in innate and adaptive immunity. In this paper, we report that resting and activated NK cells, freshly isolated from blood of healthy donors, release exosomes expressing typical protein markers of NK cells and containing killer proteins (i.e., Fas ligand and perforin molecules). These nanovesicles display cytotoxic activity against several tumor cell lines and activated, but not resting, immune cells. We also show that NK-derived exosomes undergo uptake by tumor target cells but not by resting PBMC. Exosomes purified from plasma of healthy donors express NK cell markers, including CD56+ and perforin, and exert cytotoxic activity against different human tumor target cells and activated immune cells as well. The results of this study propose an important role of NK cell-derived exosomes in immune surveillance and homeostasis. Moreover, this study supports the use of exosomes as an almost perfect example of biomimetic nanovesicles possibly useful in future therapeutic approaches against various diseases, including tumors.

Electricity Generation in Microbial Fuel Cells Using Neutral Red as an Electronophore

PubMed Central

Park, Doo Hyun; Zeikus, J. Gregory

2000-01-01

Neutral red (NR) was utilized as an electron mediator in microbial fuel cells consuming glucose to study both its efficiency during electricity generation and its role in altering anaerobic growth and metabolism of Escherichia coli and Actinobacillus succinogenes. A study of chemical fuel cells in which NADH, NR, and ferricyanide were the electron donor, the electronophore, and the electron acceptor, respectively, showed that electrical current produced from NADH was proportional to the concentration of NADH. Fourfold more current was produced from NADH in chemical fuel cells when NR was the electron mediator than when thionin was the electron mediator. In microbial fuel cells in which E. coli resting cells were used the amount of current produced from glucose when NR was the electron mediator (3.5 mA) was 10-fold more than the amount produced when thionin was the electron mediator (0.4 mA). The amount of electrical energy generated (expressed in joules per mole of substrate) and the amount of current produced from glucose (expressed in milliamperes) in NR-mediated microbial fuel cells containing either E. coli or A. succinogenes were about 10- and 2-fold greater, respectively, when resting cells were used than when growing cells were used. Cell growth was inhibited substantially when these microbial fuel cells were making current, and more oxidized end products were formed under these conditions. When sewage sludge (i.e., a mixed culture of anaerobic bacteria) was used in the fuel cell, stable (for 120 h) and equivalent levels of current were obtained with glucose, as observed in the pure-culture experiments. These results suggest that NR is better than other electron mediators used in microbial fuel cells and that sludge production can be decreased while electricity is produced in fuel cells. Our results are discussed in relation to factors that may improve the relatively low electrical efficiencies (1.2 kJ/mol) obtained with microbial fuel cells. PMID:10742202

Impact of Subsurface Temperature Variability on Meteorological Variability: An AGCM Study

NASA Astrophysics Data System (ADS)

Mahanama, S. P.; Koster, R. D.; Liu, P.

2006-05-01

Anomalous atmospheric conditions can lead to surface temperature anomalies, which in turn can lead to temperature anomalies deep in the soil. The deep soil temperature (and the associated ground heat content) has significant memory -- the dissipation of a temperature anomaly may take weeks to months -- and thus deep soil temperature may contribute to the low frequency variability of energy and water variables elsewhere in the system. The memory may even provide some skill to subseasonal and seasonal forecasts. This study uses two long-term AGCM experiments to isolate the contribution of deep soil temperature variability to variability elsewhere in the climate system. The first experiment consists of a standard ensemble of AMIP-type simulations, simulations in which the deep soil temperature variable is allowed to interact with the rest of the system. In the second experiment, the coupling of the deep soil temperature to the rest of the climate system is disabled -- at each grid cell, the local climatological seasonal cycle of deep soil temperature (as determined from the first experiment) is prescribed. By comparing the variability of various atmospheric quantities as generated in the two experiments, we isolate the contribution of interactive deep soil temperature to that variability. The results show that interactive deep soil temperature contributes significantly to surface temperature variability. Interactive deep soil temperature, however, reduces the variability of the hydrological cycle (evaporation and precipitation), largely because it allows for a negative feedback between evaporation and temperature.

Changes in mood status and neurotic levels during a 20-day bed rest

NASA Astrophysics Data System (ADS)

Ishizaki, Yuko; Ishizaki, Tatsuro; Fukuoka, Hideoki; Kim, Chang-Sun; Fujita, Masayo; Maegawa, Yuko; Fujioka, Hiroshi; Katsura, Taisaku; Suzuki, Yoji; Gunji, Atsuaki

2002-04-01

This study evaluated changes of mood status and depressive and neurotic levels in nine young male subjects during a 20-day 6° head-down tilting bed rest and examined whether exercise training modified these changes. Participants were asked to complete psychometrical inventories on before, during, and after the bed rest experiment. Depressive and neurotic levels were enhanced during bed rest period according to the Japanese version of Zung's Self-rating Depression Scale and the Japanese version of the General Health Questionnaire. Mood state "vigor" was impaired and "confusion" was increased during bed rest and recumbent control periods compared to pre-bed rest and ambulatory control periods according to the Japanese version of Profiles of Mood State, whereas the mood "tension-anxiety", "depression-dejection", "anger-hostility" and "fatigue" were relatively stable during experiment. Isometric exercise training did not modify these results. Microgravity, along with confinement to bed and isolation from familiar environments, induced impairment of mental status.

Decrease in Numbers of Naive and Resting B Cells in HIV-Infected Kenyan Adults Leads to a Proportional Increase in Total and Plasmodium falciparum-Specific Atypical Memory B Cells.

PubMed

Frosch, Anne E; Odumade, Oludare A; Taylor, Justin J; Ireland, Kathleen; Ayodo, George; Ondigo, Bartholomew; Narum, David L; Vulule, John; John, Chandy C

2017-06-15

Human immunodeficiency virus type 1 (HIV-1) infection is associated with B cell activation and exhaustion, and hypergammaglobulinemia. How these changes influence B cell responses to coinfections such as malaria is poorly understood. To address this, we compared B cell phenotypes and Abs specific for the Plasmodium falciparum vaccine candidate apical membrane Ag-1 (AMA1) in HIV-infected and uninfected adults living in Kenya. Surprisingly, HIV-1 infection was not associated with a difference in serum AMA1-specific Ab levels. HIV-infected individuals had a higher proportion of total atypical and total activated memory B cells (MBCs). Using an AMA1 tetramer to detect AMA1-specific B cells, HIV-infected individuals were also shown to have a higher proportion of AMA1-specific atypical MBCs. However, this proportional increase resulted in large part from a loss in the number of naive and resting MBCs rather than an increase in the number of atypical and activated cells. The loss of resting MBCs and naive B cells was mirrored in a population of cells specific for an Ag to which these individuals were unlikely to have been chronically exposed. Together, the data show that changes in P. falciparum Ag-specific B cell subsets in HIV-infected individuals mirror those in the overall B cell population, and suggest that the increased proportion of atypical MBC phenotypes found in HIV-1-infected individuals results from the loss of naive and resting MBCs. Copyright © 2017 by The American Association of Immunologists, Inc.

New Insights into the Instability of Discharge Products in Na-O2 Batteries.

PubMed

Landa-Medrano, Imanol; Pinedo, Ricardo; Bi, Xuanxuan; Ruiz de Larramendi, Idoia; Lezama, Luis; Janek, Jürgen; Amine, Khalil; Lu, Jun; Rojo, Teófilo

2016-08-10

Sodium-oxygen batteries currently stimulate extensive research due to their high theoretical energy density and improved operational stability when compared to lithium-oxygen batteries. Cell stability, however, needs to be demonstrated also under resting conditions before future implementation of these batteries. In this work we analyze the effect of resting periods on the stability of the sodium superoxide (NaO2) discharge product. The instability of NaO2 in the cell environment is demonstrated leading to the evolution of oxygen during the resting period and the decrease of the cell efficiency. In addition, migration of the superoxide anion (O2(-)) in the electrolyte is observed and demonstrated to be an important factor affecting Coulombic efficiency.

New Insights into the Instability of Discharge Products in Na–O 2 Batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Landa-Medrano, Imanol; Pinedo, Ricardo; Bi, Xuanxuan

2016-08-10

Sodium–oxygen batteries currently stimulate extensive research due to their high theoretical energy density and improved operational stability when compared to lithium–oxygen batteries. Cell stability, however, needs to be demonstrated also under resting conditions before future implementation of these batteries. In this work we analyze the effect of resting periods on the stability of the sodium superoxide (NaO 2) discharge product. The instability of NaO 2 in the cell environment is demonstrated leading to the evolution of oxygen during the resting period and the decrease of the cell efficiency. In addition, migration of the superoxide anion (O2–) in the electrolyte ismore » observed and demonstrated to be an important factor affecting Coulombic efficiency.« less

Comprehensive Mass Cytometry Analysis of Cell Cycle, Activation, and Coinhibitory Receptors Expression in CD4 T Cells from Healthy and HIV-Infected Individuals.

PubMed

Corneau, Aurélien; Cosma, Antonio; Even, Sophie; Katlama, Christine; Le Grand, Roger; Frachet, Véronique; Blanc, Catherine; Autran, Brigitte

2017-01-01

Mass cytometry allows large multiplex analysis of cell cycle stages together with differentiation, activation, and exhaustion markers, allowing further assessment of the quiescence status of resting CD4 T cells. Peripheral blood CD4 T lymphocytes from 8 individuals, 4 healthy donors, and 4 HIV-infected on antiretroviral treatment (T) were stained with the same 26 monoclonal antibodies and dyes targeting surface and intracellular markers of differentiation, activation, exhaustion, and cell cycle stages. Samples were run on a CYTOF-2. Patterns of naïve [TN] CD4 T cells strongly differed from all other memory subsets central-memory (CM), transitional-memory (TM), effector-memory (EM), and terminally differentiated RA-expressing (TEMRA) subsets, while stem-cell memory (SCM) and T follicular-helper cells (TfH) were close to CM and TM cells with the highest percentages in cell cycle. EM and TEMRA were the most altered by HIV infection, with an increased frequency of activated and cycling cells. Activation markers and coinhibitory receptor expression differed among cell cycle stages, with HLA-DR fitting better than CD25 or CD38 with cycle, and opposite PD-1 gradients along differentiation and cell cycle. "Resting" DR-CD25- CD4+ T cells contained similar amounts of cells in G1 than the activated DR ± CD25± ones but three fold lower cells in S-G2-M. This broad multiplex mass cytometry analysis demonstrates some subsets of the so-called "resting" CD25-DR- CD4+ T cells contain noticeable amounts of cells into cycle or expressing coinhibitory receptors, opening new avenues for a redefinition of resting peripheral blood CD4 T cells harboring the HIV reservoirs. © 2016 International Clinical Cytometry Society. © 2016 International Clinical Cytometry Society.

Face matching in a long task: enforced rest and desk-switching cannot maintain identification accuracy

PubMed Central

Alenezi, Hamood M.; Fysh, Matthew C.; Johnston, Robert A.

2015-01-01

In face matching, observers have to decide whether two photographs depict the same person or different people. This task is not only remarkably difficult but accuracy declines further during prolonged testing. The current study investigated whether this decline in long tasks can be eliminated with regular rest-breaks (Experiment 1) or room-switching (Experiment 2). Both experiments replicated the accuracy decline for long face-matching tasks and showed that this could not be eliminated with rest or room-switching. These findings suggest that person identification in applied settings, such as passport control, might be particularly error-prone due to the long and repetitive nature of the task. The experiments also show that it is difficult to counteract these problems. PMID:26312179

Integrating single-cell transcriptomic data across different conditions, technologies, and species.

PubMed

Butler, Andrew; Hoffman, Paul; Smibert, Peter; Papalexi, Efthymia; Satija, Rahul

2018-06-01

Computational single-cell RNA-seq (scRNA-seq) methods have been successfully applied to experiments representing a single condition, technology, or species to discover and define cellular phenotypes. However, identifying subpopulations of cells that are present across multiple data sets remains challenging. Here, we introduce an analytical strategy for integrating scRNA-seq data sets based on common sources of variation, enabling the identification of shared populations across data sets and downstream comparative analysis. We apply this approach, implemented in our R toolkit Seurat (http://satijalab.org/seurat/), to align scRNA-seq data sets of peripheral blood mononuclear cells under resting and stimulated conditions, hematopoietic progenitors sequenced using two profiling technologies, and pancreatic cell 'atlases' generated from human and mouse islets. In each case, we learn distinct or transitional cell states jointly across data sets, while boosting statistical power through integrated analysis. Our approach facilitates general comparisons of scRNA-seq data sets, potentially deepening our understanding of how distinct cell states respond to perturbation, disease, and evolution.

Two-Step Production of Phenylpyruvic Acid from L-Phenylalanine by Growing and Resting Cells of Engineered Escherichia coli: Process Optimization and Kinetics Modeling

PubMed Central

Hou, Ying; Hossain, Gazi Sakir; Li, Jianghua; Shin, Hyun-dong; Liu, Long; Du, Guocheng; Chen, Jian

2016-01-01

Phenylpyruvic acid (PPA) is widely used in the pharmaceutical, food, and chemical industries. Here, a two-step bioconversion process, involving growing and resting cells, was established to produce PPA from l-phenylalanine using the engineered Escherichia coli constructed previously. First, the biotransformation conditions for growing cells were optimized (l-phenylalanine concentration 20.0 g·L−1, temperature 35°C) and a two-stage temperature control strategy (keep 20°C for 12 h and increase the temperature to 35°C until the end of biotransformation) was performed. The biotransformation conditions for resting cells were then optimized in 3-L bioreactor and the optimized conditions were as follows: agitation speed 500 rpm, aeration rate 1.5 vvm, and l-phenylalanine concentration 30 g·L−1. The total maximal production (mass conversion rate) reached 29.8 ± 2.1 g·L−1 (99.3%) and 75.1 ± 2.5 g·L−1 (93.9%) in the flask and 3-L bioreactor, respectively. Finally, a kinetic model was established, and it was revealed that the substrate and product inhibition were the main limiting factors for resting cell biotransformation. PMID:27851793

Activated Tissue-Resident Mesenchymal Stromal Cells Regulate Natural Killer Cell Immune and Tissue-Regenerative Function.

PubMed

Petri, Robert Michael; Hackel, Alexander; Hahnel, Katrin; Dumitru, Claudia Alexandra; Bruderek, Kirsten; Flohe, Stefanie B; Paschen, Annette; Lang, Stephan; Brandau, Sven

2017-09-12

The interaction of mesenchymal stromal cells (MSCs) with natural killer (NK) cells is traditionally thought of as a static inhibitory model, whereby resting MSCs inhibit NK cell effector function. Here, we use a dynamic in vitro system of poly(I:C) stimulation to model the interaction of NK cells and tissue-resident MSCs in the context of infection or tissue injury. The experiments suggest a time-dependent system of regulation and feedback, where, at early time points, activated MSCs secrete type I interferon to enhance NK cell effector function, while at later time points TGF-β and IL-6 limit NK cell effector function and terminate inflammatory responses by induction of a regulatory senescent-like NK cell phenotype. Importantly, feedback of these regulatory NK cells to MSCs promotes survival, proliferation, and pro-angiogenic properties. Our data provide additional insight into the interaction of stromal cells and innate immune cells and suggest a model of time-dependent MSC polarization and licensing. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Stem Cell Therapy to Treat Diabetes Mellitus

PubMed Central

Liew, Chee Gee; Andrews, Peter W.

2008-01-01

Transplantation of pancreatic islets offers a direct treatment for type 1 diabetes and in some cases, insulin-dependent type 2 diabetes. However, its widespread use is hampered by a shortage of donor organs. Many extant studies have focused on deriving β-cell progenitors from pancreas and pluripotent stem cells. Efforts to generate β-cells in vitro will help elucidate the mechanisms of β-cell formation and thus provide a versatile in vivo system to evaluate the therapeutic potential of these cells to treat diabetes. Various successful experiments using β-cells in animal models have generated extensive interest in using human embryonic stem cells to restore normoglycemia in diabetic patients. While new techniques are continually unveiled, the success of β-cell generation rests upon successful manipulation of culture conditions and the induction of key regulatory genes implicated in pancreas development. In this review, we compare successfully conducted protocols, highlight essential steps and identify some of the remarkable shortfalls common to these methods. In addition, we discuss recent advancements in the derivation of patient-specific pluripotent stem cells that may facilitate the use of autologous β-cells in stem cell therapy. PMID:19290381

Two cell cycle blocks caused by iron chelation of neuroblastoma cells: separating cell cycle events associated with each block.

PubMed

Siriwardana, Gamini; Seligman, Paul A

2013-12-01

Studies have presented evidence that besides the well described S phase block, treatment of cancer cell lines with the iron chelator deferrioxamine (DFO) also results in an earlier block in G1 phase. In this article, measurements of cell cycle regulatory proteins define this block at a very specific point in G1. DFO treatment results in markedly decreased cyclin A protein levels. Cyclin E levels that accumulate in early to mid-G1 are increased in cells treated with DFO as compared to the resting cells. The DFO S phase block is shown after cells are arrested at G1/S by (aphidicolin) then released into DFO. The same S phase block occurs with DFO treatment of a neuroblastoma cell line relatively resistant to the G1 DFO block. These experiments clearly differentiate the S phase DFO block from the earlier block pinpointed to a point in mid-G1, before G1/S when cyclin E protein increases but before increased cyclin A synthesis. Apoptosis was observed in cells inhibited by DFO at both cell cycle arrest points.

Next-generation sequencing identifies the natural killer cell microRNA transcriptome

PubMed Central

Fehniger, Todd A.; Wylie, Todd; Germino, Elizabeth; Leong, Jeffrey W.; Magrini, Vincent J.; Koul, Sunita; Keppel, Catherine R.; Schneider, Stephanie E.; Koboldt, Daniel C.; Sullivan, Ryan P.; Heinz, Michael E.; Crosby, Seth D.; Nagarajan, Rakesh; Ramsingh, Giridharan; Link, Daniel C.; Ley, Timothy J.; Mardis, Elaine R.

2010-01-01

Natural killer (NK) cells are innate lymphocytes important for early host defense against infectious pathogens and surveillance against malignant transformation. Resting murine NK cells regulate the translation of effector molecule mRNAs (e.g., granzyme B, GzmB) through unclear molecular mechanisms. MicroRNAs (miRNAs) are small noncoding RNAs that post-transcriptionally regulate the translation of their mRNA targets, and are therefore candidates for mediating this control process. While the expression and importance of miRNAs in T and B lymphocytes have been established, little is known about miRNAs in NK cells. Here, we used two next-generation sequencing (NGS) platforms to define the miRNA transcriptomes of resting and cytokine-activated primary murine NK cells, with confirmation by quantitative real-time PCR (qRT-PCR) and microarrays. We delineate a bioinformatics analysis pipeline that identified 302 known and 21 novel mature miRNAs from sequences obtained from NK cell small RNA libraries. These miRNAs are expressed over a broad range and exhibit isomiR complexity, and a subset is differentially expressed following cytokine activation. Using these miRNA NGS data, miR-223 was identified as a mature miRNA present in resting NK cells with decreased expression following cytokine activation. Furthermore, we demonstrate that miR-223 specifically targets the 3′ untranslated region of murine GzmB in vitro, indicating that this miRNA may contribute to control of GzmB translation in resting NK cells. Thus, the sequenced NK cell miRNA transcriptome provides a valuable framework for further elucidation of miRNA expression and function in NK cell biology. PMID:20935160

The nanoscale spatial organization of B-cell receptors on immunoglobulin M- and G-expressing human B-cells.

PubMed

Lee, Jinmin; Sengupta, Prabuddha; Brzostowski, Joseph; Lippincott-Schwartz, Jennifer; Pierce, Susan K

2017-02-15

B-cell activation is initiated by the binding of antigen to the B-cell receptor (BCR). Here we used dSTORM superresolution imaging to characterize the nanoscale spatial organization of immunoglobulin M (IgM) and IgG BCRs on the surfaces of resting and antigen--activated human peripheral blood B-cells. We provide insights into both the fundamental process of antigen-driven BCR clustering and differences in the spatial organization of IgM and IgG BCRs that may contribute to the characteristic differences in the responses of naive and memory B-cells to antigen. We provide evidence that although both IgM and IgG BCRs reside in highly heterogeneous protein islands that vary in size and number of BCR single-molecule localizations, both resting and activated B-cells intrinsically maintain a high -frequency of single isolated BCR localizations, which likely represent BCR monomers. IgG BCRs are more clustered than IgM BCRs on resting cells and form larger protein islands after antigen activation. Small, dense BCR clusters likely formed via protein-protein interactions are present on the surface of resting cells, and antigen activation induces these to come together to form less dense, larger islands, a process likely governed, at least in part, by protein-lipid interactions. © 2017 Lee, Sengupta, et al. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

Leucine incorporation by aerobic anoxygenic phototrophic bacteria in the Delaware estuary

PubMed Central

Stegman, Monica R; Cottrell, Matthew T; Kirchman, David L

2014-01-01

Aerobic anoxygenic phototrophic (AAP) bacteria are well known to be abundant in estuaries, coastal regions and in the open ocean, but little is known about their activity in any aquatic ecosystem. To explore the activity of AAP bacteria in the Delaware estuary and coastal waters, single-cell 3H-leucine incorporation by these bacteria was examined with a new approach that combines infrared epifluorescence microscopy and microautoradiography. The approach was used on samples from the Delaware coast from August through December and on transects through the Delaware estuary in August and November 2011. The percent of active AAP bacteria was up to twofold higher than the percentage of active cells in the rest of the bacterial community in the estuary. Likewise, the silver grain area around active AAP bacteria in microautoradiography preparations was larger than the area around cells in the rest of the bacterial community, indicating higher rates of leucine consumption by AAP bacteria. The cell size of AAP bacteria was 50% bigger than the size of other bacteria, about the same difference on average as measured for activity. The abundance of AAP bacteria was negatively correlated and their activity positively correlated with light availability in the water column, although light did not affect 3H-leucine incorporation in light–dark experiments. Our results suggest that AAP bacteria are bigger and more active than other bacteria, and likely contribute more to organic carbon fluxes than indicated by their abundance. PMID:24824666

Leucine incorporation by aerobic anoxygenic phototrophic bacteria in the Delaware estuary.

PubMed

Stegman, Monica R; Cottrell, Matthew T; Kirchman, David L

2014-11-01

Aerobic anoxygenic phototrophic (AAP) bacteria are well known to be abundant in estuaries, coastal regions and in the open ocean, but little is known about their activity in any aquatic ecosystem. To explore the activity of AAP bacteria in the Delaware estuary and coastal waters, single-cell (3)H-leucine incorporation by these bacteria was examined with a new approach that combines infrared epifluorescence microscopy and microautoradiography. The approach was used on samples from the Delaware coast from August through December and on transects through the Delaware estuary in August and November 2011. The percent of active AAP bacteria was up to twofold higher than the percentage of active cells in the rest of the bacterial community in the estuary. Likewise, the silver grain area around active AAP bacteria in microautoradiography preparations was larger than the area around cells in the rest of the bacterial community, indicating higher rates of leucine consumption by AAP bacteria. The cell size of AAP bacteria was 50% bigger than the size of other bacteria, about the same difference on average as measured for activity. The abundance of AAP bacteria was negatively correlated and their activity positively correlated with light availability in the water column, although light did not affect (3)H-leucine incorporation in light-dark experiments. Our results suggest that AAP bacteria are bigger and more active than other bacteria, and likely contribute more to organic carbon fluxes than indicated by their abundance.

Rest

PubMed Central

2015-01-01

Rest is a health-related phenomenon. Researchers have explored the phenomenon of rest, but further concept development is recommended. The aim of my study was to develop and describe a concept of rest, from interviews with a total of 63 participants about their lived experiences of rest. I performed the developing process in two stages: first with descriptive phenomenology and second with a hermeneutic approach. The concept of rest is comprised of the essences of both rest and “non-rest,” and there is a current movement between these two conditions in peoples’ lives. The essence of rest is being in harmony in motivation, feeling, and action. The essence of non-rest is being in disharmony in motivation, feeling, and action. The essences reveal some meaning constituents. Health care professionals and researchers can use the concept as a frame of reference in health care praxis and in applied research. PMID:28462307

The Structure of Resting Bacterial Populations in Soil and Subsoil Permafrost

NASA Astrophysics Data System (ADS)

Soina, Vera S.; Mulyukin, Andrei L.; Demkina, Elena V.; Vorobyova, Elena A.; El-Registan, Galina I.

2004-09-01

The structure of individual cells in microbial populations in situ of the Arctic and Antarctic permafrost was studied by scanning and transmission electron microscopy methods and compared with that of cyst-like resting forms generated under special conditions by the non-sporeforming bacteria Arthrobacter and Micrococcus isolated from the permafrost. Electron microscopy examination of microorganisms in situ revealed several types of bacterial cells having no signs of damage, including "dwarf" curved forms similar to nanoforms. Intact bacterial cells in situ and frozen cultures of the permafrost isolates differed from vegetative cells by thickened cell walls, the altered structure of cytoplasm, and the compact nucleoid, and were similar in these features to cyst-like resting forms of non-spore-forming "permafrost" bacterial strains of Arthrobacter and Micrococcus spp. Cyst-like cells, being resistant to adverse external factors, are regarded as being responsible for survival of the non-spore-formers under prolonged exposure to subzero temperatures and can be a target to search for living microorganisms in natural environments both on the Earth and on extraterrestrial bodies.

Recombination Is Responsible for the Increased Recovery of Drug-Resistant Mutants with Hypermutated Genomes in Resting Yeast Diploids Expressing APOBEC Deaminases.

PubMed

Lada, Artem G; Stepchenkova, Elena I; Zhuk, Anna S; Kliver, Sergei F; Rogozin, Igor B; Polev, Dmitrii E; Dhar, Alok; Pavlov, Youri I

2017-01-01

DNA editing deaminases (APOBECs) are implicated in generation of mutations in somatic cells during tumorigenesis. APOBEC-dependent mutagenesis is thought to occur during transient exposure of unprotected single-stranded DNA. Mutations frequently occur in clusters ( kataegis ). We investigated mechanisms of mutant generation in growing and resting diploid yeast expressing APOBEC from sea lamprey, PmCDA1, whose kataegistic effect was previously shown to be associated with transcription. We have found that the frequency of canavanine-resistant mutants kept raising after growth cessation, while the profile of transcription remained unchanged. Surprisingly, the overall number of mutations in the genomes did not elevate in resting cells. Thus, mutations were accumulated during vigorous growth stage with both intense replication and transcription. We found that the elevated recovery of can1 mutant clones in non-growing cells is the result of loss of heterozygosity (LOH) leading to clusters of homozygous mutations in the chromosomal regions distal to the reporter gene. We confirmed that recombination frequency in resting cells was elevated by orders of magnitude, suggesting that cells were transiently committed to meiotic levels of recombination, a process referred to in yeast genetics as return-to-growth. In its extreme, on day 6 of starvation, a few mutant clones were haploid, likely resulting from completed meiosis. Distribution of mutations along chromosomes indicated that PmCDA1 was active during ongoing recombination events and sometimes produced characteristic kataegis near initial breakpoints. AID and APOBEC1 behaved similar to PmCDA1. We conclude that replication, transcription, and mitotic recombination contribute to the recovered APOBEC-induced mutations in resting diploids. The mechanism is relevant to the initial stages of oncogenic transformation in terminally differentiated cells, when recombination may lead to the LOH exposing recessive mutations induced by APOBECs in cell's history and to acquisition of new mutations near original break.

Engineering of a synthetic quadrastable gene network to approach Waddington landscape and cell fate determination

PubMed Central

Wu, Fuqing; Su, Ri-Qi; Lai, Ying-Cheng; Wang, Xiao

2017-01-01

The process of cell fate determination has been depicted intuitively as cells travelling and resting on a rugged landscape, which has been probed by various theoretical studies. However, few studies have experimentally demonstrated how underlying gene regulatory networks shape the landscape and hence orchestrate cellular decision-making in the presence of both signal and noise. Here we tested different topologies and verified a synthetic gene circuit with mutual inhibition and auto-activations to be quadrastable, which enables direct study of quadruple cell fate determination on an engineered landscape. We show that cells indeed gravitate towards local minima and signal inductions dictate cell fates through modulating the shape of the multistable landscape. Experiments, guided by model predictions, reveal that sequential inductions generate distinct cell fates by changing landscape in sequence and hence navigating cells to different final states. This work provides a synthetic biology framework to approach cell fate determination and suggests a landscape-based explanation of fixed induction sequences for targeted differentiation. DOI: http://dx.doi.org/10.7554/eLife.23702.001 PMID:28397688

Phosphorylation of a Tyrosine Residue on Zap70 by Lck and Its Subsequent Binding via an SH2 Domain May Be a Key Gatekeeper of T Cell Receptor Signaling In Vivo.

PubMed

Thill, Peter A; Weiss, Arthur; Chakraborty, Arup K

2016-09-15

The initiation of signaling in T lymphocytes in response to the binding of the T cell receptor (TCR) to cognate ligands is a key step in the emergence of adaptive immune responses. Conventional models posit that TCR signaling is initiated by the phosphorylation of receptor-associated immune receptor activation motifs (ITAMs). The cytoplasmic tyrosine kinase Zap70 binds to phosphorylated ITAMs, is subsequently activated, and then propagates downstream signaling. While evidence for such models is provided by experiments with cell lines, in vivo, Zap70 is bound to phosphorylated ITAMs in resting T cells. However, Zap70 is activated only upon TCR binding to cognate ligand. We report the results of computational studies of a new model for the initiation of TCR signaling that incorporates these in vivo observations. Importantly, the new model is shown to allow better and faster TCR discrimination between self-ligands and foreign ligands. The new model is consistent with many past experimental observations, and experiments that could further test the model are proposed. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Column formation and hysteresis in a two-fluid tornado

NASA Astrophysics Data System (ADS)

Sharifullin, B. R.; Naumov, I. V.; Herrada, M. A.; Shtern, V. N.

2018-03-01

This experimental and numerical study addresses a flow of water and sunflower oil. This flow is driven by the rotating lid in a sealed vertical cylinder. The experiments were performed in a glass container with a radius of 45 mm and a height of 45 mm with the water volume fraction of 20%. Different densities and immiscibility of liquids provide the stable and sharp interface. At the rest, the interface is flat and horizontal. As the rotation speeds up, a new water-flow cell emerges near the bottom center. This cell expands and occupies almost the entire water domain while the initial water circulation shrinks into a thin layer adjacent to the interface. The water, rising near the container axis, strongly deforms the interface (upward near the axis and downward near the sidewall). A new oil-flow cell emerges above the interface near the axis. This cell disappears as the interface approaches the lid. The water separates from the sidewall, reaches the lid, and forms a column. As the rotation is decreased, the scenario reverses, but the flow states differ from those for the increasing rotation, i.e., a hysteresis is observed. The numerical simulations agree with the experiment and help explain the flow metamorphoses.

Life and Microgravity Sciences Spacelab Mission: Human Research Pilot Study

NASA Technical Reports Server (NTRS)

Arnaud, Sara B. (Editor); Walker, Karen R. (Editor); Hargens, Alan (Editor)

1996-01-01

The Life Sciences, Microgravity Science and Spacelab Mission contains a number of human experiments directed toward identifying the functional, metabolic and neurological characteristics of muscle weakness and atrophy during space flight. To ensure the successful completion of the flight experiments, a ground-based pilot study, designed to mimic the flight protocols as closely as possible, was carried out in the head-down tilt bed rest model. This report records the rationales, procedures, preliminary results and estimated value of the pilot study, the first of its kind, for 12 of the 13 planned experiments in human research. The bed rest study was conducted in the Human Research Facility at Ames Research Center from July 11 - August 28, 1995. Eight healthy male volunteers performed the experiments before, during and after 17 days bed rest. The immediate purposes of this simulation were to integrate the experiments, provide data in a large enough sample for publication of results, enable investigators to review individual experiments in the framework of a multi-disciplinary study and relay the experience of the pilot study to the mission specialists prior to launch.

The implementation of game in a 20-day head-down tilting bed rest experiment upon mood status and neurotic levels of rest subjects

NASA Astrophysics Data System (ADS)

Ishizaki, Yuko; Fukuoka, Hideoki; Ishizaki, Tatsuro; Tanaka, Hidetaka; Ishitobi, Hiromi

2004-12-01

This study evaluated the effect of the implementation of game on mental health among participants in a bed rest (BR) experiment. Subjects were 12 healthy males aged 20-26, who participated in a 20-day 6-degrees head-down tilting BR experiment. The participants were asked to complete psychometrical questionnaires before, during, and after the experiment. We entrusted the participants to manage their leisure time and they intended a game in which all of them could take part over the experiment period. The general conversation and light-hearted mood among the subjects continued during the experimental period. Longitudinal data analysis showed that levels of neurosis and mood status did not deteriorate during the experiment, while our previous experiments, which were performed under the same protocol as this study except for the implementation of the game showed a distinct deterioration in psychosocial status. We consider that the implementation of game autonomously contributes to the positive effects on the mental health among the participants.

Cognate interactions between helper T cells and B cells. IV. Requirements for the expression of effector phase activity by helper T cells.

PubMed

Bartlett, W C; McCann, J; Shepherd, D M; Roy, M; Noelle, R J

1990-12-15

After activation with anti-CD3, activated Th (THCD3), but not resting Th, fixed with paraformaldehyde induce B cell RNA synthesis when co-cultured with resting B cells. This activity is expressed by Th of both Th1 and Th2 subtypes, as well as a third Th clone that is not classified into either subtype. It is proposed that anti-CD3 activation of Th results in the expression of Th membrane proteins that trigger B cell cycle entry. Kinetic studies reveal that 4 to 8 h of activation with anti-CD3 is sufficient for ThCD3 to express B cell-activating function. However, activation of Th with anti-CD3 for extended periods of time results in reduced Th effector activity. Inhibition of Th RNA synthesis during the anti-CD3 activation period ablates the ability of ThCD3 to induce B cell cycle entry. This indicates that de novo synthesis of proteins is required for ThCD3 to express effector function. The ability of fixed ThCD3 to induce entry of B cell into cycle is not due to an increase in expression of CD3, CD4, LFA-1, ICAM-1, class I MHC or Thy-1. Other forms of Th activation (PMA and A23187, Con A) also induced Th effector function. Furthermore, purified plasma membranes from anti-CD3 activated, but not resting Th, induced resting B cells to enter cycle. The addition of IL-4, but not IL-2, IL-5, or IFN-gamma amplified the DNA synthetic response of B cells stimulated with PM from activated Th. Taken together these data indicate that de novo expression of Th surface proteins on activated Th is required for Th to induce B cell cycle entry into G1 and the addition of IL-4 is required for the heightened progression into S phase.

Energy expenditure and balance during spaceflight on the space shuttle

NASA Technical Reports Server (NTRS)

Stein, T. P.; Leskiw, M. J.; Schluter, M. D.; Hoyt, R. W.; Lane, H. W.; Gretebeck, R. E.; LeBlanc, A. D.

1999-01-01

The objectives of this study were as follows: 1) to measure human energy expenditure (EE) during spaceflight on a shuttle mission by using the doubly labeled water (DLW) method; 2) to determine whether the astronauts were in negative energy balance during spaceflight; 3) to use the comparison of change in body fat as measured by the intake DLW EE, 18O dilution, and dual energy X-ray absorptiometry (DEXA) to validate the DLW method for spaceflight; and 4) to compare EE during spaceflight against that found with bed rest. Two experiments were conducted: a flight experiment (n = 4) on the 16-day 1996 life and microgravity sciences shuttle mission and a 6 degrees head-down tilt bed rest study with controlled dietary intake (n = 8). The bed rest study was designed to simulate the flight experiment and included exercise. Two EE determinations were done before flight (bed rest), during flight (bed rest), and after flight (recovery). Energy intake and N balance were monitored for the entire period. Results were that body weight, water, fat, and energy balance were unchanged with bed rest. For the flight experiment, decreases in weight (2.6 +/- 0.4 kg, P < 0.05) and N retention (-2. 37 +/- 0.45 g N/day, P < 0.05) were found. Dietary intake for the four astronauts was reduced in flight (3,025 +/- 180 vs. 1,943 +/- 179 kcal/day, P < 0.05). EE in flight was 3,320 +/- 155 kcal/day, resulting in a negative energy balance of 1,355 +/- 80 kcal/day (-15. 7 +/- 1.0 kcal. kg-1. day-1, P < 0.05). This corresponded to a loss of 2.1 +/- 0.4 kg body fat, which was within experimental error of the fat loss determined by 18O dilution (-1.4 +/- 0.5 kg) and DEXA (-2.4 +/- 0.4 kg). All three methods showed no change in body fat with bed rest. In conclusion, 1) the DLW method for measuring EE during spaceflight is valid, 2) the astronauts were in severe negative energy balance and oxidized body fat, and 3) in-flight energy (E) requirements can be predicted from the equation: E = 1.40 x resting metabolic rate + exercise.

Molecular definition of the identity and activation of natural killer cells.

PubMed

Bezman, Natalie A; Kim, Charles C; Sun, Joseph C; Min-Oo, Gundula; Hendricks, Deborah W; Kamimura, Yosuke; Best, J Adam; Goldrath, Ananda W; Lanier, Lewis L

2012-10-01

Using whole-genome microarray data sets of the Immunological Genome Project, we demonstrate a closer transcriptional relationship between NK cells and T cells than between any other leukocytes, distinguished by their shared expression of genes encoding molecules with similar signaling functions. Whereas resting NK cells are known to share expression of a few genes with cytotoxic CD8(+) T cells, our transcriptome-wide analysis demonstrates that the commonalities extend to hundreds of genes, many encoding molecules with unknown functions. Resting NK cells demonstrate a 'preprimed' state compared with naive T cells, which allows NK cells to respond more rapidly to viral infection. Collectively, our data provide a global context for known and previously unknown molecular aspects of NK cell identity and function by delineating the genome-wide repertoire of gene expression of NK cells in various states.

Hydrogen ion dynamics in human red blood cells

PubMed Central

Swietach, Pawel; Tiffert, Teresa; Mauritz, Jakob M A; Seear, Rachel; Esposito, Alessandro; Kaminski, Clemens F; Lew, Virgilio L; Vaughan-Jones, Richard D

2010-01-01

Our understanding of pH regulation within red blood cells (RBCs) has been inferred mainly from indirect experiments rather than from in situ measurements of intracellular pH (pHi). The present work shows that carboxy-SNARF-1, a pH fluorophore, when used with confocal imaging or flow cytometry, reliably reports pHi in individual, human RBCs, provided intracellular fluorescence is calibrated using a ‘null-point’ procedure. Mean pHi was 7.25 in CO2/HCO3−-buffered medium and 7.15 in Hepes-buffered medium, and varied linearly with extracellular pH (slope of 0.77). Intrinsic (non-CO2/HCO3−-dependent) buffering power, estimated in the intact cell (85 mmol (l cell)−1 (pH unit)−1 at resting pHi), was somewhat higher than previous estimates from cell lysates (50–70 mmol (l cell)−1 (pH unit)−1). Acute displacement of pHi (superfusion of weak acids/bases) triggered rapid pHi recovery. This was mediated via membrane Cl−/HCO3− exchange (the AE1 gene product), irrespective of whether recovery was from an intracellular acid or base load, and with no evident contribution from other transporters such as Na+/H+ exchange. H+-equivalent flux through AE1 was a linear function of [H+]i and reversed at resting pHi, indicating that its activity is not allosterically regulated by pHi, in contrast to other AE isoforms. By simultaneously monitoring pHi and markers of cell volume, a functional link between membrane ion transport, volume and pHi was demonstrated. RBC pHi is therefore tightly regulated via AE1 activity, but modulated during changes of cell volume. A comparable volume–pHi link may also be important in other cell types expressing anion exchangers. Direct measurement of pHi should be useful in future investigations of RBC physiology and pathology. PMID:20962000

Effect of leg exercise training on vascular volumes during 30 days of 6 deg head-down bed rest

NASA Technical Reports Server (NTRS)

Greenleaf, J. E.; Vernikos, J.; Wade, C. E.; Barnes, P. R.

1992-01-01

In order to investigate the effects of leg exercise training on vascular volumes during 30 d of 6-deg head-down bed rest, plasma and red cell volumes, body density, and water balance were measured in 19 men confined to bed rest (BR). One group had no exercise training (NOE), another near-maximal variable-intensity isotonic exercise (ITE) for 60 min/d, and the third near-maximal intermittent isokinetic exercise (IKE) for 60 min/d. Mean energy costs for the NOE, IKE, and ITE regimens were determined. Body densities within groups and mean urine volumes between groups were unchanged during BR. Changes in red cell volume followed changes in plasma volume. There was close coupling between resting plasma volume and plasma protein and osmotic content. It is argued that the ITE training protocol is better than the IKE protocol for maintaining plasma volume during prolonged exposure to BR.

The perpetual movements of anaphase.

PubMed

Maiato, Helder; Lince-Faria, Mariana

2010-07-01

One of the most extraordinary events in the lifetime of a cell is the coordinated separation of sister chromatids during cell division. This is truly the essence of the entire mitotic process and the reason for the most profound morphological changes in cytoskeleton and nuclear organization that a cell may ever experience. It all occurs within a very short time window known as "anaphase", as if the cell had spent the rest of its existence getting ready for this moment in an ultimate act of survival. And there is a good reason for this: no space for mistakes. Problems in the distribution of chromosomes during cell division have been correlated with aneuploidy, a common feature observed in cancers and several birth defects, and the main cause of spontaneous abortion in humans. In this paper, we critically review the mechanisms of anaphase chromosome motion that resisted the scrutiny of more than 100 years of research, as part of a tribute to the pioneering work of Miguel Mota.

Recombination Is Responsible for the Increased Recovery of Drug-Resistant Mutants with Hypermutated Genomes in Resting Yeast Diploids Expressing APOBEC Deaminases

PubMed Central

Lada, Artem G.; Stepchenkova, Elena I.; Zhuk, Anna S.; Kliver, Sergei F.; Rogozin, Igor B.; Polev, Dmitrii E.; Dhar, Alok; Pavlov, Youri I.

2017-01-01

DNA editing deaminases (APOBECs) are implicated in generation of mutations in somatic cells during tumorigenesis. APOBEC-dependent mutagenesis is thought to occur during transient exposure of unprotected single-stranded DNA. Mutations frequently occur in clusters (kataegis). We investigated mechanisms of mutant generation in growing and resting diploid yeast expressing APOBEC from sea lamprey, PmCDA1, whose kataegistic effect was previously shown to be associated with transcription. We have found that the frequency of canavanine-resistant mutants kept raising after growth cessation, while the profile of transcription remained unchanged. Surprisingly, the overall number of mutations in the genomes did not elevate in resting cells. Thus, mutations were accumulated during vigorous growth stage with both intense replication and transcription. We found that the elevated recovery of can1 mutant clones in non-growing cells is the result of loss of heterozygosity (LOH) leading to clusters of homozygous mutations in the chromosomal regions distal to the reporter gene. We confirmed that recombination frequency in resting cells was elevated by orders of magnitude, suggesting that cells were transiently committed to meiotic levels of recombination, a process referred to in yeast genetics as return-to-growth. In its extreme, on day 6 of starvation, a few mutant clones were haploid, likely resulting from completed meiosis. Distribution of mutations along chromosomes indicated that PmCDA1 was active during ongoing recombination events and sometimes produced characteristic kataegis near initial breakpoints. AID and APOBEC1 behaved similar to PmCDA1. We conclude that replication, transcription, and mitotic recombination contribute to the recovered APOBEC-induced mutations in resting diploids. The mechanism is relevant to the initial stages of oncogenic transformation in terminally differentiated cells, when recombination may lead to the LOH exposing recessive mutations induced by APOBECs in cell’s history and to acquisition of new mutations near original break. PMID:29312434

Experiment K-6-22. Growth hormone regulation, synthesis and secretion in microgravity. Part 1: Somatotroph physiology. Part 2: Immunohistochemical analysis of hypothalamic hormones. Part 3: Plasma analysis

NASA Technical Reports Server (NTRS)

Grindeland, R.; Vale, W.; Hymer, W.; Sawchenko, P.; Vasques, M.; Krasnov, I.; Kaplanski, A.; Victorov, I.

1990-01-01

The objectives of the 1887 mission were: (1) to determine if the results of the SL-3 pituitary gland experiment (1) were repeatable; and (2) to determine what effect a longer mission would have on the rat pituitary gland growth hormone (GH) system. In the 1887 experiment two issues were considered especially important. First, it was recognized that cells prepared from individual rat pituitary glands should be considered separately so that the data from the 5 glands could be analyzed in a statistically meaningful way. Second, results of the SL-3 flight involving the hollow fiber implant and HPLC GH-variant experiments suggested that the biological activity of the hormone had been negatively affected by flight. The results of the 1887 experiment documented the wisdom of addressing both issues in the protocol. Thus, the reduction in secretory capacity of flight cells during subsequent extended cell culture on Earth was documented statistically, and thereby established the validity of the SL-3 result. The results of both flight experiments thus support the contention that there is a secretory lesion in pituitary GH cells of flight animals. The primary objective of both missions was a clear definition of the effect of spaceflight on the GH cell system. There can no longer be any reasonable doubt that this system is affected in microgravity. One explanation for the reason(s) underlying the better known effects of spaceflight on organisms, viz. changes in bone, muscle and immune systems may very well rest with such changes in bGH. In spite of the fact that rats in the Cosmos 1887 flight were on Earth for two days after flight, the data show that the GH system had still not recovered from the effects of flight. Many questions remain. One of the more important concerns the GRF responsiveness of somatotrophs after flight. This will be tested in an upcoming experiment.

RING1 and YY1 binding protein suppresses breast cancer growth and metastasis.

PubMed

Zhou, Hongyan; Li, Jie; Zhang, Zhanqiang; Ye, Runyi; Shao, Nan; Cheang, Tuckyun; Wang, Shenming

2016-12-01

Evidence suggests that RING1 and YY1 binding protein (RYBP) functions as a tumor suppressor. However, its role in breast cancer remains unclear. In the present study, the expression of RYBP was assessed in breast cancer patients and cell lines. Disease-free survival durations of breast cancer patients with high RYBP expression were determined based on the ATCG dataset. The effects of RYBP overexpression on cell growth, migration and invasive potency were also assessed. Nude mouse xenograft and lung metastasis models were also used to confirm the role of RYBP. The involvement of SRRM3 in RYBP-mediated breast cancer suppression was explored using SRRM3 siRNA. The potential relationship between RYBP, SRRM3, and REST-003 was examined by qPCR. The results showed that RYBP was downregulated in breast cancer patients and in several breast cancer cell lines. Breast cancer patients with high expression levels of RYBP displayed better disease-free survival. Overexpression of RYBP in MDA-MB-231 and SK-BR-3 cells significantly decreased cell proliferation, migration, and invasion ability, and increased the proportion of cells arrested in S-phase compared with the negative control cells. Additionally, upregulation of proliferation-related cell cycle proteins (cyclin A and cyclin B1) and E-cadherin, and downregulation of snail were observed in RYBP-overexpressing cells. Overexpression of RYBP reduced tumor volume and weight as well as metastatic foci in the lungs of nude mice. SRRM3 knockdown by siRNA, which is downregulated after RYBP overexpression, suppressed cell growth and metastasis in MDA-MB-231 and SK-BR-3 cells. Furthermore, qPCR analysis revealed that REST-003 ncRNA was downregulated in cells overexpressing RYBP and in SRRM3-inhibited cells. Moreover, cell invasion ability and growth were increased after SRRM3 upregulation in RYBP-overexpressing cells, but they were decreased following si-REST-003 transfection. In conclusion, overexpression of RYBP suppresses breast cancer growth and metastasis both in vitro and in vivo. SRRM3 and REST-003, which are downregulated in cells overexpressing RYBP, may be involved in RYBP-mediated breast cancer progression.

Use it or lose it--the hazards of bed rest and inactivity.

PubMed Central

Corcoran, P. J.

1991-01-01

Professional experience and lay wisdom teach us the benefits of exercise and the hazards of idleness. Yet the myth persists that "bed rest is good for you" when ill or convalescing. Abundant scientific evidence in the past 50 years has demonstrated the specific damage done to each of the body's organ systems by inactivity. Both aging and inactivity lead to strikingly similar kinds of deterioration. I summarize the data from military and veterans' hospitals, rehabilitation experience, aerospace research, and gerontology and review the physiologic and metabolic changes of aging and inactivity, along with strategies to help prevent the iatrogenic complications of bed rest. PMID:1866946

Molecular biomarkers monitoring human skeletal muscle fibres and microvasculature following long-term bed rest with and without countermeasures

PubMed Central

Salanova, M; Schiffl, G; Püttmann, B; Schoser, B G; Blottner, D

2008-01-01

The cellular mechanisms of human skeletal muscle adaptation to disuse are largely unknown. The aim of this study was to determine the morphological and biochemical changes of the lower limb soleus and vastus lateralis muscles following 60 days of head-down tilt bed rest in women with and without exercise countermeasure using molecular biomarkers monitoring functional cell compartments. Muscle biopsies were taken before (pre) and after bed rest (post) from a bed rest-only and a bed rest exercise group (n = 8, each). NOS1 and NOS3/PECAM, markers of myofibre ‘activity’ and capillary density, and MuRF1 (E3 ubiquitin-ligase), a marker of proteolysis, were documented by confocal immunofluorescence and immunoblot analyses. Morphometrical parameters (myofibre cross-sectional area, type I/II distribution) were largely preserved in muscles from the exercise group with a robust trend for type II hypertrophy in vastus lateralis. In the bed rest-only group, the relative NOS1 immunostaining intensity was decreased at type I and II myofibre membranes, while the bed rest plus exercise group compensated for this loss particularly in soleus. In the microvascular network, NOS3 expression and the capillary-to-fibre ratio were both increased in the exercise group. Elevated MuRF1 immunosignals found in subgroups of atrophic myofibres probably reflected accelerated proteolysis. Immunoblots revealed overexpression of the MuRF1 protein in the soleus of the bed rest-only group (> 35% vs. pre). We conclude that exercise countermeasure during bed rest affected both NOS/NO signalling and proteolysis in female skeletal muscle. Maintenance of NO signalling mechanisms and normal protein turnover by exercise countermeasure may be crucial steps to attenuate human skeletal muscle atrophy and to maintain cell function following chronic disuse. PMID:18221329

Bioconversion of AHX to AOH by resting cells of Burkholderia contaminans CH-1.

PubMed

Choi, Jae-Hoon; Kikuchi, Ayaka; Pumkaeo, Panyapon; Hirai, Hirofumi; Tokuyama, Shinji; Kawagishi, Hirokazu

2016-10-01

Fairy rings are zones of stimulated grass growth owing to the interaction between a fungus and a plant. We previously reported the discovery of two novel plant-growth regulating compounds related to forming fairy rings, 2-azahypoxanthine (AHX) and 2-aza-8-oxohypoxanthine (AOH). In this study, a bacterial strain CH-1 was isolated from an airborne-contaminated nutrient medium containing AHX. The strain converted AHX to AOH and identified as Burkholderia contaminans based on the gene sequence of its 16S rDNA. The quantitative production of AOH by resting cells of the strain was achieved. Among seven Burkholderia species, two bacteria and two yeasts tested, B. contaminans CH-1 showed the highest rate of conversion of AHX to AOH. By batch system, up to 10.6 mmol AHX was converted to AOH using the resting cells. The yield of this process reached at 91%.

Network dynamics underlying the formation of sparse, informative representations in the hippocampus.

PubMed

Karlsson, Mattias P; Frank, Loren M

2008-12-24

During development, activity-dependent processes increase the specificity of neural responses to stimuli, but the role that this type of process plays in adult plasticity is unclear. We examined the dynamics of hippocampal activity as animals learned about new environments to understand how neural selectivity changes with experience. Hippocampal principal neurons fire when the animal is located in a particular subregion of its environment, and in any given environment the hippocampal representation is sparse: less than half of the neurons in areas CA1 and CA3 are active whereas the rest are essentially silent. Here we show that different dynamics govern the evolution of this sparsity in CA1 and upstream area CA3. CA1, but not CA3, produces twice as many spikes in novel compared with familiar environments. This high rate firing continues during sharp wave ripple events in a subsequent rest period. The overall CA1 population rate declines and the number of active cells decreases as the environment becomes familiar and task performance improves, but the decline in rate is not uniform across neurons. Instead, the activity of cells with initial peak spatial rates above approximately 12 Hz is enhanced, whereas the activity of cells with lower initial peak rates is suppressed. The result of these changes is that the active CA1 population comes to consist of a relatively small group of cells with strong spatial tuning. This process is not evident in CA3, indicating that a region-specific and long timescale process operates in CA1 to create a sparse, spatially informative population of neurons.

Role of T cells in the B-cell response: glutaraldehyde-fixed T-helper hybridoma cells synergize with the lymphokine IL-4 to induce B-cell activation and proliferation.

PubMed

Kubota, E; McKenzie, D T; Dutton, R W; Swain, S L

1991-01-01

Antigen-unselected helper T-cell hybridomas (Th) which activate normal resting B cells to RNA synthesis and proliferation in the presence of concanavalin A (Con A) have been developed. The response is completely Th cell dependent, and not restricted by the haplotype of the B-cell major histocompatibility complex (MHC). Culture supernatants from the Con A-stimulated Th hybridomas contain interleukin-4 (IL-4) and IL-2, but undetectable level of IL-5. The supernatant alone, however, does not induce B-cell activation or proliferation. Although the Con A-mediated Th cell-dependent B-cell response occurs in an MHC-unrestricted manner, the response of resting B cells can be blocked by monoclonal Ia antibody specific for the surface class II molecules of the responding B cell. The response is also blocked by monoclonal antibody to L3T4. Significant activation and proliferation of resting B cells can also be triggered by glutaraldehyde-fixed Th hybridomas and Con A when exogenous IL-4 is added. The stimulation with fixed Th hybridomas plus IL-4 can be inhibited by monoclonal anti-L3T4 or anti-Ia. These results suggest that maximal B-cell activation requires a direct helper T cell-B cell interaction which depends on availability of Ia on the B cell and L3T4 on the T cell, even when Con A overcomes the requirement for MHC-restricted T-cell recognition. We suggest that this signal, in conjunction with T-cell produced lymphokine IL-4, is responsible for the activation and subsequent proliferation of the B cells which occurs following interaction with T cells.

Effect of an educational game on university students' learning about action potentials.

PubMed

Luchi, Kelly Cristina Gaviao; Montrezor, Luís Henrique; Marcondes, Fernanda K

2017-06-01

The aim of this study was to evaluate the effect of an educational game that is used for teaching the mechanisms of the action potentials in cell membranes. The game was composed of pieces representing the intracellular and extracellular environments, ions, ion channels, and the Na + -K + -ATPase pump. During the game activity, the students arranged the pieces to demonstrate how the ions move through the membrane in a resting state and during an action potential, linking the ion movement with a graph of the action potential. To test the effect of the game activity on student understanding, first-year dental students were given the game to play at different times in a series of classes teaching resting membrane potential and action potentials. In all experiments, students who played the game performed better in assessments. According to 98% of the students, the game supported the learning process. The data confirm the students' perception, indicating that the educational game improved their understanding about action potentials. Copyright © 2017 the American Physiological Society.

Measurement of Conformational Changes Accompanying Desensitization in an Ionotropic Glutamate Receptor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Armstrong,N.; Jasti, J.; Beich-Frandsen, M.

2006-01-01

The canonical conformational states occupied by most ligand-gated ion channels, and many cell-surface receptors, are the resting, activated, and desensitized states. While the resting and activated states of multiple receptors are well characterized, elaboration of the structural properties of the desensitized state, a state that is by definition inactive, has proven difficult. Here we use electrical, chemical, and crystallographic experiments on the AMPA-sensitive GluR2 receptor, defining the conformational rearrangements of the agonist binding cores that occur upon desensitization of this ligand-gated ion channel. These studies demonstrate that desensitization involves the rupture of an extensive interface between domain 1 of 2-foldmore » related glutamate-binding core subunits, compensating for the ca. 21{sup o} of domain closure induced by glutamate binding. The rupture of the domain 1 interface allows the ion channel to close and thereby provides a simple explanation to the long-standing question of how agonist binding is decoupled from ion channel gating upon receptor desensitization.« less

KENNEDY SPACE CENTER, FLA. - In the Space Station Processing Facility, the Japanese Experiment Module (JEM) rests on a workstand during pre-assembly measurement activities. Developed by the Japan Aerospace Exploration Agency (JAXA), the JEM will enhance the unique research capabilities of the orbiting complex by providing an additional environment for astronauts to conduct science experiments.

NASA Image and Video Library

2003-11-05

KENNEDY SPACE CENTER, FLA. - In the Space Station Processing Facility, the Japanese Experiment Module (JEM) rests on a workstand during pre-assembly measurement activities. Developed by the Japan Aerospace Exploration Agency (JAXA), the JEM will enhance the unique research capabilities of the orbiting complex by providing an additional environment for astronauts to conduct science experiments.

Basal shuttle of NF-κB/IκBα in resting T lymphocytes regulates HIV-1 LTR dependent expression

PubMed Central

Coiras, Mayte; López-Huertas, María Rosa; Rullas, Joaquín; Mittelbrunn, Maria; Alcamí, José

2007-01-01

Background In HIV-infected T lymphocytes, NF-κB/Rel transcription factors are major elements involved in the activation of LTR-dependent transcription from latency. Most NF-κB heterodimer p65/p50 is sequestered as an inactive form in the cytoplasm of resting T lymphocytes via its interaction with IκB inhibitors. In these cells, both absolute HIV latency and low level ongoing HIV replication have been described. These situations could be related to differences in the balance between NF-κB and IκBα ratio. Actually, control of IκBα by cellular factors such as Murr-1 plays a critical role in maintaining HIV latency in unstimulated T lymphocytes. Formerly, our group demonstrated the presence of nuclear IκBα in T cells after PMA activation. Now we attempt to determine the dynamics of NF-κB/IκBα nucleocytosolic transport in absence of activation as a mechanism to explain both the maintenance of latency and the existence of low level ongoing HIV replication in resting CD4+ T lymphocytes. Results and conclusion We show that the inhibition of the nuclear export by leptomycin B in resting CD4+ T cells resulted in nuclear accumulation of both IκBα and p65/RelA, as well as formation of NF-κB/IκBα complexes. This proves the existence of a rapid shuttling of IκBα between nucleus and cytosol even in absence of cellular activation. The nuclear accumulation of IκBα in resting CD4+ T lymphocytes results in inhibition of HIV-LTR dependent transcription as well as restrains HIV replication in CD4+ T lymphocytes. On the other hand, basal NF-κB activity detected in resting CD4+ T lymphocytes was related to low level HIV replication in these cells. PMID:17686171

Two cell cycle blocks caused by iron chelation of neuroblastoma cells: separating cell cycle events associated with each block

PubMed Central

Siriwardana, Gamini; Seligman, Paul A.

2013-01-01

Abstract Studies have presented evidence that besides the well described S phase block, treatment of cancer cell lines with the iron chelator deferrioxamine (DFO) also results in an earlier block in G1 phase. In this article, measurements of cell cycle regulatory proteins define this block at a very specific point in G1. DFO treatment results in markedly decreased cyclin A protein levels. Cyclin E levels that accumulate in early to mid‐G1 are increased in cells treated with DFO as compared to the resting cells. The DFO S phase block is shown after cells are arrested at G1/S by (aphidicolin) then released into DFO. The same S phase block occurs with DFO treatment of a neuroblastoma cell line relatively resistant to the G1 DFO block. These experiments clearly differentiate the S phase DFO block from the earlier block pinpointed to a point in mid‐G1, before G1/S when cyclin E protein increases but before increased cyclin A synthesis. Apoptosis was observed in cells inhibited by DFO at both cell cycle arrest points. PMID:24744856

Histone acetylation is associated with differential gene expression in the rapid and robust memory CD8+ T-cell response

PubMed Central

Fann, Monchou; Godlove, Jason M.; Catalfamo, Marta; Wood, William H.; Chrest, Francis J.; Chun, Nicholas; Granger, Larry; Wersto, Robert; Madara, Karen; Becker, Kevin; Henkart, Pierre A.; Weng, Nan-ping

2006-01-01

To understand the molecular basis for the rapid and robust memory T-cell responses, we examined gene expression and chromatin modification by histone H3 lysine 9 (H3K9) acetylation in resting and activated human naive and memory CD8+ T cells. We found that, although overall gene expression patterns were similar, a number of genes are differentially expressed in either memory or naive cells in their resting and activated states. To further elucidate the basis for differential gene expression, we assessed the role of histone H3K9 acetylation in differential gene expression. Strikingly, higher H3K9 acetylation levels were detected in resting memory cells, prior to their activation, for those genes that were differentially expressed following activation, indicating that hyperacetylation of histone H3K9 may play a role in selective and rapid gene expression of memory CD8+ T cells. Consistent with this model, we showed that inducing high levels of H3K9 acetylation resulted in an increased expression in naive cells of those genes that are normally expressed differentially in memory cells. Together, these findings suggest that differential gene expression mediated at least in part by histone H3K9 hyperacetylation may be responsible for the rapid and robust memory CD8+ T-cell response. PMID:16868257

Roles of calpain-calpastatin system (CCS) in human T cell activation.

PubMed

Mikosik, Anna; Jasiulewicz, Aleksandra; Daca, Agnieszka; Henc, Izabella; Frąckowiak, Joanna E; Ruckemann-Dziurdzińska, Katarzyna; Foerster, Jerzy; Le Page, Aurelie; Bryl, Ewa; Fulop, Tamas; Witkowski, Jacek M

2016-11-22

The immune response is determined by the speed of the T cell reaction to antigens assured by a state of readiness for proliferation and cytokine secretion. Proliferation, apoptosis and motion of many cell types are controlled by cytoplasmic proteases - µ- and m-calpain - and their inhibitor calpastatin, together forming the "calpain-calpastatin system" (CCS), assumed to modify their targets only upon activation-dependent cytoplasmic Ca2+ increase. Contrastingly to this notion, using quantitative real time PCR and semiquantitative flow cytometry respectively, we show here that the CCS genes are constitutively expressed, and that both calpains are constitutively active in resting, circulating human CD4+ and CD8+ lymphocytes. Furthermore, we demonstrate that calpain inhibition in the resting T cells prevents them from proliferation in vitro and greatly reduces secretion of multiple cytokines. The mechanistic reason for these effects of calpain inhibition on T cell functions might be the demonstrated significant reduction of the expression of active (phosphorylated) upstream signalling molecules, including the phospholipase C gamma, p56Lck and NFκB, in the inhibitor-treated cells. Thus, we propose that the constitutive, self-regulatory calpain-calpastatin system activity in resting human T cells is a necessary, controlling element of their readiness for complex and effective response to antigenic challenge.

Potent Inhibition of HIV-1 Replication in Resting CD4 T Cells by Resveratrol and Pterostilbene

PubMed Central

Chan, Chi N.; Trinité, Benjamin

2017-01-01

ABSTRACT HIV-1 infection of resting CD4 T cells plays a crucial and numerically dominant role during virus transmission at mucosal sites and during subsequent acute replication and T cell depletion. Resveratrol and pterostilbene are plant stilbenoids associated with several health-promoting benefits. Resveratrol has been shown to inhibit the replication of several viruses, including herpes simplex viruses 1 and 2, papillomaviruses, severe acute respiratory syndrome virus, and influenza virus. Alone, resveratrol does not inhibit HIV-1 infection of activated T cells, but it does synergize with nucleoside reverse transcriptase inhibitors in these cells to inhibit reverse transcription. Here, we demonstrate that resveratrol and pterostilbene completely block HIV-1 infection at a low micromolar dose in resting CD4 T cells, primarily at the reverse transcription step. The anti-HIV effect was fully reversed by exogenous deoxynucleosides and Vpx, an HIV-1 and simian immunodeficiency virus protein that increases deoxynucleoside triphosphate (dNTP) levels. These findings are consistent with the reported ability of resveratrol to inhibit ribonucleotide reductase and to lower dNTP levels in cells. This study supports the potential use of resveratrol, pterostilbene, or related compounds as adjuvants in anti-HIV preexposure prophylaxis (PrEP) formulations. PMID:28652233

Potent Inhibition of HIV-1 Replication in Resting CD4 T Cells by Resveratrol and Pterostilbene.

PubMed

Chan, Chi N; Trinité, Benjamin; Levy, David N

2017-09-01

HIV-1 infection of resting CD4 T cells plays a crucial and numerically dominant role during virus transmission at mucosal sites and during subsequent acute replication and T cell depletion. Resveratrol and pterostilbene are plant stilbenoids associated with several health-promoting benefits. Resveratrol has been shown to inhibit the replication of several viruses, including herpes simplex viruses 1 and 2, papillomaviruses, severe acute respiratory syndrome virus, and influenza virus. Alone, resveratrol does not inhibit HIV-1 infection of activated T cells, but it does synergize with nucleoside reverse transcriptase inhibitors in these cells to inhibit reverse transcription. Here, we demonstrate that resveratrol and pterostilbene completely block HIV-1 infection at a low micromolar dose in resting CD4 T cells, primarily at the reverse transcription step. The anti-HIV effect was fully reversed by exogenous deoxynucleosides and Vpx, an HIV-1 and simian immunodeficiency virus protein that increases deoxynucleoside triphosphate (dNTP) levels. These findings are consistent with the reported ability of resveratrol to inhibit ribonucleotide reductase and to lower dNTP levels in cells. This study supports the potential use of resveratrol, pterostilbene, or related compounds as adjuvants in anti-HIV preexposure prophylaxis (PrEP) formulations. Copyright © 2017 American Society for Microbiology.

Blood lipid peroxides and muscle damage increased following intensive resistance training of female weightlifters.

PubMed

Liu, Jen-Fang; Chang, Wei-Yin; Chan, Kuei-Hui; Tsai, Wen-Yee; Lin, Chen-Li; Hsu, Mei-Chieh

2005-05-01

The aim of this study was to examine changes in muscle cell injury and antioxidant capacity of weightlifters following a 1-week intensive resistance-training regimen. Thirty-six female subjects participated in this study, and their ages ranged from 18 to 25 years. The sample group included 19 elite weightlifters with more than 3 years of weightlifting training experience, while the control group comprised 17 non-athletic individuals. Compared with non-athletes, weightlifters had significantly lower glutathione peroxidase activity and plasma vitamin C concentrations. Weightlifters also had significantly higher malondialdehyde + 4-hydroxy 2-(E)-nonenal (MDA+4-HNE) and thiobarbituric acid-reactive substance (TBARS) levels and creatine kinase (CK) activity. For weightlifters, the plasma vitamin E level and the activity of superoxide dismutase (SOD) decreased, and CK activity increased significantly (P < 0.05) after a 1-week intensive resistance-training regimen. Both the TBARS levels and CK activity returned to values of pre-intensive training after a 2-day rest. The MDA+4-HNE level strongly correlated with CK activity in weightlifters (P < 0.05). In conclusion, both long-term exercise training and 1 week of intensive resistance training resulted in increased oxidative stress and cell injury in female weightlifters. Furthermore, proper rest after intensive training was found to be important for recovery.

Regulatory role of periodontal ligament fibroblasts for innate immune cell function and differentiation.

PubMed

Konermann, Anna; Stabenow, Dirk; Knolle, Percy A; Held, Stefanie A E; Deschner, James; Jäger, Andreas

2012-10-01

Innate immunity is crucial for an effective host defense against pathogenic microorganisms in periodontal tissues. As periodontal ligament (PDL) cells synthesize immunomodulatory cytokines, the aim of this in vitro study was to investigate whether these cells can interact with innate immune cells. Resting and inflammatory primed (IL-1β, TNF-α, HMGB1) human PDL cells were co-cultured with human monocyte-derived dendritic cells or macrophages. Migration, phenotypic maturation and modulation of phagocytosis of Porphyromonas gingivalis by immune cells were investigated upon co-culture with PDL cells and/or their released soluble factors. PDL cells interacted with immune cells under both non-inflammatory and inflammatory conditions. Immune cell migration was significantly enhanced by co-culture with PDL cells, which also affected their phenotypic maturation both through cell-cell contact and through released soluble mediators. The dendritic cell maturation markers CD83 and CD86 were upregulated as much as both 'alternatively activated' M2 macrophage maturation markers CD23 and CD163. In contrast, the 'classically activated' M1 macrophage maturation marker CD64 was downregulated. Finally, PDL cells significantly enhanced the phagocytosis of Porphyromonas gingivalis by immune cells. Our experiments revealed that PDL cells are not only structural elements of the periodontium, but actively influence immune responses by interaction with innate immune cells.

Freely Chosen Index Finger Tapping Frequency Is Increased in Repeated Bouts of Tapping.

PubMed

Hansen, Ernst Albin; Ebbesen, Brian Duborg; Dalsgaard, Ane; Mora-Jensen, Mark Holten; Rasmussen, Jakob

2015-01-01

Healthy individuals (n = 40) performed index finger tapping at freely chosen frequency during repeated bouts and before and after near-maximal muscle action consisting of 3 intense flexions of the index finger metacarpal phalangeal joint. One experiment showed, unexpectedly, that a bout of tapping increased the tapping frequency in the subsequent bout. Thus, a cumulating increase of 8.2 ± 5.4% (p < .001) occurred across 4 bouts, which were all separated by 10 min rest periods. Follow-up experiments revealed that tapping frequency was still increased in consecutive bouts when rest periods were extended to 20 min. Besides, near-maximal muscle activation, followed by 5 min rest, did not affect the tapping frequency. In conclusion, freely chosen tapping frequency was increased in repeated bouts of tapping, which were separated by 10-20 min rest periods. The observed phenomenon is suggested to be termed repeated bout rate enhancement.

Glucose metabolism from mouth to muscle: a student experiment to teach glucose metabolism during exercise and rest.

PubMed

Engeroff, Tobias; Fleckenstein, Johannes; Banzer, Winfried

2017-03-01

We developed an experiment to help students understand basic regulation of postabsorptive and postprandial glucose metabolism and the availability of energy sources for physical activity in the fed and fasted state. Within a practical session, teams of two or three students (1 subject and 1 or 2 investigators) performed one of three different trials: 1) inactive, in which subjects ingested a glucose solution (75 g in 300 ml of water) and rested in the seated position until the end of the trial; 2) prior activity, in which the subject performed 15 min of walking before glucose ingestion and a subsequent resting phase; and 3) postactivity, in which the subject ingested glucose solution, walked (15 min), and rested afterwards. Glucose levels were drawn before trials (fasting value), immediately after glucose ingestion (0 min), and 5, 10, 15, 20, 25, 30, 40, 50, and 60 min thereafter. Students analyzed glucose values and worked on 12 tasks. Students evaluated the usefulness of the experiment; 54.2% of students found the experiment useful to enable them to gain a further understanding of the learning objectives and to clarify items, and 44.1% indicated that the experiment was necessary to enable them to understand the learning objectives. For 6.8% the experiment was not necessary but helpful to check what they had learned, and 3.4% found that the experiment was not necessary. The present article shows the great value of experiments within practical courses to help students gain knowledge of energy metabolism. Using an active learning strategy, students outworked complex physiological tasks and improved beneficial communication and interaction between students with different skill sets and problem-solving strategies. Copyright © 2017 the American Physiological Society.

Cyclic nucleotides induce long-term augmentation of glutamate-activated chloride current in molluscan neurons.

PubMed

Bukanova, Julia V; Solntseva, Elena I; Skrebitsky, Vladimir G

2005-12-01

1. Literature data indicate that serotonin induces the long-term potentiation of glutamate (Glu) response in molluscan neurons. The aim of present work was to elucidate whether cyclic nucleotides can cause the same effect. 2. Experiments were carried out on isolated neurons of the edible snail (Helix pomatia) using a two-microelectrode voltage-clamp method. 3. In the majority of the cells examined, the application of Glu elicited a Cl- -current. The reversal potential (Er) of this current lied between -35 and -55 mV in different cells. 4. Picrotoxin, a blocker of Cl- -channels, suppressed this current equally on both sides of Er. Furosemide, an antagonist of both Cl- -channels and the Na+/K+/Cl- -cotransporter, had a dual effect on Glu-response: decrease in conductance, and shift of Er to negative potentials. 5. A short-term (2 min) cell treatment with 8-Br-cAMP or 8-Br-cGMP caused long-term (up to 30 min) change in Glu-response. At a holding potential of -60 mV, which was close to the resting level, an increase in Glu-activated inward current was observed. This potentiation seems to be related to the right shift of Er of Glu-activated Cl- -current rather than to the increase in conductance of Cl- -channels. The blocking effect of picrotoxin rested after 8-Br-cAMP treatment. 6. The change in the Cl- -homeostasis as a possible mechanism for the observed effect of cyclic nucleotides is discussed.

Bacterial conversion of phenylalanine and aromatic carboxylic acids into dihydrodiols.

PubMed Central

Wegst, W; Tittmann, U; Eberspächer, J; Lingens, F

1981-01-01

Strain E of chloridazon-degrading bacteria, when grown on L-phenylalanine accumulates cis-2,3-dihydro-2,3-dihydroxyphenylalanine. In experiments with resting cells and during growth the bacterium converts the aromatic carboxylic acids phenylacetate, phenylpropionate, phenylbutyrate and phenyl-lactate into the corresponding cis-2,3-dihydrodiol compounds. The amino acids L-phenylalanine, N-acetyl-L-phenylalanine and t-butyloxycarbonyl-L-phenylalanine were also transformed into dihydrodiols. All seven dihydrodiols, thus obtained, were characterized both by conventional analytical techniques and by the ability to serve as substrates for a cis-dihydrodiol dehydrogenase. PMID:7306016

Alternatives to argon for gas stopping volumes in the B194 neutron imager

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bleuel, D. L.; Anderson, S.; Caggiano, J. A.

2017-05-17

In a recent experiment at Lawrence Berkeley National Laboratory, the 40Ar(d,p)41Ar excitation function between 3-7 MeV was measured, confirming a previous estimation that there may be an intolerable radiation dose from 41Ar production by slowing to rest 6.74 MeV deuterons in the gas cell of the neutron imaging facility being constructed in B194. Gas alternatives to argon are considered, including helium, nitrogen (N2), neon, sulfur hexafluoride (SF6), krypton, and xenon, as well as high atomic number solid backings such as tantalum.

Vascular uptake of rehydration fluids in hypohydrated men at rest and exercise

NASA Technical Reports Server (NTRS)

Greenleaf, J. E.; Geelen, G.; Jackson, C. G. R.; Saumet, J.-L.; Juhos, L. T.; Keil, L. C.; Fegan-Meyer, D.; Dearborn, A.; Hinghofer-Szalkay, H.; Whittam, J. H.

1992-01-01

The purpose of this study was to formulate and to evaluate rehydration drinks, which would restore total body water and plasma volume (PV), for astronauts to consume before and during extravehicular activity, a few hours before reentry, and immediately after landing. In the first experiment (rest, sitting), five healthy men (23-41 yr), previously dehydrated for 24 hr., drank six (1a, 2, 4, 5, 6, 7) fluid formulations (one each at weekly intervals) and then sat for 70 min. Pre-test PV were measured with Evans blue dye and changes in PV were calculated with the hematocrit-hemoglobin transformation equation. This rest experiment simulated hypohydrated astronauts preparing for reentry. The second experiment (exercise, supine) followed the same protocol except four healthy men (30-46 yr) worked for 70 min. in the supine position on a cycle ergometer at a mean load of 71+/-1 percent of their peak aerobic work capacity. This exercise experiment simulated conditions for astronauts with reduced total body water engaging in extravehicular activity.

Fractalkine and CX3CR1 Mediate a Novel Mechanism of Leukocyte Capture, Firm Adhesion, and Activation under Physiologic Flow

PubMed Central

Fong, Alan M.; Robinson, Lisa A.; Steeber, Douglas A.; Tedder, Thomas F.; Yoshie, Osamu; Imai, Toshio; Patel, Dhavalkumar D.

1998-01-01

Leukocyte migration into sites of inflammation involves multiple molecular interactions between leukocytes and vascular endothelial cells, mediating sequential leukocyte capture, rolling, and firm adhesion. In this study, we tested the role of molecular interactions between fractalkine (FKN), a transmembrane mucin-chemokine hybrid molecule expressed on activated endothelium, and its receptor (CX3CR1) in leukocyte capture, firm adhesion, and activation under physiologic flow conditions. Immobilized FKN fusion proteins captured resting peripheral blood mononuclear cells at physiologic wall shear stresses and induced firm adhesion of resting monocytes, resting and interleukin (IL)-2–activated CD8+ T lymphocytes and IL-2–activated NK cells. FKN also induced cell shape change in firmly adherent monocytes and IL-2–activated lymphocytes. CX3CR1-transfected K562 cells, but not control K562 cells, firmly adhered to FKN-expressing ECV-304 cells (ECV-FKN) and tumor necrosis factor α–activated human umbilical vein endothelial cells. This firm adhesion was not inhibited by pertussis toxin, EDTA/EGTA, or antiintegrin antibodies, indicating that the firm adhesion was integrin independent. In summary, FKN mediated the rapid capture, integrin-independent firm adhesion, and activation of circulating leukocytes under flow. Thus, FKN and CX3CR1 mediate a novel pathway for leukocyte trafficking. PMID:9782118

Development of an electro-responsive platform for the controlled transfection of mammalian cells

NASA Astrophysics Data System (ADS)

Hook, Andrew L.; Thissen, Helmut W.; Hayes, Jason P.; Voelcker, Nicolas H.

2005-02-01

The recent development of living microarrays as novel tools for the analysis of gene expression in an in-situ environment promises to unravel gene function within living organisms. In order to significantly enhance microarray performance, we are working towards electro-responsive DNA transfection chips. This study focuses on the control of DNA adsorption and desorption by appropriate surface modification of highly doped p++ silicon. Silicon was modified by plasma polymerisation of allylamine (ALAPP), a non-toxic surface that sustains cell growth. Subsequent high surface density grafting of poly(ethylene oxide) formed a layer resistant to biomolecule adsorption and cell attachment. Spatially controlled excimer laser ablation of the surface produced micron resolution patterns of re-exposed plasma polymer whilst the rest of the surface remained non-fouling. We observed electro-stimulated preferential adsorption of DNA to the ALAPP surface and subsequent desorption by the application of a negative bias. Cell culture experiments with HEK 293 cells demonstrated efficient and controlled transfection of cells using the expression of green fluorescent protein as a reporter. Thus, these chemically patterned surfaces are promising platforms for use as living microarrays.

Human neuroblastoma (SH-SY5Y) cell culture and differentiation in 3-D collagen hydrogels for cell-based biosensing.

PubMed

Desai, Anu; Kisaalita, William S; Keith, Charles; Wu, Z-Z

2006-02-15

Cell-based three-dimensional systems are desirable in the field of high throughput screening assays due to their potential similarity to in vivo environment. We have used SH-SY5Y human neuroblastoma cells cultured in 3-D collagen hydrogel, confocal microscopy and immunofluorescence staining, to assess the merit of the system as a functional, cell-based biosensor. Our results show differences between 2-D and 3-D resting membrane potential development profile upon differentiation. There was no statistically significant difference in SH-SY5Y proliferation rate between 2-D monolayer and 3-D collagen culture formats. A large percentage of cells (2-D, 91.30% and 3-D, 84.93%) did not develop resting membrane potential value equal to or lower than -40 mV; instead cells exhibited a heterogeneous resting membrane potential distribution. In response to high K(+) (50 mM) depolarization, 3-D cells were less responsive in terms of increase in intracellular Ca(2+), in comparison to 2-D cells, supporting the hypothesis that 2-D cell calcium dynamics may be exaggerated. L-Type Ca(2+) expression levels based on staining results was inconsistent with Bay K 8644 channel activation results, strongly suggesting that either the majority of the channels were non-functional or could not be activated by Bay K 8644. In general, the results in this study confirm the depolarization-induced differences in intracellular calcium release when cultured using a 2-D versus a 3-D matrix.

A two-step mechanism for stem cell activation during hair regeneration.

PubMed

Greco, Valentina; Chen, Ting; Rendl, Michael; Schober, Markus; Pasolli, H Amalia; Stokes, Nicole; Dela Cruz-Racelis, June; Fuchs, Elaine

2009-02-06

Hair follicles (HFs) undergo cyclic bouts of degeneration, rest, and regeneration. During rest (telogen), the hair germ (HG) appears as a small cell cluster between the slow-cycling bulge and dermal papilla (DP). Here we show that HG cells are derived from bulge stem cells (SCs) but become responsive quicker to DP-promoting signals. In vitro, HG cells also proliferate sooner but display shorter-lived potential than bulge cells. Molecularly, they more closely resemble activated bulge rather than transit-amplifying (matrix) cells. Transcriptional profiling reveals precocious activity of both HG and DP in late telogen, accompanied by Wnt signaling in HG and elevated FGFs and BMP inhibitors in DP. FGFs and BMP inhibitors participate with Wnts in exerting selective and potent stimuli to the HG both in vivo and in vitro. Our findings suggest a model where HG cells fuel initial steps in hair regeneration, while the bulge is the engine maintaining the process.

Memory reactivation during rest supports upcoming learning of related content.

PubMed

Schlichting, Margaret L; Preston, Alison R

2014-11-04

Although a number of studies have highlighted the importance of offline processes for memory, how these mechanisms influence future learning remains unknown. Participants with established memories for a set of initial face-object associations were scanned during passive rest and during encoding of new related and unrelated pairs of objects. Spontaneous reactivation of established memories and enhanced hippocampal-neocortical functional connectivity during rest was related to better subsequent learning, specifically of related content. Moreover, the degree of functional coupling during rest was predictive of neural engagement during the new learning experience itself. These results suggest that through rest-phase reactivation and hippocampal-neocortical interactions, existing memories may come to facilitate encoding during subsequent related episodes.

Memory reactivation during rest supports upcoming learning of related content

PubMed Central

Schlichting, Margaret L.; Preston, Alison R.

2014-01-01

Although a number of studies have highlighted the importance of offline processes for memory, how these mechanisms influence future learning remains unknown. Participants with established memories for a set of initial face–object associations were scanned during passive rest and during encoding of new related and unrelated pairs of objects. Spontaneous reactivation of established memories and enhanced hippocampal–neocortical functional connectivity during rest was related to better subsequent learning, specifically of related content. Moreover, the degree of functional coupling during rest was predictive of neural engagement during the new learning experience itself. These results suggest that through rest-phase reactivation and hippocampal–neocortical interactions, existing memories may come to facilitate encoding during subsequent related episodes. PMID:25331890

3D chromatin conformation correlates with replication timing and is conserved in resting cells

PubMed Central

Moindrot, Benoit; Audit, Benjamin; Klous, Petra; Baker, Antoine; Thermes, Claude; de Laat, Wouter; Bouvet, Philippe; Mongelard, Fabien; Arneodo, Alain

2012-01-01

Although chromatin folding is known to be of functional importance to control the gene expression program, less is known regarding its interplay with DNA replication. Here, using Circular Chromatin Conformation Capture combined with high-throughput sequencing, we identified megabase-sized self-interacting domains in the nucleus of a human lymphoblastoid cell line, as well as in cycling and resting peripheral blood mononuclear cells (PBMC). Strikingly, the boundaries of those domains coincide with early-initiation zones in every cell types. Preferential interactions have been observed between the consecutive early-initiation zones, but also between those separated by several tens of megabases. Thus, the 3D conformation of chromatin is strongly correlated with the replication timing along the whole chromosome. We furthermore provide direct clues that, in addition to the timing value per se, the shape of the timing profile at a given locus defines its set of genomic contacts. As this timing-related scheme of chromatin organization exists in lymphoblastoid cells, resting and cycling PBMC, this indicates that it is maintained several weeks or months after the previous S-phase. Lastly, our work highlights that the major chromatin changes accompanying PBMC entry into cell cycle occur while keeping largely unchanged the long-range chromatin contacts. PMID:22879376

Effects of ambient temperature on mechanomyography of resting quadriceps muscle.

PubMed

McKay, William P; Vargo, Michael; Chilibeck, Philip D; Daku, Brian L

2013-03-01

It has been speculated that resting muscle mechanical activity, also known as minor tremor, microvibration, and thermoregulatory tonus, has evolved to maintain core temperature in homeotherms, and may play a role in nonshivering thermogenesis. This experiment was done to determine whether resting muscle mechanical activity increases with decreasing ambient temperature. We cooled 20 healthy, human, resting, supine subjects from an ambient temperature of 40° to 12 °C over 65 min. Core temperature, midquadriceps mechanomyography, surface electromyography, and oxygen consumption (VO2) were recorded. Resting muscle mechanical and electrical activity in the absence of shivering increased significantly at temperatures below 21.5 °C. Women defended core temperature more effectively than men, and showed increased resting muscle activity earlier than men. Metabolism measured by VO2 correlated with resting muscle mechanical activity (R = 0.65; p = 0.01). Resting muscle mechanical activity may have evolved, in part, to maintain core temperature in the face of mild cooling.

Differential phosphorylation of azidothymidine, dideoxycytidine, and dideoxyinosine in resting and activated peripheral blood mononuclear cells.

PubMed Central

Gao, W Y; Shirasaka, T; Johns, D G; Broder, S; Mitsuya, H

1993-01-01

The antiviral activity of azidothymidine (AZT), dideoxycytidine (ddC), and dideoxyinosine (ddI) against HIV-1 was comparatively evaluated in PHA-stimulated PBM. The mean drug concentration which yielded 50% p24 Gag negative cultures were substantially different: 0.06, 0.2, and 6 microM for AZT, ddC, and ddI, respectively. We found that AZT was preferentially phosphorylated to its triphosphate (TP) form in PHA-PBM rather than unstimulated, resting PBM (R-PBM), producing 10- to 17-fold higher ratios of AZTTP/dTTP in PHA-PBM than in R-PBM. The phosphorylation of ddC and ddI to their TP forms was, however, much less efficient in PHA-PBM, resulting in approximately 5-fold and approximately 15-fold lower ratios of ddCTP/dCTP and ddATP/dATP, respectively, in PHA-PBM than in R-PBM. The comparative order of PHA-induced increase in cellular enzyme activities examined was: thymidine kinase > uridine kinase > deoxycytidine kinase > adenosine kinase > 5'-nucleotidase. We conclude that AZT, ddC, and ddI exert disproportionate antiviral effects depending on the activation state of the target cells, i.e., ddI and ddC exert antiviral activity more favorably in resting cells than in activated cells, while AZT preferentially protects activated cells against HIV infection. Considering that HIV-1 proviral DNA synthesis in resting lymphocytes is reportedly initiated at levels comparable with those of activated lymphocytes, the current data should have practical relevance in the design of anti-HIV chemotherapy, particularly combination chemotherapy. PMID:8387546

Is Rest Really Rest? Resting State Functional Connectivity during Rest and Motor Task Paradigms.

PubMed

Jurkiewicz, Michael T; Crawley, Adrian P; Mikulis, David J

2018-04-18

Numerous studies have identified the default mode network (DMN) within the brain of healthy individuals, which has been attributed to the ongoing mental activity of the brain during the wakeful resting-state. While engaged during specific resting-state fMRI paradigms, it remains unclear as to whether traditional block-design simple movement fMRI experiments significantly influence the default mode network or other areas. Using blood-oxygen level dependent (BOLD) fMRI we characterized the pattern of functional connectivity in healthy subjects during a resting-state paradigm and compared this to the same resting-state analysis performed on motor task data residual time courses after regressing out the task paradigm. Using seed-voxel analysis to define the DMN, the executive control network (ECN), and sensorimotor, auditory and visual networks, the resting-state analysis of the residual time courses demonstrated reduced functional connectivity in the motor network and reduced connectivity between the insula and the ECN compared to the standard resting-state datasets. Overall, performance of simple self-directed motor tasks does little to change the resting-state functional connectivity across the brain, especially in non-motor areas. This would suggest that previously acquired fMRI studies incorporating simple block-design motor tasks could be mined retrospectively for assessment of the resting-state connectivity.

Voice rest after vocal fold surgery: current practice and evidence.

PubMed

Coombs, A C; Carswell, A J; Tierney, P A

2013-08-01

Voice rest is commonly recommended after vocal fold surgery, but there is a lack of evidence base and no standard protocol. The aim of this study was to establish common practice regarding voice rest following vocal fold surgery. An online survey was circulated via e-mail invitation to members of the ENT UK Expert Panel between October and November 2011. The survey revealed that 86.5 per cent of respondents agreed that 'complete voice rest' means no sound production at all, but there was variability in how 'relative voice rest' was defined. There was no dominant type of voice rest routinely recommended after surgery for laryngeal papillomatosis or intermediate pathologies. There was considerable variability in the duration of voice rest recommended, with no statistically significant, most popular response (except for malignant lesions). Surgeons with less than 10 years of experience were more likely to recommend fewer days of voice rest. There is a lack of consistency in advice given to patients after vocal fold surgery, in terms of both type and length of voice rest. This may arise from an absence of robust evidence on which to base practice.

Mini-dystrophin Expression Down-regulates IP3-mediated Calcium Release Events in Resting Dystrophin-deficient Muscle Cells

PubMed Central

Balghi, Haouaria; Sebille, Stéphane; Mondin, Ludivine; Cantereau, Anne; Constantin, Bruno; Raymond, Guy; Cognard, Christian

2006-01-01

We present here evidence for the enhancement, at rest, of an inositol 1,4,5-trisphosphate (IP3)–mediated calcium signaling pathway in myotubes from dystrophin-deficient cell lines (SolC1(−)) as compared to a cell line from the same origin but transfected with mini-dystrophin (SolD(+)). With confocal microscopy, the number of sites discharging calcium (release site density [RSD]) was quantified and found more elevated in SolC1(−) than in SolD(+) myotubes. Variations of membrane potential had no significant effect on this difference, and higher resting [Ca2+]i in SolC1(−) (Marchand, E., B. Constantin, H. Balghi, M.C. Claudepierre, A. Cantereau, C. Magaud, A. Mouzou, G. Raymond, S. Braun, and C. Cognard. 2004. Exp. Cell Res. 297:363–379) cannot explain alone higher RSD. The exposure with SR Ca2+ channel inhibitors (ryanodine and 2-APB) and phospholipase C inhibitor (U73122) significantly reduced RSD in both cell types but with a stronger effect in dystrophin-deficient SolC1(−) myotubes. Immunocytochemistry allowed us to localize ryanodine receptors (RyRs) as well as IP3 receptors (IP3Rs), IP3R-1 and IP3R-2 isoforms, indicating the presence of both RyRs-dependent and IP3-dependent release systems in both cells. We previously reported evidence for the enhancement, through a Gi protein, of the IP3-mediated calcium signaling pathway in SolC1(−) as compared to SolD(+) myotubes during a high K+ stimulation (Balghi, H., S. Sebille, B. Constantin, S. Patri, V. Thoreau, L. Mondin, E. Mok, A. Kitzis, G. Raymond, and C. Cognard. 2006. J. Gen. Physiol. 127:171–182). Here we show that, at rest, these regulation mechanisms are also involved in the modulation of calcium release activities. The enhancement of resting release activity may participate in the calcium overload observed in dystrophin-deficient myotubes, and our findings support the hypothesis of the regulatory role of mini-dystrophin on intracellular signaling. PMID:16847098

Biochemical and electrophysiological differentiation profile of a human neuroblastoma (IMR-32) cell line.

PubMed

Rao, Raj R; Kisaalita, William S

2002-09-01

A human neuroblastoma cell line (IMR-32), when differentiated, mimics large projections of the human cerebral cortex and under certain tissue culture conditions, forms intracellular fibrillary material, commonly observed in brains of patients affected with Alzheimer's disease. Our purpose is to use differentiated IMR-32 cells as an in vitro system for magnetic field exposure studies. We have previously studied in vitro differentiation of murine neuroblastoma (N1E-115) cells with respect to resting membrane potential development. The purpose of this study was to extend our investigation to IMR-32 cells. Electrophysiological (resting membrane potential, V(m)) and biochemical (neuron-specific enolase activity [NSE]) measurements were taken every 2 d for a period of 16 d. A voltage-sensitive oxonol dye together with flow cytometry was used to measure relative changes in V(m). To rule out any effect due to mechanical cell detachment, V(m) was indirectly measured by using a slow potentiometric dye (tetramethylrhodamine methyl ester) together with confocal digital imaging microscopy. Neuron-specific enolase activity was measured by following the production of phosphoenolpyruvate from 2-phospho-d-glycerate at 240 nm. Our results indicate that in IMR-32, in vitro differentiation as characterized by an increase in NSE activity is not accompanied by resting membrane potential development. This finding suggests that pathways for morphological-biochemical and electrophysiological differentiations in IMR-32 cells are independent of one another.

Effect of neutrino rest mass on ionization equilibrium freeze-out

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grohs, Evan Bradley; Fuller, George M.; Kishimoto, Chad T.

2015-12-23

We show how small neutrino rest masses can increase the expansion rate near the photon decoupling epoch in the early Universe, causing an earlier, higher temperature freeze-out for ionization equilibrium compared to the massless neutrino case. This yields a larger free-electron fraction, thereby affecting the photon diffusion length differently than the sound horizon at photon decoupling. This neutrino-mass and recombination effect depends strongly on the neutrino rest masses. Ultimately, though below current sensitivity, this effect could be probed by next-generation cosmic microwave background experiments, giving another observational handle on neutrino rest mass.

Up-regulation of K{sub ir}2.1 by ER stress facilitates cell death of brain capillary endothelial cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kito, Hiroaki; Yamazaki, Daiju; Department of Biological Chemistry, Kyoto University, Graduate School of Pharmaceutical Sciences, Kyoto

Highlights: {yields} We found that application of endoplasmic reticulum (ER) stress with tunicamycin to brain capillary endothelial cells (BCECs) induced cell death. {yields} The ER stress facilitated the expression of inward rectifier K{sup +} channel (K{sub ir}2.1) and induced sustained membrane hyperpolarization. {yields} The membrane hyperpolarization induced sustained Ca{sup 2+} entry through voltage-independent nonspecific cation channels and consequently facilitated cell death. {yields} The K{sub ir}2.1 up-regulation by ER stress is, at least in part, responsible for cell death of BCECs under pathological conditions. -- Abstract: Brain capillary endothelial cells (BCECs) form blood brain barrier (BBB) to maintain brain homeostasis. Cellmore » turnover of BCECs by the balance of cell proliferation and cell death is critical for maintaining the integrity of BBB. Here we found that stimuli with tunicamycin, endoplasmic reticulum (ER) stress inducer, up-regulated inward rectifier K{sup +} channel (K{sub ir}2.1) and facilitated cell death in t-BBEC117, a cell line derived from bovine BCECs. The activation of K{sub ir} channels contributed to the establishment of deeply negative resting membrane potential in t-BBEC117. The deep resting membrane potential increased the resting intracellular Ca{sup 2+} concentration due to Ca{sup 2+} influx through non-selective cation channels and thereby partly but significantly regulated cell death in t-BBEC117. The present results suggest that the up-regulation of K{sub ir}2.1 is, at least in part, responsible for cell death/cell turnover of BCECs induced by a variety of cellular stresses, particularly ER stress, under pathological conditions.« less

Regulated expression of the Ras effector Rin1 in forebrain neurons

PubMed Central

Dzudzor, Bartholomew; Huynh, Lucia; Thai, Minh; Bliss, Joanne M.; Nagaoka, Yoshiko; Wang, Ying; Ch'ng, Toh Hean; Jiang, Meisheng; Martin, Kelsey C.; Colicelli, John

2009-01-01

The Ras effector Rin1 is induced concomitant with synaptogenesis in forebrain neurons, where it inhibits fear conditioning and amygdala LTP. In epithelial cells, lower levels of Rin1 orchestrate receptor endocytosis. A 945bp Rin1 promoter fragment was active in hippocampal neurons and directed accurate tissue-specific and temporal expression in transgenic mice. Regulated expression in neurons and epithelial cells was mediated in part by Snail transcriptional repressors: mutation of a conserved Snail site increased expression and endogenous Snai1 was detected at the Rin1 promoter. We also describe an element closely related to, but distinct from, the consensus site for REST, a master repressor of neuronal genes. Conversion to a consensus REST sequence reduced expression in both cell types. These results provide insight into regulated expression of a neuronal Ras effector, define a promoter useful in telencephalic neuron studies, and describe a novel REST site variant directing expression to mature neurons. PMID:19837165

[Resting forms of gram negative chemolithoautotrophic bacteria Thioalkalivibrio versutus and Thioalkalimicrobium aerophilum].

PubMed

Loĭko, N G; Soina, V S; Sorokin, D Iu; Mitiushina, L L; El'-Registan, G I

2003-01-01

The haloalkaliphilic chemoautotrophic gram-negative bacteria Thioalkalivibrio versutus, strain AL2, and Thioalkalimicrobium aerophilum, strain AL3, were shown to possess the capacity to produce resting forms, namely cyst-like refractile cells (CRC), whose production was controlled by the level of the d1 extracellular factors, exhibiting the function of anabiosis autoinducers. The conditions were elucidated that promoted the formation of CRC in the developmental cycles of the cultures studied, in condensed cell suspensions undergoing autolysis, and under the action of exogenously introduced chemical analogues of anabiosis autoinducers (alkylhydroxybenzenes). The peculiarities of the fine structure of the resting cells obtained were studied. Distinctions were revealed (with respect to viability and thermotolerance) between the CRC formed under different conditions. The relationship between the growth strategy and survival strategy of extremophilic bacteria is discussed with taking into account the effect of the d1 autoregulatory factors. A new model of CRC formation is proposed: CRC production in the life cycle of bacteria developing under conditions of increased concentration of anabiosis autoinducers.

Improvement of IFNγ ELISPOT Performance Following Overnight Resting of Frozen PBMC Samples Confirmed Through Rigorous Statistical Analysis

PubMed Central

Santos, Radleigh; Buying, Alcinette; Sabri, Nazila; Yu, John; Gringeri, Anthony; Bender, James; Janetzki, Sylvia; Pinilla, Clemencia; Judkowski, Valeria A.

2014-01-01

Immune monitoring of functional responses is a fundamental parameter to establish correlates of protection in clinical trials evaluating vaccines and therapies to boost antigen-specific responses. The IFNγ ELISPOT assay is a well-standardized and validated method for the determination of functional IFNγ-producing T-cells in peripheral blood mononuclear cells (PBMC); however, its performance greatly depends on the quality and integrity of the cryopreserved PBMC. Here, we investigate the effect of overnight (ON) resting of the PBMC on the detection of CD8-restricted peptide-specific responses by IFNγ ELISPOT. The study used PBMC from healthy donors to evaluate the CD8 T-cell response to five pooled or individual HLA-A2 viral peptides. The results were analyzed using a modification of the existing distribution free resampling (DFR) recommended for the analysis of ELISPOT data to ensure the most rigorous possible standard of significance. The results of the study demonstrate that ON resting of PBMC samples prior to IFNγ ELISPOT increases both the magnitude and the statistical significance of the responses. In addition, a comparison of the results with a 13-day preculture of PBMC with the peptides before testing demonstrates that ON resting is sufficient for the efficient evaluation of immune functioning. PMID:25546016

HIV-1 Expression Within Resting CD4+ T Cells After Multiple Doses of Vorinostat

PubMed Central

Archin, Nancy M.; Bateson, Rosalie; Tripathy, Manoj K.; Crooks, Amanda M.; Yang, Kuo-Hsiung; Dahl, Noelle P.; Kearney, Mary F.; Anderson, Elizabeth M.; Coffin, John M.; Strain, Matthew C.; Richman, Douglas D.; Robertson, Kevin R.; Kashuba, Angela D.; Bosch, Ronald J.; Hazuda, Daria J.; Kuruc, Joann D.; Eron, Joseph J.; Margolis, David M.

2014-01-01

Background. A single dose of the histone deacetylase inhibitor vorinostat (VOR) up-regulates HIV RNA expression within resting CD4+ T cells of treated, aviremic human immunodeficiency virus (HIV)–positive participants. The ability of multiple exposures to VOR to repeatedly disrupt latency has not been directly measured, to our knowledge. Methods. Five participants in whom resting CD4+ T-cell–associated HIV RNA (rc-RNA) increased after a single dose of VOR agreed to receive daily VOR Monday through Wednesday for 8 weekly cycles. VOR serum levels, peripheral blood mononuclear cell histone acetylation, plasma HIV RNA single-copy assays, rc-RNA, total cellular HIV DNA, and quantitative viral outgrowth assays from resting CD4+ T cells were assayed. Results. VOR was well tolerated, with exposures within expected parameters. However, rc-RNA measured after dose 11 (second dose of cycle 4) or dose 22 (second dose of cycle 8) increased significantly in only 3 of the 5 participants, and the magnitude of the rc-RNA increase was much reduced compared with that after a single dose. Changes in histone acetylation were blunted. Results of quantitative viral outgrowth and other assays were unchanged. Conclusions. Although HIV latency is disrupted by an initial VOR dose, the effect of subsequent doses in this protocol was much reduced. We hypothesize that the global effect of VOR results in a refractory period of ≥24 hours. The optimal schedule for VOR administration is still to be defined. PMID:24620025

Trails on 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Leading to Diagnosis of Testicular Adrenal Rest Tumor.

PubMed

Kashyap, Raghava

2018-01-01

Testicular adrenal rest tumors (TARTs) are secondary to hypertrophy of adrenal rest cells in the rete testis in settings of hypersecretion of androgens. We present a case of congenital adrenal hyperplasia with TART with clues to the diagnosis on 18 F-fluorodeoxyglucose positron emission tomography/computed tomography ( 18 F-FDG PET/CT). To the best of our knowledge, this is the first reported case on the role of 18 F-FDG PET/CT in TART.

Curcumin is a potent modulator of microglial gene expression and migration

PubMed Central

2011-01-01

Background Microglial cells are important effectors of the neuronal innate immune system with a major role in chronic neurodegenerative diseases. Curcumin, a major component of tumeric, alleviates pro-inflammatory activities of these cells by inhibiting nuclear factor kappa B (NFkB) signaling. To study the immuno-modulatory effects of curcumin on a transcriptomic level, DNA-microarray analyses were performed with resting and LPS-challenged microglial cells after short-term treatment with curcumin. Methods Resting and LPS-activated BV-2 cells were stimulated with curcumin and genome-wide mRNA expression patterns were determined using DNA-microarrays. Selected qRT-PCR analyses were performed to confirm newly identified curcumin-regulated genes. The migration potential of microglial cells was determined with wound healing assays and transwell migration assays. Microglial neurotoxicity was estimated by morphological analyses and quantification of caspase 3/7 levels in 661W photoreceptors cultured in the presence of microglia-conditioned medium. Results Curcumin treatment markedly changed the microglial transcriptome with 49 differentially expressed transcripts in a combined analysis of resting and activated microglial cells. Curcumin effectively triggered anti-inflammatory signals as shown by induced expression of Interleukin 4 and Peroxisome proliferator activated receptor α. Several novel curcumin-induced genes including Netrin G1, Delta-like 1, Platelet endothelial cell adhesion molecule 1, and Plasma cell endoplasmic reticulum protein 1, have been previously associated with adhesion and cell migration. Consequently, curcumin treatment significantly inhibited basal and activation-induced migration of BV-2 microglia. Curcumin also potently blocked gene expression related to pro-inflammatory activation of resting cells including Toll-like receptor 2 and Prostaglandin-endoperoxide synthase 2. Moreover, transcription of NO synthase 2 and Signal transducer and activator of transcription 1 was reduced in LPS-triggered microglia. These transcriptional changes in curcumin-treated LPS-primed microglia also lead to decreased neurotoxicity with reduced apoptosis of 661W photoreceptor cultures. Conclusions Collectively, our results suggest that curcumin is a potent modulator of the microglial transcriptome. Curcumin attenuates microglial migration and triggers a phenotype with anti-inflammatory and neuroprotective properties. Thus, curcumin could be a nutraceutical compound to develop immuno-modulatory and neuroprotective therapies for the treatment of various neurodegenerative disorders. PMID:21958395

The structural bases of long-term anabiosis in non-spore-forming bacteria

NASA Astrophysics Data System (ADS)

Suzina, N. E.; Mulyukin, A. L.; Dmitriev, V. V.; Nikolaev, Yu. A.; Plakunov, V. K.; El-Registan, G. I.; Duda, V. I.

Peculiarities of the structural and functional organization related to extended and long-term anabiosis were revealed for non-spore-forming bacteria both in stored laboratory cultures and natural substrates: (1) 1-3-Myr-old Eastern Siberian permafrost, (2) tundra soils, and (3) oil slurry. Different advanced or specially designed methods were used such as (a) high-resolution electron microscopy; (b) simulation of in situ conditions in laboratory by varying of growth composition media and cultivation conditions; (c) low-temperature fractionation to isolate and concentrate microbial cells from natural substrates; (d) specimen selection and preparation; (e) comparative ultrastructural and morphometric analysis of microbial cells in model cultures and natural substrates (in situ). Under laboratory conditions, the intense formation of anabiotic (resting) cells by representatives of various taxa of eubacteria and halophilic archaea were observed in 2-9-month-old cultures grown in carbon-, nitrogen-, or phosphorus-deficient media, in starved cell suspensions in the presence of sodium silicate at environmentally occurring concentrations, or on soil agar. Among resting cells were revealed cyst-like forms possessing the complicated structure. The most common peculiarities of cyst-like resting cells were thick and distinguishable capsule; thickened and multilamellar cell wall with 1 to 3 de novo synthesized murein layers; large intramembrane particles on PF- and EF-fractures; finely granulated or coarse textured cytoplasm; condensed nucleoid. The data of morphological and ultrastructural analyses of cyst-like cells, as well as their experimentally proved resistance to prolonged desiccation, heat shock, etc. and the ability to germinate under the effect of lysozyme, gives an evidence for constitutive dormancy in the studied non-spore-forming bacteria at least. Noteworthy, it was found that the majority of microorganisms in permafrost, tundra soils, and oil slurry was presented by cyst-like cells, very similar to those in laboratory cultures and encrusted with organomineral particles. Anabiotic (resting) cyst-like cells are responsible for survival of non-spore-formers in extreme Earth habitats and may be regarded as possible analogs of extraterrestrial forms of microbial life.

Effects of acute hypoxia/acidosis on intracellular pH in differentiating neural progenitor cells.

PubMed

Nordström, Tommy; Jansson, Linda C; Louhivuori, Lauri M; Akerman, Karl E O

2012-06-21

The response of differentiating mouse neural progenitor cells, migrating out from neurospheres, to conditions simulating ischemia (hypoxia and extracellular or intracellular acidosis) was studied. We show here, by using BCECF and single cell imaging to monitor intracellular pH (pH(i)), that two main populations can be distinguished by exposing migrating neural progenitor cells to low extracellular pH or by performing an acidifying ammonium prepulse. The cells dominating at the periphery of the neurosphere culture, which were positive for neuron specific markers MAP-2, calbindin and NeuN had lower initial resting pH(i) and could also easily be further acidified by lowering the extracellular pH. Moreover, in this population, a more profound acidification was seen when the cells were acidified using the ammonium prepulse technique. However, when the cell population was exposed to depolarizing potassium concentrations no alterations in pH(i) took place in this population. In contrast, depolarization caused an increase in pH(i) (by 0.5 pH units) in the cell population closer to the neurosphere body, which region was positive for the radial cell marker (GLAST). This cell population, having higher resting pH(i) (pH 6.9-7.1) also responded to acute hypoxia. During hypoxic treatment the resting pH(i) decreased by 0.1 pH units and recovered rapidly after reoxygenation. Our results show that migrating neural progenitor cells are highly sensitive to extracellular acidosis and that irreversible damage becomes evident at pH 6.2. Moreover, our results show that a response to acidosis clearly distinguishes two individual cell populations probably representing neuronal and radial cells. Copyright © 2012 Elsevier B.V. All rights reserved.

Trans-dissemination of exosomes from HIV-1-infected cells fosters both HIV-1 trans-infection in resting CD4+ T lymphocytes and reactivation of the HIV-1 reservoir.

PubMed

Chiozzini, Chiara; Arenaccio, Claudia; Olivetta, Eleonora; Anticoli, Simona; Manfredi, Francesco; Ferrantelli, Flavia; d'Ettorre, Gabriella; Schietroma, Ivan; Andreotti, Mauro; Federico, Maurizio

2017-09-01

Intact HIV-1 and exosomes can be internalized by dendritic cells (DCs) through a common pathway leading to their transmission to CD4 + T lymphocytes by means of mechanisms defined as trans-infection and trans-dissemination, respectively. We previously reported that exosomes from HIV-1-infected cells activate both uninfected quiescent CD4 + T lymphocytes, which become permissive to HIV-1, and latently infected cells, with release of HIV-1 particles. However, nothing is known about the effects of trans-dissemination of exosomes produced by HIV-1-infected cells on uninfected or latently HIV-1-infected CD4 + T lymphocytes. Here, we report that trans-dissemination of exosomes from HIV-1-infected cells induces cell activation in resting CD4 + T lymphocytes, which appears stronger with mature than immature DCs. Using purified preparations of both HIV-1 and exosomes, we observed that mDC-mediated trans-dissemination of exosomes from HIV-1-infected cells to resting CD4 + T lymphocytes induces efficient trans-infection and HIV-1 expression in target cells. Most relevant, when both mDCs and CD4 + T lymphocytes were isolated from combination anti-retroviral therapy (ART)-treated HIV-1-infected patients, trans-dissemination of exosomes from HIV-1-infected cells led to HIV-1 reactivation from the viral reservoir. In sum, our data suggest a role of exosome trans-dissemination in both HIV-1 spread in the infected host and reactivation of the HIV-1 reservoir.

Water use, waste generation, and traffic counts at interstate rest areas in Louisiana.

DOT National Transportation Integrated Search

2003-06-30

Surprisingly, little current information for design purposes exists regarding water use and waste generation at interstate rest areas. The Waterways Experiment Station of the U.S. Army Corps of Engineers carried out the last major study in 1974. This...

Executive function on the 16-day of bed rest in young healthy men

NASA Astrophysics Data System (ADS)

Ishizaki, Yuko; Fukuoka, Hideoki; Tanaka, Hidetaka; Ishizaki, Tatsuro; Fujii, Yuri; Hattori-Uchida, Yuko; Nakamura, Minako; Ohkawa, Kaoru; Kobayashi, Hodaka; Taniuchi, Shoichiro; Kaneko, Kazunari

2009-05-01

Microgravity due to prolonged bed rest may cause changes in cerebral circulation, which is related to brain function. We evaluate the effect of simulated microgravity due to a 6° head-down tilt bed rest experiment on executive function among 12 healthy young men. Four kinds of psychoneurological tests—the table tapping test, the trail making test, the pointing test and losing at rock-paper-scissors—were performed on the baseline and on day 16 of the experiment. There was no significant difference in the results between the baseline and day 16 on all tests, which indicated that executive function was not impaired by the 16-day 6° head-down tilting bed rest. However, we cannot conclude that microgravity did not affect executive function because of the possible contribution of the following factors: (1) the timing of tests, (2) the learning effect, or (3) changes in psychophysiology that were too small to affect higher brain function.

The influence of microgravity on Euglena gracilis as studied on Shenzhou 8.

PubMed

Nasir, A; Strauch, S M; Becker, I; Sperling, A; Schuster, M; Richter, P R; Weißkopf, M; Ntefidou, M; Daiker, V; An, Y A; Li, X Y; Liu, Y D; Lebert, M

2014-01-01

The German Aerospace Center (DLR) enabled German participation in the joint space campaign on the unmanned Shenzhou 8 spacecraft in November 2011. In this report, the effect of microgravity on Euglena gracilis cells is described. Custom-made dual compartment cell fixation units (containing cells in one chamber and fixative - RNA lysis buffer - in another one) were enclosed in a small container and placed in the Simbox incubator, which is an experiment support system. Cells were fixed by injecting them with fixative at different time intervals. In addition to stationary experiment slots, Simbox provides a 1 g reference centrifuge. Cell fixation units were mounted in microgravity and 1 g reference positions of Simbox. Two Simbox incubators were used, one for space flight and the other as ground reference. Cells were fixed soon after launch and shortly before return of the spaceship. Due to technical problems, only early in-flight samples (about 40 min after launch microgravity and corresponding 1 g reference) were fully mixed with fixative, therefore only data from those samples are presented. Transcription of several genes involved in signal transduction, oxidative stress defence, cell cycle regulation and heat shock responses was investigated with quantitative PCR. The data indicate that Euglena cells suffer stress upon short-term exposure to microgravity; various stress-induced genes were up-regulated. Of 32 tested genes, 18 were up-regulated, one down-regulated and the rest remained unaltered. These findings are in a good agreement with results from other research groups using other organisms. © 2013 German Botanical Society and The Royal Botanical Society of the Netherlands.

Bed rest from the perspective of the high-risk pregnant woman.

PubMed

Gupton, A; Heaman, M; Ashcroft, T

1997-01-01

To describe the experience of prolonged bed rest from the perspective of women during high-risk pregnancies. A focused ethnographic study that used interviews, participant diaries, and field notes as data sources. Participants were obtained from an acute-care hospital antepartum unit and an antepartum home care program. Twenty-four women with complications of pregnancy requiring prolonged bed rest (range, 7-50 days). A model of the stress process in pregnant women on bed rest emerged from the data analysis. Stressors were grouped into situational (sick role, lack of control, uncertainty, concerns regarding fetus's well-being, and being tired of waiting), environmental (feeling like a prisoner, being bored, and having a sense of missing out), and family (role reversal and worry about older children) categories. Two main mediators of stress were social support and coping. Families, friends, and professionals were perceived as sources of support. Women used coping strategies, such as keeping a positive attitude, taking it 1 day at a time, doing it for the baby, getting used to it, setting goals, and keeping busy. Manifestations of stress were evidenced by adverse physical symptoms, emotional reactions, and altered social relationships. Prolonged bed rest is a stressful experience for pregnant women at high risk. Understanding the stress process in pregnant women confined to bed rest may assist nurses in developing interventions to reduce stressors and enhance mediators.

Microchip Screening Platform for Single Cell Assessment of NK Cell Cytotoxicity

PubMed Central

Guldevall, Karolin; Brandt, Ludwig; Forslund, Elin; Olofsson, Karl; Frisk, Thomas W.; Olofsson, Per E.; Gustafsson, Karin; Manneberg, Otto; Vanherberghen, Bruno; Brismar, Hjalmar; Kärre, Klas; Uhlin, Michael; Önfelt, Björn

2016-01-01

Here, we report a screening platform for assessment of the cytotoxic potential of individual natural killer (NK) cells within larger populations. Human primary NK cells were distributed across a silicon–glass microchip containing 32,400 individual microwells loaded with target cells. Through fluorescence screening and automated image analysis, the numbers of NK and live or dead target cells in each well could be assessed at different time points after initial mixing. Cytotoxicity was also studied by time-lapse live-cell imaging in microwells quantifying the killing potential of individual NK cells. Although most resting NK cells (≈75%) were non-cytotoxic against the leukemia cell line K562, some NK cells were able to kill several (≥3) target cells within the 12-h long experiment. In addition, the screening approach was adapted to increase the chance to find and evaluate serial killing NK cells. Even if the cytotoxic potential varied between donors, it was evident that a small fraction of highly cytotoxic NK cells were responsible for a substantial portion of the killing. We demonstrate multiple assays where our platform can be used to enumerate and characterize cytotoxic cells, such as NK or T cells. This approach could find use in clinical applications, e.g., in the selection of donors for stem cell transplantation or generation of highly specific and cytotoxic cells for adoptive immunotherapy. PMID:27092139

Interval dosing with the HDAC inhibitor vorinostat effectively reverses HIV latency

PubMed Central

Archin, Nancie M.; Kirchherr, Jennifer L.; Sung, Julia A.M.; Clutton, Genevieve; Sholtis, Katherine; Xu, Yinyan; Allard, Brigitte; Stuelke, Erin; Kashuba, Angela D.; Kuruc, Joann D.; Gay, Cynthia L.; Goonetilleke, Nilu

2017-01-01

BACKGROUND. The histone deacetylase (HDAC) inhibitor vorinostat (VOR) can increase HIV RNA expression in vivo within resting CD4+ T cells of aviremic HIV+ individuals. However, while studies of VOR or other HDAC inhibitors have reported reversal of latency, none has demonstrated clearance of latent infection. We sought to identify the optimal dosing of VOR for effective serial reversal of HIV latency. METHODS. In a study of 16 HIV-infected, aviremic individuals, we measured resting CD4+ T cell–associated HIV RNA ex vivo and in vivo following a single exposure to VOR, and then in vivo after a pair of doses separated by 48 or 72 hours, and finally following a series of 10 doses given at 72-hour intervals. RESULTS. Serial VOR exposures separated by 72 hours most often resulted in an increase in cell-associated HIV RNA within circulating resting CD4+ T cells. VOR was well tolerated by all participants. However, despite serial reversal of latency over 1 month of VOR dosing, we did not observe a measurable decrease (>0.3 log10) in the frequency of latent infection within resting CD4+ T cells. CONCLUSIONS. These findings outline parameters for the experimental use of VOR to clear latent infection. Latency reversal can be achieved by VOR safely and repeatedly, but effective depletion of persistent HIV infection will require additional advances. In addition to improvements in latency reversal, these advances may include the sustained induction of potent antiviral immune responses capable of recognizing and clearing the rare cells in which HIV latency has been reversed. TRIAL REGISTRATION. Clinicaltrials.gov NCT01319383. FUNDING. NIH grants U01 AI095052, AI50410, and P30 CA016086 and National Center for Advancing Translational Sciences grant KL2 TR001109. PMID:28714868

Electrical tuning and transduction in short hair cells of the chicken auditory papilla.

PubMed

Tan, Xiaodong; Beurg, Maryline; Hackney, Carole; Mahendrasingam, Shanthini; Fettiplace, Robert

2013-04-01

The avian auditory papilla contains two classes of sensory receptor, tall hair cells (THCs) and short hair cells (SHCs), the latter analogous to mammalian outer hair cells with large efferent but sparse afferent innervation. Little is known about the tuning, transduction, or electrical properties of SHCs. To address this problem, we made patch-clamp recordings from hair cells in an isolated chicken basilar papilla preparation at 33°C. We found that SHCs are electrically tuned by a Ca(2+)-activated K(+) current, their resonant frequency varying along the papilla in tandem with that of the THCs, which also exhibit electrical tuning. The tonotopic map for THCs was similar to maps previously described from auditory nerve fiber measurements. SHCs also possess an A-type K(+) current, but electrical tuning was observed only at resting potentials positive to -45 mV, where the A current is inactivated. We predict that the resting potential in vivo is approximately -40 mV, depolarized by a standing inward current through mechanotransducer (MT) channels having a resting open probability of ∼0.26. The resting open probability stems from a low endolymphatic Ca(2+) concentration (0.24 mM) and a high intracellular mobile Ca(2+) buffer concentration, estimated from perforated-patch recordings as equivalent to 0.5 mM BAPTA. The high buffer concentration was confirmed by quantifying parvalbumin-3 and calbindin D-28K with calibrated postembedding immunogold labeling, demonstrating >1 mM calcium-binding sites. Both proteins displayed an apex-to-base gradient matching that in the MT current amplitude, which increased exponentially along the papilla. Stereociliary bundles also labeled heavily with antibodies against the Ca(2+) pump isoform PMCA2a.

Natural killer cells as a promising tool to tackle cancer-A review of sources, methodologies, and potentials.

PubMed

Preethy, Senthilkumar; Dedeepiya, Vidyasagar Devaprasad; Senthilkumar, Rajappa; Rajmohan, Mathaiyan; Karthick, Ramalingam; Terunuma, Hiroshi; Abraham, Samuel J K

2017-07-04

Immune cell-based therapies are emerging as a promising tool to tackle malignancies, both solid tumors and selected hematological tumors. Vast experiences in literature have documented their safety and added survival benefits when such cell-based therapies are combined with the existing treatment options. Numerous methodologies of processing and in vitro expansion protocols of immune cells, such as the dendritic cells, natural killer (NK) cells, NKT cells, αβ T cells, so-called activated T lymphocytes, γδ T cells, cytotoxic T lymphocytes, and lymphokine-activated killer cells, have been reported for use in cell-based therapies. Among this handful of immune cells of significance, the NK cells stand apart from the rest for not only their direct cytotoxic ability against cancer cells but also their added advantage, which includes their capability of (i) action through both innate and adaptive immune mechanism, (ii) tackling viruses too, giving benefits in conditions where viral infections culminate in cancer, and (iii) destroying cancer stem cells, thereby preventing resistance to chemotherapy and radiotherapy. This review thoroughly analyses the sources of such NK cells, methods for expansion, and the future potentials of taking the in vitro expanded allogeneic NK cells with good cytotoxic ability as a drug for treating cancer and/or viral infection and even as a prophylactic tool for prevention of cancer after initial remission.

Lithium Self-Discharge and Its Prevention: Direct Visualization through In Situ Electrochemical Scanning Transmission Electron Microscopy

DOE PAGES

Harrison, Katharine L.; Zavadil, Kevin R.; Hahn, Nathan T.; ...

2017-11-07

To understand the mechanism that controls low-aspect-ratio lithium deposition morphologies for Li-metal anodes in batteries, we conducted direct visualization of Li-metal deposition and stripping behavior through nanoscale in situ electrochemical scanning transmission electron microscopy (EC-STEM) and macroscale-cell electrochemistry experiments in a recently developed and promising solvate electrolyte, 4 M lithium bis(fluorosulfonyl)imide in 1,2-dimethoxyethane. In contrast to published coin cell studies in the same electrolyte, our experiments revealed low Coulombic efficiencies and inhomogeneous Li morphology during in situ observation. In addition, we conclude that this discrepancy in Coulombic efficiency and morphology of the Li deposits was dependent on the presence ofmore » a compressed lithium separator interface, as we have confirmed through macroscale (not in the transmission electron microscope) electrochemical experiments. Our data suggests that cell compression changed how the solid-electrolyte interphase formed, which is likely responsible for improved morphology and Coulombic efficiency with compression. Furthermore, during the in situ EC-STEM experiments, we observed direct evidence of nanoscale self-discharge in the solvate electrolyte (in the state of electrical isolation). This self-discharge was duplicated in the macroscale, but it was less severe with electrode compression, likely due to a more passivating and corrosion-resistant solid-electrolyte interphase formed in the presence of compression. By combining the solvate electrolyte with a protective LiAl 0.3S coating, we show that the Li nucleation density increased during deposition, leading to improved morphological uniformity. In conclusion, self-discharge was suppressed during rest periods in the cycling profile with coatings present, as evidenced through EC-STEM and confirmed with coin cell data.« less

Lithium Self-Discharge and Its Prevention: Direct Visualization through In Situ Electrochemical Scanning Transmission Electron Microscopy.

PubMed

Harrison, Katharine L; Zavadil, Kevin R; Hahn, Nathan T; Meng, Xiangbo; Elam, Jeffrey W; Leenheer, Andrew; Zhang, Ji-Guang; Jungjohann, Katherine L

2017-11-28

To understand the mechanism that controls low-aspect-ratio lithium deposition morphologies for Li-metal anodes in batteries, we conducted direct visualization of Li-metal deposition and stripping behavior through nanoscale in situ electrochemical scanning transmission electron microscopy (EC-STEM) and macroscale-cell electrochemistry experiments in a recently developed and promising solvate electrolyte, 4 M lithium bis(fluorosulfonyl)imide in 1,2-dimethoxyethane. In contrast to published coin cell studies in the same electrolyte, our experiments revealed low Coulombic efficiencies and inhomogeneous Li morphology during in situ observation. We conclude that this discrepancy in Coulombic efficiency and morphology of the Li deposits was dependent on the presence of a compressed lithium separator interface, as we have confirmed through macroscale (not in the transmission electron microscope) electrochemical experiments. Our data suggests that cell compression changed how the solid-electrolyte interphase formed, which is likely responsible for improved morphology and Coulombic efficiency with compression. Furthermore, during the in situ EC-STEM experiments, we observed direct evidence of nanoscale self-discharge in the solvate electrolyte (in the state of electrical isolation). This self-discharge was duplicated in the macroscale, but it was less severe with electrode compression, likely due to a more passivating and corrosion-resistant solid-electrolyte interphase formed in the presence of compression. By combining the solvate electrolyte with a protective LiAl 0.3 S coating, we show that the Li nucleation density increased during deposition, leading to improved morphological uniformity. Furthermore, self-discharge was suppressed during rest periods in the cycling profile with coatings present, as evidenced through EC-STEM and confirmed with coin cell data.

Lithium Self-Discharge and Its Prevention: Direct Visualization through In Situ Electrochemical Scanning Transmission Electron Microscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harrison, Katharine L.; Zavadil, Kevin R.; Hahn, Nathan T.

To understand the mechanism that controls low-aspect-ratio lithium deposition morphologies for Li-metal anodes in batteries, we conducted direct visualization of Li-metal deposition and stripping behavior through nanoscale in situ electrochemical scanning transmission electron microscopy (EC-STEM) and macroscale-cell electrochemistry experiments in a recently developed and promising solvate electrolyte, 4 M lithium bis(fluorosulfonyl)imide in 1,2-dimethoxyethane. In contrast to published coin cell studies in the same electrolyte, our experiments revealed low Coulombic efficiencies and inhomogeneous Li morphology during in situ observation. In addition, we conclude that this discrepancy in Coulombic efficiency and morphology of the Li deposits was dependent on the presence ofmore » a compressed lithium separator interface, as we have confirmed through macroscale (not in the transmission electron microscope) electrochemical experiments. Our data suggests that cell compression changed how the solid-electrolyte interphase formed, which is likely responsible for improved morphology and Coulombic efficiency with compression. Furthermore, during the in situ EC-STEM experiments, we observed direct evidence of nanoscale self-discharge in the solvate electrolyte (in the state of electrical isolation). This self-discharge was duplicated in the macroscale, but it was less severe with electrode compression, likely due to a more passivating and corrosion-resistant solid-electrolyte interphase formed in the presence of compression. By combining the solvate electrolyte with a protective LiAl 0.3S coating, we show that the Li nucleation density increased during deposition, leading to improved morphological uniformity. In conclusion, self-discharge was suppressed during rest periods in the cycling profile with coatings present, as evidenced through EC-STEM and confirmed with coin cell data.« less

Mucorales spores induce a proinflammatory cytokine response in human mononuclear phagocytes and harbor no rodlet hydrophobins.

PubMed

Wurster, Sebastian; Thielen, Vanessa; Weis, Philipp; Walther, Paul; Elias, Johannes; Waaga-Gasser, Ana Maria; Dragan, Mariola; Dandekar, Thomas; Einsele, Hermann; Löffler, Jürgen; Ullmann, Andrew J

2017-11-17

Mucormycoses are life-threatening infections in immunocompromised patients. This study characterizes the response of human mononuclear cells to different Mucorales and Ascomycota. PBMC, monocytes, and monocyte derived dendritic cells (moDCs) from healthy donors were stimulated with resting and germinated stages of Mucorales and Ascomycota. Cytokine response and expression of activation markers were studied. Both inactivated germ tubes and resting spores of Rhizopus arrhizus and other human pathogenic Mucorales species significantly stimulated mRNA synthesis and secretion of proinflammatory cytokines. Moreover, R. arrhizus spores induced the upregulation of co-stimulatory molecules on moDCs and a specific T-helper cell response. Removal of rodlet hydrophobins by hydrofluoric acid treatment of A. fumigatus conidia resulted in enhanced immunogenicity, whereas the cytokine response of PBMCs to dormant R. arrhizus spores was not influenced by hydrofluoric acid. Scanning electron micrographs of Mucorales spores did not exhibit any morphological correlates of rodlet hydrophobins. Taken together, this study revealed striking differences in the response of human mononuclear cells to resting stages of Ascomycota and Mucorales, which may be explained by absence of an immunoprotective hydrophobin layer in Mucorales spores.

The Majority of HIV Type 1 DNA in Circulating CD4+ T Lymphocytes Is Present in Non-Gut-Homing Resting Memory CD4+ T Cells

PubMed Central

Xu, Yin; Bailey, Michelle; Seddiki, Nabila; Suzuki, Kazuo; Murray, John M.; Gao, Yuan; Yan, Celine; Cooper, David A.; Kelleher, Anthony D.; Koelsch, Kersten K.; Zaunders, John

2013-01-01

Abstract Memory CD4+ T lymphocytes in peripheral blood that express integrins α4ß7 preferentially recirculate through gut-associated lymphoid tissue (GALT), a proposed site of significant HIV-1 replication. Tregs and activated CD4+ T cells in GALT could also be particularly susceptible to infection. We therefore hypothesized that infection of these subsets of memory CD4+ T cells may contribute disproportionately to the HIV-1 reservoir. A cross-sectional study of CD4+ T cell subsets of memory CD45RO+ cells in peripheral blood mononuclear cells (PBMCs) was conducted using leukapheresis from eight subjects with untreated chronic HIV-1 infection. Real-time polymerase chain reaction (PCR) was used to quantify total and integrated HIV-1 DNA levels from memory CD4+ T cells sorted into integrin β7+ vs. β7−, CD25+CD127low Treg vs. CD127high, and activated CD38+ vs. CD38−. More than 80% of total HIV-1 DNA was found to reside in the integrin β7-negative non-gut-homing subset of CD45RO+ memory CD4+ T cells. Less than 10% was found in highly purified Tregs or CD38+ activated memory cells. Similarly, integrated HIV-1 DNA copies were found to be more abundant in resting non-gut-homing memory CD4+ T cells (76%) than in their activated counterparts (23%). Our investigations showed that the majority of both total and integrated HIV-1 DNA was found within non-gut-homing resting CD4+ T cells. PMID:23971972

K+-induced alterations in airway muscle responsiveness to electrical field stimulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Murlas, C.; Ehring, G.; Suszkiw, J.

1986-07-01

We investigated possible pre- and postsynaptic effects of K+-induced depolarization on ferret tracheal smooth muscle (TSM) responsiveness to cholinergic stimulation. To assess electromechanical activity, cell membrane potential (Em) and tension (Tm) were simultaneously recorded in buffer containing 6, 12, 18, or 24 mM K+ before and after electrical field stimulation (EFS) or exogenous acetylcholine (ACh). In 6 mM K+, Em was -58.1 +/- 1.0 mV (mean +/- SE). In 12 mM K+, Em was depolarized to -52.3 +/- 0.9 mV, basal Tm did not change, and both excitatory junctional potentials and contractile responses to EFS at short stimulus duration weremore » larger than in 6 mM K+. No such potentiation occurred at a higher K+, although resting Em and Tm increased progressively above 12 mM K+. The sensitivity of ferret TSM to exogenous ACh appeared unaffected by K+. To determine whether the hyperresponsiveness in 12 mM K+ was due, in part, to augmented ACh release from intramural airway nerves, experiments were done using TSM preparations incubated with (3H)choline to measure (3H)ACh release at rest and during EFS. Although resting (3H)ACh release increased progressively in higher K+, release evoked by EFS was maximal in 12 mM K+ and declined in higher concentrations. We conclude that small elevations in the extracellular K+ concentration augment responsiveness of the airways, by increasing the release of ACh both at rest and during EFS from intramural cholinergic nerve terminals. Larger increases in K+ appear to be inhibitory, possibly due to voltage-dependent effects that occur both pre- and postsynaptically.« less

A Comparison of Tandem Walk Performance Between Bed Rest Subjects and Astronauts

NASA Technical Reports Server (NTRS)

Miller, Chris; Peters, Brian; Kofman, Igor; Philips, Tiffany; Batson, Crystal; Cerisano, Jody; Fisher, Elizabeth; Mulavara, Ajitkumar; Feiveson, Alan; Reschke, Millard;

CD40 signaling synergizes with TLR-2 in the BCR independent activation of resting B cells.

PubMed

Jain, Shweta; Chodisetti, Sathi Babu; Agrewala, Javed N

2011-01-01

Conventionally, signaling through BCR initiates sequence of events necessary for activation and differentiation of B cells. We report an alternative approach, independent of BCR, for stimulating resting B (RB) cells, by involving TLR-2 and CD40--molecules crucial for innate and adaptive immunity. CD40 triggering of TLR-2 stimulated RB cells significantly augments their activation, proliferation and differentiation. It also substantially ameliorates the calcium flux, antigen uptake capacity and ability of B cells to activate T cells. The survival of RB cells was improved and it increases the number of cells expressing activation induced deaminase (AID), signifying class switch recombination (CSR). Further, we also observed increased activation rate and decreased threshold period required for optimum stimulation of RB cells. These results corroborate well with microarray gene expression data. This study provides novel insights into coordination between the molecules of innate and adaptive immunity in activating B cells, in a BCR independent manner. This strategy can be exploited to design vaccines to bolster B cell activation and antigen presenting efficiency, leading to faster and better immune response.

Calmodulin protects cells from death under normal growth conditions and mitogenic starvation but plays a mediating role in cell death upon B-cell receptor stimulation

PubMed Central

Schmalzigaug, Robert; Ye, Qunrui; Berchtold, Martin W

2001-01-01

Calmodulin (CaM) is the main intracellular Ca2+ sensor protein responsible for mediating Ca2+ triggered processes. Chicken DT40 lymphoma B cells express CaM from the two genes, CaMI and CaMII. Here we report the phenotypes of DT40 cells with the CaMII gene knocked out. The disruption of the CaMII gene causes the intracellular CaM level to decrease by 60%. CaMII−/− cells grow more slowly and die more frequently as compared to wild type (wt) cells but do not exhibit significant differences in their cell cycle profile. Both phenotypes are more pronounced at reduced serum concentrations. Upon stimulation of the B-cell receptor (BCR), the resting Ca2+ levels remain elevated after the initial transient in CaMII−/− cells. Despite higher Ca2+ resting levels, the CaMII−/− cells are partially protected from BCR induced apoptosis indicating that CaM plays a dual role in apoptotic processes. PMID:11454062

Nitrile bioconversion by Microbacterium imperiale CBS 498-74 resting cells in batch and ultrafiltration membrane bioreactors.

PubMed

Cantarella, M; Cantarella, L; Gallifuoco, A; Spera, A

2006-03-01

The biohydration of acrylonitrile, propionitrile and benzonitrile catalysed by the NHase activity contained in resting cells of Microbacterium imperiale CBS 498-74 was operated at 5, 10 and 20 degrees C in laboratory-scale batch and membrane bioreactors. The bioreactions were conducted in buffered medium (50 mM Na(2)HPO(4)/NaH(2)PO(4), pH 7.0) in the presence of distilled water or tap-water, to simulate a possible end-pipe biotreatment process. The integral bioreactor performances were studied with a cell loading (dry cell weight; DCW) varying from 0.1 mg(DCW) per reactor to 16 mg(DCW) per reactor, in order to realize near 100% bioconversion of acrylonitrile, propionitrile and benzonitrile without consistent loss of NHase activity.

Chloride equilibrium potential in salamander cones

PubMed Central

Thoreson, Wallace B; Bryson, Eric J

2004-01-01

Background GABAergic inhibition and effects of intracellular chloride ions on calcium channel activity have been proposed to regulate neurotransmission from photoreceptors. To assess the impact of these and other chloride-dependent mechanisms on release from cones, the chloride equilibrium potential (ECl) was determined in red-sensitive, large single cones from the tiger salamander retinal slice. Results Whole cell recordings were done using gramicidin perforated patch techniques to maintain endogenous Cl- levels. Membrane potentials were corrected for liquid junction potentials. Cone resting potentials were found to average -46 mV. To measure ECl, we applied long depolarizing steps to activate the calcium-activated chloride current (ICl(Ca)) and then determined the reversal potential for the current component that was inhibited by the Cl- channel blocker, niflumic acid. With this method, ECl was found to average -46 mV. In a complementary approach, we used a Cl-sensitive dye, MEQ, to measure the Cl- flux produced by depolarization with elevated concentrations of K+. The membrane potentials produced by the various high K+ solutions were measured in separate current clamp experiments. Consistent with electrophysiological experiments, MEQ fluorescence measurements indicated that ECl was below -36 mV. Conclusions The results of this study indicate that ECl is close to the dark resting potential. This will minimize the impact of chloride-dependent presynaptic mechanisms in cone terminals involving GABAa receptors, glutamate transporters and ICl(Ca). PMID:15579212

On the shape memory of red blood cells

NASA Astrophysics Data System (ADS)

Cordasco, Daniel; Bagchi, Prosenjit

2017-04-01

Red blood cells (RBCs) undergo remarkably large deformations when subjected to external forces but return to their biconcave discoid resting shape as the forces are withdrawn. In many experiments, such as when RBCs are subjected to a shear flow and undergo the tank-treading motion, the membrane elements are also displaced from their original (resting) locations along the cell surface with respect to the cell axis, in addition to the cell being deformed. A shape memory is said to exist if after the flow is stopped the RBC regains its biconcave shape and the membrane elements also return to their original locations. The shape memory of RBCs was demonstrated by Fischer ["Shape memory of human red blood cells," Biophys. J. 86, 3304-3313 (2004)] using shear flow go-and-stop experiments. Optical tweezer and micropipette based stretch-relaxation experiments do not reveal the complete shape memory because while the RBC may be deformed, the membrane elements are not significantly displaced from their original locations with respect to the cell axis. Here we present the first three-dimensional computational study predicting the complete shape memory of RBCs using shear flow go-and-stop simulations. The influence of different parameters, namely, membrane shear elasticity and bending rigidity, membrane viscosity, cytoplasmic and suspending fluid viscosity, as well as different stress-free states of the RBC is studied. For all cases, the RBCs always exhibit shape memory. The complete recovery of the RBC in shear flow go-and-stop simulations occurs over a time that is orders of magnitude longer than that for optical tweezer and micropipette based relaxations. The response is also observed to be more complex and composed of widely disparate time scales as opposed to only one time scale that characterizes the optical tweezer and micropipette based relaxations. We observe that the recovery occurs in three phases: a rapid compression of the RBC immediately after the flow is stopped, followed by a slow recovery to the biconcave shape combined with membrane rotation, and a final rotational return of the membrane elements back to their original locations. A fast time scale on the order of a few hundred milliseconds characterizes the initial compression phase while a slow time scale on the order of tens of seconds is associated with the rotational phase. We observe that the response is strongly dependent on the stress-free state of the cells, that is, the relaxation time decreases significantly and the mode of recovery changes from rotation-driven to deformation-driven as the stress-free state becomes more non-spherical. We show that while membrane shear elasticity and non-spherical stress-free shape are necessary and sufficient for the membrane elements to return to their original locations, bending rigidity is needed for the "global" recovery of the biconcave shape. We also perform a novel relaxation simulation in which the cell axis of revolution is not aligned with the shear plane and show that the shape memory is exhibited even when the membrane elements are displaced normal to the imposed flow direction. The results presented here could motivate new experiments to determine the exact stress-free state of the RBC and also to clearly identify different tank-treading modes.

Preoperative spinal tumor embolization: an institutional experience with Onyx.

PubMed

Ghobrial, George M; Chalouhi, Nohra; Harrop, James; Dalyai, Richard T; Tjoumakaris, Stavropoula; Gonzalez, L Fernando; Hasan, David; Rosenwasser, Robert H; Jabbour, Pascal

2013-12-01

Preoperative embolization has the potential to decrease intraoperative blood loss and facilitate spinal cord decompression and tumor resection. We report our institutional experience with the embolization of hypervascular extradural spinal tumors with Onyx as well as earlier embolic agents in a series of 28 patients. A retrospective case review was conducted on patients undergoing preoperative transarterial embolization of a spinal tumor between 1995 and 2012 at our institution. Twenty-eight patients met the inclusion criteria, with a mean age of 60.6 years. Twenty-eight patients had metastatic tumors. In 14 (50%) patients the metastases were from renal cell carcinomas. Fifty-four vessels were embolized using PVA, NBCA, Onyx, coils, or embospheres. Sixteen patients were treated with Onyx, 6 patients with PVA, 3 patients with embospheres, 2 patients with NBCA, and 3 patients with a combination of embolic agents. The average decrease in tumor blush was 97.8% with Onyx versus 92.7% with the rest of the embolic agents (p=0.08). The estimated blood loss was 1616ml (range 350-5000ml). Blood loss was 750cm(3) on average with Onyx versus 1844 with the rest of the embolic agents (p=0.14). The mean length of stay was 16 days. The mortality rate was zero. Pre- and post-operative modified Rankin Score (mRS) did not differ significantly in the series (3.12 versus 3.10, respectively, p=0.9). In our experience, the use of transarterial tumor embolization as an adjunct for spinal surgery is a safe and feasible option. Copyright © 2013 Elsevier B.V. All rights reserved.

A global look into human T cell subsets before and after cryopreservation using multiparametric flow cytometry and two-dimensional visualization analysis.

PubMed

Lemieux, Jennifer; Jobin, Christine; Simard, Carl; Néron, Sonia

2016-07-01

The cryopreservation of human lymphocytes is an essential step for the achievement of several cellular therapies. Besides, T cells are considered as promising actors in cancer therapy for their cytotoxic and regulatory properties. Consequently, the development of tools to monitor the impact of freezing and thawing processes on their fine distribution may be an asset to achieve quality control in cellular therapy. In this study, the phenotypes of freshly isolated human mononuclear cells were compared to those observed following one cycle of cryopreservation and rest periods 0h, 1h and 24h after thawing but before staining. T cells were scrutinized for their distribution according to naive, memory effector, regulatory and helper subsets. Flow cytometry analyses were done using eight-color antibody panels as proposed by the Human Immunophenotyping Consortium. Data were further analyzed by using conventional directed gating and clustering software, namely SPADE and viSNE. Overall, SPADE and viSNE tools were very efficient to monitor the outcome of PBMC populations and T cell subsets. T cells were more sensitive to cryopreservation than other cells. Our results indicated that submitting the thawed cells to a 1h rest period improved the detection of some cell markers when compared to fresh samples. In contrast, cells submitted to a 24h rest period, or to none, were less representative of fresh sample distribution. The heterogeneity of PBMC, as well as the effects of freeze-thaw cycle on their distribution, can be easily monitored by using SPADE and viSNE. Copyright © 2016 Elsevier B.V. All rights reserved.

A primary cell model of HIV-1 latency that uses activation through the T cell receptor and return to quiescence to establish latent infection

PubMed Central

Kim, Michelle; Hosmane, Nina N.; Bullen, C. Korin; Capoferri, Adam; Yang, Hung-Chih; Siliciano, Janet D.; Siliciano, Robert F.

2015-01-01

A mechanistic understanding of HIV-1 latency depends upon a model system that recapitulates the in vivo condition of latently infected, resting CD4+ T lymphocytes. Latency appears to be established after activated CD4+ T cells, the principal targets of HIV-1 infection, become productively infected and survive long enough to return to a resting memory state in which viral expression is inhibited by changes in the cellular environment. This protocol describes an ex vivo primary cell system that is generated under conditions that reflect the in vivo establishment of latency. Creation of these latency model cells takes 12 weeks and, once established, the cells can be maintained and used for several months. The resulting cell population contains both uninfected and latently infected cells. This primary cell model can be used to perform drug screens, study CTL responses to HIV-1, compare viral alleles, or to expand the ex vivo lifespan of cells from HIV-1 infected individuals for extended study. PMID:25375990

Erythropoiesis and myocardial energy requirements contribute to the hypermetabolism of childhood sickle cell anemia.

PubMed

Hibbert, Jacqueline M; Creary, Melissa S; Gee, Beatrice E; Buchanan, Iris D; Quarshie, Alexander; Hsu, Lewis L

2006-11-01

We hypothesized that an elevated hemoglobin synthesis rate (SynHb) and myocardial oxygen consumption (MVO2) contribute to the excess protein and energy metabolism reported in children with sickle cell anemia. Twelve children (6-12 years old) with asymptomatic sickle cell and 9 healthy children matched for age and sex were studied. Measurements were whole-body protein turnover by [1-C]leucine, SynHb by [N]glycine, resting energy expenditure by indirect calorimetry and the systolic blood pressure-heart rate product used as an index of MVO2. Protein energy cost was calculated from protein turnover. Statistical analysis included Spearman correlations and partial correlation analyses. Although body mass index was significantly lower for sickle cell versus controls (P < 0.02), children with asymptomatic sickle cell had 52% higher protein turnover (P < 0.0005). Proportional reticulocyte count, SynHb, MVO2 and resting energy expenditure were also significantly higher in children with sickle cell (P < 0.01). Protein turnover correlated significantly with both SynHb (r = 0.63, P < 0.01) and reticulocyte percentage (r = 0.83, P < 0.0001). Partial correlation of these 3 variables showed reticulocyte percentage as the only variable to be significantly associated with protein turnover, even after adjusting for sickle cell anemia (P = 0.03). Partial correlation of log resting energy expenditure on MVO2 was significant, controlling for protein energy cost, sex and age (P = 0.03). These results indicate that metabolic demands of increased erythropoiesis and cardiac energy consumption account for much of the excess protein and energy metabolism in children with sickle cell anemia.

Regulation of neural macroRNAs by the transcriptional repressor REST

PubMed Central

Johnson, Rory; Teh, Christina Hui-Leng; Jia, Hui; Vanisri, Ravi Raj; Pandey, Tridansh; Lu, Zhong-Hao; Buckley, Noel J.; Stanton, Lawrence W.; Lipovich, Leonard

2009-01-01

The essential transcriptional repressor REST (repressor element 1-silencing transcription factor) plays central roles in development and human disease by regulating a large cohort of neural genes. These have conventionally fallen into the class of known, protein-coding genes; recently, however, several noncoding microRNA genes were identified as REST targets. Given the widespread transcription of messenger RNA-like, noncoding RNAs (“macroRNAs”), some of which are functional and implicated in disease in mammalian genomes, we sought to determine whether this class of noncoding RNAs can also be regulated by REST. By applying a new, unbiased target gene annotation pipeline to computationally discovered REST binding sites, we find that 23% of mammalian REST genomic binding sites are within 10 kb of a macroRNA gene. These putative target genes were overlooked by previous studies. Focusing on a set of 18 candidate macroRNA targets from mouse, we experimentally demonstrate that two are regulated by REST in neural stem cells. Flanking protein-coding genes are, at most, weakly repressed, suggesting specific targeting of the macroRNAs by REST. Similar to the majority of known REST target genes, both of these macroRNAs are induced during nervous system development and have neurally restricted expression profiles in adult mouse. We observe a similar phenomenon in human: the DiGeorge syndrome-associated noncoding RNA, DGCR5, is repressed by REST through a proximal upstream binding site. Therefore neural macroRNAs represent an additional component of the REST regulatory network. These macroRNAs are new candidates for understanding the role of REST in neuronal development, neurodegeneration, and cancer. PMID:19050060

Regulation of neural macroRNAs by the transcriptional repressor REST.

PubMed

Johnson, Rory; Teh, Christina Hui-Leng; Jia, Hui; Vanisri, Ravi Raj; Pandey, Tridansh; Lu, Zhong-Hao; Buckley, Noel J; Stanton, Lawrence W; Lipovich, Leonard

2009-01-01

The essential transcriptional repressor REST (repressor element 1-silencing transcription factor) plays central roles in development and human disease by regulating a large cohort of neural genes. These have conventionally fallen into the class of known, protein-coding genes; recently, however, several noncoding microRNA genes were identified as REST targets. Given the widespread transcription of messenger RNA-like, noncoding RNAs ("macroRNAs"), some of which are functional and implicated in disease in mammalian genomes, we sought to determine whether this class of noncoding RNAs can also be regulated by REST. By applying a new, unbiased target gene annotation pipeline to computationally discovered REST binding sites, we find that 23% of mammalian REST genomic binding sites are within 10 kb of a macroRNA gene. These putative target genes were overlooked by previous studies. Focusing on a set of 18 candidate macroRNA targets from mouse, we experimentally demonstrate that two are regulated by REST in neural stem cells. Flanking protein-coding genes are, at most, weakly repressed, suggesting specific targeting of the macroRNAs by REST. Similar to the majority of known REST target genes, both of these macroRNAs are induced during nervous system development and have neurally restricted expression profiles in adult mouse. We observe a similar phenomenon in human: the DiGeorge syndrome-associated noncoding RNA, DGCR5, is repressed by REST through a proximal upstream binding site. Therefore neural macroRNAs represent an additional component of the REST regulatory network. These macroRNAs are new candidates for understanding the role of REST in neuronal development, neurodegeneration, and cancer.

Molecular conformation of the full-length tumor suppressor NF2/Merlin—a small angle neutron scattering study

PubMed Central

Khajeh, Jahan Ali; Ju, Jeong Ho; Atchiba, Moussoubaou; Allaire, Marc; Stanley, Christopher; Heller, William T.; Callaway, David J.E.; Bu, Zimei

2014-01-01

Summary The tumor suppressor protein Merlin inhibits cell proliferation upon establishing cell-cell contacts. Because Merlin has high sequence similarity to the Ezrin-Radixin-Moesin (ERM) family of proteins, the structural model of ERM protein autoinhibition and cycling between closed/resting and open/active conformational states is often employed to explain Merlin function. However, recent biochemical studies suggest alternative molecular models of Merlin function. Here, we have determined the low resolution molecular structure and binding activity of Merlin and a Merlin(S518D) mutant that mimics the inactivating phosphorylation at S518 using small angle neutron scattering (SANS) and binding experiments. SANS shows that in solution both Merlin and Merlin(S518D) adopt a closed conformation, but binding experiments indicate that a significant fraction of either Merlin or Merlin(S518D) is capable of binding to the target protein NHERF1. Upon binding to the phosphatidylinositol 4,5-bisphosphate lipid, the wild-type Merlin adopts a more open conformation than in solution, but Merlin(S518D) remains in a closed conformation. This study supports a rheostat model of Merlin in NHERF1 binding, and contributes to resolve a controversy about the molecular conformation and binding activity of Merlin. PMID:24882693

Cytoskeletal stabilization of inhibitory interactions in immunologic synapses of mature human dendritic cells with natural killer cells

PubMed Central

Barreira da Silva, Rosa; Graf, Claudine

2011-01-01

Human mature dendritic cells (DCs) can efficiently stimulate natural killer (NK)–cell responses without being targeted by their cytotoxicity. To understand this important regulatory crosstalk, we characterized the development of the immunologic synapse between mature DCs and resting NK cells. Conjugates between these 2 innate leukocyte populations formed rapidly, persisted for prolonged time periods and matured with DC-derived f-actin polymerization at the synapse. Polarization of IL-12 and IL-12R to the synapse coincided with f-actin polymerization, while other activating and inhibitory molecules were enriched at the interface between DCs and NK cells earlier. Functional assays revealed that inhibition of f-actin polymerization in mature synapses led to an increase of IFN-γ secretion and cytotoxicity by NK cells. This elevated NK-cell reactivity resulted from decreased inhibitory signaling in the absence of MHC class I polarization at the interface, which was observed on inhibition of f-actin polymerization in DCs. Thus, inhibitory signaling is stabilized by f-actin at the synapse between mature DCs and resting NK cells. PMID:21917751

Thyroid and adrenal cortical rhythmicity during bed rest.

NASA Technical Reports Server (NTRS)

Vernikos-Danellis, J.; Leach, C. S.; Winget, C. M.; Rambaut, P. C.; Mack, P. B.

1972-01-01

The effects of prolonged bed rest on adrenocortical and thyroid function were assessed in eight healthy males, aged 20-40 years, who were submitted to bed rest for 56 days on a 14L:10D regimen (lights-on, 9:00 AM). Four of these subjects exercised three times daily throughout the experiment. Circulating cortisol, triiodothyronine, and thyroxine, concentrations were determined in blood samples drawn at four hourly intervals for 48-hr periods before, 10, 20, 30, 42, and 54 days during, and 10 days post-bed rest. Significant fluctuations in the circulating levels of all three hormones occurred with peaks at 7:30 AM. The suggestion is advanced that thyroid rhythms may be posture dependent.

Resting-state functional magnetic resonance imaging for surgical planning in pediatric patients: a preliminary experience.

PubMed

Roland, Jarod L; Griffin, Natalie; Hacker, Carl D; Vellimana, Ananth K; Akbari, S Hassan; Shimony, Joshua S; Smyth, Matthew D; Leuthardt, Eric C; Limbrick, David D

2017-12-01

OBJECTIVE Cerebral mapping for surgical planning and operative guidance is a challenging task in neurosurgery. Pediatric patients are often poor candidates for many modern mapping techniques because of inability to cooperate due to their immature age, cognitive deficits, or other factors. Resting-state functional MRI (rs-fMRI) is uniquely suited to benefit pediatric patients because it is inherently noninvasive and does not require task performance or significant cooperation. Recent advances in the field have made mapping cerebral networks possible on an individual basis for use in clinical decision making. The authors present their initial experience translating rs-fMRI into clinical practice for surgical planning in pediatric patients. METHODS The authors retrospectively reviewed cases in which the rs-fMRI analysis technique was used prior to craniotomy in pediatric patients undergoing surgery in their institution. Resting-state analysis was performed using a previously trained machine-learning algorithm for identification of resting-state networks on an individual basis. Network maps were uploaded to the clinical imaging and surgical navigation systems. Patient demographic and clinical characteristics, including need for sedation during imaging and use of task-based fMRI, were also recorded. RESULTS Twenty patients underwent rs-fMRI prior to craniotomy between December 2013 and June 2016. Their ages ranged from 1.9 to 18.4 years, and 12 were male. Five of the 20 patients also underwent task-based fMRI and one underwent awake craniotomy. Six patients required sedation to tolerate MRI acquisition, including resting-state sequences. Exemplar cases are presented including anatomical and resting-state functional imaging. CONCLUSIONS Resting-state fMRI is a rapidly advancing field of study allowing for whole brain analysis by a noninvasive modality. It is applicable to a wide range of patients and effective even under general anesthesia. The nature of resting-state analysis precludes any need for task cooperation. These features make rs-fMRI an ideal technology for cerebral mapping in pediatric neurosurgical patients. This review of the use of rs-fMRI mapping in an initial pediatric case series demonstrates the feasibility of utilizing this technique in pediatric neurosurgical patients. The preliminary experience presented here is a first step in translating this technique to a broader clinical practice.

Intensive Exercise Training During Bed Rest Attenuates Deconditioning

NASA Technical Reports Server (NTRS)

Greenleaf, John E.

1997-01-01

Intensive exercise training during bed rest attenuates deconditioning. Med. Sci. Sports Exerc., Vol. 29, No. 2, pp. 207-215, 1997. A 30-d 6 deg head-down bed rest project was conducted to evaluate variable high-intensity, short-duration, isotonic cycle ergometer exercise (ITE) training and high-intensity intermittent resistive isokinetic exercise (IKE) training regimens designed to maintain peak VO2 and muscle mass, strength, and endurance at ambulatory control levels throughout prolonged bed rest. Other elements of the deconditioning (adaptive) syndrome, such as proprioception, psychological performance, hypovolemia, water balance, body composition, and orthostatic tolerance, were also measured. Major findings are summarized in this paper. Compared with response during bed rest of the no exercise (NOE) control group: the ITE training regimen (a) maintained work capacity (peak VO2), (b) maintained plasma and red cell volumes, (c) induced positive body water balance, (d) decreased quality of sleep and mental concentration, and (e) had no effect on the decrease in orthostatic tolerance; the IKE training regimen (f) attenuated the decrease in peak VO2 by 50%, (g) attenuated loss of red cell volume by 40% but had no effect on loss of plasma volume, (b) induced positive body water balance, (i) had no adverse effect on quality of sleep or concentration, and 0) had no effect on the decrease in orthostatic tolerance. These findings suggest that various elements of the deconditioning syndrome can be manipulated by duration and intensity of ITE or IKE training regimens and that several different training protocols will be required to maintain or restore physiological and psychological performance of individuals confined to prolonged bed rest.

Mechanisms of appearance of the Pasteur effect in Saccharomyces cerevisiae: inactivation of sugar transport systems.

PubMed

Lagunas, R; Dominguez, C; Busturia, A; Sáez, M J

1982-10-01

Saccharomyces cerevisiae does not show a noticeable Pasteur effect (activation of sugar catabolism by anaerobiosis) when growing with an excess of sugar and nitrogen source, but it does do so after exhaustion of the nitrogen source in the medium (resting state). We have found that this different behavior of growing and resting S. cerevisiae seems due to differences in the contribution of respiration to catabolism under both states. Growing S. cerevisiae respired only 3 to 20% of the catabolized sugar, depending on the sugar present; the remainder was fermented. In contrast, resting S. cerevisiae respired as much as 25 to 100% of the catabolized sugar. These results suggest that a shift to anaerobiosis would have much greater energetic consequences in resting than in growing S. cerevisiae. In resting S. cerevisiae anaerobiosis would strongly decrease the formation of ATP; as a consequence, various regulatory mechanisms would switch on, producing the observed increase of the rate of glycolysis. The greater significance that respiration reached in resting cells was not due to an increase of the respiratory capacity itself, but to a loss of fermentation which turned respiration into the main catabolic pathway. The main mechanism involved in the loss of fermentation observed during nitrogen starvation was a progressive inactivation of the sugar transport systems that reduced the rate of fermentation to less than 10% of the value observed in growing cells. Inactivation of the sugar transports seems a consequence of the turnover of the sugar carriers whose apparent half-lives were 2 to 7 h.

Thin-layer chromatographic technique for rapid detection of bacterial phospholipases.

PubMed

Legakis, N J; Papavassiliou, J

1975-11-01

Silica gel thin-layer chromatography was employed to detect lecithinase activity induced from bacterial resting cell preparations induced from bacterial resting cell preparations incubated at 37 C for 4 h in the presence of purified egg yolk lecithin. Bacillus subtilis, Bacillus cereus, Serratia marcescens, and Pseudomonas aeruginosa hydrolyzed lecithin with the formation of free fatty acids as the sole lipid-soluble product. In none of the Escherichia coli and Citrobacter freundii strains tested could lecithinase activity be detected. Four among eight strains of Enterobacter aerogenes and one among 12 strains of Proteus tested produced negligible amounts of free fatty acid.

Action potentials and ion conductances in wild-type and CALHM1-knockout type II taste cells

PubMed Central

Saung, Wint Thu; Foskett, J. Kevin

2017-01-01

Taste bud type II cells fire action potentials in response to tastants, triggering nonvesicular ATP release to gustatory neurons via voltage-gated CALHM1-associated ion channels. Whereas CALHM1 regulates mouse cortical neuron excitability, its roles in regulating type II cell excitability are unknown. In this study, we compared membrane conductances and action potentials in single identified TRPM5-GFP-expressing circumvallate papillae type II cells acutely isolated from wild-type (WT) and Calhm1 knockout (KO) mice. The activation kinetics of large voltage-gated outward currents were accelerated in cells from Calhm1 KO mice, and their associated nonselective tail currents, previously shown to be highly correlated with ATP release, were completely absent in Calhm1 KO cells, suggesting that CALHM1 contributes to all of these currents. Calhm1 deletion did not significantly alter resting membrane potential or input resistance, the amplitudes and kinetics of Na+ currents either estimated from action potentials or recorded from steady-state voltage pulses, or action potential threshold, overshoot peak, afterhyperpolarization, and firing frequency. However, Calhm1 deletion reduced the half-widths of action potentials and accelerated the deactivation kinetics of transient outward currents, suggesting that the CALHM1-associated conductance becomes activated during the repolarization phase of action potentials. NEW & NOTEWORTHY CALHM1 is an essential ion channel component of the ATP neurotransmitter release mechanism in type II taste bud cells. Its contribution to type II cell resting membrane properties and excitability is unknown. Nonselective voltage-gated currents, previously associated with ATP release, were absent in cells lacking CALHM1. Calhm1 deletion was without effects on resting membrane properties or voltage-gated Na+ and K+ channels but contributed modestly to the kinetics of action potentials. PMID:28202574

Action potentials and ion conductances in wild-type and CALHM1-knockout type II taste cells.

PubMed

Ma, Zhongming; Saung, Wint Thu; Foskett, J Kevin

2017-05-01

Taste bud type II cells fire action potentials in response to tastants, triggering nonvesicular ATP release to gustatory neurons via voltage-gated CALHM1-associated ion channels. Whereas CALHM1 regulates mouse cortical neuron excitability, its roles in regulating type II cell excitability are unknown. In this study, we compared membrane conductances and action potentials in single identified TRPM5-GFP-expressing circumvallate papillae type II cells acutely isolated from wild-type (WT) and Calhm1 knockout (KO) mice. The activation kinetics of large voltage-gated outward currents were accelerated in cells from Calhm1 KO mice, and their associated nonselective tail currents, previously shown to be highly correlated with ATP release, were completely absent in Calhm1 KO cells, suggesting that CALHM1 contributes to all of these currents. Calhm1 deletion did not significantly alter resting membrane potential or input resistance, the amplitudes and kinetics of Na + currents either estimated from action potentials or recorded from steady-state voltage pulses, or action potential threshold, overshoot peak, afterhyperpolarization, and firing frequency. However, Calhm1 deletion reduced the half-widths of action potentials and accelerated the deactivation kinetics of transient outward currents, suggesting that the CALHM1-associated conductance becomes activated during the repolarization phase of action potentials. NEW & NOTEWORTHY CALHM1 is an essential ion channel component of the ATP neurotransmitter release mechanism in type II taste bud cells. Its contribution to type II cell resting membrane properties and excitability is unknown. Nonselective voltage-gated currents, previously associated with ATP release, were absent in cells lacking CALHM1. Calhm1 deletion was without effects on resting membrane properties or voltage-gated Na + and K + channels but contributed modestly to the kinetics of action potentials. Copyright © 2017 the American Physiological Society.

The structural bases of long-term anabiosis in non-spore-forming bacteria

NASA Astrophysics Data System (ADS)

Suzina, Natalia E.; Mulyukin, Andrey L.; Dmitriev, Vladimir V.; Nikolaev, Yury A.; Shorokhova, Anna P.; Bobkova, Yulia S.; Barinova, Ekaterina S.; Plakunov, Vladimir K.; El-Registan, Galina I.; Duda, Vitalii I.

2006-01-01

Peculiarities of the structural organization in non-spore-forming bacteria associated with long-term anabiosis were revealed both in laboratory cultures and in natural populations isolated from 1 3-Myr-old Eastern Siberian permafrost and tundra soil. Different advanced methods were used, including (a) high-resolution electron microscopy; (b) simulation of in situ conditions in the laboratory by varying the composition of growth medium and cultivation conditions; (c) low-temperature fractionation to isolate and concentrate microbial cells from natural soils; (d) comparative morphological analysis of microbial cells in model cultures and natural soils (in situ). Under laboratory conditions, the intense formation of resting cells by representatives of various taxa of eubacteria and halophilic archaea occurred in 2 9-month-old cultures grown in carbon-, nitrogen-, or phosphorus-limited media, in starved cell suspensions in the presence of sodium silicate, or on soil agar. Among resting cells, we revealed cystlike forms having a complicated structure and common features. These included a thick capsule; a thickened and multiprofile cell wall; the presence of large intramembrane particles on PF- and EF-fracture surfaces; fine-grained or lumpy cytoplasm; and a condensed nucleoid. The general morphological properties, ultrastructural organization, physiological features of cystlike cells, and their ability to germinate under the appropriate conditions suggest the existence of constitutive dormancy in non-spore-forming bacteria. It was found that the majority of microorganisms in permafrost and tundra soil are cystlike cells, very similar to those in laboratory cultures. Anabiotic (resting) cystlike cells are responsible for the survival of non-spore-formers in extreme Earth habitats and may be regarded as possible analogs of extraterrestrial forms of microbial life.

Exercise Training During Bed Rest Attenuates Deconditioning

NASA Technical Reports Server (NTRS)

Greenleaf, J. E.; Hargens, Alan R. (Technical Monitor)

1995-01-01

A 30-day 6 deg. head-down bed rest study was conducted to evaluate high-intensity, short-duration, alternating isotonic cycle ergometer exercise (ITE) training and high-intensity intermittent isokinetic exercise (IKE) training regiments designed to maintain peak VO2 and muscle mass, strength, and endurance at ambulatory control levels throughout prolonged bed rest. Other elements of the deconditioning (acclimation) syndrome, such as proprioception, psychological performance, hypovolemia, water balance, body composition, and orthostatic tolerance, were also measured. Compared with response during bed rest of the no exercise (NOE) control group: the ITE training regimen (a) maintained work capacity (peak VO2), (b) maintained plasma and red cell volume, (c) induced positive body water balance, (d) decreased quality of sleep and mental concentration, and (e) had no effect on the decrease in orthostatic tolerance; the IKE training regimen (a) attenuated the decrease in peak VO2 by 50%, (b) attenuated loss of red cell volume by 40%, but had no effect on loss of plasma volume, (c) induced positive body water balance, (d) had no adverse effect on quality of sleep or concentration, and (e) had no effect on the decrease in orthostatic tolerance. These findings suggest that various elements of the deconditioning syndrome can be manipulated by duration and intensity of ITE or IKE training regiments, and that several different training protocols will be required to maintain or restore physiological and psychological performance of individuals confined to prolonged bed rest.

Direct modulation of tracheal Cl--channel activity by 5,6- and 11,12-EET.

PubMed

Salvail, D; Dumoulin, M; Rousseau, E

1998-09-01

Using microelectrode potential measurements, we tested the involvement of Cl- conductances in the hyperpolarization induced by 5,6- and 11,12-epoxyeicosatrienoic acid (EET) in airway smooth muscle (ASM) cells. 5,6-EET and 11,12-EET (0.75 microM) caused -5.4 +/- 1.1- and -3.34 +/- 0.95-mV hyperpolarizations, respectively, of rabbit tracheal cells (from a resting membrane potential of -53.25 +/- 0.44 mV), with significant residual repolarizations remaining after the Ca2+-activated K+ channels had been blocked by 10 nM iberiotoxin. In bilayer reconstitution experiments, we demonstrated that the EETs directly inhibit a Ca2+-insensitive Cl- channel from bovine ASM; 1 microM 5,6-EET and 1.5 microM 11,12-EET lowered the unitary current amplitude by 40 (n = 6 experiments) and 44.7% (n = 4 experiments), respectively. Concentration-dependent decreases in channel open probability were observed, with estimated IC50 values of 0.26 microM for 5,6- and 1.15 microM for 11,12-EET. Furthermore, pharmacomechanical tension measurements showed that both regioisomers induced significant bronchorelaxations in epithelium-denuded ASM strips. These results suggest that 5,6- and 11,12-EET can act in ASM as epithelium-derived hyperpolarizing factors.

Comparison of Ocular Outcomes in Two 14-Day Bed Rest Studies

NASA Technical Reports Server (NTRS)

Cromwell, Ronita L.; Zanello, S. B.; Yarbough, P. O.; Tabbi, G.; Vizzeri, G.

2012-01-01

Reports of astronauts' visual changes have raised concern about ocular health during long-duration spaceflight. Some of these findings include globe flattening with hyperopic shifts, choroidal folds, optic disc edema, retinal nerve fiber layer (RNFL) thickening, and cotton wool spots. While the etiology remains unknown, it is hypothesized that, in predisposed individuals, hypertension in the brain may follow cephalad fluid shifts during spaceflight. This possible mechanism of ocular changes may also apply to analogous cases of idiopathic intracranial hypertension (IIH) or pseudotumor cerebri on Earth patients. Head-down t ilt (HDT) bed rest is a spaceflight analog that induces cephalad fluid shifts. Previous studies of the HDT position demonstrated body fluid shifts associated with changes in intraocular pressure (IOP) but the conditions of bed rest varied among experiments, making it difficult to compare data and draw conclusions. For these reasons, vision evaluation of bed rest subjects was implemented for NASA bed rest studies since 2010, in an attempt to monitor vision health in subjects subjected to bed rest. Vision monitoring is thus currently performed in all NASA-conducted bed rest campaigns

[Interfering effects of radix Salviae miltiorrhizae and lingustrazine on mm-LDL activating BKCa in ECV304 cell].

PubMed

Lin, L; Zheng, Y F; Qu, J H; Bao, G H

2001-08-01

To observe the action of minimally modified low density lipoprotein (mm-LDL) on BKCa in ECV304 cell and the interfering effects of radix salviae miltiorrhizae extract powder 764-3 (30 micrograms/ml) and lingustrazine (200 micrograms/ml) on this action. The cell-attached configuration of patch clamp technique was applied. mm-LDL (100 micrograms/ml) potentiated the activity of BKCa in ECV304. While 764-3 and lingustrazine abolished it. mm-LDL acted on vascular endothelial cell ECV304 could rapidly activate the activity of BKCa and might result in the increase of electro-chemical gradient for the resting Ca2+ influx, thus resting cytoplasmic concentration of calcium could be elevated and endothelial dysfunction would be induced. 764-3 and lingustrazine might have the protective action through decreasing the activity of BKCa.

Strain energy storage and dissipation rate in active cell mechanics

NASA Astrophysics Data System (ADS)

Agosti, A.; Ambrosi, D.; Turzi, S.

2018-05-01

When living cells are observed at rest on a flat substrate, they can typically exhibit a rounded (symmetric) or an elongated (polarized) shape. Although the cells are apparently at rest, the active stress generated by the molecular motors continuously stretches and drifts the actin network, the cytoskeleton of the cell. In this paper we theoretically compare the energy stored and dissipated in this active system in two geometric configurations of interest: symmetric and polarized. We find that the stored energy is larger for a radially symmetric cell at low activation regime, while the polar configuration has larger strain energy when the active stress is beyond a critical threshold. Conversely, the dissipation of energy in a symmetric cell is always larger than that of a nonsymmetric one. By a combination of symmetry arguments and competition between surface and bulk stress, we argue that radial symmetry is an energetically expensive metastable state that provides access to an infinite number of lower-energy states, the polarized configurations.

Strain energy storage and dissipation rate in active cell mechanics.

PubMed

Agosti, A; Ambrosi, D; Turzi, S

2018-05-01

When living cells are observed at rest on a flat substrate, they can typically exhibit a rounded (symmetric) or an elongated (polarized) shape. Although the cells are apparently at rest, the active stress generated by the molecular motors continuously stretches and drifts the actin network, the cytoskeleton of the cell. In this paper we theoretically compare the energy stored and dissipated in this active system in two geometric configurations of interest: symmetric and polarized. We find that the stored energy is larger for a radially symmetric cell at low activation regime, while the polar configuration has larger strain energy when the active stress is beyond a critical threshold. Conversely, the dissipation of energy in a symmetric cell is always larger than that of a nonsymmetric one. By a combination of symmetry arguments and competition between surface and bulk stress, we argue that radial symmetry is an energetically expensive metastable state that provides access to an infinite number of lower-energy states, the polarized configurations.

A highly reproducible quantitative viral outgrowth assay for the measurement of the replication-competent latent HIV-1 reservoir.

PubMed

Fun, Axel; Mok, Hoi Ping; Wills, Mark R; Lever, Andrew M

2017-02-24

Cure of Human Immunodeficiency Virus (HIV) infection remains elusive due to the persistence of HIV in a latent reservoir. Strategies to eradicate latent infection can only be evaluated with robust, sensitive and specific assays to quantitate reactivatable latent virus. We have taken the standard peripheral blood mononuclear cell (PBMC) based viral outgrowth methodology and from it created a logistically simpler and more highly reproducible assay to quantify replication-competent latent HIV in resting CD4 + T cells, both increasing accuracy and decreasing cost and labour. Purification of resting CD4 + T cells from whole PBMC is expedited and achieved in 3 hours, less than half the time of conventional protocols. Our indicator cell line, SupT1-CCR5 cells (a clonal cell line expressing CD4, CXCR4 and CCR5) provides a readily available standardised readout. Reproducibility compares favourably to other published assays but with reduced cost, labour and assay heterogeneity without compromising sensitivity.

Preferential and Increased Uptake of Hydroxyl-Terminated PAMAM Dendrimers by Activated Microglia in Rabbit Brain Mixed Glial Culture.

PubMed

Alnasser, Yossef; Kambhampati, Siva P; Nance, Elizabeth; Rajbhandari, Labchan; Shrestha, Shiva; Venkatesan, Arun; Kannan, Rangaramanujam M; Kannan, Sujatha

2018-04-27

Polyamidoamine (PAMAM) dendrimers are multifunctional nanoparticles with tunable physicochemical features, making them promising candidates for targeted drug delivery in the central nervous system (CNS). Systemically administered dendrimers have been shown to localize in activated glial cells, which mediate neuroinflammation in the CNS. These dendrimers delivered drugs specifically to activated microglia, producing significant neurological improvements in multiple brain injury models, including in a neonatal rabbit model of cerebral palsy. To gain further insight into the mechanism of dendrimer cell uptake, we utilized an in vitro model of primary glial cells isolated from newborn rabbits to assess the differences in hydroxyl-terminated generation 4 PAMAM dendrimer (D4-OH) uptake by activated and non-activated glial cells. We used fluorescently-labelled D4-OH (D-Cy5) as a tool for investigating the mechanism of dendrimer uptake. D4-OH PAMAM dendrimer uptake was determined by fluorescence quantification using confocal microscopy and flow cytometry. Our results indicate that although microglial cells in the mixed cell population demonstrate early uptake of dendrimers in this in vitro system, activated microglia take up more dendrimer compared to resting microglia. Astrocytes showed delayed and limited uptake. We also illustrated the differences in mechanism of uptake between resting and activated microglia using different pathway inhibitors. Both resting and activated microglia primarily employed endocytotic pathways, which are enhanced in activated microglial cells. Additionally, we demonstrated that hydroxyl terminated dendrimers are taken up by primary microglia using other mechanisms including pinocytosis, caveolae, and aquaporin channels for dendrimer uptake.

Calreticulin is expressed on the cell surface of activated human peripheral blood T lymphocytes in association with major histocompatibility complex class I molecules.

PubMed

Arosa, F A; de Jesus, O; Porto, G; Carmo, A M; de Sousa, M

1999-06-11

Calreticulin is an endoplasmic reticulum resident molecule known to be involved in the folding and assembly of major histocompatibility complex (MHC) class I molecules. In the present study, expression of calreticulin was analyzed in human peripheral blood T lymphocytes. Pulse-chase experiments in [35S]methionine-labeled T cell blasts showed that calreticulin was associated with several proteins in the endoplasmic reticulum and suggested that it was expressed at the cell surface. Indeed, the 60-kDa calreticulin was labeled by cell surface biotinylation and precipitated from the surface of activated T cells together with a protein with an apparent molecular mass of 46 kDa. Cell surface expression of calreticulin by activated T lymphocytes was further confirmed by immunofluorescence and flow cytometry, studies that showed that both CD8+ and CD4+ T cells expressed calreticulin in the plasma membrane. Low amounts of cell surface calreticulin were detected in resting T lymphocytes. By sequential immunoprecipitation using the conformation independent monoclonal antibody HC-10, we provided evidence that the cell surface 46-kDa protein co-precipitated with calreticulin is unfolded MHC I. These results show for the first time that after T cell activation, significant amounts of calreticulin are expressed on the T cell surface, where they are found in physical association with a pool of beta2-free MHC class I molecules.

REST, regulated by RA through miR-29a and the proteasome pathway, plays a crucial role in RPC proliferation and differentiation.

PubMed

Wang, Yuyao; Zhang, Dandan; Tang, Zhimin; Zhang, Yi; Gao, Huiqin; Ni, Ni; Shen, Bingqiao; Sun, Hao; Gu, Ping

2018-04-18

One of the primary obstacles in the application of retinal progenitor cells (RPCs) to the treatment of retinal degenerative diseases, such as age-related macular degeneration (AMD) and retinitis pigmentosa (RP), is their limited ability to proliferate and differentiate into specific retinal neurons. In this study, we revealed that repressor element-1-silencing transcription factor (REST), whose expression could be transcriptionally and post-transcriptionally mediated by retinoic acid (RA, one isomeride of a vitamin A derivative used as a differentiation-inducing agent in many disease treatments), plays a pivotal role in the regulation of proliferation and differentiation of RPCs. Our results show that direct knockdown of endogenous REST reduced RPC proliferation but accelerated RPC differentiation toward retinal neurons, which phenocopied the observed effects of RA on RPCs. Further studies disclosed that the expression level of REST could be downregulated by RA not only through upregulating microRNA (miR)-29a, which directly interacted with the 3'-untranslated region (3'-UTR) of the REST mRNA, but also through promoting REST proteasomal degradation. These results show us a novel functional protein, REST, which regulates RPC proliferation and differentiation, can be mediated by RA. Understanding the mechanisms of REST and RA in RPC fate determination enlightens a promising future for the application of REST and RA in the treatment of retinal degeneration diseases.

The RNA helicase DDX17 controls the transcriptional activity of REST and the expression of proneural microRNAs in neuronal differentiation.

PubMed

Lambert, Marie-Pierre; Terrone, Sophie; Giraud, Guillaume; Benoit-Pilven, Clara; Cluet, David; Combaret, Valérie; Mortreux, Franck; Auboeuf, Didier; Bourgeois, Cyril F

2018-06-21

The Repressor Element 1-silencing transcription factor (REST) represses a number of neuronal genes in non-neuronal cells or in undifferentiated neural progenitors. Here, we report that the DEAD box RNA helicase DDX17 controls important REST-related processes that are critical during the early phases of neuronal differentiation. First, DDX17 associates with REST, promotes its binding to the promoter of a subset of REST-targeted genes and co-regulates REST transcriptional repression activity. During neuronal differentiation, we observed a downregulation of DDX17 along with that of the REST complex that contributes to the activation of neuronal genes. Second, DDX17 and its paralog DDX5 regulate the expression of several proneural microRNAs that are known to target the REST complex during neurogenesis, including miR-26a/b that are also direct regulators of DDX17 expression. In this context, we propose a new mechanism by which RNA helicases can control the biogenesis of intronic miRNAs. We show that the processing of the miR-26a2 precursor is dependent on RNA helicases, owing to an intronic regulatory region that negatively impacts on both miRNA processing and splicing of its host intron. Our work places DDX17 in the heart of a pathway involving REST and miRNAs that allows neuronal gene repression.

A physiological model of tea-induced astringency.

PubMed

Nayak, A; Carpenter, G H

2008-10-20

The mechanism by which solutions containing polyphenols are perceived as astringent is not clearly understood. Salivary proline-rich proteins and histatins are products of salivary glands and rapidly bind polyphenols - thought to be the main astringent compound in such as tea and wine. However it is unclear how this interaction leads to the altered oral mouthfeel known as astringency which is characterised by a dry, puckered feeling all around the mouth. To determine the role of saliva in the perception of astringency a protocol was used to decrease the volume of saliva from the mouth (by washing with water) and then by chewing to increase the volume of saliva above resting levels. Following each of these conditions subjects tasted the same solution of black tea and were asked to rate the relative astringency. Compared to the astringency rating of black tea at rest the majority of subjects (10 out of 15) perceived an increase in astringency following washing the mouth with water. Most subjects then perceived a decrease in astringency following chewing compared to the previous state. In all subjects a reduction in salivary proteins was detected following water washout and an increase above resting levels detected following chewing although there was no change in oral mucosal wetness. A separate experiment revealed several of the proteins interacting following the water washout were salivary in origin. We conclude that salivary proteins in solution inhibit the mouthfeeling of astringency which is mediated, at least in part, by salivary proteins adhered to buccal mucosal cells.

The Amsterdam Resting-State Questionnaire reveals multiple phenotypes of resting-state cognition

PubMed Central

Diaz, B. Alexander; Van Der Sluis, Sophie; Moens, Sarah; Benjamins, Jeroen S.; Migliorati, Filippo; Stoffers, Diederick; Den Braber, Anouk; Poil, Simon-Shlomo; Hardstone, Richard; Van't Ent, Dennis; Boomsma, Dorret I.; De Geus, Eco; Mansvelder, Huibert D.; Van Someren, Eus J. W.; Linkenkaer-Hansen, Klaus

2013-01-01

Resting-state neuroimaging is a dominant paradigm for studying brain function in health and disease. It is attractive for clinical research because of its simplicity for patients, straightforward standardization, and sensitivity to brain disorders. Importantly, non-sensory experiences like mind wandering may arise from ongoing brain activity. However, little is known about the link between ongoing brain activity and cognition, as phenotypes of resting-state cognition—and tools to quantify them—have been lacking. To facilitate rapid and structured measurements of resting-state cognition we developed a 50-item self-report survey, the Amsterdam Resting-State Questionnaire (ARSQ). Based on ARSQ data from 813 participants assessed after 5 min eyes-closed rest in their home, we identified seven dimensions of resting-state cognition using factor analysis: Discontinuity of Mind, Theory of Mind, Self, Planning, Sleepiness, Comfort, and Somatic Awareness. Further, we showed that the structure of cognition was similar during resting-state fMRI and EEG, and that the test-retest correlations were remarkably high for all dimensions. To explore whether inter-individual variation of resting-state cognition is related to health status, we correlated ARSQ-derived factor scores with psychometric scales measuring depression, anxiety, and sleep quality. Mental health correlated positively with Comfort and negatively with Discontinuity of Mind. Finally, we show that sleepiness may partially explain a resting-state EEG profile previously associated with Alzheimer's disease. These findings indicate that the ARSQ readily provides information about cognitive phenotypes and that it is a promising tool for research on the neural correlates of resting-state cognition in health and disease. PMID:23964225

Acute L-arginine supplementation has no effect on cardiovascular or thermoregulatory responses to rest, exercise, and recovery in the heat.

PubMed

Tyler, Christopher J; Coffey, Thomas R M; Hodges, Gary J

2016-02-01

To investigate the effect of acute L-arginine (L-ARG) supplementation on cardiovascular and thermoregulatory responses to rest, exercise, and recovery in the heat. Eight healthy men (age 27 ± 6 years; stature 176 ± 6 cm; body mass 76 ± 4 kg; maximal power output 237 ± 39 W) participated in a double-blind, crossover study, attending the laboratory for two experimental trials. On each occasion, participants consumed 500 ml of a black currant-flavoured cordial beverage 30 min before completing a 90 min experiment in the heat (35 °C and 50% rh). The experiment consisted of 30 min of seated rest, followed by 30 min submaximal cycling (60% maximal power output) and 30 min passive seated recovery. On one visit the drink contained 10 g of dissolved L-ARG while on the other visit it did not. L-ARG supplementation increased plasma L-ARG concentrations (peak +223 ± 80% after 60 min of the 90 min experiment); however, supplementation had no effect on rectal temperature, mean skin temperature, heart rate, arterial pressure, forearm skin vascular conductance, oxygen consumption or sweat loss at rest, during exercise, or during recovery in the heat (p > 0.05). Acute ingestion of 10 g L-ARG supplementation failed to elicit any changes in the cardiovascular or thermoregulatory responses to active or passive heat exposure in young, healthy males.

Effects of twenty-four hour transport or twenty-four hour feed and water deprivation on physiologic and performance responses of feeder cattle.

PubMed

Marques, R S; Cooke, R F; Francisco, C L; Bohnert, D W

2012-12-01

The objective of this study was to compare the effects of 24-h road transport or 24-h feed and water deprivation on acute-phase and performance responses of feeder cattle. Angus × Hereford steers (n = 30) and heifers (n = 15) were ranked by gender and BW (217 ± 3 kg initial BW; 185 ± 2 d initial age) and randomly assigned to 15 pens on d -12 of the experiment (3 animals/pen; 2 steers and 1 heifer). Cattle were fed alfalfa-grass hay ad libitum and 2.3 kg/animal daily (DM basis) of a corn-based concentrate throughout the experiment (d -12 to 28). On d 0, pens were randomly assigned to 1 of 3 treatments: 1) transport for 24 h in a livestock trailer for 1,200 km (TRANS), 2) no transport but feed and water deprivation for 24 h (REST), or 3) no transport and full access to feed and water (CON). Treatments were concurrently applied from d 0 to d 1. Total DMI was evaluated daily from d -12 to d 28. Full BW was recorded before treatment application (d -1 and 0) and at the end of experiment (d 28 and 29). Blood samples were collected on d 0, 1, 4, 7, 10, 14, 21, and 28. Mean ADG was greater (P < 0.01) in CON vs. TRANS and REST cattle but similar (P = 0.46) between TRANS and REST cattle (1.27, 0.91, and 0.97 kg/d, respectively; SEM = 0.05). No treatment effects were detected for DMI (P ≥ 0.25), but CON had greater G:F vs. TRANS (P < 0.01) and REST cattle (P = 0.08) whereas G:F was similar (P = 0.21) between TRANS and REST cattle. Plasma cortisol concentrations were greater (P ≤ 0.05) in REST vs. CON and TRANS cattle on d 1, 7, 14, and 28 and also greater (P = 0.02) in TRANS vs. CON cattle on d 1. Serum NEFA concentrations were greater (P < 0.01) in REST and TRANS vs. CON cattle on d 1 and greater (P < 0.01) in REST vs. TRANS cattle on d 1. Plasma ceruloplasmin concentrations were greater (P = 0.04) in TRANS vs. CON cattle on d 1, greater (P = 0.05) in REST vs. CON on d 4, and greater (P ≤ 0.05) in REST vs. TRANS and CON on d 14. Plasma haptoglobin concentrations were greater (P < 0.01) in TRANS vs. CON and REST cattle on d 1 and greater (P ≤ 0.05) for REST vs. TRANS and CON cattle on d 7. In conclusion, 24-h transport and 24-h nutrient deprivation elicited acute-phase protein reactions and similarly reduced feedlot receiving performance of feeder cattle. These results suggest that feed and water deprivation are major contributors to the acute-phase response and reduced feedlot receiving performance detected in feeder cattle transported for long distances.

Preliminary results of the Artemia salina experiments in biostack on LDEF

NASA Technical Reports Server (NTRS)

Graul, E. H.; Ruether, W.; Hiendl, C. O.

1992-01-01

The mosaic egg of the brine shrimp, Artemia salina, resting in blastula or gastrula state represents a system that during further development, proceeds without any further development to the larval stage, the free swimming nauplius. Therefore, injury to a single cell of the egg will be manifest in the larvae. In several experiments, it was shown that the passage of a single heavy ion through the shrimp egg damaged a cellular area large enough to disturb either embryogenesis or further development of the larvae, or the integrity of the adult individual. Emergence from the egg shell was heavily disturbed by the heavy ions as was hatching. Additional late effects, due to a hit by a heavy ion, are delayed of growth and of sexual maturity, and reduced fertility. Anomalies in the body and the extremities could be observed more frequently for the nauplii which had developed from eggs hit by heavy ions.

From fission to fusion: a perspective on the research that won the Nobel Prize in Physiology or Medicine, 2013.

PubMed

Ray, Krishanu

2014-03-01

Secretion is widespread in all eukaryotic cells: all of us experience this in the course of daily life--saliva, mucus, sweat, tears, bile juice, adrenalin, etc.--the list is extremely long. How does a cell manage to repeatedly spit out some stuff without losing the rest? The answer is: through regulated vesicle trafficking within the cell. The Nobel Prize in Physiology or Medicine 2013 was awarded to Drs Randy Schekman, James E Rothman and Thomas C Südhof for their 'discoveries of machinery regulating vesicle traffic, a major transport system in our cells'. Dr Randy Schekman and his colleagues discovered a number of genes required for vesicle trafficking from the endoplasmic reticulum (ER) and Golgi; the James E Rothman group unravelled the protein machinery that allows vesicles to bud off from the membrane and fuse to their targets; and Dr Thomas C Südhof along with his colleagues revealed how calcium ions could instruct vesicles to fuse and discharge their contents with precision. These enabled the biotechnology industry to produce a variety of pharmaceutical and industrial products like insulin and hepatitis B vaccines, in a cost-efficient manner, using yeast and tissue cultured cells.

Micromechanics in the Gerbil Hemicochlea

NASA Astrophysics Data System (ADS)

Richter, C.-P.; Dallos, P.

2003-02-01

Micromechanical events in the cochlea represent the combined motions of all elements that convey vibrations from the basilar membrane (BM) to the stereocilia bundles of the inner hair cells, the sensory receptors of the mammalian cochlea. Because of the difficulty of visualizing the organ of Corti (OC), experimental data on micromechanics are extremely limited. Available results represent motions viewed either from one focal plane or from the surface of a cochlear preparation. The present experiments examine cochlear micromechanics at audio frequencies by using the hemicochlea that permits the viewing of all structures in a cochlear cross-section. Stroboscopic illumination and video-flow techniques have been used to quantify the motion of selected elements. The movements at different locations revealed a tuned response across frequencies with the best frequency increasing from more basal to more apical locations. Furthermore, the vibrations showed rotational components, such as rotations around a pivot point: the inner pillar foot. Inner and outer pillar cells, inner and outer hair cells, Deiters' cells and parts of the BM move together and form a so-called "rotating wedge". The movements of Hensen's cells represent a mode of vibration different from that of the rest of the OC.

Tolerance Induction of Temperature and Starvation with Tricalcium Phosphate on Preservation and Sporulation in Bacillus amyloliquefaciens Detected by Flow Cytometry.

PubMed

Shahrokh Esfahani, Samaneh; Emtiazi, Giti; Shafiei, Rasoul; Ghorbani, Najmeh; Zarkesh Esfahani, Seyed Hamid

2016-09-01

The Bacillus species have many applications in the preparation of various enzymes, probiotic, biofertilizer, and biomarkers for which the survival of resting cells and spore formation under different conditions are important. In this study, water and saline along with different mineral substances such as calcium carbonate, calcium phosphate, and silica were used for the detection of survival and preservation of Bacillus amyloliquefaciens. The results showed intensive death of resting cells at 8 °C, but significant survival at 28 °C after one month. However, preservation by minerals significantly decreased the rate of death and induced sporulation at both the temperatures. The resting cells were maintained at room temperature (about 60 % of the initial population survived after a month) in the presence of tricalcium phosphate. The results showed that temperature has more effect on sporulation compare with starvation. The sporulation in normal saline at 28 °C was 70 times more than that at 8 °C; meanwhile, addition of tricalcium phosphate increases sporulation by 90 times. Also, the FTIR data showed the interaction of tricalcium phosphate with spores and resting cells. The discrimination of sporulation from non-sporulation state was performed by nucleic acid staining with thiazole orange and detected by flow cytometry. The flow cytometric studies confirmed that the rates of sporulation in pure water were significantly more at 28 °C. This is the first report on the detection of bacterial spore with thiazole orange by flow cytometry and also on the interaction of tricalcium phosphate with spores by FTIR analyses.

The Impact of DIDS-Induced Inhibition of Voltage-Dependent Anion Channels (VDAC) on Cellular Response of Lymphoblastoid Cells to Ionizing Radiation.

PubMed

Skonieczna, Magdalena; Cieslar-Pobuda, Artur; Saenko, Yuriy; Foksinski, Marek; Olinski, Ryszard; Rzeszowska-Wolny, Joanna; Wiechec, Emilia

2017-01-01

The voltage-dependent anion channels (VDAC) play an essential role in the cross talk between mitochondria and the rest of the cell. Their implication in cell life and cell death has been studied extensively in recent years. In this work we studied the impact of mitochondrial membrane (VDACs) on cell survival and response to X-ionizing radiation (IR) of human lymphoblastoid K562 cells. The inhibition of VDACs was achieved by 4,4`-diisothiocyanostilbene-2,2`-disulfonic acid (DIDS) inhibitor and in vitro experiments including clonogenity assay, UV-visible spectrophotometry, comet assay and FACS analysis were implemented. Inhibition of VDAC led to augmentation of IR-induced apoptosis and ROS production. Additionally, DIDS affected repair of IR-induced DNA strand breaks and was in line with both induction of apoptosis and caspase activity. The IR-induced NO production was potently reduced by inhibition of VDAC. Our results suggest that VDAC control cellular response to ionizing radiation through modulation of the ROS- and NO-dependent signaling pathways. Inhibition of VDAC with DIDS induced apoptosis in irradiated K562 lymphoblastoid cells points at DIDS, as a promising agent to enhance the effectiveness of radiotherapy. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

A soluble biocompatible guanidine-containing polyamidoamine as promoter of primary brain cell adhesion and in vitro cell culturing

NASA Astrophysics Data System (ADS)

Tonna, Noemi; Bianco, Fabio; Matteoli, Michela; Cagnoli, Cinzia; Antonucci, Flavia; Manfredi, Amedea; Mauro, Nicolò; Ranucci, Elisabetta; Ferruti, Paolo

2014-08-01

This paper reports on a novel application of an amphoteric water-soluble polyamidoamine named AGMA1 bearing 4-butylguanidine pendants. AGMA1 is an amphoteric, prevailingly cationic polyelectrolyte with isoelectric point of about 10. At pH 7.4 it is zwitterionic with an average of 0.55 excess positive charges per unit, notwithstanding it is highly biocompatible. In this work, it was found that AGMA1 surface-adsorbed on cell culturing coverslips exhibits excellent properties as adhesion and proliferation promoter of primary brain cells such as microglia, as well as of hippocampal neurons and astrocytes. Microglia cells cultured on AGMA1-coated coverslips substrate displayed the typical resting, ramified morphology of those cultured on poly-L-lysine and poly-L-ornithine, employed as reference substrates. Mixed cultures of primary astrocytes and neuronal cells grown on AGMA1- and poly-L-lysine coated coverslips were morphologically undistinguishable. On both substrates, neurons differentiated axon and dendrites and eventually established perfectly functional synaptic contacts. Quantitative immunocytochemical staining revealed no difference between AGMA1 and poly-L-lysine. Electrophysiological experiments allowed recording neuron spontaneous activity on AGMA1. In addition, cell cultures on both AGMA1 and PLL displayed comparable excitatory and inhibitory neurotransmission, demonstrating that the synaptic contacts formed were fully functional.

21 Days head-down bed rest induces weakening of cell-mediated immunity - Some spaceflight findings confirmed in a ground-based analog.

PubMed

Kelsen, Jens; Bartels, Lars Erik; Dige, Anders; Hvas, Christian Lodberg; Frings-Meuthen, Petra; Boehme, Gisela; Thomsen, Marianne Kragh; Fenger-Grøn, Morten; Dahlerup, Jens Frederik

2012-08-01

Several studies indicate a weakening of cell-mediated immunity (CMI) and reactivation of latent herpes viruses during spaceflight. We tested the hypothesis that head-down bed rest (HDBR), a ground-based analog of spaceflight, mimics the impact of microgravity on human immunity. Seven healthy young males underwent two periods of 3 weeks HDBR in the test facility of the German Aerospace Center. As a nutritional countermeasure aimed against bone demineralisation, 90 mmol potassium bicarbonate (KHCO(3)) was administered daily in a crossover design. Blood samples were drawn on five occasions. Whole blood was stimulated with antigen i.e. Candida albicans, purified protein derivative (PPD) tuberculin, tetanus toxoid and Cytomegalovirus (CMV) (CMV-QuantiFERON). Flow cytometric analysis included CD4(+)CD25(+)CD127(-)FOXP3(+) regulatory T cells (Tregs), γδ T cells, B cells, NK cells and dendritic cells. In one of the two bed rest periods, we observed a significant decrease in production of interleukin-2 (IL-2), interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α) following phytohemagglutinin (PHA) stimulation, with a rapid normalization being observed after HDBR. The cytokine levels showed a V-shaped pattern that led to a relativeTh2-shift in cytokine balance. Only three individuals responded to the specific T cell antigens without showing signs of an altered response during HDBR, nor did we observe reactivation of CMV or Epstein-Barr virus (EBV). Of unknown significance, dietary supplementation with KHCO(3) counteracted the decrease in IL-2 levels during HDBR, while there was no impact on other immunological parameters. We conclude that discrete alterations in CMI may be induced by HDBR in selected individuals. Copyright © 2012 Elsevier Ltd. All rights reserved.

Measles virus envelope pseudotyped lentiviral vectors transduce quiescent human HSCs at an efficiency without precedent

PubMed Central

Lévy, Camille; Amirache, Fouzia; Girard-Gagnepain, Anais; Frecha, Cecilia; Roman-Rodríguez, Francisco J.; Bernadin, Ornellie; Costa, Caroline; Nègre, Didier; Gutierrez-Guerrero, Alejandra; Vranckx, Lenard S.; Clerc, Isabelle; Taylor, Naomi; Thielecke, Lars; Cornils, Kerstin; Bueren, Juan A.; Rio, Paula; Gijsbers, Rik; Cosset, François-Loïc

2017-01-01

Hematopoietic stem cell (HSC)–based gene therapy trials are now moving toward the use of lentiviral vectors (LVs) with success. However, one challenge in the field remains: efficient transduction of HSCs without compromising their stem cell potential. Here we showed that measles virus glycoprotein–displaying LVs (hemagglutinin and fusion protein LVs [H/F-LVs]) were capable of transducing 100% of early-acting cytokine-stimulated human CD34+ (hCD34+) progenitor cells upon a single application. Strikingly, these H/F-LVs also allowed transduction of up to 70% of nonstimulated quiescent hCD34+ cells, whereas conventional vesicular stomatitis virus G (VSV-G)–LVs reached 5% at the most with H/F-LV entry occurring exclusively through the CD46 complement receptor. Importantly, reconstitution of NOD/SCIDγc−/− (NSG) mice with H/F-LV transduced prestimulated or resting hCD34+ cells confirmed these high transduction levels in all myeloid and lymphoid lineages. Remarkably, for resting CD34+ cells, secondary recipients exhibited increasing transduction levels of up to 100%, emphasizing that H/F-LVs efficiently gene-marked HSCs in the resting state. Because H/F-LVs promoted ex vivo gene modification of minimally manipulated CD34+ progenitors that maintained stemness, we assessed their applicability in Fanconi anemia, a bone marrow (BM) failure with chromosomal fragility. Notably, only H/F-LVs efficiently gene-corrected minimally stimulated hCD34+ cells in unfractionated BM from these patients. These H/F-LVs improved HSC gene delivery in the absence of cytokine stimulation while maintaining their stem cell potential. Thus, H/F-LVs will facilitate future clinical applications requiring HSC gene modification, including BM failure syndromes, for which treatment has been very challenging up to now. PMID:29296856

Exposure to apoptotic activated CD4+ T cells induces maturation and APOBEC3G-mediated inhibition of HIV-1 infection in dendritic cells.

PubMed

Mohanram, Venkatramanan; Johansson, Ulrika; Sköld, Annette E; Fink, Joshua; Kumar Pathak, Sushil; Mäkitalo, Barbro; Walther-Jallow, Lilian; Spetz, Anna-Lena

2011-01-01

Dendritic cells (DCs) are activated by signaling via pathogen-specific receptors or exposure to inflammatory mediators. Here we show that co-culturing DCs with apoptotic HIV-infected activated CD4(+) T cells (ApoInf) or apoptotic uninfected activated CD4(+) T cells (ApoAct) induced expression of co-stimulatory molecules and cytokine release. In addition, we measured a reduced HIV infection rate in DCs after co-culture with ApoAct. A prerequisite for reduced HIV infection in DCs was activation of CD4(+) T cells before apoptosis induction. DCs exposed to ApoAct or ApoInf secreted MIP-1α, MIP-1β, MCP-1, and TNF-α; this effect was retained in the presence of exogenous HIV. The ApoAct-mediated induction of co-stimulatory CD86 molecules and reduction of HIV infection in DCs were partially abrogated after blocking TNF-α using monoclonal antibodies. APOBEC3G expression in DCs was increased in co-cultures of DCs and ApoAct but not by apoptotic resting CD4(+) T cells (ApoRest). Silencing of APOBEC3G in DC abrogated the HIV inhibitory effect mediated by ApoAct. Sequence analyses of an env region revealed significant induction of G-to-A hypermutations in the context of GG or GA dinucleotides in DNA isolated from DCs exposed to HIV and ApoAct. Thus, ApoAct-mediated DC maturation resulted in induction of APOBEC3G that was important for inhibition of HIV-infection in DCs. These findings underscore the complexity of differential DC responses evoked upon interaction with resting as compared with activated dying cells during HIV infection.

Measurement of the membrane potential in small cells using patch clamp methods

PubMed Central

Wilson, James R; Clark, Robert B; Banderali, Umberto

2011-01-01

The resting membrane potential, Em, of mammalian cells is a fundamental physiological parameter. Even small changes in Em can modulate excitability, contractility and rates of cell migration. At present accurate, reproducible measurements of Em and determination of its ionic basis remain significant challenges when patch clamp methods are applied to small cells. In this study, a mathematical model has been developed which incorporates many of the main biophysical principles which govern recordings of the resting potential of “small cells”. Such a prototypical cell (approx. capacitance, 6 pF; input resistance 5 GΩ) is representative of neonatal cardiac myocytes, and other cells in the cardiovascular system (endothelium, fibroblasts) and small cells in other tissues, e.g., bone (osteoclasts) articular joints (chondrocytes) and the pancreas (β cells). Two common experimental conditions have been examined: (1) when the background K+ conductance is linear; and (2) when this K+ conductance is highly nonlinear and shows pronounced inward rectification. In the case of a linear K+ conductance, the presence of a “leakage” current through the seal resistance between the cell membrane and the patch pipette always depolarizes Em. Our calculations confirm that accurate characterization of Em is possible when the seal resistance is at least five times larger than the input resistance of the targeted cell. Measurement of Em under conditions in which the main background current includes a markedly nonlinear K+ conductance (due to inward rectification) yields complex and somewhat counter-intuitive findings. In fact, there are at least two possible stable values of resting membrane potential for a cell when the nonlinear, inwardly rectifying K+ conductance interacts with the seal current. This type of bistable behavior has been reported in a variety of small mammalian cells, including those from the heart, endothelium, smooth muscle and bone. Our theoretical treatment of these two common experimental situations provides useful mechanistic insights, and suggests practical methods by which these significant limitations, and their impact, can be minimized. PMID:21829090

Iowa interstate rest area stabilization ponds : Part I. Pond design, Part II: Feasibility of wind-powered aeration.

DOT National Transportation Integrated Search

1979-09-01

"This report is presented in two parts. Part I takes a new look at the design of rest area stabilization ponds after nearly 10 years'experience with some of the existing ponds and in the light of new design standards issued by Iowa DEQ. The Iowa DOT ...

Mixed Media

ERIC Educational Resources Information Center

Rubinstein, Gary

2003-01-01

Before the author started teaching, he expected his classroom experiences to be similar to what he had seen in teaching movies like "Dangerous Minds." For instance, the first day of school in movie is always portrayed as horrible, while the rest of the year is fairly easy. In reality, the first day is fairly easy, while the rest of the year is…

Effects of Bed-Rest on Urea and Creatinine: Correlation with Changes in Fat-Free Mass

PubMed Central

Bilancio, Giancarlo; Lombardi, Cinzia; Pisot, Rado; De Santo, Natale G.; Cavallo, Pierpaolo; Cirillo, Massimo

2014-01-01

Background Bed-rest experiments are designed for investigation on catabolic effects of hypokinetic conditions and/or for microgravity simulation in on-ground aerospace research. Bed-rest effects include a reduction in fat-free mass and muscle mass. Urea and creatinine are catabolites of endogenous protein and of muscular energetic metabolism which are excreted mainly by the kidney. The study investigated on urea, creatinine, and kidney function during bed-rest. Methods Twenty healthy young men underwent a 7-day adaptation period (day-6 to day-0) and a 35-day bed-rest experiment (day1 to day35) during normocaloric diet. Urine were collected from day-3 to day0 (baseline) and from day1 to day35. Blood samples and anthropometrical data were collected at day0 (baseline) and bed-rest days 7, 14, 21, 28, and 35. Results Bed-rest reduced plasma volume, weight, fat-free mass, and muscle mass (P<0.001). During bed-rest there was a transient increase in plasma and urinary urea, a decrease in plasma creatinine, and no change in urinary creatinine. The overall integral of changes from day0 to day35 was on average +101.7 mg/dL for plasma urea (95%CI = +43.4/+159.9), +82.2 g/24 h for urinary urea (95%CI = +55.8/+108.7), −2.5 mg/dL for plasma creatinine (95%CI = −3.1/−1.9). Bed-rest reduced plasma cistatyn C also, which was used as mass-independent marker of glomerular filtration rate (−13.1%, P<0.05). Correlations with final reduction in fat-free mass and muscle mass were significant for the overall integral of changes in urinary urea from day0 to day35 (R = 0.706, P<0.001) and for early changes in urinary urea and plasma urea from day0 to day7 (R = 0.566, P = 0.009 and R = 0.715, P<0.001, respectively). Conclusions Study results shows that urea is a marker of catabolic conditions secondary to hypokinetic conditions. PMID:25265226

Effects of bed-rest on urea and creatinine: correlation with changes in fat-free mass.

PubMed

Bilancio, Giancarlo; Lombardi, Cinzia; Pisot, Rado; De Santo, Natale G; Cavallo, Pierpaolo; Cirillo, Massimo

2014-01-01

Bed-rest experiments are designed for investigation on catabolic effects of hypokinetic conditions and/or for microgravity simulation in on-ground aerospace research. Bed-rest effects include a reduction in fat-free mass and muscle mass. Urea and creatinine are catabolites of endogenous protein and of muscular energetic metabolism which are excreted mainly by the kidney. The study investigated on urea, creatinine, and kidney function during bed-rest. Twenty healthy young men underwent a 7-day adaptation period (day-6 to day-0) and a 35-day bed-rest experiment (day1 to day35) during normocaloric diet. Urine were collected from day-3 to day0 (baseline) and from day1 to day35. Blood samples and anthropometrical data were collected at day0 (baseline) and bed-rest days 7, 14, 21, 28, and 35. Bed-rest reduced plasma volume, weight, fat-free mass, and muscle mass (P<0.001). During bed-rest there was a transient increase in plasma and urinary urea, a decrease in plasma creatinine, and no change in urinary creatinine. The overall integral of changes from day0 to day35 was on average +101.7 mg/dL for plasma urea (95%CI = +43.4/+159.9), +82.2 g/24 h for urinary urea (95%CI = +55.8/+108.7), -2.5 mg/dL for plasma creatinine (95%CI = -3.1/-1.9). Bed-rest reduced plasma cistatyn C also, which was used as mass-independent marker of glomerular filtration rate (-13.1%, P<0.05). Correlations with final reduction in fat-free mass and muscle mass were significant for the overall integral of changes in urinary urea from day0 to day35 (R = 0.706, P<0.001) and for early changes in urinary urea and plasma urea from day0 to day7 (R = 0.566, P = 0.009 and R = 0.715, P<0.001, respectively). Study results shows that urea is a marker of catabolic conditions secondary to hypokinetic conditions.

Lag threads organize the brain’s intrinsic activity

PubMed Central

Mitra, Anish; Snyder, Abraham Z.; Blazey, Tyler; Raichle, Marcus E.

2015-01-01

It has been widely reported that intrinsic brain activity, in a variety of animals including humans, is spatiotemporally structured. Specifically, propagated slow activity has been repeatedly demonstrated in animals. In human resting-state fMRI, spontaneous activity has been understood predominantly in terms of zero-lag temporal synchrony within widely distributed functional systems (resting-state networks). Here, we use resting-state fMRI from 1,376 normal, young adults to demonstrate that multiple, highly reproducible, temporal sequences of propagated activity, which we term “lag threads,” are present in the brain. Moreover, this propagated activity is largely unidirectional within conventionally understood resting-state networks. Modeling experiments show that resting-state networks naturally emerge as a consequence of shared patterns of propagation. An implication of these results is that common physiologic mechanisms may underlie spontaneous activity as imaged with fMRI in humans and slowly propagated activity as studied in animals. PMID:25825720

Noradrenaline decreases spike voltage threshold and induces electrographic sharp waves in turtle medial cortex in vitro.

PubMed

Lorenzo, Daniel; Velluti, Julio C

2004-01-01

The noradrenergic modulation of neuronal properties has been described at different levels of the mammalian brain. Although the anatomical characteristics of the noradrenergic system are well known in reptiles, functional data are scarce. In our study the noradrenergic modulation of cortical electrogenesis in the turtle medial cortex was studied in vitro using a combination of field and intracellular recordings. Turtle EEG consists of a low voltage background interspersed by spontaneous large sharp waves (LSWs). Noradrenaline (NA, 5-40 microM) induced (or enhanced) the generation of LSWs in a dose-dependent manner. Pharmacological experiments suggest the participation of alpha and beta receptors in this effect. In medial cortex neurons NA induced a hyperpolarization of the resting potential and a decrease of input resistance. Both effects were observed also after TTX treatment. Noradrenaline increased the response of the cells to depolarizing pulses, resulting in an upward shift of the frequency/current relation. In most cells the excitability change was mediated by a decrease of the spike voltage threshold resulting in the reduction of the amount of depolarization needed to fire the cell (voltage threshold minus resting potential). As opposed to the mechanisms reported in mammalian neurons, no changes in the frequency adaptation or the post-train afterhyperpolarization were observed. The NA effects at the cellular level were not reproduced by noradrenergic agonists. Age- and species-dependent properties in the pharmacology of adrenergic receptors could be involved in this result. Cellular effects of NA in turtle cortex are similar to those described in mammals, although the increase in cellular excitability seems to be mediated by a different mechanism. Copyright 2004 S. Karger AG, Basel

Mobile Cloud Computing with SOAP and REST Web Services

NASA Astrophysics Data System (ADS)

Ali, Mushtaq; Fadli Zolkipli, Mohamad; Mohamad Zain, Jasni; Anwar, Shahid

2018-05-01

Mobile computing in conjunction with Mobile web services drives a strong approach where the limitations of mobile devices may possibly be tackled. Mobile Web Services are based on two types of technologies; SOAP and REST, which works with the existing protocols to develop Web services. Both the approaches carry their own distinct features, yet to keep the constraint features of mobile devices in mind, the better in two is considered to be the one which minimize the computation and transmission overhead while offloading. The load transferring of mobile device to remote servers for execution called computational offloading. There are numerous approaches to implement computational offloading a viable solution for eradicating the resources constraints of mobile device, yet a dynamic method of computational offloading is always required for a smooth and simple migration of complex tasks. The intention of this work is to present a distinctive approach which may not engage the mobile resources for longer time. The concept of web services utilized in our work to delegate the computational intensive tasks for remote execution. We tested both SOAP Web services approach and REST Web Services for mobile computing. Two parameters considered in our lab experiments to test; Execution Time and Energy Consumption. The results show that RESTful Web services execution is far better than executing the same application by SOAP Web services approach, in terms of execution time and energy consumption. Conducting experiments with the developed prototype matrix multiplication app, REST execution time is about 200% better than SOAP execution approach. In case of energy consumption REST execution is about 250% better than SOAP execution approach.

Acetylcholine release from the rabbit isolated superior cervical ganglion preparation.

PubMed

Dawes, P M; Vizi, E S

1973-06-01

1. The rabbit isolated superior cervical ganglion preparation has been used to measure the release of acetylcholine from the tissue at rest and during preganglionic nerve stimulation.2. In the presence of physostigmine, the resting release of acetylcholine was 0.13 +/- 0.01 (nmol/g)/min (10 experiments) and that during stimulation with 300 shocks at 10 Hz was 3.1 +/- 0.4 (pmol/g)/volley in 4 experiments (means +/- S.E.M.). The volley output was independent of the frequency of stimulation over the range 1 to 10 Hz but was higher at 0.3 Hz.3. Tetrodotoxin, 0.8 muM, had no effect on the resting release of acetylcholine but reduced the stimulated release below detectable levels (2 pmol). Lowering the temperature of the bathing fluid to 5 degrees C reduced to below detectable levels both the resting release and that produced by nerve stimulation.4. The resting release of acetylcholine was increased by a potassium-rich (49.4 mM K(+)) bathing solution and by replacing the sodium chloride in the solution with lithium chloride (113 mM Li(+)).5. (-)-Noradrenaline bitartrate, 3 muM, and (+/-)-adrenaline bitartrate, 1.5 muM, reduced by 70% the output of acetylcholine induced by stimulation at 0.3 Hz, but failed to reduce the resting release or that evoked by stimulation at 10 Hz. The inhibition was reversed by phentolamine.6. It is concluded that the rabbit superior cervical ganglion in vitro is a suitable preparation for studying transmitter release and that the ganglion blocking effect of catecholamines is due to a reduction in transmitter release.

The Effects of Acute High-Intensity Interval Training on Hematological Parameters in Sedentary Subjects.

PubMed

Belviranli, Muaz; Okudan, Nilsel; Kabak, Banu

2017-07-19

The objective of the study was to determine the effects of acute high-intensity interval training (HIIT) on hematological parameters in sedentary men. Ten healthy, non-smoker, and sedentary men aged between 18 and 24 years participated in the study. All subjects performed four Wingate tests with 4 min intervals between the tests. Blood samples were collected at pre-exercise, immediately after, 3 and 6 h after the fourth Wingate test. Hematological parameters were analyzed in these samples. The results showed that hematocrit percentage, hemoglobin values, red cell count, mean cell volume, platelet count, total white cell count, and counts of the white cell subgroups increased immediately after the acute HIIT and their values began to return to resting levels 3 h after exercise, and completely returned to resting levels 6 h after exercise. In conclusion, acute HIIT causes an inflammatory response in blood.

Membrane currents in the oocyte of the toad Bufo arenarum.

PubMed

Kotsias, Basilio A; Damiano, Alicia E; Godoy, Sebastian; Assef, Yanina; Ibarra, Cristina; Cantiello, Horacio F

2002-03-01

The amphibian oocyte cell model is widely used for heterologous expression of ionic channels and receptors. Little is known, however, about the physiology of oocyte cell models other than Xenopus laevis. In this study, the two-electrode voltage clamp technique was used to assess the most common electrical patterns of oocytes of the South American toad Bufo arenarum. Basal membrane resistance, resting potential, and ionic currents were determined in this cell model. The oocyte transmembrane resistance was 0.35 M(Omega), and the resting potential in normal saline was about -33 mV with a range between -20 mV and -50 mV. This is, to our knowledge, the first attempt to begin an understanding of the ion transport mechanisms of Bufo arenarum oocytes. This cell model may provide a viable alternative to the expression of ion channels, in particular those endogenously observed in Xenopus laevis oocytes. Copyright 2002 Wiley-Liss, Inc.

Simultaneous recording of electrical activity and the underlying ionic currents in NG108-15 cells cultured on gold substrate.

PubMed

Acosta-García, Ma Cristina; Morales-Reyes, Israel; Jiménez-Anguiano, Anabel; Batina, Nikola; Castellanos, N P; Godínez-Fernández, R

2018-02-01

This paper shows the simultaneous recording of electrical activity and the underlying ionic currents by using a gold substrate to culture NG108-15 cells. Cells grown on two different substrates (plastic Petri dishes and gold substrates) were characterized quantitatively through scanning electron microscopy (SEM) as well as qualitatively by optical and atomic force microscopy (AFM). No significant differences were observed between the surface area of cells cultured on gold substrates and Petri dishes, as indicated by measurements performed on SEM images. We also evaluated the electrophysiological compatibility of the cells through standard patch-clamp experiments by analyzing features such as the resting potential, membrane resistance, ionic currents, etc. Cells grown on both substrates showed no significant differences in their dependency on voltage, as well as in the magnitude of the Na+ and K+ current density; however, cells cultured on the gold substrate showed a lower membrane capacitance when compared to those grown on Petri dishes. By using two separate patch-clamp amplifiers, we were able to record the membrane current with the conventional patch-clamp technique and through the gold substrate simultaneously. Furthermore, the proposed technique allowed us to obtain simultaneous recordings of the electrical activity (such as action potentials firing) and the underlying membrane ionic currents. The excellent conductivity of gold makes it possible to overcome important difficulties found in conventional electrophysiological experiments such as those presented by the resistance of the electrolytic bath solution. We conclude that the technique here presented constitutes a solution to the problem of the simultaneous recording of electrical activity and the underlying ionic currents, which for decades, had been solved only partially.

STABILIZATION OF SPIDER CRAB NERVE MEMBRANES BY ALKALINE EARTHS, AS MANIFESTED IN RESTING POTENTIAL MEASUREMENTS

PubMed Central

Guttman, Rita

1940-01-01

1. The alkaline earths, Ba, Sr, Ca, and Mg, in isotonic solutions of their chlorides, have, in general, no effect upon the resting potential of non-medullated spider crab nerve. 2. Ba, Sr, and Ca can, however, prevent the depressing action of K upon the resting potential. The order of effectiveness of these ions in this regard is the following: Ba > Sr > Ca. 3. Ba, Sr, Ca, and Mg oppose the depressing action of veratrine sulfate upon the resting potential. The order of effectiveness is Ba > Sr > Ca > Mg. The relation between drop in potential caused by veratrine sulfate and the logarithm of the veratrine sulfate concentration is a linear one. 4. The action of various other organic ions and molecules which depress the resting potential: saponin, amyl urethane, chloral hydrate, and Na salicylate is neutralized by Ba. 5. Hypertonic sea water solutions do not affect the resting potential. Also, preliminary experiments indicate that the nerves do not shrink in hypertonic solutions although they swell in hypotonic sea water. 6. The alkaline earths depress excitability reversibly. The various organic agents which depress the resting potential also depress excitability, in most cases, reversibly, but the concentrations necessary to depress excitability are much smaller than those necessary to depress the resting potential. 7. The relation of these findings to theories put forward as possible explanations of resting potential phenomena is considered. PMID:19873160

Inversion group (IG) fitting: A new T1 mapping method for modified look-locker inversion recovery (MOLLI) that allows arbitrary inversion groupings and rest periods (including no rest period).

PubMed

Sussman, Marshall S; Yang, Issac Y; Fok, Kai-Ho; Wintersperger, Bernd J

2016-06-01

The Modified Look-Locker Inversion Recovery (MOLLI) technique is used for T1 mapping in the heart. However, a drawback of this technique is that it requires lengthy rest periods in between inversion groupings to allow for complete magnetization recovery. In this work, a new MOLLI fitting algorithm (inversion group [IG] fitting) is presented that allows for arbitrary combinations of inversion groupings and rest periods (including no rest period). Conventional MOLLI algorithms use a three parameter fitting model. In IG fitting, the number of parameters is two plus the number of inversion groupings. This increased number of parameters permits any inversion grouping/rest period combination. Validation was performed through simulation, phantom, and in vivo experiments. IG fitting provided T1 values with less than 1% discrepancy across a range of inversion grouping/rest period combinations. By comparison, conventional three parameter fits exhibited up to 30% discrepancy for some combinations. The one drawback with IG fitting was a loss of precision-approximately 30% worse than the three parameter fits. IG fitting permits arbitrary inversion grouping/rest period combinations (including no rest period). The cost of the algorithm is a loss of precision relative to conventional three parameter fits. Magn Reson Med 75:2332-2340, 2016. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

Effect of oral administration of GABA on temperature regulation in humans during rest and exercise at high ambient temperature.

PubMed

Miyazawa, Taiki; Kawabata, Takashi; Suzuki, Takashi; Imai, Daiki; Hamamoto, Takeshi; Yoshikawa, Takahiro; Miyagawa, Toshiaki

2009-12-01

Centric administration of gamma-aminobutyric acid (GABA) has been implicated to affect temperature regulation in animals during rest or under anesthesia. However, there are few reports concerning the effects of the oral administration of GABA on temperature regulation in humans during rest and exercise. In order to clarify the effects and underlying mechanisms, we measured several parameters related to temperature regulation of humans during rest and exercise at high ambient temperature (35 degrees C). On two occasions, eight endurance-trained men rested for 20 min and cycled at 65% VO2peak for 30 min. In control trial (trial-C), subjects drank the sample which was a sports drink of 200 mL (placebo) before the rest period. In another trial (trial-G), subjects drank the sample which was a sports drink containing 1000 mg of GABA (GABA drink) before the rest period. In trial-G, the plasma GABA concentrations were maintained higher than those in trial-C during the experiment. An increase of esophageal temperature during rest and exercise was inhibited in trial-G. Sweat rate, and plasma catecholamine concentrations during exercise were inhibited in trial-G. Esophageal temperature inhibition is suggested to be induced by the suppression of cold-sensitive neurons during rest, and the inhibition of plasma catecholamine concentrations caused by the GABA-induced attenuation of the sympathetic nervous system during exercise.

Payload Specialist Charles Walker with handheld protein growth experiment

NASA Image and Video Library

1985-11-26

61B-02-014 (26 Nov-3 Dec 1985) --- Payload Specialist Charles D. Walker works with the handheld protein growth experiment -- one of a series of tests being flown to study the possibility of crystallizing biological materials. Walker rests the experiment against the larger continuous flow electrophoresis systems experiment.

Resting-state EEG, Impulsiveness, and Personality in Daily and Nondaily Smokers†

PubMed Central

Rass, Olga; Ahn, Woo-Young; O’Donnell, Brian F.

2015-01-01

Objectives Resting EEG is sensitive to transient, acute effects of nicotine administration and abstinence, but the chronic effects smoking on EEG are poorly characterized. This study measures the resting EEG profile of chronic smokers in a non-deprived, non-peak state to test whether differences in smoking behavior and personality traits affect pharmaco-EEG response. Methods Resting EEG, impulsiveness, and personality measures were collected from daily smokers (n=22), nondaily smokers (n=31), and non-smokers (n=30). Results Daily smokers had reduced resting delta and alpha EEG power and higher impulsiveness (Barratt Impulsiveness Scale) compared to nondaily smokers and non-smokers. Both daily and nondaily smokers discounted delayed rewards more steeply, reported lower conscientiousness (NEO-FFI) and reported greater disinhibition and experience seeking (Sensation Seeking Scale) than non-smokers. Nondaily smokers reported greater sensory hedonia than nonsmokers. Conclusions Altered resting EEG power in daily smokers demonstrates differences in neural signaling that correlated with greater smoking behavior and dependence. Although nondaily smokers share some characteristics with daily smokers that may predict smoking initiation and maintenance, they differ on measures of impulsiveness and resting EEG power. Significance Resting EEG in non-deprived chronic smokers provides a standard for comparison to peak and trough nicotine states and may serve as a biomarker for nicotine dependence, relapse risk, and recovery. PMID:26051750

Clinical-grade mesenchymal stromal cells produced under various good manufacturing practice processes differ in their immunomodulatory properties: standardization of immune quality controls.

PubMed

Menard, Cedric; Pacelli, Luciano; Bassi, Giulio; Dulong, Joelle; Bifari, Francesco; Bezier, Isabelle; Zanoncello, Jasmina; Ricciardi, Mario; Latour, Maelle; Bourin, Philippe; Schrezenmeier, Hubert; Sensebé, Luc; Tarte, Karin; Krampera, Mauro

2013-06-15

Clinical-grade mesenchymal stromal cells (MSCs) are usually expanded from bone marrow (BMMSCs) or adipose tissue (ADSCs) using processes mainly differing in the use of fetal calf serum (FCS) or human platelet lysate (PL). We aimed to compare immune modulatory properties of clinical-grade MSCs using a combination of fully standardized in vitro assays. BMMSCs expanded with FCS (BMMSC-FCS) or PL (BMMSC-PL), and ADSC-PL were analyzed in quantitative phenotypic and functional experiments, including their capacity to inhibit the proliferation of T, B, and NK cells. The molecular mechanisms supporting T-cell inhibition were investigated. These parameters were also evaluated after pre-stimulation of MSCs with inflammatory cytokines. BMMSC-FCS, BMMSC-PL, and ADSC-PL displayed significant differences in expression of immunosuppressive and adhesion molecules. Standardized functional assays revealed that resting MSCs inhibited proliferation of T and NK cells, but not B cells. ADSC-PL were the most potent in inhibiting T-cell growth, a property ascribed to interferon-γ-dependent indoleamine 2,3-dioxygenase activity. MSCs did not stimulate allogeneic T cell proliferation but were efficiently lysed by activated NK cells. The systematic use of quantitative and reproducible validation techniques highlights differences in immunological properties of MSCs produced using various clinical-grade processes. ADSC-PL emerge as a promising candidate for future clinical trials.

Clinical-Grade Mesenchymal Stromal Cells Produced Under Various Good Manufacturing Practice Processes Differ in Their Immunomodulatory Properties: Standardization of Immune Quality Controls

PubMed Central

Menard, Cedric; Pacelli, Luciano; Bassi, Giulio; Dulong, Joelle; Bifari, Francesco; Bezier, Isabelle; Zanoncello, Jasmina; Ricciardi, Mario; Latour, Maelle; Bourin, Philippe; Schrezenmeier, Hubert; Sensebé, Luc

2013-01-01

Clinical-grade mesenchymal stromal cells (MSCs) are usually expanded from bone marrow (BMMSCs) or adipose tissue (ADSCs) using processes mainly differing in the use of fetal calf serum (FCS) or human platelet lysate (PL). We aimed to compare immune modulatory properties of clinical-grade MSCs using a combination of fully standardized in vitro assays. BMMSCs expanded with FCS (BMMSC-FCS) or PL (BMMSC-PL), and ADSC-PL were analyzed in quantitative phenotypic and functional experiments, including their capacity to inhibit the proliferation of T, B, and NK cells. The molecular mechanisms supporting T-cell inhibition were investigated. These parameters were also evaluated after pre-stimulation of MSCs with inflammatory cytokines. BMMSC-FCS, BMMSC-PL, and ADSC-PL displayed significant differences in expression of immunosuppressive and adhesion molecules. Standardized functional assays revealed that resting MSCs inhibited proliferation of T and NK cells, but not B cells. ADSC-PL were the most potent in inhibiting T-cell growth, a property ascribed to interferon-γ-dependent indoleamine 2,3-dioxygenase activity. MSCs did not stimulate allogeneic T cell proliferation but were efficiently lysed by activated NK cells. The systematic use of quantitative and reproducible validation techniques highlights differences in immunological properties of MSCs produced using various clinical-grade processes. ADSC-PL emerge as a promising candidate for future clinical trials. PMID:23339531

Effects of prestudy and poststudy rest on memory: Support for temporal interference accounts of forgetting.

PubMed

Ecker, Ullrich K H; Tay, Jia-Xin; Brown, Gordon D A

2015-06-01

According to interference-based theories of memory, including temporal-distinctiveness theory, both prestudy and poststudy rest should have beneficial impacts on memory performance. Specifically, higher temporal isolation of a memorandum should reduce proactive and/or retroactive interference, and thus should result in better recall. In the present study, we investigated the effects of prestudy and poststudy rest in a free recall paradigm. Participants studied three lists of words, separated by either a short or a long period of low mental activity (a tone-detection task). Recall targeted the second list; this list was studied in one of four conditions, defined by the fully crossed factors of prestudy and poststudy rest duration. Two experiments revealed a beneficial effect of prestudy rest (and, to a lesser extent, of poststudy rest) on list recall. This result is in line with interference-based theories of memory. By contrast, a beneficial effect of prestudy rest is not predicted by consolidation accounts of memory and forgetting; our results thus require additional assumptions and/or a better specification of the consolidation process and its time course in order to be reconciled with consolidation theory.

Maternal Rest/Nrsf Regulates Zebrafish Behavior through snap25a/b

PubMed Central

Moravec, Cara E.; Samuel, John; Weng, Wei; Wood, Ian C.

2016-01-01

During embryonic development, regulation of gene expression is key to creating the many subtypes of cells that an organism needs throughout its lifetime. Recent work has shown that maternal genetics and environmental factors have lifelong consequences on diverse processes ranging from immune function to stress responses. The RE1-silencing transcription factor (Rest) is a transcriptional repressor that interacts with chromatin-modifying complexes to repress transcription of neural-specific genes during early development. Here we show that in zebrafish, maternally supplied rest regulates expression of target genes during larval development and has lifelong impacts on behavior. Larvae deprived of maternal rest are hyperactive and show atypical spatial preferences. Adult male fish deprived of maternal rest present with atypical spatial preferences in a novel environment assay. Transcriptome sequencing revealed 158 genes that are repressed by maternal rest in blastula stage embryos. Furthermore, we found that maternal rest is required for target gene repression until at least 6 dpf. Importantly, disruption of the RE1 sites in either snap25a or snap25b resulted in behaviors that recapitulate the hyperactivity phenotype caused by absence of maternal rest. Both maternal rest mutants and snap25a RE1 site mutants have altered primary motor neuron architecture that may account for the enhanced locomotor activity. These results demonstrate that maternal rest represses snap25a/b to modulate larval behavior and that early Rest activity has lifelong behavioral impacts. SIGNIFICANCE STATEMENT Maternal factors deposited in the oocyte have well-established roles during embryonic development. We show that, in zebrafish, maternal rest (RE1-silencing transcription factor) regulates expression of target genes during larval development and has lifelong impacts on behavior. The Rest transcriptional repressor interacts with chromatin-modifying complexes to limit transcription of neural genes. We identify several synaptic genes that are repressed by maternal Rest and demonstrate that snap25a/b are key targets of maternal rest that modulate larval locomotor activity. These results reveal that zygotic rest is unable to compensate for deficits in maternally supplied rest and uncovers novel temporal requirements for Rest activity, which has implications for the broad roles of Rest-mediated repression during neural development and in disease states. PMID:27605615

HMGN proteins modulate chromatin regulatory sites and gene expression during activation of naïve B cells

PubMed Central

Zhang, Shaofei; Zhu, Iris; Deng, Tao; Furusawa, Takashi; Rochman, Mark; Vacchio, Melanie S.; Bosselut, Remy; Yamane, Arito; Casellas, Rafael; Landsman, David; Bustin, Michael

2016-01-01

The activation of naïve B lymphocyte involves rapid and major changes in chromatin organization and gene expression; however, the complete repertoire of nuclear factors affecting these genomic changes is not known. We report that HMGN proteins, which bind to nucleosomes and affect chromatin structure and function, co-localize with, and maintain the intensity of DNase I hypersensitive sites genome wide, in resting but not in activated B cells. Transcription analyses of resting and activated B cells from wild-type and Hmgn−/− mice, show that loss of HMGNs dampens the magnitude of the transcriptional response and alters the pattern of gene expression during the course of B-cell activation; defense response genes are most affected at the onset of activation. Our study provides insights into the biological function of the ubiquitous HMGN chromatin binding proteins and into epigenetic processes that affect the fidelity of the transcriptional response during the activation of B cell lymphocytes. PMID:27112571

Prenatal arsenic exposure alters REST/NRSF and microRNA regulators of embryonic neural stem cell fate in a sex-dependent manner

PubMed Central

Tyler, Christina R.; Labrecque, Matthew T.; Solomon, Elizabeth R.; Guo, Xun; Allan, Andrea M.

2016-01-01

Exposure to arsenic, a common environmental toxin found in drinking water, leads to a host of neurological pathologies. We have previously demonstrated that developmental exposure to a low level of arsenic (50 ppb) alters epigenetic processes that underlie deficits in adult hippocampal neurogenesis leading to aberrant behavior. It is unclear if arsenic impacts the programming and regulation of embryonic neurogenesis during development when exposure occurs. The master negative regulator of neural-lineage, REST/NRSF, controls the precise timing of fate specification and differentiation of neural stem cells (NSCs). Early in development (embryonic day 14), we observed increased expression of Rest, its co-repressor, CoREST, and the inhibitory RNA binding/splicing protein, Ptbp1, and altered expression of mRNA spliced isoforms of Pbx1 that are directly regulated by these factors in the male brain in response to prenatal 50 ppb arsenic exposure. These increases were concurrent with decreased expression of microRNA-9 (miR-9), miR-9*, and miR-124, all of which are REST/NRSF targets and inversely regulate Rest expression to allow for maturation of NSCs. Exposure to arsenic decreased the formation of neuroblasts in vitro from NSCs derived from male pup brains. The female response to arsenic was limited to increased expression of CoREST and Ptbp2, an RNA binding protein that allows for appropriate splicing of genes involved in the progression of neurogenesis. These changes were accompanied by increased neuroblast formation in vitro from NSCs derived from female pups. Unexposed male mice express transcriptomic factors to induce differentiation earlier in development compared to unexposed females. Thus, arsenic exposure likely delays differentiation of NSCs in males while potentially inducing precocious differentiation in females early in development. These effects are mitigated by embryonic day 18 of development. Arsenic-induced dysregulation of the regulatory loop formed by REST/NRSF, its target microRNAs, miR-9 and miR-124, and RNA splicing proteins, PTBP1 and 2, leads to aberrant programming of NSC function that is perhaps perpetuated into adulthood inducing deficits in differentiation we have previously observed. PMID:27751817

Mean 24-hours sympathetic nervous system activity decreases during head-down tilted bed rest but not during microgravity

NASA Astrophysics Data System (ADS)

Christensen, Nj; Heer, M.; Ivanova, K.; Norsk, P.

Sympathetic nervous system activity is closely related to gravitational stress in ground based experiments. Thus a high activity is present in the standing-up position and a very low activity is observed during acute head-out water immersion. Adjustments in sympathetic activity are necessary to maintain a constant blood pressure during variations in venous return. Head-down tilted bed rest is applied as a model to simulate changes observed during microgravity. The aim of the present study was to test the hypothesis that mean 24-hours sympathetic activity was low and similar during space flight and in ground based observation obtained during long-term head-down tilted bed rest. Forearm venous plasma noradrenaline was measured by a radioenzymatic technique as an index of muscle sympathetic activity and thrombocyte noradrenaline and adrenaline were measured as indices of mean 24-hours sympathoadrenal activity. Previous results have indicated that thrombocyte noradrenaline level has a half-time of 2 days. Thus to reflect sympathetic activity during a specific experiment the study period must last for at least 6 days and a sample must be obtained within 12 hours after the experiment has ended. Ten normal healthy subjects were studied before and during a 14 days head-down tilted bed rest as well as during an ambulatory study period of a similar length. The whole experiment was repeated while the subjects were on a low calorie diet. Thrombocyte noradrenaline levels were studied in 4 cosmonauts before and within 12 hours after landing after more than 7 days in flight. Thrombocyte noradrenaline decreased markedly during the head-down tilted bed rest (p<0.001), whereas there were no significant changes in the ambulatory study. Plasma noradrenaline decreased in the adaptation period but not during the intervention. During microgravity thrombocyte noradrenaline increased in four cosmonauts and the percentage changes were significantly different in cosmonauts and in subjects participating in the head down tilted bed rest study (170± 29% (Mean± SEM) vs. 57± 7%, respectively; p<0.001). The elevated sympathetic nervous system activity is most likely a regulatory response to combined effects of a reduced plasma volume and an increased vascular capacity in flight.

Acute Infection with Epstein-Barr Virus Targets and Overwhelms the Peripheral Memory B-Cell Compartment with Resting, Latently Infected Cells

PubMed Central

Hochberg, Donna; Souza, Tatyana; Catalina, Michelle; Sullivan, John L.; Luzuriaga, Katherine; Thorley-Lawson, David A.

2004-01-01

In this paper we demonstrate that during acute infection with Epstein-Barr virus (EBV), the peripheral blood fills up with latently infected, resting memory B cells to the point where up to 50% of all the memory cells may carry EBV. Despite this massive invasion of the memory compartment, the virus remains tightly restricted to memory cells, such that, in one donor, fewer than 1 in 104 infected cells were found in the naive compartment. We conclude that, even during acute infection, EBV persistence is tightly regulated. This result confirms the prediction that during the early phase of infection, before cellular immunity is effective, there is nothing to prevent amplification of the viral cycle of infection, differentiation, and reactivation, causing the peripheral memory compartment to fill up with latently infected cells. Subsequently, there is a rapid decline in infected cells for the first few weeks that approximates the decay in the cytotoxic-T-cell responses to viral replicative antigens. This phase is followed by a slower decline that, even by 1 year, had not reached a steady state. Therefore, EBV may approach but never reach a stable equilibrium. PMID:15113901

Salience Network Connectivity Modulates Skin Conductance Responses in Predicting Arousal Experience

PubMed Central

Xia, Chenjie; Touroutoglou, Alexandra; Quigley, Karen S.; Barrett, Lisa Feldman; Dickerson, Bradford C.

2017-01-01

Individual differences in arousal experience have been linked to differences in resting-state salience network connectivity strength. In this study, we investigated how adding task-related skin conductance responses (SCR), a measure of sympathetic autonomic nervous system activity, can predict additional variance in arousal experience. Thirty-nine young adults rated their subjective experience of arousal to emotionally evocative images while SCRs were measured. They also underwent a separate resting-state fMRI scan. Greater SCR reactivity (an increased number of task-related SCRs) to emotional images and stronger intrinsic salience network connectivity independently predicted more intense experiences of arousal. Salience network connectivity further moderated the effect of SCR reactivity: In individuals with weak salience network connectivity, SCR reactivity more significantly predicted arousal experience, whereas in those with strong salience network connectivity, SCR reactivity played little role in predicting arousal experience. This interaction illustrates the degeneracy in neural mechanisms driving individual differences in arousal experience and highlights the intricate interplay between connectivity in central visceromotor neural circuitry and peripherally expressed autonomic responses in shaping arousal experience. PMID:27991182

Effects Of Exercise During Prolonged Bed Rest

NASA Technical Reports Server (NTRS)

Arnaud, S.; Berry, P; Cohen, M.; Danelis, J.; Deroshia, C.; Greenleaf, J.; Harris, B.; Keil, L.; Bernauer, E.; Bond, M.;

Nonlinear microscopy as diagnostic tool for the discrimination of activated T cells

NASA Astrophysics Data System (ADS)

Gavgiotaki, E.; Filippidis, G.; Zerva, I.; Agelaki, S.; Georgoulias, V.; Athanassakis, I.

2017-07-01

Third Harmonic Generation (THG) imaging was applied to mouse resting and activated T-cells. Quantification of THG signal, which corresponded to lipid droplets, could distinguish activated Tcells, allowing follow-up of immune response development.

Responses of proenkephalin Peptide F to aerobic exercise stress in the plasma and white blood cell biocompartments.

PubMed

Kraemer, William J; Fragala, Maren S; van Henegouwen, Wendy R H Beijersbergen; Gordon, Scott E; Bush, Jill A; Volek, Jeff S; Triplett, N Travis; Dunn-Lewis, Courtenay; Comstock, Brett A; Szivak, Tunde K; Flanagan, Shawn D; Hooper, David R; Luk, Hui-Ying; Mastro, Andrea M

2013-04-01

Proenkephalin Peptide F [107-140] is an enkephalin-containing peptide found predominantly within the adrenal medulla, co-packaged with epinephrine within the chromaffin granules. In vivo studies indicate that Peptide F has classic opioid analgesia effects; in vitro studies suggest potential immune cell interactions. In this investigation we examined patterns of Peptide F concentrations in different bio-compartments of the blood at rest and following sub-maximal cycle exercise to determine if Peptide F interacts with the white blood cell (WBC) bio-compartment during aerobic exercise. Eight physically active men (n=8) performed sub-maximal (80-85% V˙O2peak) cycle ergometer exercise for 30 min. Plasma Peptide F and WBC Peptide F immunoreactivity were examined pre-exercise, mid-exercise and immediately post-, 5-min post-, 15-min post-, 30-min post- and 60-min post-exercise and at similar time-points during a control condition (30 min rest). Peptide F concentrations significantly (p<0.05) increased at 5 and 60 min post-exercise, compared to pre-exercise concentrations. No significant increases in Peptide F concentrations in the WBC fraction were observed during or after exercise. However, a significant decrease was observed at 30 min post-exercise. An ultradian pattern of Peptide F distribution was apparent during rest. Furthermore, concentrations of T cells, B cells, NK cells, and total WBCs demonstrated significant changes in response to aerobic exercise. Data indicated that Peptide F was bound in significant molar concentrations in the WBC fraction and that this biocompartment may be one of the tissue targets for binding interactions. These data indicate that Peptide F is involved with immune cell modulation in the white blood circulatory biocompartment of blood. Copyright © 2013. Published by Elsevier Inc.

Normal muscle oxygen consumption and fatigability in sickle cell patients despite reduced microvascular oxygenation and hemorheological abnormalities.

PubMed

Waltz, Xavier; Pichon, Aurélien; Lemonne, Nathalie; Mougenel, Danièle; Lalanne-Mistrih, Marie-Laure; Lamarre, Yann; Tarer, Vanessa; Tressières, Benoit; Etienne-Julan, Maryse; Hardy-Dessources, Marie-Dominique; Hue, Olivier; Connes, Philippe

2012-01-01

Although it has been hypothesized that muscle metabolism and fatigability could be impaired in sickle cell patients, no study has addressed this issue. We compared muscle metabolism and function (muscle microvascular oxygenation, microvascular blood flow, muscle oxygen consumption and muscle microvascular oxygenation variability, which reflects vasomotion activity, maximal muscle force and local muscle fatigability) and the hemorheological profile at rest between 16 healthy subjects (AA), 20 sickle cell-hemoglobin C disease (SC) patients and 16 sickle cell anemia (SS) patients. Muscle microvascular oxygenation was reduced in SS patients compared to the SC and AA groups and this reduction was not related to hemorhelogical abnormalities. No difference was observed between the three groups for oxygen consumption and vasomotion activity. Muscle microvascular blood flow was higher in SS patients compared to the AA group, and tended to be higher compared to the SC group. Multivariate analysis revealed that muscle oxygen consumption was independently associated with muscle microvascular blood flow in the two sickle cell groups (SC and SS). Finally, despite reduced muscle force in sickle cell patients, their local muscle fatigability was similar to that of the healthy subjects. Sickle cell patients have normal resting muscle oxygen consumption and fatigability despite hemorheological alterations and, for SS patients only, reduced muscle microvascular oxygenation and increased microvascular blood flow. Two alternative mechanisms can be proposed for SS patients: 1) the increased muscle microvascular blood flow is a way to compensate for the lower muscle microvascular oxygenation to maintain muscle oxygen consumption to normal values or 2) the reduced microvascular oxygenation coupled with a normal resting muscle oxygen consumption could indicate that there is slight hypoxia within the muscle which is not sufficient to limit mitochondrial respiration but increases muscle microvascular blood flow.

Spontaneous fluctuation of the resting membrane potential in Paramecium: amplification caused by intracellular Ca2+.

PubMed

Nakaoka, Yasuo; Imaji, Takafumi; Hara, Masahiro; Hashimoto, Noboru

2009-01-01

The ciliated protozoan Paramecium spontaneously changes its swimming direction in the absence of external stimuli. Such behavior is based on resting potential fluctuations, the amplitudes of which reach a few mV. When the resting potential fluctuation is positive and large, a spike-like depolarization is frequently elicited that reverses the beating of the cilia associated with directional changes during swimming. We aimed to study how the resting potential fluctuation is amplified. Simultaneous measurements of the resting potential and intracellular Ca(2+) ([Ca(2+)](i)) from a deciliated cell showed that positive potential fluctuations were frequently accompanied by a small increase in [Ca(2+)](i). This result suggests that Ca(2+) influx through the somatic membrane occurs during the resting state. The mean amplitude of the resting potential fluctuation was largely decreased by either an intracellular injection of a calcium chelater (BAPTA) or by an extracellular addition of Ba(2+). Hence, a small increase in [Ca(2+)](i) amplifies the resting potential fluctuation. Simulation analysis of the potential fluctuation was made by assuming that Ca(2+) and K(+) channels of surface membrane are fluctuating between open and closed states. The simulated fluctuation increased to exhibit almost the same amplitude as the measured fluctuation using the assumption that a small Ca(2+) influx activates Ca(2+) channels in a positive feedback manner.

Elevated body temperature and increased blood vessel sensitivity in spontaneously hypertensive rats.

PubMed

Price, J M; Wilmoth, F R

1990-04-01

Body temperature (BT) was significantly greater in spontaneously hypertensive rats (SHR) than in Wistar-Kyoto (WKY) rats regardless of the time of day, length of rectal probe, sex, age, or commercial vendor. Bath temperature (theta) for excised aortic rings was controlled by a thermoelectric Peltier module with an accuracy of 0.1 degree C. At peak force in individual contractions of norepinephrine (NE) dose-response experiments, theta was changed from 37 to 39 degrees C. Active and resting wall tension (Tw) were increased, and the mean effective dose (ED50) was decreased in the SHR aorta with and without endothelium. For the WKY aorta, active and resting Tw were increased, but ED50 was the same with and without endothelium. These results were supported by experiments where theta was decreased from 39 to 37 degrees C and by experiments on Sprague-Dawley rats. Potassium dose-response experiments with aorta from SHR and WKY rats show an increase in sensitivity at 39 degrees C, but active Tw is the same at 39 and 37 degrees C. When compared at the BT of each rat, the NE ED50 was lower and resting Tw was higher in the SHR aorta than in the WKY aorta, but active Tw was the same.(ABSTRACT TRUNCATED AT 250 WORDS)

Ring-Shaped Microlanes and Chemical Barriers as a Platform for Probing Single-Cell Migration.

PubMed

Schreiber, Christoph; Segerer, Felix J; Wagner, Ernst; Roidl, Andreas; Rädler, Joachim O

2016-05-31

Quantification and discrimination of pharmaceutical and disease-related effects on cell migration requires detailed characterization of single-cell motility. In this context, micropatterned substrates that constrain cells within defined geometries facilitate quantitative readout of locomotion. Here, we study quasi-one-dimensional cell migration in ring-shaped microlanes. We observe bimodal behavior in form of alternating states of directional migration (run state) and reorientation (rest state). Both states show exponential lifetime distributions with characteristic persistence times, which, together with the cell velocity in the run state, provide a set of parameters that succinctly describe cell motion. By introducing PEGylated barriers of different widths into the lane, we extend this description by quantifying the effects of abrupt changes in substrate chemistry on migrating cells. The transit probability decreases exponentially as a function of barrier width, thus specifying a characteristic penetration depth of the leading lamellipodia. Applying this fingerprint-like characterization of cell motion, we compare different cell lines, and demonstrate that the cancer drug candidate salinomycin affects transit probability and resting time, but not run time or run velocity. Hence, the presented assay allows to assess multiple migration-related parameters, permits detailed characterization of cell motility, and has potential applications in cell biology and advanced drug screening.

Optimal culture conditions for the generation of natural killer cell-induced dendritic cells for cancer immunotherapy.

PubMed

Nguyen-Pham, Thanh-Nhan; Yang, Deok-Hwan; Nguyen, Truc-Anh Thi; Lim, Mi-Seon; Hong, Cheol Yi; Kim, Mi-Hyun; Lee, Hyun Ju; Lee, Youn-Kyung; Cho, Duck; Bae, Soo-Young; Ahn, Jae-Sook; Kim, Yeo-Kyeoung; Chung, Ik-Joo; Kim, Hyeoung-Joon; Lee, Je-Jung

2012-01-01

Dendritic cell (DC)-based vaccines continue to be considered an attractive tool for cancer immunotherapy. DCs require an additional signal from the environment or other immune cells to polarize the development of immune responses toward T helper 1 (Th1) or Th2 responses. DCs play a role in natural killer (NK) cell activation, and NK cells are also able to activate and induce the maturation of DCs. We investigated the types of NK cells that can induce the maturation and enhanced function of DCs and the conditions under which these interactions occur. DCs that were activated by resting NK cells in the presence of inflammatory cytokines exhibited increased expression of several costimulatory molecules and an enhanced ability to produce IL-12p70. NK cell-stimulated DCs potently induced Th1 polarization and exhibited the ability to generate tumor antigen-specific cytotoxic T lymphocyte responses. Our data demonstrate that functional DCs can be generated by coculturing immature DCs with freshly isolated resting NK cells in the presence of Toll-like receptor agonists and proinflammatory cytokines and that the resulting DCs effectively present antigens to induce tumor-specific T-cell responses, which suggests that these cells may be useful for cancer immunotherapy.

HIV dynamics linked to memory CD4+ T cell homeostasis.

PubMed

Murray, John M; Zaunders, John; Emery, Sean; Cooper, David A; Hey-Nguyen, William J; Koelsch, Kersten K; Kelleher, Anthony D

2017-01-01

The dynamics of latent HIV is linked to infection and clearance of resting memory CD4+ T cells. Infection also resides within activated, non-dividing memory cells and can be impacted by antigen-driven and homeostatic proliferation despite suppressive antiretroviral therapy (ART). We investigated whether plasma viral level (pVL) and HIV DNA dynamics could be explained by HIV's impact on memory CD4+ T cell homeostasis. Median total, 2-LTR and integrated HIV DNA levels per μL of peripheral blood, for 8 primary (PHI) and 8 chronic HIV infected (CHI) individuals enrolled on a raltegravir (RAL) based regimen, exhibited greatest changes over the 1st year of ART. Dynamics slowed over the following 2 years so that total HIV DNA levels were equivalent to reported values for individuals after 10 years of ART. The mathematical model reproduced the multiphasic dynamics of pVL, and levels of total, 2-LTR and integrated HIV DNA in both PHI and CHI over 3 years of ART. Under these simulations, residual viremia originated from reactivated latently infected cells where most of these cells arose from clonal expansion within the resting phenotype. Since virion production from clonally expanded cells will not be affected by antiretroviral drugs, simulations of ART intensification had little impact on pVL. HIV DNA decay over the first year of ART followed the loss of activated memory cells (120 day half-life) while the 5.9 year half-life of total HIV DNA after this point mirrored the slower decay of resting memory cells. Simulations had difficulty reproducing the fast early HIV DNA dynamics, including 2-LTR levels peaking at week 12, and the later slow loss of total and 2-LTR HIV DNA, suggesting some ongoing infection. In summary, our modelling indicates that much of the dynamical behavior of HIV can be explained by its impact on memory CD4+ T cell homeostasis.

PATHWAYS OF GLUCOSE CATABOLISM IN BACILLUS CEREUS1

PubMed Central

Goldman, Manuel; Blumenthal, Harold J.

1964-01-01

Goldman, Manuel (The University of Michigan, Ann Arbor), and Harold J. Blumenthal. Pathways of glucose catabolism in Bacillus cereus. J. Bacteriol. 87:377–386. 1964.—Estimates by a radiorespirometric method of the pathways of glucose catabolism of resting-cell suspensions of Bacillus cereus strain terminalis indicate that the Embden-Meyerhof pathway predominates at every stage of development, including the sporogenic and germinative phases. At the filamentous, granular, forespore, and transitional stages, 98% of the glucose was catabolized by the Embden-Meyerhof pathway, and the remainder by the hexose monophosphate oxidative pathway. Estimates of the pathways in resting spore-suspensions arrested at defined stages of development indicate that 20% of the glucose was catabolized through the hexose monophosphate pathway in germinated spores, and 10% in the swollen and elongated stages of postgermination. In cells which had completed the first cell division, the figure fell to about 2%, a level similar to that found for vegetative cells at later stages of development. The key Embden-Meyerhof enzymes, hexokinase, phosphohexoisomerase, phosphofructokinase, and aldolase, as well as several other enzymes, were present at all stages of germination and postgerminative development, supporting the radioisotopic data obtained with whole cells. As indicated by the release of C14O2 from glucose-6-C14, terminal respiration of resting-cell suspensions operates maximally in vegetative cells at the granular, fore-spore, and transitional stages. There was marked inhibition of terminal respiration during the development of spores into vegetative cells. Only slight activity occurred in the earliest vegetative stages, and maximal operation developed after about ten cell divisions. Fumarase was absent in spores until sometime late in the elongation stage. At this point, a weak but definite activity appeared which increased during later stages of development so that, by the end of about the sixth cell division, fumarase had a specific activity about 80 times that observed at elongation. PMID:14151060

Pancreatic acinar cells: ionic dependence of acetylcholine-induced membrane potential and resistance change.

PubMed Central

Nishiyama, A; Petersen, O H

1975-01-01

1. Intracellular recordings of membrane potential, input resistance and time constant have been made in vitro from the exocrine acinar cells of the mouse pancreas using glass micro-electrodes. The acinar cells were stimulated by acetylcholine (ACh). In some cases ACh was simply directly added to the tissue superfusion bath, in other experiments ACh was applied locally to pancreatic acini by micro-iontophoresis. 2. Current-voltage relations were investigated by injecting rectangular de- or hyperpolarizing current pulses through the recording micro-electrode. Within a relatively wide range (-20 to -70 mV) there was a linear relation between injected current and change in membrane potential. The slope of such linear curves corresponded to an input resistance of about 3-8 M omega. The membrane time constant was about 5-10 msec. 3. ACh depolarized the cell membrane and caused a marked reduction of input resistance and time constant. The minimum latency of the ACh-induced depolarization (microiontophoretic application) was 100-300 msec. Maximal depolarization was about 20 mV. The effect of this local ACh application was abolished by atropine (1-4 x 10-6 M). The blocking effect of atropine was fully reversible. 4. Stimulating with ACh during the passage of large depolarizing current pulses made it possible simultaneously to observe the effect of ACh at two different levels of resting potential (RP). At the spontaneous RP of about minus 40 mV ACh evoked a depolarization of usual magnitude (15-20 mV) while at the artificially displaced level of about -10 mV a small hyperpolarization (about 5 mV) was observed. It therefore appears that the reversal potential of the transmitter equilibrium potential is about -20 mV. 5. Replacement of the superfusion fluid C1 by sulphate or methylsulphate caused an initial short-lasting depolarization, thereafter the normal resting potential was reassumed... PMID:1142124

Reduction of the HIV-1 reservoir in resting CD4+ T-lymphocytes by high dosage intravenous immunoglobulin treatment: a proof-of-concept study.

PubMed

Lindkvist, Annica; Edén, Arvid; Norström, Melissa M; Gonzalez, Veronica D; Nilsson, Staffan; Svennerholm, Bo; Karlsson, Annika C; Sandberg, Johan K; Sönnerborg, Anders; Gisslén, Magnus

2009-07-01

The latency of HIV-1 in resting CD4+ T-lymphocytes constitutes a major obstacle for the eradication of virus in patients on antiretroviral therapy (ART). As yet, no approach to reduce this viral reservoir has proven effective. Nine subjects on effective ART were included in the study and treated with high dosage intravenous immunoglobulin (IVIG) for five consecutive days. Seven of those had detectable levels of replication-competent virus in the latent reservoir and were thus possible to evaluate. Highly purified resting memory CD4+ T-cells were activated and cells containing replication-competent HIV-1 were quantified. HIV-1 from plasma and activated memory CD4+ T-cells were compared with single genome sequencing (SGS) of the gag region. T-lymphocyte activation markers and serum interleukins were measured. The latent HIV-1 pool decreased with in median 68% after IVIG was added to effective ART. The reservoir decreased in five, whereas no decrease was found in two subjects with detectable virus. Plasma HIV-1 RNA >or= 2 copies/mL was detected in five of seven subjects at baseline, but in only one at follow-up after 8-12 weeks. The decrease of the latent HIV-1 pool and the residual plasma viremia was preceded by a transitory low-level increase in plasma HIV-1 RNA and serum interleukin 7 (IL-7) levels, and followed by an expansion of T regulatory cells. The magnitude of the viral increase in plasma correlated to the size of the latent HIV-1 pool and SGS of the gag region showed that viral clones from plasma clustered together with virus from activated memory T-cells, pointing to the latent reservoir as the source of HIV-1 RNA in plasma. The findings from this uncontrolled proof-of-concept study suggest that the reservoir became accessible by IVIG treatment through activation of HIV-1 gene expression in latently-infected resting CD4+ T-cells. We propose that IVIG should be further evaluated as an adjuvant to effective ART.

Improvements and validation of the erythropoiesis control model for bed rest simulation

NASA Technical Reports Server (NTRS)

Leonard, J. I.

1977-01-01

The most significant improvement in the model is the explicit formulation of separate elements representing erythropoietin production and red cell production. Other modifications include bone marrow time-delays, capability to shift oxyhemoglobin affinity and an algorithm for entering experimental data as time-varying driving functions. An area of model development is suggested by applying the model to simulating onset, diagnosis and treatment of a hematologic disorder. Recommendations for further improvements in the model and suggestions for experimental application are also discussed. A detailed analysis of the hematologic response to bed rest including simulation of the recent Baylor Medical College bed rest studies is also presented.

T cell-recruiting triplebody 19-3-19 mediates serial lysis of malignant B-lymphoid cells by a single T cell

PubMed Central

Roskopf, Claudia C.; Schiller, Christian B.; Braciak, Todd A.; Kobold, Sebastian; Schubert, Ingo A.; Fey, Georg H.; Hopfner, Karl-Peter; Oduncu, Fuat S.

2014-01-01

Triplebody 19-3-19, an antibody-derived protein, carries three single chain fragment variable domains in tandem in a single polypeptide chain. 19-3-19 binds CD19-bearing lymphoid cells via its two distal domains and primary T cells via its CD3-targeting central domain in an antigen-specific manner. Here, malignant B-lymphoid cell lines and primary cells from patients with B cell malignancies were used as targets in cytotoxicity tests with pre-stimulated allogeneic T cells as effectors. 19-3-19 mediated up to 95% specific lysis of CD19-positive tumor cells and, at picomolar EC50 doses, had similar cytolytic potency as the clinically successful agent BlinatumomabTM. 19-3-19 activated resting T cells from healthy unrelated donors and mediated specific lysis of both autologous and allogeneic CD19-positive cells. 19-3-19 led to the elimination of 70% of CD19-positive target cells even with resting T cells as effectors at an effector-to-target cell ratio of 1 : 10. The molecule is therefore capable of mediating serial lysis of target cells by a single T cell. These results highlight that central domains capable of engaging different immune effectors can be incorporated into the triplebody format to provide more individualized therapy tailored to a patient’s specific immune status. PMID:25115385

Induced venous pooling and cardiorespiratory responses to exercise after bed rest

NASA Technical Reports Server (NTRS)

Convertino, V. A.; Sandler, H.; Webb, P.; Annis, J. F.

1982-01-01

Venous pooling induced by a specially constructed garment is investigated as a possible means for reversing the reduction in maximal oxygen uptake regularly observed following bed rest. Experiments involved a 15-day period of bed rest during which four healthy male subjects, while remaining recumbent in bed, received daily 210-min venous pooling treatments from a reverse gradient garment supplying counterpressure to the torso. Results of exercise testing indicate that while maximal oxygen uptake endurance time and plasma volume were reduced and maximal heart rate increased after bed rest in the control group, those parameters remained essentially unchanged for the group undergoing venous pooling treatment. Results demonstrate the importance of fluid shifts and venous pooling within the cardiovascular system in addition to physical activity to the maintenance of cardiovascular conditioning.

Metformin inhibits cell cycle progression of B-cell chronic lymphocytic leukemia cells.

PubMed

Bruno, Silvia; Ledda, Bernardetta; Tenca, Claudya; Ravera, Silvia; Orengo, Anna Maria; Mazzarello, Andrea Nicola; Pesenti, Elisa; Casciaro, Salvatore; Racchi, Omar; Ghiotto, Fabio; Marini, Cecilia; Sambuceti, Gianmario; DeCensi, Andrea; Fais, Franco

2015-09-08

B-cell chronic lymphocytic leukemia (CLL) was believed to result from clonal accumulation of resting apoptosis-resistant malignant B lymphocytes. However, it became increasingly clear that CLL cells undergo, during their life, iterative cycles of re-activation and subsequent clonal expansion. Drugs interfering with CLL cell cycle entry would be greatly beneficial in the treatment of this disease. 1, 1-Dimethylbiguanide hydrochloride (metformin), the most widely prescribed oral hypoglycemic agent, inexpensive and well tolerated, has recently received increased attention for its potential antitumor activity. We wondered whether metformin has apoptotic and anti-proliferative activity on leukemic cells derived from CLL patients. Metformin was administered in vitro either to quiescent cells or during CLL cell activation stimuli, provided by classical co-culturing with CD40L-expressing fibroblasts. At doses that were totally ineffective on normal lymphocytes, metformin induced apoptosis of quiescent CLL cells and inhibition of cell cycle entry when CLL were stimulated by CD40-CD40L ligation. This cytostatic effect was accompanied by decreased expression of survival- and proliferation-associated proteins, inhibition of signaling pathways involved in CLL disease progression and decreased intracellular glucose available for glycolysis. In drug combination experiments, metformin lowered the apoptotic threshold and potentiated the cytotoxic effects of classical and novel antitumor molecules. Our results indicate that, while CLL cells after stimulation are in the process of building their full survival and cycling armamentarium, the presence of metformin affects this process.

Viscoelastic behavior of basaltic ash from Stromboli volcano inferred from intermittent compression experiments

NASA Astrophysics Data System (ADS)

Kurokawa, A. K.; Miwa, T.; Okumura, S.; Uesugi, K.

2017-12-01

After ash-dominated Strombolian eruption, considerable amount of ash falls back to the volcanic conduit forming a dense near-surface region compacted by weights of its own and other fallback clasts (Patrick et al., 2007). Gas accumulation below this dense cap causes a substantial increase in pressure within the conduit, causing the volcanic activity to shift to the preliminary stages of a forthcoming eruption (Del Bello et al., 2015). Under such conditions, rheology of the fallback ash plays an important role because it controls whether the fallback ash can be the cap. However, little attention has been given to the point. We examined the rheology of ash collected at Stromboli volcano via intermittent compression experiments changing temperature and compression time/rate. The ash deformed at a constant rate during compression process, and then it was compressed without any deformation during rest process. The compression and rest processes repeated during each experiment to see rheological variations with progression of compaction. Viscoelastic changes during the experiment were estimated by Maxwell model. The results show that both elasticity and viscosity increases with decreasing porosity. On the other hand, the elasticity shows strong rate-dependence in the both compression and rest processes while the viscosity dominantly depends on the temperature, although the compression rate also affects the viscosity in the case of the compression process. Thus, the ash behaves either elastically or viscously depending on experimental process, temperature, and compression rate/time. The viscoelastic characteristics can be explained by magnitude relationships between the characteristic relaxation times and times for compression and rest processes. This indicates that the balance of the time scales is key to determining the rheological characteristics and whether the ash behaves elastically or viscously may control cyclic Strombolian eruptions.

Antigen challenge leads to in vivo activation and elimination of highly polarized TH1 memory T cells

PubMed Central

Hayashi, Nobuki; Liu, Dacai; Min, Booki; Ben-Sasson, Shlomo Z.; Paul, William E.

2002-01-01

TH1 memory T cells derived from T cell receptor transgenic mice, in which the T cell antigen receptor is specific for a cytochrome C peptide in association with I-Ek, were transferred into normal B10.A mice and allowed to adopt a resting phenotype. When challenged, 30–60 days after transfer, with i.v. cytochrome C, the transgenic cells rapidly became activated, expressed mRNA for IFNγ, and began to divide. However, after 48 h, the frequency of the cells fell progressively, reaching levels only slightly above the limit of detection by day 8 and thereafter remain depressed for up to 90 days. The remaining cells were anergic as shown by limitation in proliferation and IFNγ production in response to in vitro antigen stimulation. Even if challenged with antigen emulsified in complete Freund's adjuvant, the overall pattern was similar, except that in the draining lymph nodes, the surviving antigen-specific cells were not anergic, although spleen cells were still strikingly anergic. Thus, antigenic challenge of mice possessing resting memory TH1 CD4 T cells leads to the unanticipated loss of most of the specific cells and an apparent depletion rather than enhancement of immunologic memory. PMID:11959916

Left ventricular torsional mechanics and myocardial iron load in beta-thalassaemia major: a potential role of titin degradation.

PubMed

Chen, Mei-Pian; Li, Shu-Na; Lam, Wendy W M; Ho, Yuen-Chi; Ha, Shau-Yin; Chan, Godfrey C F; Cheung, Yiu-Fai

2014-04-12

Iron may damage sarcomeric proteins through oxidative stress. We explored the left ventricular (LV) torsional mechanics in patients with beta-thalassaemia major and its relationship to myocardial iron load. Using HL-1 cell and B6D2F1 mouse models, we further determined the impact of iron load on proteolysis of the giant sarcomeric protein titin. In 44 thalassaemia patients aged 25 ± 7 years and 38 healthy subjects, LV torsion and twisting velocities were determined at rest using speckle tracking echocardiography. Changes in LV torsional parameters during submaximal exercise testing were further assessed in 32 patients and 17 controls. Compared with controls, patients had significantly reduced LV apical rotation, torsion, systolic twisting velocity, and diastolic untwisting velocity. T2* cardiac magnetic resonance findings correlated with resting diastolic untwisting velocity. The increments from baseline and resultant LV torsion and systolic and diastolic untwisting velocities during exercise were significantly lower in patients than controls. Significant correlations existed between LV systolic torsion and diastolic untwisting velocities in patients and controls, both at rest and during exercise. In HL-1 cells and ventricular myocardium of B6D2F1 mice overloaded with iron, the titin-stained pattern of sarcomeric structure became disrupted. Gel electrophoresis of iron-overloaded mouse myocardial tissue further showed significant decrease in the amount of titin isoforms and increase in titin degradation products. Resting and dynamic LV torsional mechanics is impaired in patients with beta-thalassaemia major. Cell and animal models suggest a potential role of titin degradation in iron overload-induced alteration of LV torsional mechanics.

Effects of bergamot ( Citrus bergamia (Risso) Wright & Arn.) essential oil aromatherapy on mood states, parasympathetic nervous system activity, and salivary cortisol levels in 41 healthy females.

PubMed

Watanabe, Eri; Kuchta, Kenny; Kimura, Mari; Rauwald, Hans Wilhelm; Kamei, Tsutomu; Imanishi, Jiro

2015-01-01

Bergamot essential oil (BEO) is commonly used against psychological stress and anxiety in aromatherapy. The primary aim of the present study was to obtain first clinical evidence for these psychological and physiological effects. A secondary aim was to achieve some fundamental understanding of the relevant pharmacological processes. Endocrinological, physiological, and psychological effects of BEO vapor inhalation on 41 healthy females were tested using a random crossover study design. Volunteers were exposed to 3 experimental setups (rest (R), rest + water vapor (RW), rest + water vapor + bergamot essential oil (RWB)) for 15 min each. Immediately after each setup, saliva samples were collected and the volunteers rested for 10 min. Subsequently, they completed the Profile of Mood States, State-Trait Anxiety Inventory, and Fatigue Self-Check List. High-frequency (HF) heart rate values, an indicator for parasympathetic nervous system activity, were calculated from heart rate variability values measured both during the 15 min of the experiment and during the subsequent 10 min of rest. Salivary cortisol (CS) levels in the saliva samples were analyzed using ELISA. CS of all 3 conditions R, RW, and RWB were found to be significantly distinct (p = 0.003). In the subsequent multiple comparison test, the CS value of RWB was significantly lower when compared to the R setup. When comparing the HF values of the RWB setup during the 10 min of rest after the experiment to those of RW, this parameter was significantly increased (p = 0.026) in the RWB setup for which scores for negative emotions and fatigue were also improved. These results demonstrate that BEO inhaled together with water vapor exerts psychological and physiological effects in a relatively short time. © 2015 S. Karger GmbH, Freiburg.

Acetylcholine release from the rabbit isolated superior cervical ganglion preparation

PubMed Central

Dawes, P. M.; Vizi, E. S.

1973-01-01

1. The rabbit isolated superior cervical ganglion preparation has been used to measure the release of acetylcholine from the tissue at rest and during preganglionic nerve stimulation. 2. In the presence of physostigmine, the resting release of acetylcholine was 0·13 ± 0·01 (nmol/g)/min (10 experiments) and that during stimulation with 300 shocks at 10 Hz was 3·1 ± 0·4 (pmol/g)/volley in 4 experiments (means ± S.E.M.). The volley output was independent of the frequency of stimulation over the range 1 to 10 Hz but was higher at 0·3 Hz. 3. Tetrodotoxin, 0·8 μM, had no effect on the resting release of acetylcholine but reduced the stimulated release below detectable levels (2 pmol). Lowering the temperature of the bathing fluid to 5° C reduced to below detectable levels both the resting release and that produced by nerve stimulation. 4. The resting release of acetylcholine was increased by a potassium-rich (49·4 mM K+) bathing solution and by replacing the sodium chloride in the solution with lithium chloride (113 mM Li+). 5. (-)-Noradrenaline bitartrate, 3 μM, and (±)-adrenaline bitartrate, 1·5 μM, reduced by 70% the output of acetylcholine induced by stimulation at 0·3 Hz, but failed to reduce the resting release or that evoked by stimulation at 10 Hz. The inhibition was reversed by phentolamine. 6. It is concluded that the rabbit superior cervical ganglion in vitro is a suitable preparation for studying transmitter release and that the ganglion blocking effect of catecholamines is due to a reduction in transmitter release. PMID:4733726

Which species, Alexandrium catenella (Group I) or A. pacificum (Group IV), is really responsible for past paralytic shellfish poisoning outbreaks in Jinhae-Masan Bay, Korea?

PubMed

Shin, Hyeon Ho; Li, Zhun; Kim, Eun Song; Park, Jong-Woo; Lim, Weol Ae

2017-09-01

Paralytic shellfish poisoning (PSP) caused the deaths of four people in coastal area of Korea, mainly Jinhae-Masan Bay and adjacent areas, in April 1986 and in 1996. The PSP outbreaks were caused by the consumption of mussels, Mytilus edulis. The organism that caused PSP was identified, from morphological data only, as Alexandrium tamarense which is recently renamed as A. catenella, however recent studies have shown that the morphological diagnostic characteristics used to identify Alexandrium species have uncertainties and molecular tools and other criteria should be considered as well. The organism that caused past PSP outbreaks and incidents in Korea therefore need to be carefully reconsidered. The aim of this study was to re-evaluate the species really responsible for past outbreaks of PSP in Jinhae-Masan Bay, Korea. The temporal production and fluxes of the resting cysts of Alexandrium species were investigated for one year (from March 2011 to February 2012) using a sediment trap, and the morphology and phylogeny of vegetative cells germinated from the resting cysts were analysed. The production of Alexandrium species peaked in August and November, when temporal discrepancies were found in the water temperature (22.4 and 22.7°C in August, 19.1 and 19.6°C in November) and salinity (29.5 and 26.1 psu in August, 30.5 and 31.8 psu in November). The morphological data revealed that Alexandrium species germinated from resting cysts collected in August have a ventral pore on the 1' plate, whereas the 1' plate in Alexandrium species germinated from resting cysts collected in November lacks a ventral pore. Molecular phylogenetic data for the vegetative cells from the germination experiments allowed the August and November peaks to be assigned to Alexandrium catenella (Group I) and A. pacificum (Group IV), respectively. This indicates that the production of resting cysts of A. catenella can be enhanced by relatively high water temperature. This result is not consistent with those of previous studies that A. catenella responsible for PSP outbreaks was found at relatively low water temperature. In addition, large subunit ribosomal sequences data revealed that A. pacificum isolates from Korea were closely related to those from Australia, Japan and New Zealand where the PSP toxicity of shellfish and blooms occurred in the 1990s, indicating that the introduction of toxic dinoflagellates were related to ballast water from bulk-cargo shipping. Based on these results, we concluded that past PSP outbreaks in Jinhae-Masan Bay of Korea could have been caused by A. pacificum rather than by A. catenella. Copyright © 2017 Elsevier B.V. All rights reserved.

Calpain expression in lymphoid cells. Increased mRNA and protein levels after cell activation.

PubMed

Deshpande, R V; Goust, J M; Chakrabarti, A K; Barbosa, E; Hogan, E L; Banik, N L

1995-02-10

Although calpain is ubiquitously present in human tissues and is thought to play a role in demyelination, its activity is very low in resting normal lymphocytes. To determine the nature of calpain expression at the mRNA and protein levels in human lymphoid cells, we studied human T lymphocytic, B lymphocytic, and monocytic lines as well as peripheral blood mononuclear cells. Stimulation of cells with the phorbol ester phorbol myristate acetate and the calcium ionophore A23187 resulted in increased calpain mRNA and protein expression. Calpain mRNA expression is also increased in human T cells stimulated with anti-CD3. A dissociation between the increases of RNA and protein suggested that calpain could be released from the cells; the subsequent experiments showed its presence in the extracellular environment. 5,6-Dichloro-1b-D-ribofuranosylbenzimidazole, a reversible inhibitor of mRNA synthesis, reduced calpain mRNA levels by 50-67% and protein levels by 72-91%. Its removal resulted in resumption of both calpain mRNA and protein synthesis. Cycloheximide, a translational inhibitor, reduced calpain protein levels by 77-81% and calpain mRNA levels by 96% in activated THP-1 cells. Interferon-gamma induced calpain mRNA and protein in U-937 and THP-1 cells. Dexamethasone increased mRNA expression in THP-1 cells. Our results indicate that activation of lymphoid cells results in de novo synthesis and secretion of calpain.

Altered Calcium Dynamics in Cardiac Cells Grown on Silane-Modified Surfaces

PubMed Central

Ravenscroft-Chang, Melissa S.; Stohlman, Jayna; Molnar, Peter; Natarajan, Anupama; Canavan, Heather E.; Teliska, Maggie; Stancescu, Maria; Krauthamer, Victor; Hickman, J.J.

2013-01-01

Chemically defined surfaces were created using self-assembled monolayers (SAMs) of hydrophobic and hydrophilic silanes as models for implant coatings, and the morphology and physiology of cardiac myocytes plated on these surfaces were studied in vitro. We focused on changes in intracellular Ca2+ because of its essential role in regulating heart cell function. The SAM-modified coverslips were analyzed using X-ray Photoelectron Spectroscopy to verify composition. The morphology and physiology of the cardiac cells were examined using fluorescence microscopy and intracellular Ca2+ imaging. The imaging experiments used the fluorescent ratiometric dye fura-2, AM to establish both the resting Ca2+ concentration and the dynamic responses to electrical stimulation. A significant difference in excitation-induced Ca2+ changes on the different silanated surfaces was observed. However, no significant change was noted based on the morphological analysis. This result implies a difference in internal Ca2+ dynamics, and thus cardiac function, occurs when the composition of the surface is different, and this effect is independent of cellular morphology. This finding has implications for histological examination of tissues surrounding implants, the choice of materials that could be beneficial as implant coatings and understanding of cell-surface interactions in cardiac systems. PMID:19828193

Resting-state EEG, impulsiveness, and personality in daily and nondaily smokers.

PubMed

Rass, Olga; Ahn, Woo-Young; O'Donnell, Brian F

2016-01-01

Resting EEG is sensitive to transient, acute effects of nicotine administration and abstinence, but the chronic effects of smoking on EEG are poorly characterized. This study measures the resting EEG profile of chronic smokers in a non-deprived, non-peak state to test whether differences in smoking behavior and personality traits affect pharmaco-EEG response. Resting EEG, impulsiveness, and personality measures were collected from daily smokers (n=22), nondaily smokers (n=31), and non-smokers (n=30). Daily smokers had reduced resting delta and alpha EEG power and higher impulsiveness (Barratt Impulsiveness Scale) compared to nondaily smokers and non-smokers. Both daily and nondaily smokers discounted delayed rewards more steeply, reported lower conscientiousness (NEO-FFI), and reported greater disinhibition and experience seeking (Sensation Seeking Scale) than non-smokers. Nondaily smokers reported greater sensory hedonia than nonsmokers. Altered resting EEG power in daily smokers demonstrates differences in neural signaling that correlated with greater smoking behavior and dependence. Although nondaily smokers share some characteristics with daily smokers that may predict smoking initiation and maintenance, they differ on measures of impulsiveness and resting EEG power. Resting EEG in non-deprived chronic smokers provides a standard for comparison to peak and trough nicotine states and may serve as a biomarker for nicotine dependence, relapse risk, and recovery. Copyright © 2015 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Keratins Regulate p38MAPK-Dependent Desmoglein Binding Properties in Pemphigus

PubMed Central

Vielmuth, Franziska; Walter, Elias; Fuchs, Michael; Radeva, Mariya Y.; Buechau, Fanny; Magin, Thomas M.; Spindler, Volker; Waschke, Jens

2018-01-01

Keratins are crucial for the anchorage of desmosomes. Severe alterations of keratin organization and detachment of filaments from the desmosomal plaque occur in the autoimmune dermatoses pemphigus vulgaris and pemphigus foliaceus (PF), which are mainly caused by autoantibodies against desmoglein (Dsg) 1 and 3. Keratin alterations are a structural hallmark in pemphigus pathogenesis and correlate with loss of intercellular adhesion. However, the significance for autoantibody-induced loss of intercellular adhesion is largely unknown. In wild-type (wt) murine keratinocytes, pemphigus autoantibodies induced keratin filament retraction. Under the same conditions, we used murine keratinocytes lacking all keratin filaments (KtyII k.o.) as a model system to dissect the role of keratins in pemphigus. KtyII k.o. cells show compromised intercellular adhesion without antibody (Ab) treatment, which was not impaired further by pathogenic pemphigus autoantibodies. Nevertheless, direct activation of p38MAPK via anisomycin further decreased intercellular adhesion indicating that cell cohesion was not completely abrogated in the absence of keratins. Direct inhibition of Dsg3, but not of Dsg1, interaction via pathogenic autoantibodies as revealed by atomic force microscopy was detectable in both cell lines demonstrating that keratins are not required for this phenomenon. However, PF-IgG shifted Dsg1-binding events from cell borders toward the free cell surface in wt cells. This led to a distribution pattern of Dsg1-binding events similar to KtyII k.o. cells under resting conditions. In keratin-deficient keratinocytes, PF-IgG impaired Dsg1-binding strength, which was not different from wt cells under resting conditions. In addition, pathogenic autoantibodies were capable of activating p38MAPK in both KtyII wt and k.o. cells, the latter of which already displayed robust p38MAPK activation under resting conditions. Since inhibition of p38MAPK blocked autoantibody-induced loss of intercellular adhesion in wt cells and restored baseline cell cohesion in keratin-deficient cells, we conclude that p38MAPK signaling is (i) critical for regulation of cell adhesion, (ii) regulated by keratins, and (iii) targets both keratin-dependent and -independent mechanisms. PMID:29616033

Hyperemic stress myocardial perfusion cardiovascular magnetic resonance in mice at 3 Tesla: initial experience and validation against microspheres.

PubMed

Jogiya, Roy; Makowski, Markus; Phinikaridou, Alkystsis; Patel, Ashish S; Jansen, Christian; Zarinabad, Niloufar; Chiribiri, Amedeo; Botnar, Rene; Nagel, Eike; Kozerke, Sebastian; Plein, Sven

2013-07-21

Dynamic first pass contrast-enhanced myocardial perfusion is the standard CMR method for the estimation of myocardial blood flow (MBF) and MBF reserve in man, but it is challenging in rodents because of the high temporal and spatial resolution requirements. Hyperemic first pass myocardial perfusion CMR during vasodilator stress in mice has not been reported. Five C57BL/6 J mice were scanned on a clinical 3.0 Tesla Achieva system (Philips Healthcare, Netherlands). Vasodilator stress was induced via a tail vein catheter with an injection of dipyridamole. Dynamic contrast-enhanced perfusion imaging (Gadobutrol 0.1 mmol/kg) was based on a saturation recovery spoiled gradient echo method with 10-fold k-space and time domain undersampling (k-t PCA). One week later the mice underwent repeat anaesthesia and LV injections of fluorescent microspheres at rest and at stress. Microspheres were analysed using confocal microscopy and fluorescence-activated cell sorting. Mean MBF at rest measured by Fermi-function constrained deconvolution was 4.1 ± 0.5 ml/g/min and increased to 9.6 ± 2.5 ml/g/min during dipyridamole stress (P = 0.005). The myocardial perfusion reserve was 2.4 ± 0.54. The mean count ratio of stress to rest microspheres was 2.4 ± 0.51 using confocal microscopy and 2.6 ± 0.46 using fluorescence. There was good agreement between cardiovascular magnetic resonance CMR and microspheres with no significant difference (P = 0.84). First-pass myocardial stress perfusion CMR in a mouse model is feasible at 3 Tesla. Rest and stress MBF values were consistent with existing literature and perfusion reserve correlated closely to microsphere analysis. Data were acquired on a 3 Tesla scanner using an approach similar to clinical acquisition protocols, potentially facilitating translation of imaging findings between rodent and human studies.

Role of resting cysts in Chilean Alexandrium catenella dinoflagellate blooms revisited.

PubMed

Mardones, Jorge I; Bolch, Chris; Guzmán, Leonardo; Paredes, Javier; Varela, Daniel; Hallegraeff, Gustaaf M

2016-05-01

The detection of sparse Alexandrium catenella-resting cysts in sediments of southern Chilean fjords has cast doubts on their importance in the recurrence of massive toxic dinoflagellate blooms in the region. The role of resting cysts and the existence of different regional Chilean populations was studied by culturing and genetic approaches to define: (1) cyst production; (2) dormancy period; (3) excystment success; (4) offspring viability and (5) strain mating compatibility. This study newly revealed a short cyst dormancy (minimum 69 days), the role of key abiotic factors (in decreasing order salinity, irradiance, temperature and nutrients) controlling cyst germination (max. 60%) and germling growth rates (up to 0.36-0.52div.day -1 ). Amplified fragment length polymorphism (AFLP) characterization showed significant differences in genetic distances (GD) among A. catenella populations that were primarily determined by the geographical origin of isolates and most likely driven by oceanographic dispersal barriers. A complex heterothallic mating system pointed to variable reproductive compatibility (RCs) among Chilean strains that was high among northern (Los Lagos/North Aysén) and southern populations (Magallanes), but limited among the genetically differentiated central (South Aysén) populations. Field cyst surveys after a massive 2009 bloom event revealed the existence of exceptional high cyst densities in particular areas of the fjords (max. 14.627cystscm -3 ), which contrast with low cyst concentrations (<221.3cystscm -3 ) detected by previous oceanographic campaigns. In conclusion, the present study suggests that A. catenella resting cysts play a more important role in the success of this species in Chilean fjords than previously thought. Results from in vitro experiments suggest that pelagic-benthic processes can maintain year-round low vegetative cell concentrations in the water column, but also can explain the detection of high cysts aggregations after the 2009-bloom event. Regional drivers that lead to massive outbreaks, however, are still unknown but potential scenarios are discussed. Copyright © 2016 Elsevier B.V. All rights reserved.

K/sup +/-induced alterations in airway muscle responsiveness to electrical field stimulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Murlas, C.; Ehring, G.; Suszkiw, J.

1986-07-01

The authors investigated possible pre- and postsynaptic effects of K/sup +/-induced depolarization on ferret tracheal smooth muscle (TSM) responsiveness to cholinergic stimulation. To assess electromechanical activity, cell membrane potential (E/sub m/) and tension (T/sub m/) were simultaneously recorded in buffer containing 6, 12, 18, or 24 mM K/sup +/ before and after electrical field stimulation (EFS) or exogenous acetylcholine (ACh). In 6 mM K/sup +/ E/sub m/ was -58.1 +/- 1.0 m V (mean +/- SE). In 12 mM K/sup +/, E/sub m/ was depolarized to -52.3 +/- 0.9 mV, basal T/sub m/ did not change, and both excitatory junctionalmore » potentials and contractile responses to EFS at short stimulus duration were larger than in 6 mM K/sup +/. No such potentiation occurred at a higher K/sup +/, although resting E/sub m/ and T/sub m/ increased progressively above 12 mM K/sup +/. The sensitivity of ferret TSM to exogenous ACh appeared unaffected by K/sup +/. To determine whether the hyperresponsiveness in 12 mM K/sup +/ was due, in part, to augmented ACh release from intramural airway nerves, experiments were done using TSM preparations incubated with (/sup 3/H)choline to measure (/sup 3/H)ACh release at rest and during EFS. Although resting (/sup 3/H)ACh release increased progressively in higher K/sup +/, release evoked by EFS was maximal in 12 mM K/sup +/ and declined in higher concentrations. They conclude that small elevations in the extracellular K/sup +/ concentration augment responsiveness of the airways, by increasing the release of ACh both at rest and during EFS from intramural cholinergic nerve terminals. Larger increases in K/sup +/ appear to be inhibitory, possibly due to voltage-dependent effects that occur both pre- and postsynaptically.« less

Quantitative Analysis of Electrochemical and Electrode Stability with Low Self-Discharge Lithium-Sulfur Batteries

DOE PAGES

Chung, Sheng-Heng; Han, Pauline; Manthiram, Arumugam

2017-06-07

The viability of employing high-capacity sulfur cathodes in building high-energy-density lithium-sulfur batteries is limited by rapid self-discharge, short shelf life, and severe structural degradation during cell resting (static instability). Unfortunately, the static instability has largely been ignored in the literature. We present in this letter a longterm self-discharge study by quantitatively analyzing the control lithium-sulfur batteries with a conventional cathode configuration, which provides meaningful insights into the cathode failure mechanisms during resting. Lastly, utilizing the understanding obtained with the control cells, we design and present low self-discharge (LSD) lithium-sulfur batteries for investigating the long-term self-discharge effect and electrode stability.

Quantitative Analysis of Electrochemical and Electrode Stability with Low Self-Discharge Lithium-Sulfur Batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chung, Sheng-Heng; Han, Pauline; Manthiram, Arumugam

The viability of employing high-capacity sulfur cathodes in building high-energy-density lithium-sulfur batteries is limited by rapid self-discharge, short shelf life, and severe structural degradation during cell resting (static instability). Unfortunately, the static instability has largely been ignored in the literature. We present in this letter a longterm self-discharge study by quantitatively analyzing the control lithium-sulfur batteries with a conventional cathode configuration, which provides meaningful insights into the cathode failure mechanisms during resting. Lastly, utilizing the understanding obtained with the control cells, we design and present low self-discharge (LSD) lithium-sulfur batteries for investigating the long-term self-discharge effect and electrode stability.

Parameters of hormetic stress and resilience to trauma in rats.

PubMed

Plumb, Traci N; Cullen, Patrick K; Minor, Thomas R

2015-01-01

Hormesis is the process by which small stresses build resilience to large stresses. We pre-exposed rats to various parameters of mild-to-moderate stress prior to traumatic stress in the present experiments to assess the potential benefits of hormetic training on resilience to traumatic, uncontrollable stress. Rats underwent varying stress pre-training parameters prior to exposure to uncontrollable traumatic stress in the learned helplessness procedure. The ability to prevent the exaggerated fear responding and escape deficits that normally follow experience with traumatic stress were used as a measure of the benefits of hormetic training. Four experiments examined the effects of number of training sessions, stressor severity and pattern of rest between pre-training stress sessions. Repeated exposure to mild restraint stress or moderate shock stress eliminated both the enhanced fear conditioning and shuttle-escape deficits that result from exposure to traumatic, inescapable shock. The pattern of rest did not contribute to resilience when the pre-exposure stressor was mild, but was vital when the pre-exposure stressor was moderate, with an alternation of stress and rest being the most effective procedure. The data also suggest that the level of resilience may increase with the number of pre-exposure sessions.

Cellular and Molecular Level Responses After Radiofrequency Radiation Exposure, Alone or in Combination with X-rays or Chemicals

DTIC Science & Technology

1992-07-27

cell surface marker CD22 , which plays a role in early B-cell activation, is present within the cytoplasm of all B- cells, but expressed only on the...surface of a subpopulation of those cells. CD22 is an activation receptor associated with cell proliferation of small resting B-cells, and acts as an...adhesion molecule mediating the binding of B-cells to other hematopoietic cells (Stamenkovic & Seed, 1990). The CD22 surface glycoprotein is the putative

Joint US/USSR study: Comparison of effects of horizontal and head-down bed rest

NASA Technical Reports Server (NTRS)

Sandler, Harold; Grigoriev, Anatoli I.

1990-01-01

An account is given of the results of the first joint U.S./U.S.S.R. bed rest study. The study was accomplished in two parts: A soviet part (May to June 1979) and an American part (July to August 1979). Both studies were conducted under identical conditions and provided a basis for comparison of physiologic reactions and standardizing procedures and methods. Each experiment consisted of three periods: 14 days of pre-bed rest control, 7 days of bed rest, and a 10 to 14 day recovery period. Ten males participated in each study, with five subjects experiencing horizontal bed rest and five subjects a -6 deg head-down body position. Biochemical and hormonal measurements were made of blood and urine, with particular attention to electrolyte metabolism and kidney function; cardio-pulmonary changes at rest and exercise; influence of Lower Body Negative Pressure (LBNP); and incremental exercise using a bicyle ergometer while supine and sitting. Expected moderate changes were noted to occur for various physiologic parameters. Clinical evidence pointed to the fact that head-down bed rest when compared to horizontal conditions more closely matched the conditions seen after manned spaceflight. For the most part, statistically significant differences between the two body positions were not observed.

Noise-induced effects on multicellular biopacemaker spontaneous activity: Differences between weak and strong pacemaker cells

NASA Astrophysics Data System (ADS)

Aghighi, Alireza; Comtois, Philippe

2017-09-01

Self-organization of spontaneous activity of a network of active elements is important to the general theory of reaction-diffusion systems as well as for pacemaking activity to initiate beating of the heart. Monolayer cultures of neonatal rat ventricular myocytes, consisting of resting and pacemaker cells, exhibit spontaneous activation of their electrical activity. Similarly, one proposed approach to the development of biopacemakers as an alternative to electronic pacemakers for cardiac therapy is based on heterogeneous cardiac cells with resting and spontaneously beating phenotypes. However, the combined effect of pacemaker characteristics, density, and spatial distribution of the pacemaker cells on spontaneous activity is unknown. Using a simple stochastic pattern formation algorithm, we previously showed a clear nonlinear dependency of spontaneous activity (occurrence and amplitude of spontaneous period) on the spatial patterns of pacemaker cells. In this study, we show that this behavior is dependent on the pacemaker cell characteristics, with weaker pacemaker cells requiring higher density and larger clusters to sustain multicellular activity. These multicellular structures also demonstrated an increased sensitivity to voltage noise that favored spontaneous activity at lower density while increasing temporal variation in the period of activity. This information will help researchers overcome the current limitations of biopacemakers.

Improved NADPH Regeneration for Fungal Cytochrome P450 Monooxygenase by Co-Expressing Bacterial Glucose Dehydrogenase in Resting-Cell Biotransformation of Recombinant Yeast.

PubMed

Jeon, Hyunwoo; Durairaj, Pradeepraj; Lee, Dowoo; Ahsan, Md Murshidul; Yun, Hyungdon

2016-12-28

Fungal cytochrome P450 (CYP) enzymes catalyze versatile monooxygenase reactions and play a major role in fungal adaptations owing to their essential roles in the production avoid metabolites critical for pathogenesis, detoxification of xenobiotics, and exploitation avoid substrates. Although fungal CYP-dependent biotransformation for the selective oxidation avoid organic compounds in yeast system is advantageous, it often suffers from a shortage avoid intracellular NADPH. In this study, we aimed to investigate the use of bacterial glucose dehydrogenase (GDH) for the intracellular electron regeneration of fungal CYP monooxygenase in a yeast reconstituted system. The benzoate hydroxylase FoCYP53A19 and its homologous redox partner FoCPR from Fusarium oxysporum were co-expressed with the BsGDH from Bacillus subtilis in Saccharomyces cerevisiae for heterologous expression and biotransformations. We attempted to optimize several bottlenecks concerning the efficiency of fungal CYP-mediated whole-cell-biotransformation to enhance the conversion. The catalytic performance of the intracellular NADPH regeneration system facilitated the hydroxylation of benzoic acid to 4-hydroxybenzoic acid with high conversion in the resting-cell reaction. The FoCYP53A19 +FoCPR+BsGDH reconstituted system produced 0.47 mM 4-hydroxybenzoic acid (94% conversion) in the resting-cell biotransformations performed in 50 mM phosphate buffer (pH 6.0) containing 0.5 mM benzoic acid and 0.25% glucose for 24 h at 30°C. The "coupled-enzyme" system can certainly improve the overall performance of NADPH-dependent whole-cell biotransformations in a yeast system.

Inhibiting NANOG Enhances Efficacy of BH3 Mimetics | Center for Cancer Research

Cancer.gov

BCL-2 family proteins regulate cell fate. Some members promote cell survival while others induce programmed cell death. A third group, the BH3-only members, modulates the activities of the rest of the family. Some cancers, including those of the colon and rectum, express elevated levels of pro-survival BCL-2 members, which may protect cancer cells from chemotherapy. BH3

Overview of potential procedural and participant-related confounds for neuroimaging of the resting state

PubMed Central

Duncan, Niall W.; Northoff, Georg

2013-01-01

Studies of intrinsic brain activity in the resting state have become increasingly common. A productive discussion of what analysis methods are appropriate, of the importance of physiologic correction and of the potential interpretations of results has been ongoing. However, less attention has been paid to factors other than physiologic noise that may confound resting-state experiments. These range from straightforward factors, such as ensuring that participants are all instructed in the same manner, to more obscure participant-related factors, such as body weight. We provide an overview of such potentially confounding factors, along with some suggested approaches for minimizing their impact. A particular theme that emerges from the overview is the range of systematic differences between types of study groups (e.g., between patients and controls) that may influence resting-state study results. PMID:22964258

Lifespan differences in nonlinear dynamics during rest and auditory oddball performance.

PubMed

Müller, Viktor; Lindenberger, Ulman

2012-07-01

Electroencephalographic recordings (EEG) were used to assess age-associated differences in nonlinear brain dynamics during both rest and auditory oddball performance in children aged 9.0-12.8 years, younger adults, and older adults. We computed nonlinear coupling dynamics and dimensional complexity, and also determined spectral alpha power as an indicator of cortical reactivity. During rest, both nonlinear coupling and spectral alpha power decreased with age, whereas dimensional complexity increased. In contrast, when attending to the deviant stimulus, nonlinear coupling increased with age, and complexity decreased. Correlational analyses showed that nonlinear measures assessed during auditory oddball performance were reliably related to an independently assessed measure of perceptual speed. We conclude that cortical dynamics during rest and stimulus processing undergo substantial reorganization from childhood to old age, and propose that lifespan age differences in nonlinear dynamics during stimulus processing reflect lifespan changes in the functional organization of neuronal cell assemblies. © 2012 Blackwell Publishing Ltd.

Use of bed rest and head-down tilt to simulate spaceflight-induce immune system changes

NASA Technical Reports Server (NTRS)

Schmitt, D. A.; Schaffar, L.; Taylor, G. R.; Loftin, K. C.; Schneider, V. S.; Koebel, A.; Abbal, M.; Sonnenfeld, G.; Lewis, D. E.; Reuben, J. R.;

Process parameter optimization for hydantoinase-mediated synthesis of optically pure carbamoyl amino acids of industrial value using Pseudomonas aeruginosa resting cells.

PubMed

Engineer, Anupama S; Dhakephalkar, Anita P; Gaikaiwari, Raghavendra P; Dhakephalkar, Prashant K

2013-12-01

Hydantoinase-mediated enzymatic synthesis of optically pure carbamoyl amino acids was investigated as an environmentally friendly, energy-efficient alternative to the otherwise energy-intensive, polluting chemical synthesis. Hydantoinase-producing bacterial strain was identified as Pseudomonas aeruginosa by 16S rRNA gene sequencing and biochemical profiling using the BIOLOG Microbial Identification System. Hydantoinase activity was assessed using hydantoin analogs and 5-monosubstituted hydantoins as substrates in a colorimetric assay. The hydantoinase gene was PCR amplified using gene-specific primers and sequenced on an automated gene analyzer. Hydantoinase gene sequence of P. aeruginosa MCM B-887 revealed maximum homology of only 87 % with proven hydantoinase gene sequences in GenBank. MCM B-887 resting cells converted >99 % of substrate into N-carbamoyl amino acids under optimized condition at 42 °C, pH 8.0, and 100 mM substrate concentration in <120 min. Hydantoin hydrolyzing activity was D-selective and included broad substrate profile of 5-methyl hydantoin, 5-phenyl hydantoin, 5-hydroxyphenyl hydantoin, o-chlorophenyl hydantoin, as well as hydantoin analogs such as allantoin, dihydrouracil, etc. MCM B-887 resting cells may thus be suitable for bio-transformations leading to the synthesis of optically pure, unnatural carbamoyl amino acids of industrial importance.

[Cardiac manifestations of sickle cell anemia].

PubMed

Gacon, P H; Donatien, Y

HEMOGLOBINS S AND C: Drepanocytosis, the occurrence of sickle cells (drepanocytes) in the blood, is an inherited condition. Electrophoresis demonstrates hemoglobin SS in homozygous subjects who present the typical clinical features of severe hemolytic sickle-cell anemia. Heterozygous subjects have sickle-cell anemia trait, an asymptomatic condition associated with a 50% hemoglobin S and 50% hemoglobin C at electrophoresis. Hemoglobin S and C are transmitted by Mendelian inheritance. CARDIAC DISORDERS: Well-known, cardiac disorders occur in more than 82% of homozygous subjects while only 2% of heterozygous subjects are affected. Heart murmur, radiological cardiomegaly, or eletrocardiographic anomalies are often the only signs. There is a risk of fatal heart failure in children and neonates. Acute rheumatic fever or infectious endocarditis, particularly due to pneumococcal or Haemophilus influenzae infection, may trigger heart failure. CARDIAC ANOMALIES: Patients with sickle-cell anemia can develop an "anemic heart" expressed by an elevated cardiac output and systemic ejection volume at rest and a fall in arteriolar peripheral resistance. Patients who develop cor pulmonae have an elevated pulmonary pressure at exercise and experience venous occlusive events with a progressive reduction in the pulmonary vascular bed and development of a left-right shunt. Myocardiopathy leads to left ventricular dysfunction contrasting with the dilated right heart seen at echocardiography and rare cases of transmural infarction.

Why was the 2012 bloom so early? Using chilling and warming metrics to resolve interannual variability in the timing of Alexandrium fundyense bloom initiation

NASA Astrophysics Data System (ADS)

Fischer, A. D.; Anderson, D. M.; Moore, S.; Brosnahan, M.

2016-02-01

The Nauset Marsh System (NMS) on Cape Cod (MA, USA) has recurrent Alexandrium fundyense blooms that have caused nearly annual shellfishing closures due to paralytic shellfish poisoning. Blooms were observed over a multi-year period (2009-2015) to examine the effects of seasonal cooling and warming on the transition from resting cysts to vegetative cells in the plankton. The life cycle processes of cyst dormancy, germination, and vegetative cell growth are all uniquely sensitive to temperature, which can translate to changes in bloom initiation phenology. Bloom initiation (>100 cells/l-1) occurred as early as 14 February 2012, and as late as 15 April 2015. To quantitatively examine the mechanisms responsible for this two-month range, laboratory studies were performed. In experiments mimicking winter's onset, mature cysts were exposed to chilling temperatures (2-8°C), and at regular intervals the germination potential of cyst cohorts was evaluated. Next, in experiments mimicking a range of late-winter, early-spring temperatures, the time to germination was observed for cold-conditioned cysts. To account for the interannual temperature variability in the NMS and enable comparison to laboratory studies, we calculated growing degree-days and chilling-units, both metrics that tabulate accumulated temperature exposures. Here we pair laboratory studies with seven years of bloom data to present a conceptual model of three temperature-dependent phases of bloom initiation for A. fundyense: 1) Winter dormancy. As temperatures cool, cysts enter a state of dormancy during which germination is physiologically inhibited, until they experience a threshold of winter chilling. 2) Quiescence. Cysts are physiologically able to germinate, but require a specific amount of heat, oxygen, and light. 3) Growth. Germling cells transform to vegetative cells, which divide asexually as a function of heat to create the bloom. These results help to explain differences in bloom timing between years, and provide insights into potential responses of A. fundyense to climate change.

Iron differentially modulates the CD4-lck and CD8-lck complexes in resting peripheral blood T-lymphocytes.

PubMed

Arosa, F A; de Sousa, M

1995-03-01

Clinical and experimental studies performed in situations of iron overload have demonstrated that iron impairs several T-cell functions. We have examined the effect of iron in the form of ferric citrate on the CD4-lck and CD8-lck complexes in view of the key role played by the tyrosine kinase p56lck in regulating T-cell functions. Ferric citrate was seen to differentially modulate the CD4-lck and CD8-lck complexes in resting peripheral blood T-lymphocytes (PBLs) cultured in the presence of this metal salt for periods of 20 to 24 hr. Thus, whereas ferric citrate invariably induced a marked decrease in the in vitro activity of the CD4-associated lck by three- to fourfold at 100 microM (P < 3 x 10(-5)), it did not affect significantly the in vitro activity of the CD8-associated lck, although modest decreases were observed in some experiments. Immunoprecipitation and subsequent lck-immunoblotting revealed that the marked decrease in CD4-lck activity induced by 100 microM of ferric citrate was due to a decrease in the amount of p56lck on CD4 immunoprecipitates. Furthermore, flow cytometry analysis showed a decrease in the surface expression of the CD4 molecule in iron-treated PBLs, as judged by a decrease in the mean fluorescence intensity (MFI), that was accompanied by a decrease in the percentage of CD4+ T-lymphocytes. In marked contrast, whereas the surface expression of the CD8 molecule was slightly decreased, the percentage of CD8+ T-lymphocytes remained constant. This differential effect of ferric citrate on the CD4+ and CD8+ T-cell subsets led to a marked decrease in the CD4/CD8 ratios in iron-treated PBLs after the 20- to 24-hr period (P < 0.001). The present results indicate that iron in the form of ferric citrate can modulate key molecules involved in the process of T-cell activation and therefore influence T-cell-mediated functions.

One-pot conjugated linoleic acid production from castor oil by Rhizopus oryzae lipase and resting cells of Lactobacillus plantarum.

PubMed

Khaskheli, Abid Ali; Talpur, Farah Naz; Cebeci Aydin, Aysun; Jawaid, Sana; Surhio, Muhammad Ali; Afridi, Hassan Imran

2017-10-01

Conjugated linoleic acid (CLA) has attracted as novel type of fatty acids having unusual health-promoting properties such as anticarcinogenic and antiobesitic effects. The present work employed castor oil as substrate for one-pot production of CLA using washed cells of Lactobacillus plantarum (L. plantarum) and lipases as catalysts. Among the screened lipases, the lipase Rhizopus oryzae (ROL) greatly assisted resting cells to produce CLA. Mass spectral analysis of the product showed that two major isomers of CLA were produced in the reaction mixture i.e. cis-9, trans-11 56.55% and trans-10, cis-12 43.45%. Optimum factors for CLA synthesis were found as substrate concentration (8 mg/mL), pH (6.5), washed cell concentration (12% w/v), and incubation time of 20 h. Hence, the combination of ROL with L. plantarum offers one pot production of CLA selectively using castor oil as a cost-effective substrate.

Space Flight Effects on Intracellular Ions in Sublingual Cells of Non-Human Primates

NASA Technical Reports Server (NTRS)

Arnaud, Sara B.; Dotsenko, R.; Fung, P.; Navidi, M.; Silver, B.; Wade, Charles E. (Technical Monitor)

1994-01-01

We have used a novel technique that quantifies minerals and electrolytes from smears of sublingual cells by x-ray microanalysis to monitor metabolic changes in bed rest subjects. Increases in intracellular calcium (Ca), phosphorus (P), and potassium (K) were characteristic of subjects whose exercise regimen was inadequate to maintain calcium metabolism. To test the effects of space flight on intracellular ions, we analyzed cells from 2-4 kg Rhesus monkeys before and after 2 weeks in space or chair restraint (CR). There were increases in sublingual cell Ca, P and K after space flight which paralleled the clinical estimates of metabolic status of the animals and exceeded the levels found during CR on R+11. Increases after 2 weeks CR were 26% in Ca, 6% in P and 29% in K. Species similarity ill responses of intracellular ions to inactivity imposed by bed rest, restraint or microgravity suggest that this innovative non-invasive technique would be a useful in-flight monitor of exercise countermeasures directed toward maintaining calcium balance.

Activation of raphe nuclei triggers rapid and distinct effects on parallel olfactory bulb output channels

PubMed Central

Kapoor, Vikrant; Provost, Allison; Agarwal, Prateek; Murthy, Venkatesh N.

2015-01-01

The serotonergic raphe nuclei are involved in regulating brain states over time-scales of minutes and hours. We examined more rapid effects of serotonergic activation on two classes of principal neurons in the mouse olfactory bulb, mitral and tufted cells, which send olfactory information to distinct targets. Brief stimulation of the raphe nuclei led to excitation of tufted cells at rest and potentiation of their odor responses. While mitral cells at rest were also excited by raphe activation, their odor responses were bidirectionally modulated, leading to improved pattern separation of odors. In vitro whole-cell recordings revealed that specific optogenetic activation of raphe axons affected bulbar neurons through dual release of serotonin and glutamate. Therefore, the raphe nuclei, in addition to their role in neuromodulation of brain states, are also involved in fast, sub-second top-down modulation, similar to cortical feedback. This modulation can selectively and differentially sensitize or decorrelate distinct output channels. PMID:26752161

Liquid-phase electron microscopy of molecular drug response in breast cancer cells reveals irresponsive cell subpopulations related to lack of HER2 homodimers.

PubMed

Peckys, Diana B; Korf, Ulrike; Wiemann, Stefan; de Jonge, Niels

2017-08-09

The development of drug resistance in cancer poses a major clinical problem. An example is human epidermal growth factor receptor 2 (HER2) overexpressing breast cancer often treated with anti-HER2 antibody therapies, such as trastuzumab. Since drug resistance is rooted mainly in tumor cell heterogeneity, we examined the drug effect in different subpopulations of SKBR3 breast cancer cells, and compared the results with a drug resistant cell line, HCC1954. Correlative light microscopy and liquid-phase scanning transmission electron microscopy (STEM) were used to quantitatively analyze HER2 responses upon drug binding, whereby many tens of whole cells were imaged. Trastuzumab was found to selectively cross-link and down regulate HER2 homodimers from the plasma membranes of bulk cancer cells. In contrast, HER2 resided mainly as monomers in rare subpopulations of resting- and cancer stem cells (CSCs), and these monomers were not internalized after drug binding. The HER2 distribution was hardly influenced by trastuzumab for the HCC1954 cells. These findings show that resting cells and CSCs are irresponsive to the drug, and thus point towards a molecular explanation behind the origin of drug resistance. This analytical method is broadly applicable to study membrane protein interactions in the intact plasma membrane, while accounting for cell heterogeneity. © 2017 by The American Society for Cell Biology.

Environmental Impact of Tributyltin-Resistant Marine Bacteria in the Indigenous Microbial Population of Tributyltin-Polluted Surface Sediments.

PubMed

Mimura, Haruo; Yagi, Masahiro; Yoshida, Kazutoshi

2017-01-01

　We compared the TBT-resistant ability of resting cells prepared from isolates that formed colonies on nutrient agar plates containing 100 µM tributyltin (TBT) chloride, such as Photobacterium sp. TKY1, Halomonas sp. TKY2, and Photobacterium sp. NGY1, with those from taxonomically similar type strains. Photobacterium sp. TKY1 showed the highest ability among those three isolates. The number of surviving Photobacterium sp. TKY1 cells was hardly decreased after 1 h of exposure to 100 µM TBTCl, regardless of the number of resting cells in the range from 10 9.4 to 10 4.2 CFU mL -1 . In such an experimental condition, the maximum number of TBT molecules available to associate with a single cell was estimated to be approximately 6.0 x 10 11.8 . Resting cells prepared from type strains Photobacterium ganghwense JCM 12487 T and P. halotolerans LMG 22194 T , which have 16S rDNA sequences highly homologous with those of Photobacterium sp. TKY1, showed sensitivity to TBT, indicating that TBT-resistant marine bacterial species are not closely related in spite of their taxonomic similarity. We also estimated the impact of TBT-resistant bacterial species to indigenous microbial populations of TBT-polluted surface sediments. The number of surviving TBT-sensitive Vibrio natriegens ATCC 14048 T cells, 10 6.2±0.3 CFU mL -1 , was reduced to 10 4.4±0.4 CFU mL -1 when TBT-resistant Photobacterium sp. TKY1 cells, 10 9.1±0.2 CFU mL -1 , coexisted with 10 9.4±0.2 CFU mL -1 of V. natriegens ATCC 14048 T cells in the presence of 100 µM TBTCl. These results indicate that the toxicity of TBT to TBT-sensitive marine bacterial populations might be enhanced when a TBT-resistant marine bacterial species inhabits TBT-polluted surface sediments.

Resting and Activated Natural Tregs Decrease in the Peripheral Blood of Patients with Atherosclerosis.

PubMed

Yazdani, Mohammadreza; Khosropanah, Shahdad; Hosseini, Ahmad; Doroudchi, Mehrnoosh

2016-12-01

Atherosclerosis is a chronic inflammatory disease affecting large and medium arteries. CD4+ T cells are known to play a role in the progression of the disease. CD4+CD25+Foxp3+ natural Treg (nTreg) cells seem to have a protective role in the disease and their reduction in acute coronary syndrome is recently shown. To investigate the frequency of nTreg subsets in the peripheral blood of patients with atherosclerosis. Confirmation of atherosclerosis was done by angiography and 15 ml heparinized blood was obtained from each of the 13 non-diabetic patients and 13 non-diabetic, non-smoker individuals with normal/insignificant coronary artery disease confirmed by angiography. Lipid profiles of the patients and controls were measured at the time of sampling. Mononuclear cells were used for both RNA extraction and immunophenotyping by real-time PCR and flowcytometry techniques, respectively. In natural Treg subsets, the frequency of CD4+CD45RO-CD25+Foxp3lo T-cells (resting nTregs) was greater in controls than patients (p=0.02). The frequency of CD4+CD45RO+CD25hiFoxp3hi T-cells (activated nTregs) was significantly higher in controls compared with patients (p=0.02). However, the frequency of CD4+CD25+CD45RO+Foxp3- T-cells (effector/memory T-cell) increased in patients compared with controls (p=0.01). Both the MFI and gene expression of Foxp3 were higher in control group than in patients (p=0.015 and p=0.017, respectively). Moreover, the TGF-β gene expression showed a decrease in the peripheral blood mononuclear cells of patients compared with controls (p=0.03). Decrease in both subsets of resting and activated nTregs along with a decrease in the expression of Foxp3 and TGF-β genes in patients with atherosclerosis suggests phenotypic changes in these subsets, which may as well be correlated with a more inflammatory profile in their lymphocytes.

Cytokines Induce Faster Membrane Diffusion of MHC Class I and the Ly49A Receptor in a Subpopulation of Natural Killer Cells

PubMed Central

Bagawath-Singh, Sunitha; Staaf, Elina; Stoppelenburg, Arie Jan; Spielmann, Thiemo; Kambayashi, Taku; Widengren, Jerker; Johansson, Sofia

2016-01-01

Cytokines have the potential to drastically augment immune cell activity. Apart from altering the expression of a multitude of proteins, cytokines also affect immune cell dynamics. However, how cytokines affect the molecular dynamics within the cell membrane of immune cells has not been addressed previously. Molecular movement is a vital component of all biological processes, and the rate of motion is, thus, an inherent determining factor for the pace of such processes. Natural killer (NK) cells are cytotoxic lymphocytes, which belong to the innate immune system. By fluorescence correlation spectroscopy, we investigated the influence of cytokine stimulation on the membrane density and molecular dynamics of the inhibitory receptor Ly49A and its ligand, the major histocompatibility complex class I allele H-2Dd, in freshly isolated murine NK cells. H-2Dd was densely expressed and diffused slowly in resting NK cells. Ly49A was expressed at a lower density and diffused faster. The diffusion rate in resting cells was not altered by disrupting the actin cytoskeleton. A short-term stimulation with interleukin-2 or interferon-α + β did not change the surface density of moving H-2Dd or Ly49A, despite a slight upregulation at the cellular level of H-2Dd by interferon-α + β, and of Ly49A by IL-2. However, the molecular diffusion rates of both H-2Dd and Ly49A increased significantly. A multivariate analysis revealed that the increased diffusion was especially marked in a subpopulation of NK cells, where the diffusion rate was increased around fourfold compared to resting NK cells. After IL-2 stimulation, this subpopulation of NK cells also displayed lower density of Ly49A and higher brightness per entity, indicating that Ly49A may homo-cluster to a larger extent in these cells. A faster diffusion of inhibitory receptors could enable a faster accumulation of these molecules at the immune synapse with a target cell, eventually leading to a more efficient NK cell response. It has previously been assumed that cytokines regulate immune cells primarily via alterations of protein expression levels or posttranslational modifications. These findings suggest that cytokines may also modulate immune cell efficiency by increasing the molecular dynamics early on in the response. PMID:26870035

Resting connectivity between salience nodes predicts recognition memory.

PubMed

Andreano, Joseph M; Touroutoglou, Alexandra; Dickerson, Bradford C; Barrett, Lisa F

2017-06-01

The resting connectivity of the brain's salience network, particularly the ventral subsystem of the salience network, has been previously associated with various measures of affective reactivity. Numerous studies have demonstrated that increased affective arousal leads to enhanced consolidation of memory. This suggests that individuals with greater ventral salience network connectivity will exhibit greater responses to affective experience, leading to a greater enhancement of memory by affect. To test this hypothesis, resting ventral salience connectivity was measured in 41 young adults, who were then exposed to neutral and negative affect inductions during a paired associate memory test. Memory performance for material learned under both negative and neutral induction was tested for correlation with resting connectivity between major ventral salience nodes. The results showed a significant interaction between mood induction (negative vs neutral) and connectivity between ventral anterior insula and pregenual anterior cingulate cortex, indicating that salience node connectivity predicted memory for material encoded under negative, but not neutral induction. These findings suggest that the network state of the perceiver, measured prior to affective experience, meaningfully influences the extent to which affect modulates memory. Implications of these findings for individuals with affective disorder, who show alterations in both connectivity and memory, are considered. © The Author (2017). Published by Oxford University Press.

Clinical Resting-state fMRI in the Preoperative Setting

PubMed Central

Lee, Megan H.; Miller-Thomas, Michelle M.; Benzinger, Tammie L.; Marcus, Daniel S.; Hacker, Carl D.; Leuthardt, Eric C.; Shimony, Joshua S.

2017-01-01

The purpose of this manuscript is to provide an introduction to resting-state functional magnetic resonance imaging (RS-fMRI) and to review the current application of this new and powerful technique in the preoperative setting using our institute’s extensive experience. RS-fMRI has provided important insights into brain physiology and is an increasingly important tool in the clinical setting. As opposed to task-based functional MRI wherein the subject performs a task while being scanned, RS-fMRI evaluates low-frequency fluctuations in the blood oxygen level dependent (BOLD) signal while the subject is at rest. Multiple resting state networks (RSNs) have been identified, including the somatosensory, language, and visual networks, which are of primary importance for presurgical planning. Over the past 4 years, we have performed over 300 RS-fMRI examinations in the clinical setting and these have been used to localize eloquent somatosensory and language cortices before brain tumor resection. RS-fMRI is particularly useful in this setting for patients who are unable to cooperate with the task-based paradigm, such as young children or those who are sedated, paretic, or aphasic. Although RS-fMRI is still investigational, our experience indicates that this method is ready for clinical application in the presurgical setting. PMID:26848556

Effect of stimulation and hyperpolarization on non-electrolyte and sodium permeability in perfused axons of squid.

PubMed

Hidalgo, C; Latorre, R

1970-11-01

1. The permeability for micro-injected [(3)H]ethylene glycol was measured in resting state and during stimulation at 100/sec in squid giant axons. No detectable changes during electrical activity were observed.2. The influxes of urethane, tritiated water, ethylene glycol, urea and sodium were measured in internally perfused squid axons. Ethylene glycol and urea influxes were determined simultaneously with sodium influxes. The electrical stimulation of the fibre produced an increase in the influx of sodium but did not alter the influxes of the non-electrolytes listed above.3. Experiments were done with the combined voltage clamp-perfusion technique. The influxes of ethylene glycol and sodium were simultaneously measured in resting state and during maximum sodium current under stimulation at 10/sec. The influx of sodium increased in these conditions but the influx of ethylene glycol remained constant. In some experiments, the fibre was hyperpolarized to 10 or 20 mV, above the resting potential and the influxes of ethylene glycol and sodium were measured. The sodium influx decreased to 60% at 20 mV above the resting potential whereas the influx of ethylene glycol remained constant.4. These results indicate that in the giant axons of the squid Dosidicus gigas, sodium and non-electrolytes fluxes are not coupled.

Effect of stimulation and hyperpolarization on non-electrolyte and sodium permeability in perfused axons of squid

PubMed Central

Hidalgo, Cecilia; Latorre, Ramón

1970-01-01

1. The permeability for micro-injected [3H]ethylene glycol was measured in resting state and during stimulation at 100/sec in squid giant axons. No detectable changes during electrical activity were observed. 2. The influxes of urethane, tritiated water, ethylene glycol, urea and sodium were measured in internally perfused squid axons. Ethylene glycol and urea influxes were determined simultaneously with sodium influxes. The electrical stimulation of the fibre produced an increase in the influx of sodium but did not alter the influxes of the non-electrolytes listed above. 3. Experiments were done with the combined voltage clamp—perfusion technique. The influxes of ethylene glycol and sodium were simultaneously measured in resting state and during maximum sodium current under stimulation at 10/sec. The influx of sodium increased in these conditions but the influx of ethylene glycol remained constant. In some experiments, the fibre was hyperpolarized to 10 or 20 mV, above the resting potential and the influxes of ethylene glycol and sodium were measured. The sodium influx decreased to 60% at 20 mV above the resting potential whereas the influx of ethylene glycol remained constant. 4. These results indicate that in the giant axons of the squid Dosidicus gigas, sodium and non-electrolytes fluxes are not coupled. PMID:5500991

Does a bishop pray when he prays? And does his brain distinguish between different religions?

PubMed

Silveira, Sarita; Bao, Yan; Wang, Lingyan; Pöppel, Ernst; Avram, Mihai; Simmank, Fabian; Zaytseva, Yuliya; Blautzik, Janusch

2015-12-01

Does a religion shape belief-related decisions and influence neural processing? We investigated an eminent bishop of the Catholic Church in Germany by using functional magnetic resonance imaging (fMRI) to assess neural processing while he was responding to short sentences of the Christian Bible, the Islamic Quran, and the Daodejing ascribed to Laozi in Experiment 1. In Experiment 2, continuous praying was further compared to the resting state activity. In contrast to explicit statements of agreeing or not agreeing to different statements from the Bible and the Quran, we found in Experiment 1 no difference in neural activation when the bishop was reading these statements from the two religions. However, compared to reading statements from the Bible, reading statements from the Daodejing resulted in significantly higher activation in the left inferior and middle frontal cortices and the left middle temporal gyrus, although he equally agreed to both statements explicitly. In Experiment 2, no difference during continuous praying and the resting state activity was observed. Our results confirm the difference between explicit and implicit processing, and they suggest that a highly religious person may pray always-or never. On a more general level this observation suggests that ritualized activities might be subliminally represented in resting state activities. © 2015 The Institute of Psychology, Chinese Academy of Sciences and Wiley Publishing Asia Pty Ltd.

Parent Cardiac Response in the Context of Their Child’s Completion of the Cold Pressor Task: A Pilot Study

PubMed Central

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

Men exhibit greater fatigue resistance than women in alternated bench press and leg press exercises.

PubMed

Monteiro, Estêvão R; Steele, James; Novaes, Jefferson S; Brown, Amanda F; Cavanaugh, Mark T; Vingren, Jakob L; Behm, David G

2017-11-17

The purpose of this study was to evaluate the influence of sex, exercise order, and rest interval on neuromuscular fatigue resistance for an alternated strength training sequence of bench press (BP) and leg press (LP) exercises. Twelve women and 16 men, both recreationally trained, performed four sessions in a random order: 1) BP followed by LP with three-minutes rest (BP+LP with rest), 2) LP followed by BP with three-minutes rest (LP+BP with rest), 3) BP followed by LP without rest interval (BP+LP no rest), and 4) LP followed by BP without rest interval (LP+BP no rest). Participants performed four sets with 100% of 10RM load to concentric failure with the goal of completing the maximum number of repetitions in both exercises. The fatigue index was analyzed from the first and last sets of each exercise bout. A main effect for sex showed that women exhibited 25.5% (p=0.001) and 24.5% (p=0.001) greater BP and LP fatigue than men respectively when performing 10RM. Men exhibited greater BP (p<0.0001; 34.1%) and LP (p<0.0001; 30.5%) fatigue resistance when a rest period was provided. Men did not show an exercise order effect for BP fatigue and exhibited greater (p=0.0003; 14.5%) LP fatigue resistance when BP was performed first. The present study demonstrated the greater fatigue resistance of men when performing 10RM BP and LP exercises. Since men tend to experience less fatigue with the second exercise in the exercise pairing, women's training programs should be adjusted to ensure they do not parallel men's resistance training programs.

Decreasing ventromedial prefrontal cortex deactivation in risky decision making after simulated microgravity: effects of −6° head-down tilt bed rest

PubMed Central

Rao, Li-Lin; Zhou, Yuan; Liang, Zhu-Yuan; Rao, Henyi; Zheng, Rui; Sun, Yan; Tan, Cheng; Xiao, Yi; Tian, Zhi-Qiang; Chen, Xiao-Ping; Wang, Chun-Hui; Bai, Yan-Qiang; Chen, Shan-Guang; Li, Shu

2014-01-01

Space is characterized by risk and uncertainty. As humans play an important role in long-duration space missions, the ability to make risky decisions effectively is important for astronauts who spend extended time periods in space. The present study used the Balloon Analog Risk Task to conduct both behavioral and fMRI experiments to evaluate the effects of simulated microgravity on individuals' risk-taking behavior and the neural basis of the effect. The results showed that participants' risk-taking behavior was not affected by bed rest. However, we found that the ventromedial prefrontal cortex (VMPFC) showed less deactivation after bed rest and that the VMPFC activation in the active choice condition showed no significant difference between the win outcome and the loss outcome after bed rest, although its activation was significantly greater in the win outcome than in the loss outcome before bed rest. These results suggested that the participants showed a decreased level of value calculation after the bed rest. Our findings can contribute to a better understanding of the effect of microgravity on individual higher-level cognitive functioning. PMID:24904338

MAOA-a novel decision maker of apoptosis and autophagy in hormone refractory neuroendocrine prostate cancer cells

PubMed Central

Lin, Yi-Cheng; Chang, Yi-Ting; Campbell, Mel; Lin, Tzu-Ping; Pan, Chin-Chen; Lee, Hsin-Chen; Shih, Jean C.; Chang, Pei-Ching

2017-01-01

Autophagy and apoptosis are two well-controlled mechanisms regulating cell fate. An understanding of decision-making between these two pathways is in its infancy. Monoamine oxidase A (MAOA) is a mitochondrial enzyme that is well-known in psychiatric research. Emerging reports showed that overexpression MAOA is associated with prostate cancer (PCa). Here, we show that MAOA is involved in mediating neuroendocrine differentiation of PCa cells, a feature associated with hormone-refractory PCa (HRPC), a lethal type of disease. Following recent reports showing that NED of PCa requires down-regulation of repressor element-1 silencing transcription factor (REST) and activation of autophagy; we observe that MAOA is a novel direct target gene of REST. Reactive oxygen species (ROS) produced by overexpressed MAOA plays an essential role in inhibiting apoptosis and activating autophagy in NED PCa cells. MAOA inhibitors significantly reduced NED and autophagy activation of PCa cells. Our results here show MAOA as a new decision-maker for activating autophagy and MAOA inhibitors may be useful as a potential therapy for neuroendocrine tumors. PMID:28402333

MAOA-a novel decision maker of apoptosis and autophagy in hormone refractory neuroendocrine prostate cancer cells.

PubMed

Lin, Yi-Cheng; Chang, Yi-Ting; Campbell, Mel; Lin, Tzu-Ping; Pan, Chin-Chen; Lee, Hsin-Chen; Shih, Jean C; Chang, Pei-Ching

2017-04-12

Autophagy and apoptosis are two well-controlled mechanisms regulating cell fate. An understanding of decision-making between these two pathways is in its infancy. Monoamine oxidase A (MAOA) is a mitochondrial enzyme that is well-known in psychiatric research. Emerging reports showed that overexpression MAOA is associated with prostate cancer (PCa). Here, we show that MAOA is involved in mediating neuroendocrine differentiation of PCa cells, a feature associated with hormone-refractory PCa (HRPC), a lethal type of disease. Following recent reports showing that NED of PCa requires down-regulation of repressor element-1 silencing transcription factor (REST) and activation of autophagy; we observe that MAOA is a novel direct target gene of REST. Reactive oxygen species (ROS) produced by overexpressed MAOA plays an essential role in inhibiting apoptosis and activating autophagy in NED PCa cells. MAOA inhibitors significantly reduced NED and autophagy activation of PCa cells. Our results here show MAOA as a new decision-maker for activating autophagy and MAOA inhibitors may be useful as a potential therapy for neuroendocrine tumors.

Changes in intrinsic excitability of ganglion cells in degenerated retinas of RCS rats.

PubMed

Ren, Yi-Ming; Weng, Chuan-Huang; Zhao, Cong-Jian; Yin, Zheng-Qin

2018-01-01

To evaluate the intrinsic excitability of retinal ganglion cells (RGCs) in degenerated retinas. The intrinsic excitability of various morphologically defined RGC types using a combination of patch-clamp recording and the Lucifer yellow tracer in retinal whole-mount preparations harvested from Royal College of Surgeons (RCS) rats, a common retinitis pigmentosa (RP) model, in a relatively late stage of retinal degeneration (P90) were investigated. Several parameters of RGC morphologies and action potentials (APs) were measured and compared to those of non-dystrophic control rats, including dendritic stratification, dendritic field diameter, peak amplitude, half width, resting membrane potential, AP threshold, depolarization to threshold, and firing rates. Compared with non-dystrophic control RGCs, more depolarizations were required to reach the AP threshold in RCS RGCs with low spontaneous spike rates and in RCS OFF cells (especially A2o cells), and RCS RGCs maintained their dendritic morphologies, resting membrane potentials and capabilities to generate APs. RGCs are relatively well preserved morphologically and functionally, and some cells are more susceptible to decreased excitability during retinal degeneration. These findings provide valuable considerations for optimizing RP therapeutic strategies.

Adult neurogenesis and neuronal regeneration in the central nervous system of teleost fish.

PubMed

Zupanc, Günther K H; Sîrbulescu, Ruxandra F

2011-09-01

Teleost fish are distinguished by their ability to constitutively generate new neurons in the adult central nervous system ('adult neurogenesis'), and to regenerate whole neurons after injury ('neuronal regeneration'). In the brain, new neurons are produced in large numbers in several dozens of proliferation zones. In the spinal cord, proliferating cells are present in the ependymal layer and throughout the parenchyma. In the retina, new cells arise from the ciliary marginal zone and from Müller glia. Experimental evidence has suggested that both radial glia and non-glial cells can function as adult stem cells. The proliferative activity of these cells can be regulated by molecular factors, such as fibroblast growth factor and Notch, as well as by social and behavioral experience. The young cells may either reside near the respective proliferation zone, or migrate to specific target areas. Approximately half of the newly generated cells persist for the rest of the fish's life, and many of them differentiate into neurons. After injury, a massive surge of apoptotic cell death occurs at the lesion site within a few hours. Apoptosis is followed by a marked increase in cell proliferation and neurogenesis, leading to repair of the tissue. The structural regeneration is paralleled by partial or complete recovery of function. Recent investigations have led to the identification of several dozens of molecular factors that are potentially involved in the process of regeneration. © 2011 The Authors. European Journal of Neuroscience © 2011 Federation of European Neuroscience Societies and Blackwell Publishing Ltd.

Mammalian transcription factor LSF is a target of ERK signaling

PubMed Central

Pagon, Zrinka; Volker, Janet; Cooper, Geoffrey M.; Hansen, Ulla

2012-01-01

LSF is a mammalian transcription factor that is rapidly and quantitatively phosphorylated upon growth induction of resting, peripheral human T cells, as assayed by a reduction in its electrophoretic mobility. The DNA-binding activity of LSF in primary T cells is greatly increased after this phosphorylation event [Volker et al., 1997]. We demonstrate here that LSF is also rapidly and quantitatively phosphorylated upon growth induction in NIH 3T3 cells, although its DNA-binding activity is not significantly altered. Three lines of experimentation established that ERK is responsible for phosphorylating LSF upon growth induction in both cell types. First, phosphorylation of LSF by ERK is sufficient to cause the reduced electrophoretic mobility of LSF. Second, the amount of ERK activity correlates with the extent of LSF phosphorylation in both primary human T cells and NIH 3T3 cells. Finally, specific inhibitors of the Ras/Raf/MEK/ERK pathway inhibit LSF modification in vivo. This phosphorylation by ERK is not sufficient for activation of LSF DNA-binding activity, as evidenced both in vitro and in mouse fibroblasts. Nonetheless, activation of ERK is a prerequisite for the substantial increase in LSF DNA-binding activity upon activation of resting T cells, indicating that ERK phosphorylation is necessary but not sufficient for activation of LSF in this cell type. PMID:12858339

Investigation of biochemical property changes in activation-induced CD 8 + T cell apoptosis using Raman spectroscopy

NASA Astrophysics Data System (ADS)

Lee, Young Ju; Ahn, Hyung Joon; Lee, Gi-Ja; Jung, Gyeong Bok; Lee, Gihyun; Kim, Dohyun; Shin, Jae-Ho; Jin, Kyung-Hyun; Park, Hun-Kuk

2015-07-01

The study was to investigate the changes in biochemical properties of activated mature CD8+ T cells related to apoptosis at a molecular level. We confirmed the activation and apoptosis of CD8+ T cells by fluorescence-activated cell sorting and atomic force microscopy and then performed Raman spectral measurements on activated mature CD8+ T cells and cellular deoxyribose nucleic acid (DNA). In the activated mature CD8+ T cells, there were increases in protein spectra at 1002 and 1234 cm-1. In particular, to assess the apoptosis-related DNA spectral signatures, we investigated the spectra of the cellular DNA isolated from resting and activated mature CD8+ T cells. Raman spectra at 765 to 786 cm-1 and 1053 to 1087 cm-1 were decreased in activated mature DNA. In addition, we analyzed Raman spectrum using the multivariate statistical method including principal component analysis. Raman spectra of activated mature DNA are especially well-discriminated from those of resting DNA. Our findings regarding the biochemical and structural changes associated with apoptosis in activated mature T cells and cellular DNA according to Raman spectroscopy provide important insights into allospecific immune responses generated after organ transplantation, and may be useful for therapeutic manipulation of the immune response.

An electrophysiological study on the effects of Pa-1G (a phospholipase A(2)) from the venom of king brown snake, Pseudechis australis, on neuromuscular function.

PubMed

Fatehi, M; Rowan, E G; Harvey, A L

2002-01-01

The effects of Pa-1G, a phospholipase A(2) (PLA(2)) from the venom of the Australian king brown snake (Pseudechis australis) were determined on the release of acetylcholine, muscle resting membrane potential and motor nerve terminal action potential at mouse neuromuscular junction. Intracellular recording from endplate regions of mouse triangularis sterni nerve-muscle preparations revealed that Pa-1G (800 nM) significantly reduced the amplitude of endplate potentials within 10 min exposure. The quantal content of endplate potentials was decreased to 58+/-6% of control after 30 min exposure to 800 nM Pa-1G. The toxin also caused a partial depolarisation of mouse muscle fibres within 60 min exposure. Extracellular recording of action potentials at motor nerve terminals showed that Pa-1G reduced the waveforms associated with both sodium and potassium conductances. To investigate whether this was a direct or indirect effect of the toxin on these ionic currents, whole cell patch clamp experiments were performed using human neuroblastoma (SK-N-SH) cells and B82 mouse fibroblasts stably transfected with rKv1.2. Patch clamp recording experiments confirmed that potassium currents sensitive to alpha-dendrotoxin recorded from B82 cells and sodium currents in SK-N-SH cells were not affected by the toxin. Since neither facilitation of acetylcholine release at mouse neuromuscular junction nor depression of potassium currents in B82 cells has been observed, the apparent blockade of potassium currents at mouse motor nerve endings induced by the toxin is unlikely to be due to a selective block of potassium channels.

Nerve Impulses in Plants

ERIC Educational Resources Information Center

Blatt, F. J.

1974-01-01

Summarizes research done on the resting and action potential of nerve impulses, electrical excitation of nerve cells, electrical properties of Nitella, and temperature effects on action potential. (GS)

Resting lymphocyte transduction with measles virus glycoprotein pseudotyped lentiviral vectors relies on CD46 and SLAM

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhou Qi; Schneider, Irene C.; Gallet, Manuela

2011-05-10

The measles virus (MV) glycoproteins hemagglutinin (H) and fusion (F) were recently shown to mediate transduction of resting lymphocytes by lentiviral vectors. MV vaccine strains use CD46 or signaling lymphocyte activation molecule (SLAM) as receptor for cell entry. A panel of H protein mutants derived from vaccine strain or wild-type MVs that lost or gained CD46 or SLAM receptor usage were investigated for their ability to mediate gene transfer into unstimulated T lymphocytes. The results demonstrate that CD46 is sufficient for efficient vector particle association with unstimulated lymphocytes. For stable gene transfer into these cells, however, both MV receptors weremore » found to be essential.« less

Combining regio- and enantioselectivity of lipases for the preparation of (R)-4-chloro-2-butanol.

PubMed

Méndez, Jonh J; Oromi, Mireia; Cervero, Maria; Balcells, Mercè; Torres, Mercè; Canela, Ramon

2007-01-01

Preparation of 98% ee (R)-4-chloro-2-butanol was carried out by the enzymatic hydrolysis of chlorohydrin esters, using fungal resting cells and commercial enzymes. Hydrolyzes were carried out using lipases from Candida antarctica (Novozym 435), C. rugosa, Rhizomucor miehei (Lipozyme IM), Burkolia cepacia, and resting cells of Rhizopus oryzae and Aspergillus flavus. The influence of the enzyme, the solvent, the temperature, and the alkyl chain length on the selectivity of hydrolyzes of isomeric mixtures of chlorohydrin esters is described. Regioselectivity was higher than 95% for some of the tested lipases. Novozym 435 allowed preparation of the (R)-4-chloro-2-butanol after 15 min of reaction at 30-40 degrees C. (c) 2006 Wiley-Liss, Inc.

Assessment of Immune Status, Latent Viral Reactivation and Stress during Long Duration Bed Rest as an Analog for Spaceflight

NASA Technical Reports Server (NTRS)

Crucian, Brian E.; Stowe, Raymond P.; Mehta, Satish K.; Yetman, Deborah L.; Leaf, Melanie J.; Pierson, Duane L.; Sams, Clarence F.

2007-01-01

As logistical access for in-flight space research becomes more limited, the use of ground based spaceflight analogs for life science studies will increase. These studies are particularly important as NASA progresses towards the Lunar and eventually Mars missions outlined in the 2005 Vision for Space Exploration. Countermeasures must be developed to mitigate the clinical risks associated with exploration class space missions. In an effort to coordinate studies across multiple disciplines, NASA has selected 90-day bed rest as the analog of choice, and initiated the Flight Analogs Project to implement research studies with or without the evaluation of countermeasures. Although bed rest is not the analog of choice to evaluate spaceflight-associated immune dysfunction, a standard Immune Assessment was developed for subjects participating in the 90-day bed best studies. The Immune Assessment consists of: leukocyte subset distribution, T cell functional responses, intracellular cytokine production profiles, latent viral reactivation, virus specific T cell levels, virus specific T cell function, stress hormone levels and a behavioral assessment using stress questionnaires. The purpose of the assessment during the initial studies (without countermeasure) is to establish control data against which future studies (with countermeasure) will be evaluated. It is believed that some of the countermeasures planned to be evaluated in future studies, such as exercise, pharmacologic intervention or nutritional supplementation, have the ability to impact immune function. Therefore immunity will likely be monitored during those studies. The data generated during the first three control studies showed that the subjects in general did not display altered peripheral leukocyte subsets, constitutive immune activation, significant latent viral reactivation (EBV, VZV) or altered T cell function. Interestingly, for some subjects the level of constitutively activated T cells (CD8+/CD69+) and virus-specific T cells (CMV and EBV) both decreased during the studies. This likely reflects the isolation of the subjects (from an immunological perspective) and absence of everyday subclinical challenges to the immune system. Cortisol levels (plasma and saliva) did not vary significantly during the studies. This probably reflects a lack of physiological stress during the study and the stress of readaptation to the 1xG environment at R+1. These data demonstrate the absence of significant immune alteration during 90-day bed rest, and establish control data against which future studies (including countermeasures) may be compared.

Effect of reconstructive vascular surgery on red cell deformability--preliminary results.

PubMed Central

Irwin, S T; Rocks, M J; McGuigan, J A; Patterson, C C; Morris, T C; O'Reilly, M J

1983-01-01

Using a simple filtration method, red cell deformability was measured in healthy control subjects and in patients with peripheral vascular disease. Impaired red cell deformability was demonstrated in patients with rest pain or gangrene and in patients with intermittent claudication. An improvement in red cell deformability was demonstrated after successful reconstructive vascular surgery in both patient groups. An improvement in red cell deformability was demonstrated in patients undergoing major limb amputation. PMID:6619311

Mixed Signals.

ERIC Educational Resources Information Center

Danforth, Eric L.

2003-01-01

According to the Education Commission of the States, 14 states prohibit pagers and/or cell phones in schools, 8 states have repealed bans, and the rest have no statutes on the issue. Ten states, including some that have repealed bans, grant policymaking authority to local boards. Presents arguments pro and con on cell phones and school district…

Measuring alterations in oscillatory brain networks in schizophrenia with resting-state MEG: State-of-the-art and methodological challenges.

PubMed

Alamian, Golnoush; Hincapié, Ana-Sofía; Pascarella, Annalisa; Thiery, Thomas; Combrisson, Etienne; Saive, Anne-Lise; Martel, Véronique; Althukov, Dmitrii; Haesebaert, Frédéric; Jerbi, Karim

2017-09-01

Neuroimaging studies provide evidence of disturbed resting-state brain networks in Schizophrenia (SZ). However, untangling the neuronal mechanisms that subserve these baseline alterations requires measurement of their electrophysiological underpinnings. This systematic review specifically investigates the contributions of resting-state Magnetoencephalography (MEG) in elucidating abnormal neural organization in SZ patients. A systematic literature review of resting-state MEG studies in SZ was conducted. This literature is discussed in relation to findings from resting-state fMRI and EEG, as well as to task-based MEG research in SZ population. Importantly, methodological limitations are considered and recommendations to overcome current limitations are proposed. Resting-state MEG literature in SZ points towards altered local and long-range oscillatory network dynamics in various frequency bands. Critical methodological challenges with respect to experiment design, and data collection and analysis need to be taken into consideration. Spontaneous MEG data show that local and global neural organization is altered in SZ patients. MEG is a highly promising tool to fill in knowledge gaps about the neurophysiology of SZ. However, to reach its fullest potential, basic methodological challenges need to be overcome. MEG-based resting-state power and connectivity findings could be great assets to clinical and translational research in psychiatry, and SZ in particular. Copyright © 2017 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.

Clinical physiology of bed rest

NASA Technical Reports Server (NTRS)

Greenleaf, John E.

1993-01-01

Maintenance of optimal health in humans requires the proper balance between exercise, rest, and sleep as well as time in the upright position. About one-third of a lifetime is spent sleeping; and it is no coincidence that sleeping is performed in the horizontal position, the position in which gravitational influence on the body is minimal. Although enforced bed rest is necessary for the treatment of some ailments, in some cases it has probably been used unwisely. In addition to the lower hydrostatic pressure with the normally dependent regions of the cardiovascular system, body fuid compartments during bed rest in the horizontal body position, and virtual elimination of compression on the long bones of the skeletal system during bed rest (hypogravia), there is often reduction in energy metabolism due to the relative confinement (hypodynamia) and alteration of ambulatory circadian variations in metabolism, body temperature, and many hormonal systems. If patients are also moved to unfamiliar surroundings, they probably experience some feelings of anxiety and some sociopsychological problems. Adaptive physiological responses during bed rest are normal for that environment. They are attempts by the body to reduce unnecessary energy expenditure, to optimize its function, and to enhance its survival potential. Many of the deconditioning responses begin within the first day or two of bed rest; these early responses have prompted physicians to insist upon early resumption of the upright posture and ambulation of bedridden patients.

Combining eicosapentaenoic acid, decosahexaenoic acid and arachidonic acid, using a fully crossed design, affect gene expression and eicosanoid secretion in salmon head kidney cells in vitro.

PubMed

Holen, Elisabeth; He, Juyun; Espe, Marit; Chen, Liqiou; Araujo, Pedro

2015-08-01

Future feed for farmed fish are based on untraditional feed ingredients, which will change nutrient profiles compared to traditional feed based on marine ingredients. To understand the impact of oils from different sources on fish health, n-6 and n-3 polyunsaturated fatty acids (PUFAs) were added to salmon head kidney cells, in a fully crossed design, to monitor their individual and combined effects on gene expression. Exposing salmon head kidney cells to single fatty acids, arachidonic acid (AA) or decosahexaenoic acid (DHA), resulted in down-regulation of cell signaling pathway genes and specific fatty acid metabolism genes as well as reduced prostaglandin E2 (PGE2) secretion. Eicosapentaenoic acid (EPA) had no impact on gene transcription in this study, but reduced the cell secretion of PGE2. The combined effect of AA + EPA resulted in up-regulation of eicosanoid pathway genes and the pro-inflammatory cytokine, tumor necrosis factor alpha (TNF-α), Bclx (an inducer of apoptosis) and fatty acid translocase (CD36) as well as increased cell secretion of PGE2 into the media. Adding single fatty acids to salmon head kidney cells decreased inflammation markers in this model. The combination AA + EPA acted differently than the rest of the fatty acid combinations by increasing the inflammation markers in these cells. The concentration of fatty acid used in this experiment did not induce any lipid peroxidation responses. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effects of nifedipine on anorectal smooth muscle in vitro.

PubMed

Cook, T A; Brading, A F; Mortensen, N J

1999-06-01

Glyceryl trinitrate reduces anal resting pressure and aids the healing of anal fissures. However, some patients develop tachyphylaxis and the fissure fails to heal, suggesting that other agents are needed. This study assesses the effects of nifedipine (a calcium channel antagonist) in modulating resting tone and agonist-induced contractions in human internal anal sphincter (IAS) and rectal circular muscle. Smooth muscle strips from the IAS and rectal circular muscle from ten patients undergoing surgical resection were mounted for isometric tension recording in a superfusion organ bath. The effects of noradrenaline and carbachol were assessed in the presence of various perfusates. LAS strips developed tone and spontaneous activity. Noradrenaline produced dose-dependent contractions. In calcium-free Krebs solution, tone and activity were abolished and no contractions were elicited in response to noradrenaline. Nifedipine also abolished tone and spontaneous activity, but contractions to noradrenaline were only slightly attenuated. In contrast, rectal smooth muscle strips developed spontaneous activity but no resting tone and contracted in response to carbachol. In calcium-free Krebs solution, the spontaneous activity and carbachol contractions were abolished. Addition of nifedipine to the perfusate abolished spontaneous activity and greatly reduced contractions. These data suggest that spontaneous activity and resting tone are dependent on extracellular calcium and flux across the cells. Agonist-induced contraction in the IAS is attributable mainly to the release of calcium from intracellular stores, whereas rectal circular smooth muscle depends principally on extracellular calcium entering the cell for contraction. The attenuation of contractions in both tissues and the abolition of resting tone in the IAS suggest that nifedipine may be useful in the management of patients with anorectal disorders.

Normal Muscle Oxygen Consumption and Fatigability in Sickle Cell Patients Despite Reduced Microvascular Oxygenation and Hemorheological Abnormalities

PubMed Central

Waltz, Xavier; Pichon, Aurélien; Lemonne, Nathalie; Mougenel, Danièle; Lalanne-Mistrih, Marie-Laure; Lamarre, Yann; Tarer, Vanessa; Tressières, Benoit; Etienne-Julan, Maryse; Hardy-Dessources, Marie-Dominique; Hue, Olivier; Connes, Philippe

2012-01-01

Background/Aim Although it has been hypothesized that muscle metabolism and fatigability could be impaired in sickle cell patients, no study has addressed this issue. Methods We compared muscle metabolism and function (muscle microvascular oxygenation, microvascular blood flow, muscle oxygen consumption and muscle microvascular oxygenation variability, which reflects vasomotion activity, maximal muscle force and local muscle fatigability) and the hemorheological profile at rest between 16 healthy subjects (AA), 20 sickle cell-hemoglobin C disease (SC) patients and 16 sickle cell anemia (SS) patients. Results Muscle microvascular oxygenation was reduced in SS patients compared to the SC and AA groups and this reduction was not related to hemorhelogical abnormalities. No difference was observed between the three groups for oxygen consumption and vasomotion activity. Muscle microvascular blood flow was higher in SS patients compared to the AA group, and tended to be higher compared to the SC group. Multivariate analysis revealed that muscle oxygen consumption was independently associated with muscle microvascular blood flow in the two sickle cell groups (SC and SS). Finally, despite reduced muscle force in sickle cell patients, their local muscle fatigability was similar to that of the healthy subjects. Conclusions Sickle cell patients have normal resting muscle oxygen consumption and fatigability despite hemorheological alterations and, for SS patients only, reduced muscle microvascular oxygenation and increased microvascular blood flow. Two alternative mechanisms can be proposed for SS patients: 1) the increased muscle microvascular blood flow is a way to compensate for the lower muscle microvascular oxygenation to maintain muscle oxygen consumption to normal values or 2) the reduced microvascular oxygenation coupled with a normal resting muscle oxygen consumption could indicate that there is slight hypoxia within the muscle which is not sufficient to limit mitochondrial respiration but increases muscle microvascular blood flow. PMID:23285055

B Cells and B Cell Blasts Withstand Cryopreservation While Retaining Their Functionality for Producing Antibody.

PubMed

Fecher, Philipp; Caspell, Richard; Naeem, Villian; Karulin, Alexey Y; Kuerten, Stefanie; Lehmann, Paul V

2018-05-31

In individuals who have once developed humoral immunity to an infectious/foreign antigen, the antibodies present in their body can mediate instant protection when the antigen re-enters. Such antigen-specific antibodies can be readily detected in the serum. Long term humoral immunity is, however, also critically dependent on the ability of memory B cells to engage in a secondary antibody response upon re-exposure to the antigen. Antibody molecules in the body are short lived, having a half-life of weeks, while memory B cells have a life span of decades. Therefore, the presence of serum antibodies is not always a reliable indicator of B cell memory and comprehensive monitoring of humoral immunity requires that both serum antibodies and memory B cells be assessed. The prevailing view is that resting memory B cells and B cell blasts in peripheral blood mononuclear cells (PBMC) cannot be cryopreserved without losing their antibody secreting function, and regulated high throughput immune monitoring of B cell immunity is therefore confined to-and largely limited by-the need to test freshly isolated PBMC. Using optimized protocols for freezing and thawing of PBMC, and four color ImmunoSpot ® analysis for the simultaneous detection of all immunoglobulin classes/subclasses we show here that both resting memory B cells and B cell blasts retain their ability to secrete antibody after thawing, and thus demonstrate the feasibility of B cell immune monitoring using cryopreserved PBMC.

Hypervolemia from Drinking Hyperhydration Solutions at Rest and Exercise

NASA Technical Reports Server (NTRS)

Greenleaf, John E.; Looft-Wilson, Robin; Jackson, Catherine G. R.; Geelen, Ghislaine; Barnes, Paul R.; Jensen, Christopher D.; Whittam, James H.

1995-01-01

The mechanism of muscular fatigue from physical work and exercise (high metabolism) is not clear, but involves disturbances of muscle surface membrane excitation-contraction coupling from changes in sarcoplasmic reticulum Ca2+ release, cell H+ and Pi responses, and carbohydrate metabolism. Fatigue in people at rest (low metabolism) involves both psychological and physiological factors, probably in different proportions. One common factor appears to be the level and distribution of water and electrolytes within muscle cells and other vascular, interstitial, body fluid compartments. The vascular fluid volume, composed of plasma and red blood cells, is a primary regulatory factor for cardiovascular function; reduction of vascular volume (hypovolemia) and total body water (hypohydration) adversely affect exercise performance. Plasma volume and plasma ionic-osmotic constituent concentrations are also regulatory factors for body thermoregulation, which is often compromised from exercise induced hypovolemia and hypohydration. Rehydration of dehydrated people on earth is relatively easy with appropriate food (osmols), fluid, and a restful environment. But ad libitum drinking under stressful conditions; e.g., heat, exercise, or prior dehydration, results in involuntary dehydration defined as the delay in full fluid replacement (euhydration) during and following loss of body fluid. Astronauts, with their reduced total body water are euhydrated while in weightlessness, but become "dehydrated" during reentry and landing. Thus, people subjected to acute or chronic stress are probably somewhat "dehydrated" as well as fatigued. Many rehydration drinks are more concentrated (hypertonic-hyperosmotic) with respect to the normal plasma osmolality of 285 mOsm/kg H2O and more of the drink osmols are contributed by carbohydrates than by ionized substances. There have been few studies on the efficacy of various drink formulations for increasing body fluid compartment volumes, especially plasma volume, in rested hydrated subjects. Recent findings from our laboratory have indicated that drinks containing greater concentrations of ionized substances (Performance 1 and AstroAde) up to 157 mEq/L Na+ induced greater levels of hypervolemia in resting, moderately dehydrated men, and were also better than water for attenuating the characteristic hypovolemia during supine, submaximal, leg ergometer exercise.

Rest Intervals Reduce the Number of Loading Bouts Required to Enhance Bone Formation

PubMed Central

Srinivasan, Sundar; Ausk, Brandon J.; Bain, Steven D.; Gardiner, Edith M.; Kwon, Ronald Y.; Gross, Ted S.

2015-01-01

Purpose As our society becomes increasingly sedentary, compliance with exercise regimens that require numerous high-energy activities each week become less likely. Alternatively, given an osteogenic exercise intervention that required minimal effort, it is reasonable to presume that participation would be enhanced. Insertion of brief rest-intervals between each cycle of mechanical loading holds potential to achieve this result as substantial osteoblast function is activated by many fewer loading repetitions within each loading bout. Here, we examined the complementary hypothesis that the number of bouts/wk of rest-inserted loading could be reduced from 3/wk without loss of osteogenic efficacy. Methods We conducted a series of 3 wk in vivo experiments that non-invasively exposed the right tibiae of mice to either cyclic (1 Hz) or rest-inserted loading interventions and quantified osteoblast function via dynamic histomorphometry. Results While reducing loading bouts from 3/wk (i.e., 9 total bouts) to 1/wk (3 total bouts) effectively mitigated the osteogenic benefit of cyclic loading, the same reduction did not significantly reduce periosteal bone formation parameters induced by rest-inserted loading. The osteogenic response was robust to the timing of the rest-inserted loading bouts (3 bouts in the first week vs 1 bout/wk for three weeks). However, elimination of any single bout of the three 1/wk bouts mitigated the osteogenic response to rest-inserted loading. Finally, periosteal osteoblast function assessed after the 3 wk intervention was not sensitive to the timing or number of rest-inserted loading bouts. Conclusions We conclude that rest-inserted loading holds potential to retain the osteogenic benefits of mechanical loading with significantly reduced frequency of bouts of activity while also enabling greater flexibility in the timing of the activity. PMID:25207932

Changes of Cytokines during a Spaceflight Analog - a 45-Day Head-Down Bed Rest

PubMed Central

Zhang, Shusong; Pang, Xuewen; Liu, Hongju; Li, Li; Sun, Xiuyuan; Zhang, Yu; Wu, Hounan; Chen, Xiaoping; Ge, Qing

2013-01-01

Spaceflight is associated with deregulation in the immune system. Head-down bed rest (HDBR) at -6° is believed to be the most practical model for examining multi-system responses to microgravity in humans during spaceflight. In the present study, a 45-day HDBR was performed to investigate the alterations in human immune cell distributions and their functions in response to various stimuli. The effect of countermeasure, Rhodiola rosea (RR) treatment, was also examined. A significant decrease of interferon-γ (IFN-γ) and interleukin-17 (IL-17) productions by activated T cells, increase of IL-1β and IL-18 by activated B and myeloid cells were observed during HDBR. The upregulation of serum cortisol was correlated with the changes of IL-1 family cytokines. In addition, a significant increase of memory T and B cell and regulatory T cells (Treg) were also detected. The uptake of RR further decreased IFN-γ level and slowed down the upregulation of IL-1 family cytokines. These data suggest that for prolonged HDBR and spaceflight, the decreased protective T cell immunity and enhanced proinflammatory cytokines should be closely monitored. The treatment with RR may play an important role in suppressing proinflammatory cytokines but not in boosting protective T cell immunity. PMID:24143230

Mechanisms of HIV persistence in HIV reservoirs.

PubMed

Mzingwane, Mayibongwe L; Tiemessen, Caroline T

2017-03-01

The establishment and maintenance of HIV reservoirs that lead to persistent viremia in patients on antiretroviral drugs remains the greatest challenge of the highly active antiretroviral therapy era. Cellular reservoirs include resting memory CD4+ T lymphocytes, implicated as the major HIV reservoir, having a half-life of approximately 44 months while this is less than 6 hours for HIV in plasma. In some individuals, persistent viremia consists of invariant HIV clones not detected in circulating resting CD4+ T lymphocytes suggesting other possible sources of residual viremia. Some anatomical reservoirs that may harbor such cells include the brain and the central nervous system, the gastrointestinal tract and the gut-associated lymphoid tissue and other lymphoid organs, and the genital tract. The presence of immune cells and other HIV susceptible cells, occurring in differing compositions in anatomical reservoirs, coupled with variable and poor drug penetration that results in suboptimal drug concentrations in some sites, are all likely factors that fuel the continued low-level replication and persistent viremia during treatment. Latently, HIV-infected CD4+ T cells harboring replication-competent virus, HIV cell-to-cell spread, and HIV-infected T cell homeostatic proliferation due to chronic immune activation represent further drivers of this persistent HIV viremia during highly active antiretroviral therapy. Copyright © 2017 John Wiley & Sons, Ltd.

The Role of Graphic Orientations in Children's Drawings of Familiar and Novel Objects at Rest and in Motion.

ERIC Educational Resources Information Center

Ives, William; Rovet, Joanne

1979-01-01

Reports three experiments which investigate: whether familiar objects have standard graphic orientations (Experiment 1); the relationship between use of object orientations and more conventional methods in depicting familiar objects in motion (Experiment 2); and whether orientations are used differently in novel objects whose only defining feature…

Cardiovascular consequences of bed rest: effect on maximal oxygen uptake

NASA Technical Reports Server (NTRS)

Convertino, V. A.

1997-01-01

Maximal oxygen uptake (VO2max) is reduced in healthy individuals confined to bed rest, suggesting it is independent of any disease state. The magnitude of reduction in VO2max is dependent on duration of bed rest and the initial level of aerobic fitness (VO2max), but it appears to be independent of age or gender. Bed rest induces an elevated maximal heart rate which, in turn, is associated with decreased cardiac vagal tone, increased sympathetic catecholamine secretion, and greater cardiac beta-receptor sensitivity. Despite the elevation in heart rate, VO2max is reduced primarily from decreased maximal stroke volume and cardiac output. An elevated ejection fraction during exercise following bed rest suggests that the lower stroke volume is not caused by ventricular dysfunction but is primarily the result of decreased venous return associated with lower circulating blood volume, reduced central venous pressure, and higher venous compliance in the lower extremities. VO2max, stroke volume, and cardiac output are further compromised by exercise in the upright posture. The contribution of hypovolemia to reduced cardiac output during exercise following bed rest is supported by the close relationship between the relative magnitude (% delta) and time course of change in blood volume and VO2max during bed rest, and also by the fact that retention of plasma volume is associated with maintenance of VO2max after bed rest. Arteriovenous oxygen difference during maximal exercise is not altered by bed rest, suggesting that peripheral mechanisms may not contribute significantly to the decreased VO2max. However reduction in baseline and maximal muscle blood flow, red blood cell volume, and capillarization in working muscles represent peripheral mechanisms that may contribute to limited oxygen delivery and, subsequently, lowered VO2max. Thus, alterations in cardiac and vascular functions induced by prolonged confinement to bed rest contribute to diminution of maximal oxygen uptake and reserve capacity to perform physical work.

Protein turnover, amino acid requirements and recommendations for athletes and active populations

PubMed Central

Poortmans, J.R.; Carpentier, A.; Pereira-Lancha, L.O.; Lancha, A.

2012-01-01

Skeletal muscle is the major deposit of protein molecules. As for any cell or tissue, total muscle protein reflects a dynamic turnover between net protein synthesis and degradation. Noninvasive and invasive techniques have been applied to determine amino acid catabolism and muscle protein building at rest, during exercise and during the recovery period after a single experiment or training sessions. Stable isotopic tracers (13C-lysine, 15N-glycine, 2H5-phenylalanine) and arteriovenous differences have been used in studies of skeletal muscle and collagen tissues under resting and exercise conditions. There are different fractional synthesis rates in skeletal muscle and tendon tissues, but there is no major difference between collagen and myofibrillar protein synthesis. Strenuous exercise provokes increased proteolysis and decreased protein synthesis, the opposite occurring during the recovery period. Individuals who exercise respond differently when resistance and endurance types of contractions are compared. Endurance exercise induces a greater oxidative capacity (enzymes) compared to resistance exercise, which induces fiber hypertrophy (myofibrils). Nitrogen balance (difference between protein intake and protein degradation) for athletes is usually balanced when the intake of protein reaches 1.2 g·kg−1·day−1 compared to 0.8 g·kg−1·day−1 in resting individuals. Muscular activities promote a cascade of signals leading to the stimulation of eukaryotic initiation of myofibrillar protein synthesis. As suggested in several publications, a bolus of 15-20 g protein (from skimmed milk or whey proteins) and carbohydrate (± 30 g maltodextrine) drinks is needed immediately after stopping exercise to stimulate muscle protein and tendon collagen turnover within 1 h. PMID:22666780

Implication of Highly Cytotoxic Natural Killer Cells for Esophageal Squamous Cell Carcinoma Treatment.

PubMed

Lim, Kee Siang; Mimura, Kosaku; Kua, Ley-Fang; Shiraishi, Kensuke; Kono, Koji

2018-04-20

Esophageal squamous cell carcinoma (ESCC) is an aggressive upper gastrointestinal cancer and effective treatments are limited. Previous studies reported that natural killer (NK) cells expanded by coculturing with K562-mb15-41BBL feeder cells, a genetically modified K562 leukemia cell line that expresses membrane-bound interleukin (IL)-15 and 41BBL ligand, were highly proliferative and highly cytotoxic. Here, we investigated the potential of expanded NK cells for ESCC treatment. We analyzed both genetic and surface expression levels of NKG2D ligands (NKG2DLs) in ESCC using publicly available microarray data sets and ESCC cell lines. The cytotoxicity of resting and of IL-2-activated NK cells against ESCC cell lines was compared with that of expanded NK cells. We then also investigated the effect of epithelial mesenchymal transition (EMT) inducers, GSK3β inhibitor and epidermal growth factor, on NKG2DLs expressions. As a result, MICA and MICB were significantly overexpressed in ESCC compared with adjacent normal tissues and surface NKG2DLs were expressed in ESCC cell lines. Expanded NK cells were much potent than IL-2-activated and resting NK cells against ESCC cell lines. Blocking of NKG2D with anti-NKG2D monoclonal antibody dampened expanded NK cell cytotoxicity, suggesting that the NKG2DLs-NKG2D interaction is crucial for NK cells to eliminate ESCC cells. EMT inducers concurrently induced EMT and NKG2DLs expression in ESCC cell lines rendering transitioned cells more sensitive to expanded NK cells. In conclusion, expanded NK cells were highly cytotoxic against NKG2DLs-expressing ESCC cells, particularly the EMT phenotype. These results provide a strong rationale for clinical use of these NK cells in ESCC patients.

The CB1 Neutral Antagonist Tetrahydrocannabivarin Reduces Default Mode Network and Increases Executive Control Network Resting State Functional Connectivity in Healthy Volunteers.

PubMed

Rzepa, Ewelina; Tudge, Luke; McCabe, Ciara

2015-09-10

The cannabinoid cannabinoid type 1 (CB1) neutral antagonist tetrahydrocannabivarin (THCv) has been suggested as a possible treatment for obesity, but without the depressogenic side-effects of inverse antagonists such as Rimonabant. However, how THCv might affect the resting state functional connectivity of the human brain is as yet unknown. We examined the effects of a single 10mg oral dose of THCv and placebo in 20 healthy volunteers in a randomized, within-subject, double-blind design. Using resting state functional magnetic resonance imaging and seed-based connectivity analyses, we selected the amygdala, insula, orbitofrontal cortex, and dorsal medial prefrontal cortex (dmPFC) as regions of interest. Mood and subjective experience were also measured before and after drug administration using self-report scales. Our results revealed, as expected, no significant differences in the subjective experience with a single dose of THCv. However, we found reduced resting state functional connectivity between the amygdala seed region and the default mode network and increased resting state functional connectivity between the amygdala seed region and the dorsal anterior cingulate cortex and between the dmPFC seed region and the inferior frontal gyrus/medial frontal gyrus. We also found a positive correlation under placebo for the amygdala-precuneus connectivity with the body mass index, although this correlation was not apparent under THCv. Our findings are the first to show that treatment with the CB1 neutral antagonist THCv decreases resting state functional connectivity in the default mode network and increases connectivity in the cognitive control network and dorsal visual stream network. This effect profile suggests possible therapeutic activity of THCv for obesity, where functional connectivity has been found to be altered in these regions. © The Author 2015. Published by Oxford University Press on behalf of CINP.

Neuron-Glia Interactions and Nervous System Homeostasis

DTIC Science & Technology

1988-06-01

active neuron states, the mechanisms which glial cells and neurons use to modulate each others metabolic state and the chemical, electrical and... mechanisms by which axons/neurons and their glial cell investments communicate to actively regulate the ionic microenvironment of the nervous system and...of the glial cell in maintenance of the ionic homeostasis of the perineural environment during resting and active neuron states, the mechanisms which

Fail-safe designs for large capacity battery systems

DOEpatents

Kim, Gi-Heon; Smith, Kandler; Ireland, John; Pesaran, Ahmad A.; Neubauer, Jeremy

2016-05-17

Fail-safe systems and design methodologies for large capacity battery systems are disclosed. The disclosed systems and methodologies serve to locate a faulty cell in a large capacity battery, such as a cell having an internal short circuit, determine whether the fault is evolving, and electrically isolate the faulty cell from the rest of the battery, preventing further electrical energy from feeding into the fault.

[Natural killer cell cytotoxic activity in critical pediatric patients with suspected hemophagocytic syndrome].

PubMed

Martínez, I; Fernández, L; Valentín, J; Castillo, C; Chamorro, C; Pérez-Martínez, A

2015-05-01

To determine the role of natural killer (NK) cytotoxic activity in patients with suspected hemophagocytic lymphohistiocytosis syndrome (HLH). A prospective study was conducted from September 2008 to February 2014. The study was carried out in the Hematological Oncology Laboratory of Hospital Infantil Universitario Niño Jesús, Madrid (Spain). We analyzed 30 peripheral blood samples from intensive care patients with suspected HLH. There were 18 males and 12 females, with a mean age of 4.7 years (range 0.2-22). NK cell cytotoxicity was compared with healthy controls according to age and sex. In vitro NK cell cytotoxicity against the K562 cell line was determined by time-resolved fluorescence (Europium-TDA) under resting conditions, after interleukin 15 stimulation, and following block with Fas ligand antibody. NK cell cytotoxicity. A total of 20 patients showed a significant decrease of NK cell activity compared with controls (P=.001). Nine of these patients were diagnosed with primary HLH. A total of 10 patients were diagnosed with secondary HLH. Cytotoxic activity was normal in 10 subjects. None of them were diagnosed with HLH. Interleukin 15 stimulation increased NK cell cytotoxicity in secondary HLH, and blocking Fas ligand on NK cells decreased cytotoxic activity in primary HLH patients (P=.001). In our experience, NK cell cytotoxic activity measured by time-resolved fluorescence is a simple and useful clinical diagnostic test for HLH. Interleukin 15 stimulation and Fas ligand blocking on NK cells could help differentiate between primary and secondary HLH. Copyright © 2014 Elsevier España, S.L.U. and SEMICYUC. All rights reserved.

Trip Report - June 1989 Swallow Float Deployment with RUM

DTIC Science & Technology

1990-12-01

Float 1. with its external geophone package resting on the sediment, and float 3, equipped with an infra - sonic hydrophone and tethered to the bottom...an external, triaxial geophone package resting on the ocean bottom and the other equippd with an infrasonic hydrophone and bottom-tethered by a 0.5... infrasonic hydrophone and bottom-tethered by a 0.5-meter line, are presented in this report Introduction An experiment designed to compare the ambient sound

Default mode network activation and Transcendental Meditation practice: Focused Attention or Automatic Self-transcending?

PubMed

Travis, Frederick; Parim, Niyazi

2017-02-01

This study used subjective reports and eLORETA analysis to assess to what extent Transcendental Meditation (TM) might involve focused attention-voluntary control of mental content. Eighty-seven TM subjects with one month to five years TM experience participated in this study. Regression analysis of years TM practice and self-reported transcendental experiences (lack of time, space and body sense) during meditation practice was flat (r=.07). Those practicing Transcendental Meditation for 1month reported as much transcending as those with 5years of practice. The eLORETA comparison of eyes-closed rest/task and TM practice/task identified similar areas of activation: theta and alpha activation during rest and TM in the posterior cingulate and precuneus, part of the default mode network, and beta2 and beta3 activation during the task in anterior cingulate, ventral lateral and dorsolateral prefrontal cortices, part of the central executive network. In addition, eLORETA comparison of rest and TM identified higher beta temporal activation during rest and higher theta orbitofrontal activation during TM. Thus, it does not seem accurate to include TM practice with meditations in the catgory of Focused Attention, which are characterized by gamma EEG and DMN deactivation. Mixing meditations with different procedures into a single study confounds exploration of meditation effects and confounds application of meditation practices to different subject populations. Copyright © 2016 Elsevier Inc. All rights reserved.

Anaphylactic Reactions After Discontinuation of Hymenoptera Venom Immunotherapy: A Clonal Mast Cell Disorder Should Be Suspected.

PubMed

Bonadonna, Patrizia; Zanotti, Roberta; Pagani, Mauro; Bonifacio, Massimiliano; Scaffidi, Luigi; Olivieri, Elisa; Franchini, Maurizio; Reccardini, Federico; Costantino, Maria Teresa; Roncallo, Chiara; Mauro, Marina; Boni, Elisa; Rizzini, Fabio Lodi; Bilò, Maria Beatrice; Marcarelli, Anna Rosaria; Passalacqua, Giovanni

2017-12-16

Up to 75% of patients with severe anaphylactic reactions after Hymenoptera sting are at risk of further severe reactions if re-stung. Venom immunotherapy (VIT) is highly effective in protecting individuals with ascertained Hymenoptera venom allergy (HVA) and previous severe reactions. After a 3- to 5-year VIT course, most patients remain protected after VIT discontinuation. Otherwise, a lifelong treatment should be considered in high-risk patients (eg, in mastocytosis). Several case reports evidenced that patients with mastocytosis and HVA, although protected during VIT, can re-experience severe and sometimes fatal reactions after VIT discontinuation. To evaluate whether patients who lost protection after VIT discontinuation may suffer from clonal mast cell disorders. The survey describes the characteristics of patients who received a full course of VIT for previous severe reactions and who experienced another severe reaction at re-sting after VIT discontinuation. Those with a Red Española de Mastocitosis score of 2 or more or a serum basal tryptase level of more than 25 ng/mL underwent a hematological workup (bone marrow biopsy, KIT mutation, expression of aberrant CD25) and/or skin biopsy. Nineteen patients (mean age, 56.3 years; 89.5% males) were evaluated. All of them had received at least 4 years of VIT and were protected. After VIT discontinuation they were re-stung and developed, in all but 1 case, severe anaphylactic reactions (12 with loss of consciousness, in the absence of urticaria/angioedema). Eighteen patients (94.7%) had a clonal mast cell disorder, 8 of them with normal tryptase. Looking at this selected population, we suggest that mastocytosis should be considered in patients developing severe reactions at re-sting after VIT discontinuation and, as a speculation, patients with mastocytosis and HVA should be VIT-treated lifelong. Copyright © 2017. Published by Elsevier Inc.

Changes in functional connectivity dynamics associated with vigilance network in taxi drivers.

PubMed

Shen, Hui; Li, Zhenfeng; Qin, Jian; Liu, Qiang; Wang, Lubin; Zeng, Ling-Li; Li, Hong; Hu, Dewen

2016-01-01

An increasing number of neuroimaging studies have suggested that the fluctuations of low-frequency resting-state functional connectivity (FC) are not noise but are instead linked to the shift between distinct cognitive states. However, there is very limited knowledge about whether and how the fluctuations of FC at rest are influenced by long-term training and experience. Here, we investigated how the dynamics of resting-state FC are linked to driving behavior by comparing 20 licensed taxi drivers with 20 healthy non-drivers using a sliding window approach. We found that the driving experience could be effectively decoded with 90% (p<0.001) accuracy by the amplitude of low-frequency fluctuations in some specific connections, based on a multivariate pattern analysis technique. Interestingly, the majority of these connections fell within a set of distributed regions named "the vigilance network". Moreover, the decreased amplitude of the FC fluctuations within the vigilance network in the drivers was negatively correlated with the number of years that they had driven a taxi. Furthermore, temporally quasi-stable functional connectivity segmentation revealed significant differences between the drivers and non-drivers in the dwell time of specific vigilance-related transient brain states, although the brain's repertoire of functional states was preserved. Overall, these results suggested a significant link between the changes in the time-dependent aspects of resting-state FC within the vigilance network and long-term driving experiences. The results not only improve our understanding of how the brain supports driving behavior but also shed new light on the relationship between the dynamics of functional brain networks and individual behaviors. Copyright © 2015 Elsevier Inc. All rights reserved.

Exercise-Induced Fatigue and Caffeine Supplementation Affect Psychomotor Performance but Not Covert Visuo-Spatial Attention

PubMed Central

Connell, Charlotte J. W.; Thompson, Benjamin; Kuhn, Gustav; Gant, Nicholas

2016-01-01

Fatigue resulting from strenuous exercise can impair cognition and oculomotor control. These impairments can be prevented by administering psychostimulants such as caffeine. This study used two experiments to explore the influence of caffeine administered at rest and during fatiguing physical exercise on spatial attention—a cognitive function that is crucial for task-based visually guided behavior. In independent placebo-controlled studies, cohorts of 12 healthy participants consumed caffeine and rested or completed 180 min of stationary cycling. Covert attentional orienting was measured in both experiments using a spatial cueing paradigm. We observed no alterations in attentional facilitation toward spatial cues suggesting that covert attentional orienting is not influenced by exercise fatigue or caffeine supplementation. Response times were increased (impaired) after exercise and this deterioration was prevented by caffeine supplementation. In the resting experiment, response times across all conditions and cues were decreased (improved) with caffeine. Covert spatial attention was not influenced by caffeine. Together, the results of these experiments suggest that covert attentional orienting is robust to the effects of fatiguing exercise and not influenced by caffeine. However, exercise fatigue impairs response times, which can be prevented by caffeine, suggesting that pre-motor planning and execution of the motor responses required for performance of the cueing task are sensitive to central nervous system fatigue. Caffeine improves response time in both fatigued and fresh conditions, most likely through action on networks controlling motor function. PMID:27768747

Exercise-Induced Fatigue and Caffeine Supplementation Affect Psychomotor Performance but Not Covert Visuo-Spatial Attention.

PubMed

Connell, Charlotte J W; Thompson, Benjamin; Kuhn, Gustav; Gant, Nicholas

2016-01-01

Fatigue resulting from strenuous exercise can impair cognition and oculomotor control. These impairments can be prevented by administering psychostimulants such as caffeine. This study used two experiments to explore the influence of caffeine administered at rest and during fatiguing physical exercise on spatial attention-a cognitive function that is crucial for task-based visually guided behavior. In independent placebo-controlled studies, cohorts of 12 healthy participants consumed caffeine and rested or completed 180 min of stationary cycling. Covert attentional orienting was measured in both experiments using a spatial cueing paradigm. We observed no alterations in attentional facilitation toward spatial cues suggesting that covert attentional orienting is not influenced by exercise fatigue or caffeine supplementation. Response times were increased (impaired) after exercise and this deterioration was prevented by caffeine supplementation. In the resting experiment, response times across all conditions and cues were decreased (improved) with caffeine. Covert spatial attention was not influenced by caffeine. Together, the results of these experiments suggest that covert attentional orienting is robust to the effects of fatiguing exercise and not influenced by caffeine. However, exercise fatigue impairs response times, which can be prevented by caffeine, suggesting that pre-motor planning and execution of the motor responses required for performance of the cueing task are sensitive to central nervous system fatigue. Caffeine improves response time in both fatigued and fresh conditions, most likely through action on networks controlling motor function.

Glutamatergic stimulation of the left dentate gyrus abolishes depressive-like behaviors in a rat learned helplessness paradigm.

PubMed

Seo, Jeho; Cho, Hojin; Kim, Gun Tae; Kim, Chul Hoon; Kim, Dong Goo

2017-10-01

Episodic experiences of stress have been identified as the leading cause of major depressive disorder (MDD). The occurrence of MDD is profoundly influenced by the individual's coping strategy, rather than the severity of the stress itself. Resting brain activity has been shown to alter in several mental disorders. However, the functional relationship between resting brain activity and coping strategies has not yet been studied. In the present study, we observed different patterns of resting brain activity in rats that had determined either positive (resilient to stress) or negative (vulnerable to stress) coping strategies, and examined whether modulation of the preset resting brain activity could influence the behavioral phenotype associated with negative coping strategy (i.e., depressive-like behaviors). We used a learned helplessness paradigm-a well-established model of MDD-to detect coping strategies. Differences in resting state brain activity between animals with positive and negative coping strategies were assessed using 18 F-fluorodeoxyglucose positron emission tomography (FDG-PET). Glutamatergic stimulation was used to modulate resting brain activity. After exposure to repeated uncontrollable stress, seven of 23 rats exhibited positive coping strategies, while eight of 23 rats exhibited negative coping strategies. Increased resting brain activity was observed only in the left ventral dentate gyrus of the positive coping rats using FDG-PET. Furthermore, glutamatergic stimulation of the left dentate gyrus abolished depressive-like behaviors in rats with negative coping strategies. Increased resting brain activity in the left ventral dentate gyrus helps animals to select positive coping strategies in response to future stress. Copyright © 2016 Elsevier Inc. All rights reserved.

Vectorcardiographic results from Skylab medical experiment M092: Lower body negative pressure

NASA Technical Reports Server (NTRS)

Hoffler, G. W.; Johnson, R. L.; Nicogossian, A. E.; Bergman, S. A., Jr.; Jackson, M. M.

1974-01-01

Vectorcardiograms were recorded via a modified Frank lead system from all crewmen of the three Skylab missions in conjuction with the Lower Body Negative Pressure - M092 Experiment. Data were analyzed by a specially developed computer program (VECTAN). Design of the test sequences allowed direct comparisons of supine resting, Earth based (reference) vectorcardiograms with those taken during lower body negative pressure stress and those obtained at rest in orbit, as well as combinations of these conditions. Results revealed several statistically significant space flight related changes; namely, increased testing and lower body negative pressure stressed heart rates, modestly increased PR interval and corrected QTC interval, and greatly increased P and QPS loop maximal amplitudes. In addition, orientation changes in the QRS maximum vector and the J-vector at rest in space seem quite consistent among crewmen and different from those caused by the application of lower body negative pressure. No clinical abnormalities were observed. Etiology of these findings is conjectured to be, at least in part, related to fluid mass shifts occurring in weightlessness and attendant alterations in cardiovascular dynamics and myocardial autonomic control mechanisms.

A peptide representing the carboxyl-terminal tail of the met receptor inhibits kinase activity and invasive growth.

PubMed

Bardelli, A; Longati, P; Williams, T A; Benvenuti, S; Comoglio, P M

1999-10-08

Interaction of the hepatocyte growth factor (HGF) with its receptor, the Met tyrosine kinase, results in invasive growth, a genetic program essential to embryonic development and implicated in tumor metastasis. Met-mediated invasive growth requires autophosphorylation of the receptor on tyrosines located in the kinase activation loop (Tyr(1234)-Tyr(1235)) and in the carboxyl-terminal tail (Tyr(1349)-Tyr(1356)). We report that peptides derived from the Met receptor tail, but not from the activation loop, bind the receptor and inhibit the kinase activity in vitro. Cell delivery of the tail receptor peptide impairs HGF-dependent Met phosphorylation and downstream signaling. In normal and transformed epithelial cells, the tail receptor peptide inhibits HGF-mediated invasive growth, as measured by cell migration, invasiveness, and branched morphogenesis. The Met tail peptide inhibits the closely related Ron receptor but does not significantly affect the epidermal growth factor, platelet-derived growth factor, or vascular endothelial growth factor receptor activities. These experiments show that carboxyl-terminal sequences impair the catalytic properties of the Met receptor, thus suggesting that in the resting state the nonphosphorylated tail acts as an intramolecular modulator. Furthermore, they provide a strategy to selectively target the MET proto-oncogene by using small, cell-permeable, peptide derivatives.

Inhibitory actions of the gamma-aminobutyric acid in pediatric Sturge-Weber syndrome.

PubMed

Tyzio, Roman; Khalilov, Ilgam; Represa, Alfonso; Crepel, Valerie; Zilberter, Yuri; Rheims, Sylvain; Aniksztejn, Laurent; Cossart, Rosa; Nardou, Romain; Mukhtarov, Marat; Minlebaev, Marat; Epsztein, Jérôme; Milh, Mathieu; Becq, Helene; Jorquera, Isabel; Bulteau, Christine; Fohlen, Martine; Oliver, Viviana; Dulac, Olivier; Dorfmüller, Georg; Delalande, Olivier; Ben-Ari, Yehezkel; Khazipov, Roustem

2009-08-01

The mechanisms of epileptogenesis in Sturge-Weber syndrome (SWS) are unknown. We explored the properties of neurons from human pediatric SWS cortex in vitro and tested in particular whether gamma-aminobutyric acid (GABA) excites neurons in SWS cortex, as has been suggested for various types of epilepsies. Patch-clamp and field potential recordings and dynamic biphoton imaging were used to analyze cortical tissue samples obtained from four 6- to 14-month-old pediatric SWS patients during surgery. Neurons in SWS cortex were characterized by a relatively depolarized resting membrane potential, as was estimated from cell-attached recordings of N-methyl-D-aspartate channels. Many cells spontaneously fired action potentials at a rate proportional to the level of neuronal depolarization. The reversal potential for GABA-activated currents, assessed by cell-attached single channel recordings, was close to the resting membrane potential. All spontaneously firing neurons recorded in cell-attached mode or imaged with biphoton microscopy were inhibited by GABA. Spontaneous epileptiform activity in the form of recurrent population bursts was suppressed by glutamate receptor antagonists, the GABA(A) receptor agonist isoguvacine, and the positive allosteric GABA(A) modulator diazepam. Blockade of GABA(A) receptors aggravated spontaneous epileptiform activity. The NKCC1 antagonist bumetanide had little effect on epileptiform activity. SWS cortical neurons have a relatively depolarized resting membrane potential and spontaneously fire action potentials that may contribute to increased network excitability. In contrast to previous data depicting excitatory and proconvulsive actions of GABA in certain pediatric and adult epilepsies, GABA plays mainly an inhibitory and anticonvulsive role in SWS pediatric cortex.

PTEN Is a Negative Regulator of NK Cell Cytolytic Function

PubMed Central

Briercheck, Edward L.; Trotta, Rossana; Chen, Li; Hartlage, Alex S.; Cole, Jordan P.; Cole, Tyler D.; Mao, Charlene; Banerjee, Pinaki P.; Hsu, Hsiang-Ting; Mace, Emily M.; Ciarlariello, David; Mundy-Bosse, Bethany L.; Garcia-Cao, Isabel; Scoville, Steven D.; Yu, Lianbo; Pilarski, Robert; Carson, William E.; Leone, Gustavo; Pandolfi, Pier Paolo; Yu, Jianhua; Orange, Jordan S.; Caligiuri, Michael A.

2015-01-01

Human NK cells are characterized by their ability to initiate an immediate and direct cytolytic response to virally infected or malignantly transformed cells. Within human peripheral blood, the more mature CD56dim NK cell efficiently kills malignant targets at rest, whereas the less mature CD56bright NK cells cannot. In this study, we show that resting CD56bright NK cells express significantly more phosphatase and tensin homolog deleted on chromosome 10 (PTEN) protein when compared with CD56dim NK cells. Consistent with this, forced overexpression of PTEN in NK cells resulted in decreased cytolytic activity, and loss of PTEN in CD56bright NK cells resulted in elevated cytolytic activity. Comparable studies in mice showed PTEN overexpression did not alter NK cell development or NK cell–activating and inhibitory receptor expression yet, as in humans, did decrease expression of downstream NK activation targets MAPK and AKT during early cytolysis of tumor target cells. Confocal microscopy revealed that PTEN overexpression disrupts the NK cell’s ability to organize immunological synapse components including decreases in actin accumulation, polarization of the microtubule organizing center, and the convergence of cytolytic granules. In summary, our data suggest that PTEN normally works to limit the NK cell’s PI3K/AKT and MAPK pathway activation and the consequent mobilization of cytolytic mediators toward the target cell and suggest that PTEN is among the active regulatory components prior to human NK cells transitioning from the noncytolytic CD56bright NK cell to the cytolytic CD56dim NK cells. PMID:25595786

Abdominal pain in adult sickle cell disease patients: a nigerian experience.

PubMed

Akingbola, T S; Kolude, B; Aneni, E C; Raji, A A; Iwara, K U; Aken'Ova, Y A; Soyannwo, O A

2011-12-01

Abdominal pain is a relatively frequent occurrence in sickle cell disease. The aetiology of abdominal pain in sickle cell disease is often difficult to diagnose clinically. Despite the frequent occurrence, diagnostic dilemma, and the need for an accurate, early diagnosis, abdominal pain in sickle cell disease has not been rigorously studied. We therefore sought to describe the different presentations and patterns of abdominal pain in persons with sickle cell disease. A prospective case series of 20 patients was done in which data was collected on demographic characteristics, hemoglobin electrophoresis patterns, a description of the abdominal pain including sites, severity, and type of pain, packed cell volume and the provisional and final diagnosis. Haemoglobin S patients were 17 in number constituting eightyfive percent (85%) of our study population whilst the rest 3 were Hb S+C. Most patients (70%) had one site of abdominal pain. The pain was mainly colicky or tightening, moderate to severe in nature and, in some cases, associated with vomiting. We did not find any significant difference between the steady state PCV and the PCV during the acute abdominal pain episodes. The final diagnosis showed that only 38.8% of the patients had vasoocclusive crises and the reliability index between the provisional diagnosis and the final diagnosis was 67%. Abdominal pain in sickle cell disease may present in different ways and it is important to recognize that the possible diagnoses are numerous. Not all cases are due to vasoocclusive crises. Early diagnosis and prompt treatment can be life saving.

Immune Response and Function: Exercise Conditioning Versus Bed-Rest and Spaceflight Deconditioning

NASA Technical Reports Server (NTRS)

Greenleaf, J. E.; Jackson, C. G. R.; Lawless, D.

1994-01-01

Immune responses measured at rest immediately or some hours after exercise training (some with and some without increase in maximal oxygen uptake) gave variable and sometimes conflicting results; therefore, no general conclusions can be drawn. On the other hand, most immune responses were either unchanged (immunoglobulin, T cells, CD4+, and natural killer activity) or decreased (blood properdin, neutrophil phagocytic activity, salivary lysozymes, brain immunoglobulin A and G, and liver B lymphocytes and phytohemagglutinin activity) during prolonged bed rest. Some data suggested that exercise training during bed rest may partially ameliorate the decreased functioning of the immune system. Exercise and change in body position, especially during prolonged bed rest with plasma fluid shifts and diuresis, may induce a change in plasma protein concentration and content, which can influence drug metabolism as well as immune function. Leukocytosis, accompanied by lymphopenia and a depressed lymphocyte response, occurs in astronauts on return to Earth from spaceflight; recovery may depend on time of exposure to microgravity. It is clear that the effect of drugs and exercise used as countermeasures for microgravity deconditioning should be evaluated for their effect on an astronaut's immune system to assure optimal health and performance on long-duration space missions.

A novel thermal management system for improving discharge/charge performance of Li-ion battery packs under abuse

NASA Astrophysics Data System (ADS)

Arora, Shashank; Kapoor, Ajay; Shen, Weixiang

2018-02-01

Parasitic load, which describes electrical energy consumed by battery thermal management system (TMS), is an important design criterion for battery packs. Passive TMSs using phase change materials (PCMs) are thus generating much interest. However, PCMs suffer from low thermal conductivities. Most current thermal conductivity enhancement techniques involve addition of foreign particles to PCMs. Adding foreign particles increases effective thermal conductivity of PCM-systems but at expense of their latent heat capacity. This paper presents an alternate approach for improving thermal performance of PCM-based TMSs. The introduced technique involves placing battery cells in a vertically inverted position within the battery-pack. It is demonstrated through experiments that inverted cell-layout facilitates build-up of convection current in the pack, which in turn minimises thermal variations within the PCM matrix by enabling PCM mass transfer between the top and the bottom regions of the battery pack. The proposed system is found capable of maintaining tight control over battery cell temperature even during abusive usage, defined as high-rate repetitive cycling with minimal rest periods. In addition, this novel TMS can recover waste heat from PCM-matrix through thermoelectric devices, thereby resulting in a negative parasitic load for TMS.

Chemometrical assessment of the electrical parameters obtained by long-term operating freshwater sediment microbial fuel cells.

PubMed

Mitov, Mario; Bardarov, Ivo; Mandjukov, Petko; Hubenova, Yolina

2015-12-01

The electrical parameters of nine freshwater sediment microbial fuel cells (SMFCs) were monitored for a period of over 20 months. The developed SMFCs, divided into three groups, were started up and continuously operated under different constant loads (100, 510 and 1100 Ω) for 2.5 months. At this stage of the experiment, the highest power density values, reaching 1.2 ± 0.2 mW/m(2), were achieved by the SMFCs loaded with 510 Ω. The maximum power obtained at periodical polarization during the rest period, however, ranged between 26.2 ± 2.8 and 35.3 ± 2.8 mW/m(2), strongly depending on the internal cell resistance. The statistical evaluation of data derived from the polarization curves shows that after 300 days of operation all examined SMFCs reached a steady-state and the system might be assumed as homoscedastic. The estimated values of standard and expanded uncertainties of the electric parameters indicate a high repeatability and reproducibility of the SMFCs' performance. Results obtained in subsequent discharge-recovery cycles reveal the opportunity for practical application of studied SMFCs as autonomous power sources.

Alpha-fetoprotein, stem cells and cancer: how study of the production of alpha-fetoprotein during chemical hepatocarcinogenesis led to reaffirmation of the stem cell theory of cancer.

PubMed

Sell, Stewart

2008-01-01

Identification of the cells in the liver that produce alpha-fetoprotein during development, in response to liver injury and during the early stages of chemical hepatocarcinogenesis led to the conclusion that maturation arrest of liver-determined tissue stem cells was the cellular process that gives rise to hepatocellular carcinomas. When the cellular changes in these processes were compared to that of the formation of teratocarcinomas, the hypothesis arose that all cancers arise from maturation arrest of tissue-determined stem cells. This was essentially a reinterpretation of the embryonal rest theory of cancer whereby tissue stem cells take the role of embryonal rests. A corollary of the stem cell theory of the origin of cancer is that cancers contain the same functional cell populations as normal tissues: stem cells, transit-amplifying cells and mature cells. Cancer stem cells retain the essential feature of normal stem cells: the ability to self-renew. Growth of cancers is due to continued proliferation of cancer transit-amplifying cells that do not differentiate to mature cells (maturation arrest). On the other hand, cancer stem cells generally divide very rarely and contribute little to tumor growth. However, the presence of cancer stem cells in tumors is believed to be responsible for the properties of immortalization, transplantability and resistance to therapy characteristic of cancers. Current therapies for cancer (chemotherapy, radiotherapy, antiangiogenesis and differentiation therapy) are directed against the cancer transit-amplifying cells. When these therapies are discontinued, the cancer reforms from the cancer stem cells. Therapy directed toward interruption of the cell signaling pathways that maintain cancer stem cells could lead to new modalities to the prevention of regrowth of the cancer. Copyright 2008 S. Karger AG, Basel.

ALPHA-FETOPROTEIN (AFP), STEM CELLS, AND CANCER: HOW STUDY OF THE PRODUCTION OF AFP DURING CHEMICAL HEPATOCARCINOGENESIS LED TO REAFFIRMATION OF THE STEM CELL THEORY OF CANCER

PubMed Central

Sell, Stewart

2008-01-01

Identification of the cells in the liver that produce alpha-fetoprotein (AFP) during development, in response to liver injury, and during the early stages of chemical hepatocarcinogenesis led to the conclusion that maturation arrest of liver-determined tissue stem cells was the cellular process that gives rise to hepatocellular carcinomas (HCC). When the cellular changes in these processes were compared that of the formation of teratocarcinomas, the hypothesis arose that all cancers arise from maturation arrest of tissue determined stem cells. This was essentially a reinterpretation of the embryonal rest theory of cancer whereby tissue stem cells take the role of embryonal rests. A corollary of the stem cell theory of the origin of cancer is that cancers contain the same functional cell populations as do normal tissues: stem cells, transit-amplifying cells, and mature cells. Cancer stem cells retain the essential feature of normal stem cells: the ability to self-renew. Growth of cancers is due to continued proliferation of cancer transit-amplifying cells that do not differentiate to mature cells (maturation arrest). On the other hand, cancer stem cells generally divide very rarely and contribute little to tumor growth. However, the presence of cancer stem cells in tumors is believed to be responsible for the properties of immortalization, transplantability and resistance to therapy characteristic of cancers. Current therapies for cancer (chemotherapy, radiotherapy, anti-angiogenesis and differentiation therapy) are directed against the cancer transit amplifying cells. When these therapies are discontinued, the cancer re-forms from the cancer stem cells. Therapy directed toward interruption of the cell-signaling pathways that maintain cancer stem cells could lead to new modalities to the prevention of re-growth of the cancer. PMID:18612221

CD83 Antibody Inhibits Human B Cell Responses to Antigen as well as Dendritic Cell-Mediated CD4 T Cell Responses.

PubMed

Wong, Kuan Y; Baron, Rebecca; Seldon, Therese A; Jones, Martina L; Rice, Alison M; Munster, David J

2018-05-15

Anti-CD83 Ab capable of Ab-dependent cellular cytotoxicity can deplete activated CD83 + human dendritic cells, thereby inhibiting CD4 T cell-mediated acute graft-versus-host disease. As CD83 is also expressed on the surface of activated B lymphocytes, we hypothesized that anti-CD83 would also inhibit B cell responses to stimulation. We found that anti-CD83 inhibited total IgM and IgG production in vitro by allostimulated human PBMC. Also, Ag-specific Ab responses to immunization of SCID mice xenografted with human PBMC were inhibited by anti-CD83 treatment. This inhibition occurred without depletion of all human B cells because anti-CD83 lysed activated CD83 + B cells by Ab-dependent cellular cytotoxicity and spared resting (CD83 - ) B cells. In cultured human PBMC, anti-CD83 inhibited tetanus toxoid-stimulated B cell proliferation and concomitant dendritic cell-mediated CD4 T cell proliferation and expression of IFN-γ and IL-17A, with minimal losses of B cells (<20%). In contrast, the anti-CD20 mAb rituximab depleted >80% of B cells but had no effect on CD4 T cell proliferation and cytokine expression. By virtue of the ability of anti-CD83 to selectively deplete activated, but not resting, B cells and dendritic cells, with the latter reducing CD4 T cell responses, anti-CD83 may be clinically useful in autoimmunity and transplantation. Advantages might include inhibited expansion of autoantigen- or alloantigen-specific B cells and CD4 T cells, thus preventing further production of pathogenic Abs and inflammatory cytokines while preserving protective memory and regulatory cells. Copyright © 2018 by The American Association of Immunologists, Inc.

Microbial Transformations of Selenium

PubMed Central

Doran, J. W.; Alexander, M.

1977-01-01

Resting cell suspensions of a strain of Corynebacterium isolated from soil formed dimethyl selenide from selenate, selenite, elemental selenium, selenomethionine, selenocystine, and methaneseleninate. Extracts of the bacterium catalyzed the production of dimethyl selenide from selenite, elemental selenium, and methaneseleninate, and methylation of the inorganic Se compounds was enhanced by S-adenosylmethionine. Neither trimethylselenonium nor methaneselenonate was metabolized by the Corynebacterium. Resting cell suspensions of a methionine-utilizing pseudomonad converted selenomethionine to dimethyl diselenide. Six of 10 microorganisms able to grow on cystine used selenocystine as a sole source of carbon and formed elemental selenium, and one of the isolates, a pseudomonad, was found also to produce selenide. Soil enrichments converted trimethylselenonium to dimethyl selenide. Bacteria capable of utilizing trimethylselenonium, dimethyl selenide, and dimethyl diselenide as carbon sources were isolated from soil. PMID:16345188

Bacterial Utilization of Ether Glycols

PubMed Central

Fincher, Edward L.; Payne, W. J.

1962-01-01

A soil bacterium capable of using oligo- and polyethylene glycols and ether alcohols as sole sources of carbon for aerobic growth was isolated. The effects of substituent groups added to the ether bonds on the acceptability of the compounds as substrates were studied. Mechanisms for the incorporation of two-carbon compounds were demonstrated by the observation that acetate, glyoxylate, ethylene glycol, and a number of the tricarboxylic acid cycle intermediates served as growth substrates in minimal media. The rate of oxidation of the short-chained ethylene glycols by adapted resting cells varied directly with increasing numbers of two-carbon units in the chains from one to four. The amount of oxygen consumed per carbon atom of oligo- and polyethylene glycols was 100% of theoretical, but only 67% of theoretical for ethylene glycol. Resting cells oxidized oligo- and polyethylene glycols with 2 to 600 two-carbon units in the chains. Longer chained polyethylene glycols (up to 6,000) were oxidized at a very slow rate by these cells. Dehydrogenation of triethylene glycol by adapted cells was observed, coupling the reaction with methylene blue reduction. PMID:13945208

Changes in intrinsic excitability of ganglion cells in degenerated retinas of RCS rats

PubMed Central

Ren, Yi-Ming; Weng, Chuan-Huang; Zhao, Cong-Jian; Yin, Zheng-Qin

2018-01-01

AIM To evaluate the intrinsic excitability of retinal ganglion cells (RGCs) in degenerated retinas. METHODS The intrinsic excitability of various morphologically defined RGC types using a combination of patch-clamp recording and the Lucifer yellow tracer in retinal whole-mount preparations harvested from Royal College of Surgeons (RCS) rats, a common retinitis pigmentosa (RP) model, in a relatively late stage of retinal degeneration (P90) were investigated. Several parameters of RGC morphologies and action potentials (APs) were measured and compared to those of non-dystrophic control rats, including dendritic stratification, dendritic field diameter, peak amplitude, half width, resting membrane potential, AP threshold, depolarization to threshold, and firing rates. RESULTS Compared with non-dystrophic control RGCs, more depolarizations were required to reach the AP threshold in RCS RGCs with low spontaneous spike rates and in RCS OFF cells (especially A2o cells), and RCS RGCs maintained their dendritic morphologies, resting membrane potentials and capabilities to generate APs. CONCLUSION RGCs are relatively well preserved morphologically and functionally, and some cells are more susceptible to decreased excitability during retinal degeneration. These findings provide valuable considerations for optimizing RP therapeutic strategies. PMID:29862172

Effectiveness of Integrative Restoration (iRest) Yoga Nidra on Mindfulness, Sleep, and Pain in Health Care Workers.

PubMed

Livingston, Eva; Collette-Merrill, Katreena

This article examines the effectiveness of Integrative Restoration (iRest) Yoga Nidra meditation on mindfulness, sleep, and pain in health care workers. As health care workers provide emotional support to patients, it is not uncommon for workers to experience both physical and mental exhaustion. One holistic approach to support employees is mindfulness training. iRest Yoga Nidra is a complementary and integrative health therapy that increases mindfulness. A pre-/postinterveniton descriptive survey design was used. Before and after experiencing iRest meditation, participants completed a 51-item questionnaire consisting of demographics plus 3 validated instruments: the Five-Facet Mindfulness Questionnaire (FFMQ), the Epworth Sleepiness Scale (ESS), and Department of Defense/Veterans Administration (DoD/VA) Pain Supplemental Questions (PSQ). A total of 15 participants completed both questionnaires. Postintervention FFMQ scores were significantly higher than preintervention (z = -3.294, P = .001). The highest subscale scores were "acting with awareness" and "nonjudging of inner experience." There was a not a significant difference in the mean ESS scores at baseline and follow-up. However, there was a strong negative correlation between the mean ESS improvement score and the number of weeks attended (rs = -0.705, P = .003). There was a not a significant difference in the mean pain baseline and follow-up scores. This study showed significant improvement in mindfulness of health care workers following a guided 8-week iRest Yoga Nidra program. The results of this study may provide some insight into helping health care workers deal with the demands of their profession in a positive manner, thus leading to an improved workplace environment.

Granular controls on the dispersion of bed load tracers

NASA Astrophysics Data System (ADS)

Jerolmack, D. J.; Martin, R. L.; Phillips, C. B.

2014-12-01

Coarse particles are transported in a river as bed load, i.e., they move in frequent contact with and are supported by the granular bed. This movement is typically intermittent and may be described by a series of steps are rests, the distributions of which determine particle dispersion. Laboratory and field studies of bed load tracer dispersion have reported sub- and super-diffusive behavior, both of which have been successfully reproduced with stochastic transport models. Although researchers have invoked heavy-tailed step lengths as the cause of anomalous dispersion, most observations report thin-tailed distributions. Little attention has been paid to rest periods, and stochastic transport models have not been connected to the underlying mechanics of particle motion. Based on theoretical and experimental evidence, we argue that step lengths are thin-tailed and do not control the longterm dispersion of bed load tracers; they are determined by momentum balance between the fluid and solid. Using laboratory experiments with both marbles and natural sediments, we demonstrate that the rest time distribution is power law, and argue that this distribution controls asymptotic dispersion. Observed rest times far exceed any hydrodynamic timescale. Experiments reveal that rest times of deposited particles are governed by fluctuations in river bed elevation; in particular, the return time for the bed to scour to the base of a deposited particle. Stochastic fluctuations in bed elevation are describable by an Ornstein-Uhlenbeck (mean-reverting random walk) model that contains two parameters, which we show are directly related to the granular shear rate and range of bed elevation fluctuations, respectively. Combining these results with the theory of asymmetric random walks (particles only move downstream), we predict superdiffusive behavior that is in quantitative agreement with our observations of tracer dispersion in a natural river.

Exercise and training effects on gastric emptying of carbohydrate beverages.

PubMed

Rehrer, N J; Beckers, E; Brouns, F; Hoor ten, F; Saris, W H

1989-10-01

Carbohydrate containing drinks are commonly consumed as an ergogenic aid during endurance sports activities. The efficacy of a given drink is limited by the rate of absorption, which is in turn limited by gastric emptying. A myriad of factors influence gastric emptying. The influence of several of these factors (training status, exercise intensity, and carbohydrate composition) was investigated by repeated experiments using a nasogastric tube and a modification of the technique of George. A group of well-trained bicyclists and a group of untrained subjects performed similar experiments. Three different carbohydrate containing drinks (15 g.100 ml-1 glucose (G), 15 g.100 ml-1 maltodextrin plus 3 g.100 ml-1 fructose (MD), 7 g.100 ml-1 sucrose (I] and artificially sweetened water were compared during rest and 50 and 70% Wmax bicycling. Experimental design was crossover. There was a trend for the carbohydrate drinks to empty initially more slowly under the influence of exercise. Differences in drink volume remaining in the stomach were significant (P less than 0.05), with I at 10 min (70%, mean = 48.9%; rest, mean = 30.5%) and at 20 min (70%, mean = 28.9%; rest, mean = 23.8%) and with MD at 10 min (70%, mean = 71.1%; rest, mean = 55.9%). A similar trend was also seen with 50% Wmax exercise; however, this trend was only significant with MD at 10 min (50%, mean = 72.1%; rest, mean = 55.9%). Drink composition was a much stronger inhibitor of gastric emptying. However, all drinks emptied exponentially with fast-phase initial emptying rates. No differences in gastric emptying or secretion were observed between trained and untrained subjects.

Water tribology on graphene.

PubMed

N'guessan, Hartmann E; Leh, Aisha; Cox, Paris; Bahadur, Prashant; Tadmor, Rafael; Patra, Prabir; Vajtai, Robert; Ajayan, Pulickel M; Wasnik, Priyanka

2012-01-01

Classical experiments show that the force required to slide liquid drops on surfaces increases with the resting time of the drop, t(rest), and reaches a plateau typically after several minutes. Here we use the centrifugal adhesion balance to show that the lateral force required to slide a water drop on a graphene surface is practically invariant with t(rest). In addition, the drop's three-phase contact line adopts a peculiar micrometric serrated form. These observations agree well with current theories that relate the time effect to deformation and molecular re-orientation of the substrate surface. Such molecular re-orientation is non-existent on graphene, which is chemically homogenous. Hence, graphene appears to provide a unique tribological surface test bed for a variety of liquid drop-surface interactions.

Origins of Newton's First Law

NASA Astrophysics Data System (ADS)

Hecht, Eugene

2015-02-01

Anyone who has taught introductory physics should know that roughly a third of the students initially believe that any object at rest will remain at rest, whereas any moving body not propelled by applied forces will promptly come to rest. Likewise, about half of those uninitiated students believe that any object moving at a constant speed must be continually pushed if it is to maintain its motion.1 That's essentially Aristotle's law of motion and it is so "obviously" borne out by experience that it was accepted by scholars for 2000 years, right through the Copernican Revolution. But, of course, it's fundamentally wrong. This paper tells the story of how the correct understanding, the law of inertia, evolved and how Newton came to make it his first law.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Słonina, Dorota, E-mail: z5slonin@cyfronet.pl; Biesaga, Beata; Janecka, Anna

Purpose: In our previous study, using the micronucleus assay, a low-dose hyper-radiosensitivity (HRS)-like phenomenon was observed for normal fibroblasts of 2 of the 40 cancer patients investigated. In this article we report, for the first time, the survival response of primary fibroblasts from 25 of these patients to low-dose irradiation and answer the question regarding the effect of G2-phase enrichment on HRS elicitation. Methods and Materials: The clonogenic survival of asynchronous as well as G2-phase enriched fibroblast populations was measured. Separation of G2-phase cells and precise cell counting was performed using a fluorescence-activated cell sorter. Sorted and plated cells weremore » irradiated with single doses (0.1-4 Gy) of 6-MV x-rays. For each patient, at least 4 independent experiments were performed, and the induced-repair model was fitted over the whole data set to confirm the presence of HRS effect. Results: The HRS response was demonstrated for the asynchronous and G2-phase enriched cell populations of 4 patients. For the rest of patients, HRS was not defined in either of the 2 fibroblast populations. Thus, G2-phase enrichment had no effect on HRS elicitation. Conclusions: The fact that low-dose hyper-radiosensitivity is not a common effect in normal human fibroblasts implies that HRS may be of little consequence in late-responding connective tissues with regard to radiation fibrosis.« less

Xenopus laevis oocyte maturation is affected by metal chlorides.

PubMed

Marin, Matthieu; Slaby, Sylvain; Marchand, Guillaume; Demuynck, Sylvain; Friscourt, Noémie; Gelaude, Armance; Lemière, Sébastien; Bodart, Jean-François

2015-08-01

Few studies have been conducted using Xenopus laevis germ cells as oocytes, though these cells offer many advantages allowing both electrophysiological studies and morphological examination. Our aim was to investigate the effects of metal (cadmium, lead, cobalt and zinc) exposures using cell biology approaches. First, cell survival was evaluated with both phenotypical and electrophysiological approaches. Secondly, the effect of metals on oocyte maturation was assessed with morphological observations and electrophysiological recordings. From survival experiments, our results showed that metal chlorides did not affect cell morphology but strongly depolarized X. laevis oocyte resting potential. In addition, cadmium chloride was able to inhibit progesterone-induced oocyte maturation. By contrast, zinc, but also to a lesser extent cadmium, cobalt and lead, were able to enhance spontaneous oocyte maturation in the absence of progesterone stimulation. Finally, electrophysiological recordings revealed that some metal chlorides (lead, cadmium) exposures could disturb calcium signaling in X. laevis oocyte by modifying calcium-activated chloride currents. Our results demonstrated the high sensitivity of X. laevis oocytes toward exogenous metals such as lead and cadmium. In addition, the cellular events recorded might have a predictive value of effects occurring later on the ability of oocytes to be fertilized. Together, these results suggest a potential use of this cellular lab model as a tool for ecotoxicological assessment of contaminated fresh waters. Copyright © 2015 Elsevier Ltd. All rights reserved.

Changes of glucose utilization by erythrocytes, lactic acid concentration in the serum and blood cells, and haematocrit value during one hour rest after maximal effort in individuals differing in physical efficiency.

PubMed

Tomasik, M

1982-01-01

Glucose utilization by the erythrocytes, lactic acid concentration in the blood and erythrocytes, and haematocrit value were determined before exercise and during one hour rest following maximal exercise in 97 individuals of either sex differing in physical efficiency. In the investigations reported by the author individuals with strikingly high physical fitness performed maximal work one-third greater than that performed by individuals with medium fitness. The serum concentration of lactic acid was in all individuals above the resting value still after 60 minutes of rest. On the other hand, this concentration returned to the normal level in the erythrocytes but only in individuals with strikingly high efficiency. Glucose utilization by the erythrocytes during the restitution period was highest immediately after the exercise in all studied individuals and showed a tendency for more rapid return to resting values again in individuals with highest efficiency. The investigation of very efficient individuals repeated twice demonstrated greater utilization of glucose by the erythrocytes at the time of greater maximal exercise. This was associated with greater lactic acid concentration in the serum and erythrocytes throughout the whole one-hour rest period. The observed facts suggest an active participation of erythrocytes in the process of adaptation of the organism to exercise.

Systemic Immune Activation and HIV Shedding in the Female Genital Tract.

PubMed

Spencer, LaShonda Y; Christiansen, Shawna; Wang, Chia-Hao H; Mack, Wendy J; Young, Mary; Strickler, Howard D; Anastos, Kathryn; Minkoff, Howard; Cohen, Mardge; Geenblatt, Ruth M; Karim, Roksana; Operskalski, Eva; Frederick, Toni; Homans, James D; Landay, Alan; Kovacs, Andrea

2016-02-01

Plasma HIV RNA is the most significant determinant of cervical HIV shedding. However, shedding is also associated with sexually transmitted infections (STIs) and cervical inflammation. The mechanism by which this occurs is poorly understood. There is evidence that systemic immune activation promotes viral entry, replication, and HIV disease progression. We hypothesized that systemic immune activation would be associated with an increase in HIV genital shedding. Clinical assessments, HIV RNA in plasma and genital secretions, and markers of immune activation (CD38(+)DR(+) and CD38(-)DR(-)) on CD4(+) and CD8(+) T cells in blood were evaluated in 226 HIV+ women enrolled in the Women's Interagency HIV Study. There were 569 genital evaluations of which 159 (28%) exhibited HIV RNA shedding, defined as HIV viral load >80 copies per milliliter. We tested associations between immune activation and shedding using generalized estimating equations with logit link function. In the univariate model, higher levels of CD4(+) and CD8(+) T-cell activation in blood were significantly associated with genital tract shedding. However, in the multivariate model adjusting for plasma HIV RNA, STIs, and genital tract infections, only higher levels of resting CD8(+) T cells (CD38(-)DR(-)) were significantly inversely associated with HIV shedding in the genital tract (odds ratios = 0.44, 95% confidence interval: 0.21 to 0.9, P = 0.02). The association of systemic immune activation with genital HIV shedding is multifactorial. Systemic T-cell activation is associated with genital tract shedding in univariate analysis but not when adjusting for plasma HIV RNA, STIs, and genital tract infections. In addition, women with high percentage of resting T cells are less likely to have HIV shedding compared with those with lower percentages. These findings suggest that a higher percentage of resting cells, as a result of maximal viral suppression with treatment, may decrease local genital activation, HIV shedding, and transmission.

The GBAR experiment: gravitational behaviour of antihydrogen at rest

NASA Astrophysics Data System (ADS)

Perez, P.; Sacquin, Y.

2012-09-01

The recently recommended experiment GBAR is foreseen to run at CERN at the AD/ELENA antiproton source. It aims at performing the first measurement of the Earth's gravitational acceleration on antimatter by observing the free-fall of antihydrogen atoms. This requires creating anti-atoms at an unprecedented low energy. The different steps of the experiment and their present status are reviewed.

Reduced DIDS-sensitive chloride conductance in Ae1-/- mouse erythrocytes

PubMed Central

Alper, Seth L.; Vandorpe, David H.; Peters, Luanne L.; Brugnara, Carlo

2008-01-01

The resting membrane potential of the human erythrocyte is largely determined by a constitutive Cl- conductance ∼100-fold greater than the resting cation conductance. The 4,4′-diisothiocyanostilbene-2,2′-disulfonic acid (DIDS)-sensitive electroneutral Cl- transport mediated by the human erythroid Cl-/HCO3- exchanger, AE1 (SLC4A1, band 3) is ≥10,000-fold greater than can be accounted for by the Cl- conductance of the red cell. The molecular identities of conductive anion pathways across the red cell membrane remain poorly defined. We have examined red cell Cl- conductance in the Ae1-/- mouse as a genetic test of the hypothesis that Ae1 mediates DIDS-sensitive Cl- conductance in mouse red cells. We report here that wildtype mouse red cell membrane potential resembles that of human red cells in the predominance of its Cl- conductance. We show with four technical approaches that the DIDS-sensitive component of erythroid Cl- conductance is reduced or absent from Ae1-/- red cells. These results are consistent with the hypothesis that the Ae1 anion exchanger polypeptide can operate infrequently in a conductive mode. However, the fragile red cell membrane of the Ae1-/- mouse red cell exhibits reduced abundance or loss of multiple polypeptides. Thus, loss of one or more distinct, DIDS-sensitive anion channel polypeptide(s) from the Ae1-/- red cell membrane cannot be ruled out as an explanation for the reduced DIDS-sensitive anion conductance. PMID:18329299

Frontline Science: IL-18 primes murine NK cells for proliferation by promoting protein synthesis, survival, and autophagy.

PubMed

El-Darawish, Yosif; Li, Wen; Yamanishi, Kyosuke; Pencheva, Magdalena; Oka, Naoto; Yamanishi, Hiromichi; Matsuyama, Tomohiro; Tanaka, Yoshimasa; Minato, Nagahiro; Okamura, Haruki

2018-03-30

Combined stimulation by IL-2 and IL-18 effectively promotes proliferation of NK cells, whereas singular stimulation does not. In this study, synergistic effects of these cytokines on NK cells proliferation was analyzed, focusing on the roles of IL-18. In splenic resting NK cells from IL-18KO mice, IL-18 rapidly activated NF-κB independently of IL-2, and activated or up-regulated various molecules downstream of PI3K/AKT and mTOR, including S6, Bcl-XL, ATG5, and LC3II, accompanying increases in cell growth and survival. Thus, IL-18 alone was revealed to augment various cellular processes (gene transcription, protein synthesis, survival) in the absence or presence of IL-2. Notably, combined IL-18 and IL-2 promoted autophagosome formation. In addition, priming NK cells with IL-18 augmented IL-2R, especially CD25, and enabled cells to respond to IL-2, resulting in activation of STAT3 and STAT5, followed by increase of cyclin B1 leading to proliferation. However, IL-2 alone failed to activate STAT3 or STAT5 in resting IL18KO NK cells. These results clarify the distinct roles of IL-2 and IL-18 in NK cell proliferation, and the intrinsic roles of IL-18 in various cellular processes, suggesting a range of functions of IL-18 expressed in an array of nonhematopoietic cells. ©2018 Society for Leukocyte Biology.

High Power Orbit Transfer Vehicle

DTIC Science & Technology

2003-07-01

multijunction device is a stack of individual single-junction cells in descending order of band gap. The top cell captures the high-energy photons and passes...the rest of the photons on to be absorbed by lower-band-gap cells. Multijunction devices achieve a higher total conversion efficiency because they...minimum temperatures on the thruster modules and main bus. In the MATLAB code for these calculations, maximum and minimum temperatures are plotted

Dysregulated B Cell Expression of RANKL and OPG Correlates with Loss of Bone Mineral Density in HIV Infection

PubMed Central

Titanji, Kehmia; Vunnava, Aswani; Sheth, Anandi N.; Delille, Cecile; Lennox, Jeffrey L.; Sanford, Sara E.; Foster, Antonina; Knezevic, Andrea; Easley, Kirk A.

2014-01-01

HIV infection is associated with high rates of osteopenia and osteoporosis, but the mechanisms involved are unclear. We recently reported that bone loss in the HIV transgenic rat model was associated with upregulation of B cell expression of the key osteoclastogenic cytokine receptor-activator of NF-κB ligand (RANKL), compounded by a simultaneous decline in expression of its physiological moderator, osteoprotegerin (OPG). To clinically translate these findings we performed cross-sectional immuno-skeletal profiling of HIV-uninfected and antiretroviral therapy-naïve HIV-infected individuals. Bone resorption and osteopenia were significantly higher in HIV-infected individuals. B cell expression of RANKL was significantly increased, while B cell expression of OPG was significantly diminished, conditions favoring osteoclastic bone resorption. The B cell RANKL/OPG ratio correlated significantly with total hip and femoral neck bone mineral density (BMD), T- and/or Z-scores in HIV infected subjects, but revealed no association at the lumbar spine. B cell subset analyses revealed significant HIV-related increases in RANKL-expressing naïve, resting memory and exhausted tissue-like memory B cells. By contrast, the net B cell OPG decrease in HIV-infected individuals resulted from a significant decline in resting memory B cells, a population containing a high frequency of OPG-expressing cells, concurrent with a significant increase in exhausted tissue-like memory B cells, a population with a lower frequency of OPG-expressing cells. These data validate our pre-clinical findings of an immuno-centric mechanism for accelerated HIV-induced bone loss, aligned with B cell dysfunction. PMID:25393853

Dual-Affinity Re-Targeting proteins direct T cell–mediated cytolysis of latently HIV-infected cells

PubMed Central

Sung, Julia A.M.; Pickeral, Joy; Liu, Liqin; Stanfield-Oakley, Sherry A.; Lam, Chia-Ying Kao; Garrido, Carolina; Pollara, Justin; LaBranche, Celia; Bonsignori, Mattia; Moody, M. Anthony; Yang, Yinhua; Parks, Robert; Archin, Nancie; Allard, Brigitte; Kirchherr, Jennifer; Kuruc, JoAnn D.; Gay, Cynthia L.; Cohen, Myron S.; Ochsenbauer, Christina; Soderberg, Kelly; Liao, Hua-Xin; Montefiori, David; Moore, Paul; Johnson, Syd; Koenig, Scott; Haynes, Barton F.; Nordstrom, Jeffrey L.; Margolis, David M.; Ferrari, Guido

2015-01-01

Enhancement of HIV-specific immunity is likely required to eliminate latent HIV infection. Here, we have developed an immunotherapeutic modality aimed to improve T cell–mediated clearance of HIV-1–infected cells. Specifically, we employed Dual-Affinity Re-Targeting (DART) proteins, which are bispecific, antibody-based molecules that can bind 2 distinct cell-surface molecules simultaneously. We designed DARTs with a monovalent HIV-1 envelope-binding (Env-binding) arm that was derived from broadly binding, antibody-dependent cellular cytotoxicity–mediating antibodies known to bind to HIV-infected target cells coupled to a monovalent CD3 binding arm designed to engage cytolytic effector T cells (referred to as HIVxCD3 DARTs). Thus, these DARTs redirected polyclonal T cells to specifically engage with and kill Env-expressing cells, including CD4+ T cells infected with different HIV-1 subtypes, thereby obviating the requirement for HIV-specific immunity. Using lymphocytes from patients on suppressive antiretroviral therapy (ART), we demonstrated that DARTs mediate CD8+ T cell clearance of CD4+ T cells that are superinfected with the HIV-1 strain JR-CSF or infected with autologous reservoir viruses isolated from HIV-infected–patient resting CD4+ T cells. Moreover, DARTs mediated CD8+ T cell clearance of HIV from resting CD4+ T cell cultures following induction of latent virus expression. Combined with HIV latency reversing agents, HIVxCD3 DARTs have the potential to be effective immunotherapeutic agents to clear latent HIV-1 reservoirs in HIV-infected individuals. PMID:26413868

The kinase inhibitors sunitinib and sorafenib differentially affect NK cell antitumor reactivity in vitro.

PubMed

Krusch, Matthias; Salih, Julia; Schlicke, Manuela; Baessler, Tina; Kampa, Kerstin Maria; Mayer, Frank; Salih, Helmut Rainer

2009-12-15

Sunitinib and Sorafenib are protein kinase inhibitors (PKI) approved for treatment of patients with advanced renal cell cancer (RCC). However, long-term remissions of advanced RCC have only been observed after IL-2 treatment, which underlines the importance of antitumor immune responses in RCC patients. Because PKI, besides affecting tumor cells, also may inhibit signaling in immune effector cells, we determined how Sunitinib and Sorafenib influence antitumor immunity. We found that cytotoxicity and cytokine production of resting and IL-2-activated PBMC are inhibited by pharmacological concentrations of Sorafenib but not Sunitinib. Analysis of granule-mobilization within PBMC revealed that this was due to impaired reactivity of NK cells, which substantially contribute to antitumor immunity by directly killing target cells and shaping adaptive immune responses by secreting cytokines like IFN-gamma. Analyses with resting and IL-2-activated NK cells revealed that both PKI concentration dependently inhibit cytotoxicity and IFN-gamma production of NK cells in response to tumor targets. This was due to impaired PI3K and ERK phosphorylation which directly controls NK cell reactivity. However, while Sorafenib inhibited NK cell effector functions and signaling at levels achieved upon recommended dosing, pharmacological concentrations of Sunitinib had no effect, and this was observed upon stimulation of NK cell reactivity by tumor target cells and upon IL-2 treatment. In light of the important role of NK cells in antitumor immunity, and because multiple approaches presently aim to combine PKI treatment with immunotherapeutic strategies, our data demonstrate that choice and dosing of the most suitable PKI in cancer treatment requires careful consideration.

Pulling Rank: Military Rank Affects Hormone Levels and Fairness in an Allocation Experiment.

PubMed

Siart, Benjamin; Pflüger, Lena S; Wallner, Bernard

2016-01-01

Status within social hierarchies has great effects on the lives of socially organized mammals. Its effects on human behavior and related physiology, however, is relatively little studied. The present study investigated the impact of military rank on fairness and behavior in relation to salivary cortisol (C) and testosterone (T) levels in male soldiers. For this purpose 180 members of the Austrian Armed Forces belonging to two distinct rank groups participated in two variations of a computer-based guard duty allocation experiment. The rank groups were (1) warrant officers (high rank, HR) and (2) enlisted men (low rank, LR). One soldier from each rank group participated in every experiment. At the beginning of the experiment, one participant was assigned to start standing guard and the other participant at rest. The participant who started at rest could choose if and when to relieve his fellow soldier and therefore had control over the experiment. In order to trigger perception of unfair behavior, an additional experiment was conducted which was manipulated by the experimenter. In the manipulated version both soldiers started in the standing guard position and were never relieved, believing that their opponent was at rest , not relieving them. Our aim was to test whether unfair behavior causes a physiological reaction. Saliva samples for hormone analysis were collected at regular intervals throughout the experiment. We found that in the un-manipulated setup high-ranking soldiers spent less time standing guard than lower ranking individuals. Rank was a significant predictor for C but not for T levels during the experiment. C levels in the HR group were higher than in the LR group. C levels were also elevated in the manipulated experiment compared to the un-manipulated experiment, especially in LR. We assume that the elevated C levels in HR were caused by HR feeling their status challenged by the situation of having to negotiate with an individual of lower military rank. This would be in line with the observation that unequally shared duty favored HR in most cases. We conclude that social status, in the form of military rank affects fairness behavior in social interaction and endocrine levels.

Pulling Rank: Military Rank Affects Hormone Levels and Fairness in an Allocation Experiment

PubMed Central

Siart, Benjamin; Pflüger, Lena S.; Wallner, Bernard

2016-01-01

Status within social hierarchies has great effects on the lives of socially organized mammals. Its effects on human behavior and related physiology, however, is relatively little studied. The present study investigated the impact of military rank on fairness and behavior in relation to salivary cortisol (C) and testosterone (T) levels in male soldiers. For this purpose 180 members of the Austrian Armed Forces belonging to two distinct rank groups participated in two variations of a computer-based guard duty allocation experiment. The rank groups were (1) warrant officers (high rank, HR) and (2) enlisted men (low rank, LR). One soldier from each rank group participated in every experiment. At the beginning of the experiment, one participant was assigned to start standing guard and the other participant at rest. The participant who started at rest could choose if and when to relieve his fellow soldier and therefore had control over the experiment. In order to trigger perception of unfair behavior, an additional experiment was conducted which was manipulated by the experimenter. In the manipulated version both soldiers started in the standing guard position and were never relieved, believing that their opponent was at rest, not relieving them. Our aim was to test whether unfair behavior causes a physiological reaction. Saliva samples for hormone analysis were collected at regular intervals throughout the experiment. We found that in the un-manipulated setup high-ranking soldiers spent less time standing guard than lower ranking individuals. Rank was a significant predictor for C but not for T levels during the experiment. C levels in the HR group were higher than in the LR group. C levels were also elevated in the manipulated experiment compared to the un-manipulated experiment, especially in LR. We assume that the elevated C levels in HR were caused by HR feeling their status challenged by the situation of having to negotiate with an individual of lower military rank. This would be in line with the observation that unequally shared duty favored HR in most cases. We conclude that social status, in the form of military rank affects fairness behavior in social interaction and endocrine levels. PMID:27891109

Focal Gray Matter Plasticity as a Function of Long Duration Head-down Tilt Bed Rest

NASA Technical Reports Server (NTRS)

Koppelmans, V.; DeDios, Y. E.; Wood, S. J.; Reuter-Lorenz, P. A.; Kofman, I.; Bloomberg, J. J.; Mulavara, A. P.; Koppelmans, V.

2014-01-01

Long duration spaceflight (i.e., > or = 22 days) has been associated with changes in sensorimotor systems, resulting in difficulties that astronauts experience with posture control, locomotion, and manual control. The microgravity environment is an important causal factor for spaceflight induced sensorimotor changes. Whether these sensorimotor changes may be related to structural and functional brain changes is yet unknown. However, experimental studies revealed changes in the gray matter (GM) of the brain after simulated microgravity. Thus, it is possible that spaceflight may affect brain structure and thereby cognitive functioning and motor behavior. Long duration head-down tilt bed rest has been suggested as an exclusionary analog to study microgravity effects on the sensorimotor system. Bed rest mimics microgravity in body unloading and bodily fluid shifts. In consideration of the health and performance of crewmembers both in- and post-flight, we are conducting a prospective longitudinal 70-day bed rest study as an analog to investigate the effects of microgravity on the brain. VBM analysis revealed a progressive decrease from pre- to in- bed rest in GM volume in bilateral areas including the frontal medial cortex, the insular cortex and the caudate. Over the same time period, there was a progressive increase in GM volume in the cerebellum, occipital-, and parietal cortex, including the precuneus. The majority of these changes did not fully recover during the post-bed rest period. Analysis of lobular GM volumes obtained with BRAINS showed significantly increased volume from pre-bed rest to in-bed rest in GM of the parietal lobe and the third ventricle. Temporal GM volume at 70 days in bed rest was smaller than that at the first pre-bed rest measurement. Trend analysis showed significant positive linear and negative quadratic relationships between parietal GM and time, a positive linear relationship between third ventricle volume and time, and a negative linear relationship between cerebellar GM volume and time. FM performance improved from pre-bed rest session 1 to session 2. From the second pre-bed rest measure to the last-day-in-bed rest, there was a significant decrease in performance that only partially recovered post-bed rest. No significant association was observed between changes in brain volume and changes in functional mobility. Extended bed rest, which is an analog for microgravity, can result in local volumetric GM increase and decrease and adversely affect functional mobility. These changes in brain structure and performance were not related in this sample. Whether the effects of bed rest dissipate at longer times post-bed rest, and if they are associated with behavior are important questions that warrant further research including more subjects and longer follow-up times.

Epithelial Cell Rests of Malassez Contain Unique Stem Cell Populations Capable of Undergoing Epithelial–Mesenchymal Transition

PubMed Central

Xiong, Jimin; Mrozik, Krzysztof; Gronthos, Stan

2012-01-01

The epithelial cell rests of Malassez (ERM) are odontogenic epithelial cells located within the periodontal ligament matrix. While their function is unknown, they may support tissue homeostasis and maintain periodontal ligament space or even contribute to periodontal regeneration. We investigated the notion that ERM contain a subpopulation of stem cells that could undergo epithelial–mesenchymal transition and differentiate into mesenchymal stem-like cells with multilineage potential. For this purpose, ERM collected from ovine incisors were subjected to different inductive conditions in vitro, previously developed for the characterization of bone marrow mesenchymal stromal/stem cells (BMSC). We found that ex vivo-expanded ERM expressed both epithelial (cytokeratin-8, E-cadherin, and epithelial membrane protein-1) and BMSC markers (CD44, CD29, and heat shock protein-90β). Integrin α6/CD49f could be used for the enrichment of clonogenic cell clusters [colony-forming units-epithelial cells (CFU-Epi)]. Integrin α6/CD49f-positive-selected epithelial cells demonstrated over 50- and 7-fold greater CFU-Epi than integrin α6/CD49f-negative cells and unfractionated cells, respectively. Importantly, ERM demonstrated stem cell-like properties in their differentiation capacity to form bone, fat, cartilage, and neural cells in vitro. When transplanted into immunocompromised mice, ERM generated bone, cementum-like and Sharpey's fiber-like structures. Additionally, gene expression studies showed that osteogenic induction of ERM triggered an epithelial–mesenchymal transition. In conclusion, ERM are unusual cells that display the morphological and phenotypic characteristics of ectoderm-derived epithelial cells; however, they also have the capacity to differentiate into a mesenchymal phenotype and thus represent a unique stem cell population within the periodontal ligament. PMID:22122577

An overview of the issues: physiological effects of bed rest and restricted physical activity

NASA Technical Reports Server (NTRS)

Convertino, V. A.; Bloomfield, S. A.; Greenleaf, J. E.

1997-01-01

Reduction of exercise capacity with confinement to bed rest is well recognized. Underlying physiological mechanisms include dramatic reductions in maximal stroke volume, cardiac output, and oxygen uptake. However, bed rest by itself does not appear to contribute to cardiac dysfunction. Increased muscle fatigue is associated with reduced muscle blood flow, red cell volume, capillarization and oxidative enzymes. Loss of muscle mass and bone density may be reflected by reduced muscle strength and higher risk for injury to bones and joints. The resultant deconditioning caused by bed rest can be independent of the primary disease and physically debilitating in patients who attempt to reambulate to normal active living and working. A challenge to clinicians and health care specialists has been the identification of appropriate and effective methods to restore physical capacity of patients during or after restricted physical activity associated with prolonged bed rest. The examination of physiological responses to bed rest deconditioning and exercise training in healthy subjects has provided significant information to develop effective rehabilitation treatments. The successful application of acute exercise to enhance orthostatic stability, daily endurance exercise to maintain aerobic capacity, or specific resistance exercises to maintain musculoskeletal integrity rather than the use of surgical, pharmacological, and other medical treatments for clinical conditions has been enhanced by investigation and understanding of underlying mechanisms that distinguish physical deconditioning from the disease. This symposium presents an overview of cardiovascular and musculoskeletal deconditioning associated with reduced physical work capacity following prolonged bed rest and exercise training regimens that have proven successful in ameliorating or reversing these adverse effects.

Reduced brain resting-state network specificity in infants compared with adults.

PubMed

Wylie, Korey P; Rojas, Donald C; Ross, Randal G; Hunter, Sharon K; Maharajh, Keeran; Cornier, Marc-Andre; Tregellas, Jason R

2014-01-01

Infant resting-state networks do not exhibit the same connectivity patterns as those of young children and adults. Current theories of brain development emphasize developmental progression in regional and network specialization. We compared infant and adult functional connectivity, predicting that infants would exhibit less regional specificity and greater internetwork communication compared with adults. Functional magnetic resonance imaging at rest was acquired in 12 healthy, term infants and 17 adults. Resting-state networks were extracted, using independent components analysis, and the resulting components were then compared between the adult and infant groups. Adults exhibited stronger connectivity in the posterior cingulate cortex node of the default mode network, but infants had higher connectivity in medial prefrontal cortex/anterior cingulate cortex than adults. Adult connectivity was typically higher than infant connectivity within structures previously associated with the various networks, whereas infant connectivity was frequently higher outside of these structures. Internetwork communication was significantly higher in infants than in adults. We interpret these findings as consistent with evidence suggesting that resting-state network development is associated with increasing spatial specificity, possibly reflecting the corresponding functional specialization of regions and their interconnections through experience.

Simultaneous tDCS-fMRI Identifies Resting State Networks Correlated with Visual Search Enhancement.

PubMed

Callan, Daniel E; Falcone, Brian; Wada, Atsushi; Parasuraman, Raja

2016-01-01

This study uses simultaneous transcranial direct current stimulation (tDCS) and functional MRI (fMRI) to investigate tDCS modulation of resting state activity and connectivity that underlies enhancement in behavioral performance. The experiment consisted of three sessions within the fMRI scanner in which participants conducted a visual search task: Session 1: Pre-training (no performance feedback), Session 2: Training (performance feedback given), Session 3: Post-training (no performance feedback). Resting state activity was recorded during the last 5 min of each session. During the 2nd session one group of participants underwent 1 mA tDCS stimulation and another underwent sham stimulation over the right posterior parietal cortex. Resting state spontaneous activity, as measured by fractional amplitude of low frequency fluctuations (fALFF), for session 2 showed significant differences between the tDCS stim and sham groups in the precuneus. Resting state functional connectivity from the precuneus to the substantia nigra, a subcortical dopaminergic region, was found to correlate with future improvement in visual search task performance for the stim over the sham group during active stimulation in session 2. The after-effect of stimulation on resting state functional connectivity was measured following a post-training experimental session (session 3). The left cerebellum Lobule VIIa Crus I showed performance related enhancement in resting state functional connectivity for the tDCS stim over the sham group. The ability to determine the relationship that the relative strength of resting state functional connectivity for an individual undergoing tDCS has on future enhancement in behavioral performance has wide ranging implications for neuroergonomic as well as therapeutic, and rehabilitative applications.

A Comparative Study of Standardized Infinity Reference and Average Reference for EEG of Three Typical Brain States

PubMed Central

Zheng, Gaoxing; Qi, Xiaoying; Li, Yuzhu; Zhang, Wei; Yu, Yuguo

2018-01-01

The choice of different reference electrodes plays an important role in deciphering the functional meaning of electroencephalography (EEG) signals. In recent years, the infinity zero reference using the reference electrode standard technique (REST) has been increasingly applied, while the average reference (AR) was generally advocated as the best available reference option in previous classical EEG studies. Here, we designed EEG experiments and performed a direct comparison between the influences of REST and AR on EEG-revealed brain activity features for three typical brain behavior states (eyes-closed, eyes-open and music-listening). The analysis results revealed the following observations: (1) there is no significant difference in the alpha-wave-blocking effect during the eyes-open state compared with the eyes-closed state for both REST and AR references; (2) there was clear frontal EEG asymmetry during the resting state, and the degree of lateralization under REST was higher than that under AR; (3) the global brain functional connectivity density (FCD) and local FCD have higher values for REST than for AR under different behavior states; and (4) the value of the small-world network characteristic in the eyes-closed state is significantly (in full, alpha, beta and gamma frequency bands) higher than that in the eyes-open state, and the small-world effect under the REST reference is higher than that under AR. In addition, the music-listening state has a higher small-world network effect than the eyes-closed state. The above results suggest that typical EEG features might be more clearly presented by applying the REST reference than by applying AR when using a 64-channel recording. PMID:29593490

Electromyography Biofeedback Exergames to Enhance Grip Strength and Motivation.

PubMed

Garcia-Hernandez, Nadia; Garza-Martinez, Karen; Parra-Vega, Vicente

2018-02-01

Hand strength weakness affects the performance of most activities of daily living. This study aims to design, develop, and test an electromyography (EMG) biofeedback training system based on serious games to promote motivation and synchronization and proper work intensity in grip exercises for improving hand strength. An EMG surface sensor, soft balls with different stiffness and three exergames, conforms the system to drive videogame clues in response to EMG-inferred grip strength, while overseeing motivation. An experiment was designed to study the effect of performing handgrip (HG) exercises with the proposed system versus traditional exercises. Participants, organized into two groups, followed a training program for each hand. One group followed a HG exergame training (ET) with the dominant hand and traditional HG training with the nondominant hand and inverse sequence by the second group. Initial and final grip forces were measured using a digital dynamometer. Questionnaires evaluated motivation and user experience, and exercise performance was evaluated in terms of work and rest time percentage and maximal voluntary contraction percentage over contraction periods. Data were analyzed for statistically significant differences and increase of means. Participants showed significantly better exercise performance and higher grip forces, with sustained intrinsic motivation and user experience, with the ET. Improvement in force level arises evidently from the synchronized work-rest time pattern and appropriated intensity of the muscle activity. This leads to support that EMG biofeedback exergames improve motor neurons firing and resting.

The Transliminal Brain at Rest: Baseline EEG, Unusual Experiences, and Access to Unconscious Mental Activity

PubMed Central

Fleck, Jessica I.; Green, Deborah L.; Stevenson, Jennifer L.; Payne, Lisa; Bowden, Edward M.; Jung-Beeman, Mark; Kounios, John

2008-01-01

Transliminality reflects individual differences in the threshold at which unconscious processes or external stimuli enter into consciousness. Individuals high in transliminality possess characteristics such as magical ideation, belief in the paranormal, and creative personality traits, and also report the occurrence of manic/mystic experiences. The goal of the present research was to determine if resting brain activity differs for individuals high versus low in transliminality. We compared baseline EEG recordings (eyes-closed) between individuals high versus low in transliminality, assessed using The Revised Transliminality Scale of Lange et al. (2000). Identifying reliable differences at rest between high- and low-transliminality individuals would support a predisposition for transliminality-related traits. Individuals high in transliminality exhibited lower alpha, beta, and gamma power than individuals low in transliminality over left posterior association cortex and lower high alpha, low beta, and gamma power over the right superior temporal region. In contrast, when compared to individuals low in transliminality, individuals high in transliminality exhibited greater gamma power over the frontal-midline region. These results are consistent with prior research reporting reductions in left temporal/parietal activity, as well as the desynchronization of right temporal activity in schizotypy and related schizophrenia spectrum disorders. Further, differences between high- and low-transliminality groups extend existing theories linking altered hemispheric asymmetries in brain activity to a predisposition toward schizophrenia, paranormal beliefs, and unusual experiences. PMID:18814870

Densified edge seals for fuel cell components

DOEpatents

DeCasperis, Anthony J.; Roethlein, Richard J.; Breault, Richard D.

1982-01-01

A porous fuel cell component, such as an electrode substrate, has a densified edge which forms an improved gas seal during operation when soaked with electrolyte. The edges are made from the same composition as the rest of the component and are made by compressing an increased thickness of this material along the edges during the fabrication process.

Kaposi's-sarcoma-associated-herpesvirus-activated dendritic cells promote HIV-1 trans-infection and suppress CD4{sup +} T cell proliferation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Wan; Qin, Yan; Bai, Lei

2013-06-05

Infection of Kaposi's sarcoma-associated herpesvirus (KSHV) is commonly occurred in AIDS patients. KSHV and HIV-1 act cooperatively in regulating infection with each other and in human carcinogenesis. Dendritic cells (DCs), as the pivotal cells in host immunity, may be modulated by both viruses, for immunoevasion and dissemination, therefore, the interaction between DCs and each virus has been a prior focus for pathogenesis elucidation. Here, we assessed the potential effect of KSHV on DC–HIV-1 interaction. We found that KSHV stimulation could promote maturation of monocyte-derived DCs (MDDCs) and impaired the ability of MDDCs to drive proliferation of resting CD4{sup +} Tmore » cells, demonstrating the immunosuppression induced by KSHV. More importantly, KSHV-stimulated MDDCs could capture more HIV-1 and efficiently transferred these infectious viruses to Hut/CCR5 T cell line. Our results reveal the novel modulation of DC-mediated HIV-1 dissemination by KSHV, and highlight the importance of studying DC–HIV-1 interaction to elucidate HIV/AIDS pathogenesis. - Highlights: ► KSHV impaired the ability of MDDCs to drive proliferation of resting CD4{sup +} T cells. ► KSHV stimulation matured MDDCs and enhanced HIV-1 endocytosis. ► KSHV stimulated MDDCs increased ICAM-1 expression and tighten contact with T cells. ► KSHV-stimulated MDDCs promoted HIV-1 trans-infection of CD4{sup +} T cells.« less

Dynamic motion of red blood cells in simple shear flow

NASA Astrophysics Data System (ADS)

Sui, Y.; Chew, Y. T.; Roy, P.; Cheng, Y. P.; Low, H. T.

2008-11-01

A three-dimensional numerical model is proposed to simulate the dynamic motion of red blood cells (RBCs) in simple shear flow. The RBCs are approximated by ghost cells consisting of Newtonian liquid drops enclosed by Skalak membranes which take into account the membrane shear elasticity and the membrane area incompressibility. The RBCs have an initially biconcave discoid resting shape, and the internal liquid is assumed to have the same physical properties as the matrix fluid. The simulation is based on a hybrid method, in which the immersed boundary concept is introduced into the framework of the lattice Boltzmann method, and a finite element model is incorporated to obtain the forces acting on the nodes of the cell membrane which is discretized into flat triangular elements. The dynamic motion of RBCs is investigated in simple shear flow under a broad range of shear rates. At large shear rates, the cells are found to carry out a swinging motion, in which periodic inclination oscillation and shape deformation superimpose on the membrane tank treading motion. With the shear rate decreasing, the swinging amplitude of the cell increases, and finally triggers a transition to tumbling motion. This is the first direct numerical simulation that predicts both the swinging motion of the RBCs and the shear rate induced transition, which have been observed in a recent experiment. It is also found that as the mode changes from swinging to tumbling, the apparent viscosity of the suspension increases monotonically.

The effect of trinitrobenzene sulfonic acid (TNB) on colonocyte arachidonic acid metabolism.

PubMed

Stratton, M D; Sexe, R; Peterson, B; Kaminski, D L; Li, A P; Longo, W E

1996-02-01

In previous studies we found that luminal perfusion of the isolated left colon of the rabbit with the hapten, trinitrobenzene, resulted in the production of an acute inflammatory process associated with alterations in eicosanoid metabolism. As the colitis was attenuated by cyclooxygenase inhibitors it is possible that the inflammation was mediated by arachidonic acid metabolites. In the present study it was intended to evaluate the effect of trinitrobenzene on eicosanoid metabolism in transformed human colonic cells by exposing Caco-2++ cells to various doses of trinitrobenzene. Cell injury was evaluated by measuring lactate dehydrogenase levels and cyclooxygenase and lipoxygenase activity was evaluated by measuring prostanoid and leukotriene production. In separate experiments resting and trinitrobenzene stimulated cells were treated with indomethacin and dexamethasone. Trinitrobenzene produced increased prostaglandin E2 and 6-keto prostaglandin F1alpha++ and increased lactate dehydrogenase levels. Leukotriene B4 was significantly increased compared to control values at the highest TNB concentration administered. Indomethacin inhibited the lactate dehydrogenase and prostanoid changes, suggesting that the inflammatory changes produced were mediated by the prostanoids. Dexamethasone administered for 1 hr prior to trinitrobenzene decreased the 6-keto prostaglandin F1alpha but did not alter trinitrobenzene produced changes in lactate dehydrogenase concentrations. Exposure of Caco-2 cells to dexamethasone for 24 hr decreased the trinitrobenzene produced lactate dehydrogenase and eicosanoid changes. The results suggest that trinitrobenzene produces an acute injury to Caco-2 cells that may be mediated by the cyclooxygenase enzymes.

Regulation of IFN regulatory factor 4 expression in human T cell leukemia virus-I-transformed T cells.

PubMed

Sharma, Sonia; Grandvaux, Nathalie; Mamane, Yael; Genin, Pierre; Azimi, Nazli; Waldmann, Thomas; Hiscott, John

2002-09-15

IFN regulatory factor (IRF)-4 is a lymphoid/myeloid-restricted member of the IRF transcription factor family that plays an essential role in the homeostasis and function of mature lymphocytes. IRF-4 expression is tightly regulated in resting primary T cells and is transiently induced at the mRNA and protein levels after activation by Ag-mimetic stimuli such as TCR cross-linking or treatment with phorbol ester and calcium ionophore (PMA/ionomycin). However, IRF-4 is constitutively upregulated in human T cell leukemia virus type I (HTLV-I) infected T cells as a direct gene target for the HTLV-I Tax oncoprotein. In this study we demonstrate that chronic IRF-4 expression in HTLV-I-infected T lymphocytes is associated with a leukemic phenotype, and we examine the mechanisms by which continuous production of IRF-4 is achieved in HTLV-I-transformed T cells. IRF-4 expression in HTLV-1-infected cells is driven through activation of the NF-kappaB and NF-AT pathways, resulting in the binding of p50, p65, and c-Rel to the kappaB1 element and p50, c-Rel, and NF-ATp to the CD28RE element within the -617 to -209 region of the IRF-4 promoter. Furthermore, mutation of either the kappaB1 or CD28RE sites blocks Tax-mediated transactivation of the human IRF-4 promoter in T cells. These experiments constitute the first detailed analysis of human IRF-4 transcriptional regulation within the context of HTLV-I infection and transformation of CD4(+) T lymphocytes.

The effects of beta 2-agonists and methylxanthines on neutrophil function in vitro.

PubMed

Llewellyn-Jones, C G; Stockley, R A

1994-08-01

Therapeutic agents which affect polymorphonuclear neutrophil (PMN) functions have the potential to reduce or increase PMN activation and, hence, influence the progression of lung inflammation. We have assessed the effects of the beta 2-agonist, terbutaline, and the methylxanthine, aminophylline, on PMN functions in vitro at both therapeutic and higher concentrations. At therapeutic levels, both agents increased PMN chemotaxis to formyl-methionyl-leucyl-phenylalanine (FMLP) in a dose-dependent manner from a control value of 22.5 +/- 3.58 cells.field-1 to 26.1 +/- 4.73 cells.field-1 with 4 mg.l-1 terbutaline, and to 26.3 +/- 4.49 cells.field-1 with 20 mg.l-1 aminophylline. When the cells were preincubated with higher doses of the agents in separate experiments there was inhibition of chemotaxis from a control value of 31.1 +/- 2.06 cells.field-1 to 18.3 +/- 0.82 cells.field-1 at 160 mg.l-1 terbutaline, and to 16.1 +/- 0.77 cells.field-1 at 400 mg.l-1 aminophylline. A similar effect was seen when the PMNs were preincubated with terbutaline and aminophylline prior to assessment of superoxide anion generation, with stimulation of superoxide release at therapeutic levels of the drugs and inhibition at higher doses (19% increase from resting control cells at terbutaline 4 mg.l-1 and 53% reduction at 160 mg.l-1; 28% increase with aminophylline 20 mg.l-1 and 22% reduction at 400 mg.l-1). Both terbutaline and aminophylline had no effect on PMN degranulation, as assessed by the degradation of fibronectin.(ABSTRACT TRUNCATED AT 250 WORDS)

Cell membrane organization is important for inner hair cell MET-channel gating

NASA Astrophysics Data System (ADS)

Effertz, Thomas; Scharr, Alexandra L.; Ricci, Anthony J.

2018-05-01

Specialized sensory cells, hair cells, translate mechanical stimuli into electro/chemical responses. This process, termed mechano-electrical transduction (MET), is localized to the hair cell's sensory organelle, the hair bundle. The mature hair bundle comprises three rows of actin filled stereocilia, arranged in a staircase pattern. Deflections towards the tallest row of stereocilia activate MET channels, residing at the top of stereocilia. While other MET channels can be activated or modulated by changes to their lipid environment, this remains unknown for the mammalian auditory MET channel. We show here that the effect of lipid and cholesterol depletion from the cell membrane affect the MET current as well. We used γ-cyclodextrin to extract lipids form the membrane, reversibly reducing the peak MET current, current adaptation, and decreasing the channels resting open probability. The recovery after γ-cyclodextrin treatment was slower than the initial peak current reduction, suggesting that a specific lipid organization is required for normal MET channel function, which requires time reestablish. Extraction of cholesterol, using Mβ-cyclodextrin, irreversibly reduces the peak MET current and reversibly increases the channel resting open probability, suggesting that cholesterol restricts MET channel opening. This restriction could be useful to increase the channel's signal to noise ratio. Together this data suggests that the cell membrane is part of the force relay machinery to the MET channel and could possibly restrict gating associated conformational changes of the MET channel.

Mechanics of a heartbeat

NSF Multimedia

2017-05-31

Microtubule network in a heart cell at rest and microtubules decorated with a fluorescent protein so they can be visualized with high-resolution microscopy. (Bottom) Compressed microtubules buckle and provide a spring-like resistance to contraction.

Are fingernails a key to unlocking the puzzle of mammalian limb regeneration?

PubMed

Lehoczky, Jessica A

2017-06-01

Some mammalian digit tips, including those of mice and human children, can regenerate following amputation, whereas mammalian limb regeneration does not occur. One major difference between the digit tip and the rest of the limb is the presence of the nail, which is necessary for this type of regeneration. This couples well with the finding that canonical Wnt signalling and Lgr6, an agonist of Wnt signalling that marks nail stem cells, are necessary for digit tip regeneration. This viewpoint essay discusses the role of the nail in digit tip regeneration and explores whether nail stem cells and their presumptive niche can be solely accountable for why regeneration is possible in the digit tip, but not the rest of the limb. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Production of isopropyl cis-6-hexadecenoate by regiospecific desaturation of isopropyl palmitate by a double mutant of a Rhodococcus strain.

PubMed

Koike, K; Takaiwa, M; Ara, K; Inoue, S; Kimura, Y; Ito, S

2000-02-01

Resting cells of a double mutant noted as KSM-MT66, derived from Rhodococcus sp. strain KSM-B-3 by UV irradiation, were found to cis-desaturate isopropyl hexadecanoate, yielding isopropyl cis-6-hexadecenoate. Addition of sodium glutamate (1.0%), Mg SO4 (2 mM), and thiamine (2 mM) increased the productivity of the unsaturated product in phosphate buffer. Optimal temperature and pH for the reaction were around 26 degrees C and 7, respectively. Under the optimized conditions, more than 50 g/l of isopropyl cis-6-hexadecenoate was produced after a 3-day incubation by resting cells of the mutant. Thus, cis-6-hexadecenoic acid, the main component of human sebaceous lipids, can be manufactured economically by the rhodococcal bioconversion.

Perception, Action, and Experience: Unraveling the Golden Braid

ERIC Educational Resources Information Center

Clark, Andy

2009-01-01

Much of our human mental life looks to involve a seamless unfolding of perception, action and experience: a golden braid in which each element twines intimately with the rest. We see the very world we act in and we act in the world we see. But more than this, visual experience presents us with the world in a way apt for the control and fine…

Genipin-induced inhibition of uncoupling protein-2 sensitizes drug-resistant cancer cells to cytotoxic agents.

PubMed

Mailloux, Ryan J; Adjeitey, Cyril Nii-Klu; Harper, Mary-Ellen

2010-10-13

Uncoupling protein-2 (UCP2) is known to suppress mitochondrial reactive oxygen species (ROS) production and is employed by drug-resistant cancer cells to mitigate oxidative stress. Using the drug-sensitive HL-60 cells and the drug-resistant MX2 subline as model systems, we show that genipin, a UCP2 inhibitor, sensitizes drug-resistant cells to cytotoxic agents. Increased MX2 cell death was observed upon co-treatment with genipin and different doses of menadione, doxorubicin, and epirubicin. DCFH-DA fluorimetry revealed that the increase in MX2 cell death was accompanied by enhanced cellular ROS levels. The drug-induced increase in ROS was linked to genipin-mediated inhibition of mitochondrial proton leak. State 4 and resting cellular respiratory rates were higher in the MX2 cells in comparison to the HL-60 cells, and the increased respiration was readily suppressed by genipin in the MX2 cells. UCP2 accounted for a remarkable 37% of the resting cellular oxygen consumption indicating that the MX2 cells are functionally reliant on this protein. Higher amounts of UCP2 protein were detected in the MX2 versus the HL-60 mitochondria. The observed effects of genipin were absent in the HL-60 cells pointing to the selectivity of this natural product for drug-resistant cells. The specificity of genipin for UCP2 was confirmed using CHO cells stably expressing UCP2 in which genipin induced an ∼22% decrease in state 4 respiration. These effects were absent in empty vector CHO cells expressing no UCP2. Thus, the chemical inhibition of UCP2 with genipin sensitizes multidrug-resistant cancer cells to cytotoxic agents.

A defucosylated bispecific multivalent molecule exhibits broad HIV-1 neutralizing activity and enhanced ADCC against reactivated HIV-1 latently infected cells.

PubMed

Kong, Desheng; Wang, Yan; Ji, Ping; Li, Wei; Ying, Tianlei; Huang, Jinghe; Wang, Chen; Wu, Yanling; Wang, Yanping; Chen, Weizao; Hao, Yanling; Hong, Kunxue; Shao, Yiming; Dimitrov, Dimiter S; Jiang, Shibo; Ma, Liying

2018-05-11

Current treatments cannot completely eradicate HIV-1 owing to the presence of latently infected cells which harbor transcriptionally silent HIV-1. However, defucosylated antibodies can readily kill latently infected cells after their activation to express envelope glycoprotein (Env) through antibody-dependent cellular cytotoxicity (ADCC). We herein aimed to test a defucosylated bispecific multivalent molecule consisting of domain-antibody and single-domain CD4, LSEVh-LS-F, for its HIV-1 neutralizing activity and ADCC against the reactivated latently infected cells, compared with the non-defucosylated molecule LSEVh-LS. LSEVh-LS-F's neutralizing activity against a panel of newly characterized Chinese HIV-1 clinical isolates was assessed by using TZM-bl- and PBMC-based assays. LSEVh-LS-F-mediated ADCC in the presence of NK cells against cell lines that stably express Env proteins, HIV-1-infected cells and LRA-reactivated HIV-1 latent cells, was measured using a lactate dehydrogenase (LDH) cytotoxicity assay or flow cytometry. LSEVh-LS-F and LSEVh-LS were equally effective in neutralized infection of all HIV-1 isolates tested with IC50 and IC90 values 3∼4-fold lower than those of VRC01. LSEVh-LS-F was more effective in NK-mediated killing of HIV-1 Env-expressing cell lines, HIV-1-infected cells, latency reactivation agents-reactivated ACH2 cells, and reactivated latently infected resting CD4 T cell line as well as resting CD4 T lymphocytes isolated from patients receiving highly active anti-retroviral therapy (HAART). LSEVh-LS-F exhibits broad HIV-1 neutralizing activity and enhanced ADCC against HIV-1-infected cells, reactivated latently infected cell lines and primary CD4 T cells, thus being a promising candidate therapeutic for eradicating the HIV-1 reservoir.

Intracellular pH regulation in unstimulated Calliphora salivary glands is Na+ dependent and requires V-ATPase activity.

PubMed

Schewe, Bettina; Blenau, Wolfgang; Walz, Bernd

2012-04-15

Salivary gland cells of the blowfly Calliphora vicina have a vacuolar-type H(+)-ATPase (V-ATPase) that lies in their apical membrane and energizes the secretion of a KCl-rich primary saliva upon stimulation with serotonin (5-hydroxytryptamine). Whether and to what extent V-ATPase contributes to intracellular pH (pH(i)) regulation in unstimulated gland cells is unknown. We used the fluorescent dye BCECF to study intracellular pH(i) regulation microfluorometrically and show that: (1) under resting conditions, the application of Na(+)-free physiological saline induces an intracellular alkalinization attributable to the inhibition of the activity of a Na(+)-dependent glutamate transporter; (2) the maintenance of resting pH(i) is Na(+), Cl(-), concanamycin A and DIDS sensitive; (3) recovery from an intracellular acid load is Na(+) sensitive and requires V-ATPase activity; (4) the Na(+)/H(+) antiporter is not involved in pH(i) recovery after a NH(4)Cl prepulse; and (5) at least one Na(+)-dependent transporter and the V-ATPase maintain recovery from an intracellular acid load. Thus, under resting conditions, the V-ATPase and at least one Na(+)-dependent transporter maintain normal pH(i) values of pH 7.5. We have also detected the presence of a Na(+)-dependent glutamate transporter, which seems to act as an acid loader. Despite this not being a common pH(i)-regulating transporter, its activity affects steady-state pH(i) in C. vicina salivary gland cells.

Infants use compression information to infer objects’ weights: Examining cognition, exploration, and prospective action in a preferential-reaching task

PubMed Central

Hauf, Petra; Paulus, Markus; Baillargeon, Renée

2012-01-01

The present research used a preferential-reaching task to examine whether 9- and 11-month-olds (n = 144) could infer the relative weights of two objects resting on a soft, compressible platform. Experiment 1 established that infants reached preferentially for the lighter of two boxes. In Experiments 2 to 4, infants saw two boxes identical except in weight resting on a cotton wool platform. Infants reached prospectively for the lighter box, but only when their initial exploratory activities provided critical information. At 11 months, infants succeeded as long as they first determined that the platform was compressible; at 9 months, infants succeeded only if they also explored the boxes and thus had advance knowledge that they differed in weight. PMID:22861050

Ca2+-Citrate Uptake and Metabolism in Lactobacillus casei ATCC 334

PubMed Central

Mortera, Pablo; Pudlik, Agata; Magni, Christian; Alarcón, Sergio

2013-01-01

The putative citrate metabolic pathway in Lactobacillus casei ATCC 334 consists of the transporter CitH, a proton symporter of the citrate-divalent metal ion family of transporters CitMHS, citrate lyase, and the membrane-bound oxaloacetate decarboxylase complex OAD-ABDH. Resting cells of Lactobacillus casei ATCC 334 metabolized citrate in complex with Ca2+ and not as free citrate or the Mg2+-citrate complex, thereby identifying Ca2+-citrate as the substrate of the transporter CitH. The pathway was induced in the presence of Ca2+ and citrate during growth and repressed by the presence of glucose and of galactose, most likely by a carbon catabolite repression mechanism. The end products of Ca2+-citrate metabolism by resting cells of Lb. casei were pyruvate, acetate, and acetoin, demonstrating the activity of the membrane-bound oxaloacetate decarboxylase complex OAD-ABDH. Following pyruvate, the pathway splits into two branches. One branch is the classical citrate fermentation pathway producing acetoin by α-acetolactate synthase and α-acetolactate decarboxylase. The other branch yields acetate, for which the route is still obscure. Ca2+-citrate metabolism in a modified MRS medium lacking a carbohydrate did not significantly affect the growth characteristics, and generation of metabolic energy in the form of proton motive force (PMF) was not observed in resting cells. In contrast, carbohydrate/Ca2+-citrate cometabolism resulted in a higher biomass yield in batch culture. However, also with these cells, no generation of PMF was associated with Ca2+-citrate metabolism. It is concluded that citrate metabolism in Lb. casei is beneficial when it counteracts acidification by carbohydrate metabolism in later growth stages. PMID:23709502

Simultaneous two-photon imaging of cerebral oxygenation and capillary blood flow in atherosclerotic mice

NASA Astrophysics Data System (ADS)

Lu, Xuecong; Li, Baoqiang; Moeini, Mohammad; Lesage, Frédéric

2017-02-01

Gradual changes in brain microvasculature and cerebral capillary blood flow occurring with atherosclerosis may significantly contribute to cognition decline due to their role in brain tissue oxygenation. However, previous stud- ies of the relationship between cerebral capillary blood flow and brain tissue oxygenation are limited. This study aimed to investigate vascular and concomitant changes in brain tissue pO2 with atherosclerosis. Experiments in young healthy C57B1/6 mice (n=6 , WT), young atherosclerotic mice (n=6 , ATX Y) and old atherosclerotic mice (n=6 , ATX O) were performed imaging on the left sensory-motor cortex at resting state under urethane (1.5 g/kg) anesthesia using two-photon fluorescence microscopy. The results showed that pO2 around capillaries, correlated with red blood cell (RBC) flux, increased with atherosclerosis.

Cleanrooms and tissue banking how happy I could be with either GMP or GTP?

PubMed

Klykens, J; Pirnay, J-P; Verbeken, G; Giet, O; Baudoux, E; Jashari, R; Vanderkelen, A; Ectors, N

2013-12-01

The regulatory framework of tissue banking introduces a number of requirements for monitoring cleanrooms for processing tissue or cell grafts. Although a number of requirements were clearly defined, some requirements are open for interpretation. This study aims to contribute to the interpretation of GMP or GTP guidelines for tissue banking. Based on the experience of the participating centers, the results of the monitoring program were evaluated to determine the feasibility of a cleanroom in tissue banking and the monitoring program. Also the microbial efficacy of a laminar airflow cabinet and an incubator in a cleanroom environment was evaluated. This study indicated that a monitoring program of a cleanroom at rest in combination with (final) product testing is a feasible approach. Although no statistical significance (0.90 < p < 0.95) was found there is a strong indication that a Grade D environment is not the ideal background environment for a Grade A obtained through a laminar airflow cabinet. The microbial contamination of an incubator in a cleanroom is limited but requires closed containers for tissue and cell products.

Comparison of colony stimulation factors on in vitro rat and human neutrophil function.

PubMed

Wheeler, J G; Huffine, M E; Childress, S; Sikes, J

1994-01-01

The effects of rhCSFs on in vitro polymorphonuclear leukocyte (PMN) function were studied in Sprague-Dawley neonatal and adult rats and adult and umbilical cord derived human PMN to compare species response. Following in vitro exposure to buffer or rhCSFs (50-100 micrograms/ml), PMN oxidative burst, chemotactic activity and adherence protein expression were measured. RhG-CSF increased the oxidative burst of adult rat PMN as measured by chemiluminescence and altered CD11b/CD18 in resting neonatal rat but not adult rat cells. RhGM-CSF had no effect on adult rat PMN function in vitro, but led to modest changes in adult rat PMN diapedesis across rat peritoneum. No responses were noted to rhM-CSF. Human PMN responded best to GM-CSF (particularly in the neonate), intermediately to G-CSF and none to M-CSF. These experiments show that the profile of cytokine effects is not similar in adult and neonatal rat PMN when compared to human cells. The diversity of actions in other species must be considered when using rhCSFs in animal models.

Executive Control and the Experience of Regret

ERIC Educational Resources Information Center

Burns, Patrick; Riggs, Kevin J.; Beck, Sarah R.

2012-01-01

The experience of regret rests on a counterfactual analysis of events. Previous research indicates that regret emerges at around 6 years of age, marginally later than the age at which children begin to answer counterfactual questions correctly. We hypothesized that the late emergence of regret relative to early counterfactual thinking is a result…

The neurotoxicant PCB-95 by increasing the neuronal transcriptional repressor REST down-regulates caspase-8 and increases Ripk1, Ripk3 and MLKL expression determining necroptotic neuronal death.

PubMed

Guida, Natascia; Laudati, Giusy; Serani, Angelo; Mascolo, Luigi; Molinaro, Pasquale; Montuori, Paolo; Di Renzo, Gianfranco; Canzoniero, Lorella M T; Formisano, Luigi

2017-10-15

Our previous study showed that the environmental neurotoxicant non-dioxin-like polychlorinated biphenyl (PCB)-95 increases RE1-silencing transcription factor (REST) expression, which is related to necrosis, but not apoptosis, of neurons. Meanwhile, necroptosis is a type of a programmed necrosis that is positively regulated by receptor interacting protein kinase 1 (RIPK1), RIPK3 and mixed lineage kinase domain-like (MLKL) and negatively regulated by caspase-8. Here we evaluated whether necroptosis contributes to PCB-95-induced neuronal death through REST up-regulation. Our results demonstrated that in cortical neurons PCB-95 increased RIPK1, RIPK3, and MLKL expression and decreased caspase-8 at the gene and protein level. Furthermore, the RIPK1 inhibitor necrostatin-1 or siRNA-mediated RIPK1, RIPK3 and MLKL expression knockdown significantly reduced PCB-95-induced neuronal death. Intriguingly, PCB-95-induced increases in RIPK1, RIPK3, MLKL expression and decreases in caspase-8 expression were reversed by knockdown of REST expression with a REST-specific siRNA (siREST). Notably, in silico analysis of the rat genome identified a REST consensus sequence in the caspase-8 gene promoter (Casp8-RE1), but not the RIPK1, RIPK3 and MLKL promoters. Interestingly, in PCB-95-treated neurons, REST binding to the Casp8-RE1 sequence increased in parallel with a reduction in its promoter activity, whereas under the same experimental conditions, transfection of siREST or mutation of the Casp8-RE1 sequence blocked PCB-95-induced caspase-8 reduction. Since RIPK1, RIPK3 and MLKL rat genes showed no putative REST binding site, we assessed whether the transcription factor cAMP Responsive Element Binding Protein (CREB), which has a consensus sequence in all three genes, affected neuronal death. In neurons treated with PCB-95, CREB protein expression decreased in parallel with a reduction in binding to the RIPK1, RIPK3 and MLKL gene promoter sequence. Furthermore, CREB overexpression was associated with reduced promoter activity of the RIPK1, RIPK3 and MLKL genes. Collectively, these results indicate that PCB-95 was associated with REST-induced necroptotic cell death by increasing RIPK1, RIPK3 and MLKL expression and reducing caspase-8 levels. In addition, since REST is involved in several neurological disorders, therapies that block REST-induced necroptosis could be a new strategy to revert the neurodetrimental effects associated to its overexpression. Copyright © 2017 Elsevier Inc. All rights reserved.

Wide-area mapping of resting state hemodynamic correlations at microvascular resolution with multi-contrast optical imaging (Conference Presentation)

NASA Astrophysics Data System (ADS)

Senarathna, Janaka; Hadjiabadi, Darian; Gil, Stacy; Thakor, Nitish V.; Pathak, Arvind P.

2017-02-01

Different brain regions exhibit complex information processing even at rest. Therefore, assessing temporal correlations between regions permits task-free visualization of their `resting state connectivity'. Although functional MRI (fMRI) is widely used for mapping resting state connectivity in the human brain, it is not well suited for `microvascular scale' imaging in rodents because of its limited spatial resolution. Moreover, co-registered cerebral blood flow (CBF) and total hemoglobin (HbT) data are often unavailable in conventional fMRI experiments. Therefore, we built a customized system that combines laser speckle contrast imaging (LSCI), intrinsic optical signal (IOS) imaging and fluorescence imaging (FI) to generate multi-contrast functional connectivity maps at a spatial resolution of 10 μm. This system comprised of three illumination sources: a 632 nm HeNe laser (for LSCI), a 570 nm ± 5 nm filtered white light source (for IOS), and a 473 nm blue laser (for FI), as well as a sensitive CCD camera operating at 10 frames per second for image acquisition. The acquired data enabled visualization of changes in resting state neurophysiology at microvascular spatial scales. Moreover, concurrent mapping of CBF and HbT-based temporal correlations enabled in vivo mapping of how resting brain regions were linked in terms of their hemodynamics. Additionally, we complemented this approach by exploiting the transit times of a fluorescent tracer (Dextran-FITC) to distinguish arterial from venous perfusion. Overall, we demonstrated the feasibility of wide area mapping of resting state connectivity at microvascular resolution and created a new toolbox for interrogating neurovascular function.

Study of DNA extraction methods for use in loop-mediated isothermal amplification detection of single resting cysts in the toxic dinoflagellates Alexandrium tamarense and A. catenella.

PubMed

Nagai, Satoshi; Yamamoto, Keigo; Hata, Naotugu; Itakura, Shigeru

2012-09-01

In a previous study, we experienced instable amplification and a low amplification success in loop-mediated isothermal amplification (LAMP) reactions from naturally occurring vegetative cells or resting cysts of the toxic dinoflagellates Alexandrium tamarense and Alexandrium catenella. In this study, we examined 4 methods for extracting DNA from single resting cysts of A. tamarense and A. catenella to obtain more stable and better amplification success and to facilitate unambiguous detection using the LAMP method. Apart from comparing the 4 different DNA extraction methods, namely, (1) boiling in Tris-EDTA (TE) buffer, (2) heating at 65 °C in hexadecyltrimethylammonium bromide buffer, (3) boiling in 0.5% Chelex buffer, and (4) boiling in 5% Chelex buffer, we also examined the need for homogenization to crush the resting cysts before DNA extraction in each method. Homogenization of resting cysts was found to be essential for DNA extraction in all 4 methods. The detection time was significantly shorter in 5% Chelex buffer than in the other buffers and the amplification success was 100% (65/65), indicating the importance of DNA extraction and the effectiveness of 5% Chelex buffer in the Alexandrium LAMP. Copyright © 2012 Elsevier B.V. All rights reserved.

Regulation of voltage-gated Ca(2+) currents by Ca(2+)/calmodulin-dependent protein kinase II in resting sensory neurons.

PubMed

Kostic, Sandra; Pan, Bin; Guo, Yuan; Yu, Hongwei; Sapunar, Damir; Kwok, Wai-Meng; Hudmon, Andy; Wu, Hsiang-En; Hogan, Quinn H

2014-09-01

Calcium/calmodulin-dependent protein kinase II (CaMKII) is recognized as a key element in encoding depolarization activity of excitable cells into facilitated voltage-gated Ca(2+) channel (VGCC) function. Less is known about the participation of CaMKII in regulating VGCCs in resting cells. We examined constitutive CaMKII control of Ca(2+) currents in peripheral sensory neurons acutely isolated from dorsal root ganglia (DRGs) of adult rats. The small molecule CaMKII inhibitor KN-93 (1.0μM) reduced depolarization-induced ICa by 16-30% in excess of the effects produced by the inactive homolog KN-92. The specificity of CaMKII inhibition on VGCC function was shown by the efficacy of the selective CaMKII blocking peptide autocamtide-2-related inhibitory peptide in a membrane-permeable myristoylated form, which also reduced VGCC current in resting neurons. Loss of VGCC currents is primarily due to reduced N-type current, as application of mAIP selectively reduced N-type current by approximately 30%, and prior N-type current inhibition eliminated the effect of mAIP on VGCCs, while prior block of L-type channels did not reduce the effect of mAIP on total ICa. T-type currents were not affected by mAIP in resting DRG neurons. Transduction of sensory neurons in vivo by DRG injection of an adeno-associated virus expressing AIP also resulted in a loss of N-type currents. Together, these findings reveal a novel molecular adaptation whereby sensory neurons retain CaMKII support of VGCCs despite remaining quiescent. Published by Elsevier Inc.

Signal Sampling for Efficient Sparse Representation of Resting State FMRI Data

PubMed Central

Ge, Bao; Makkie, Milad; Wang, Jin; Zhao, Shijie; Jiang, Xi; Li, Xiang; Lv, Jinglei; Zhang, Shu; Zhang, Wei; Han, Junwei; Guo, Lei; Liu, Tianming

2015-01-01

As the size of brain imaging data such as fMRI grows explosively, it provides us with unprecedented and abundant information about the brain. How to reduce the size of fMRI data but not lose much information becomes a more and more pressing issue. Recent literature studies tried to deal with it by dictionary learning and sparse representation methods, however, their computation complexities are still high, which hampers the wider application of sparse representation method to large scale fMRI datasets. To effectively address this problem, this work proposes to represent resting state fMRI (rs-fMRI) signals of a whole brain via a statistical sampling based sparse representation. First we sampled the whole brain’s signals via different sampling methods, then the sampled signals were aggregate into an input data matrix to learn a dictionary, finally this dictionary was used to sparsely represent the whole brain’s signals and identify the resting state networks. Comparative experiments demonstrate that the proposed signal sampling framework can speed-up by ten times in reconstructing concurrent brain networks without losing much information. The experiments on the 1000 Functional Connectomes Project further demonstrate its effectiveness and superiority. PMID:26646924

Electron shuttle-mediated biotransformation of hexahydro-1,3,5-trinitro-1,3,5-triazine adsorbed to granular activated carbon.

PubMed

Millerick, Kayleigh; Drew, Scott R; Finneran, Kevin T

2013-08-06

Granular activated carbon (GAC) effectively removes hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) from groundwater but generates RDX-laden GAC that must be disposed of or regenerated. Batch reactors containing GAC to which RDX was preadsorbed were used in experiments to test the potential for adsorbed RDX reduction and daughter product formation using (i) chemically reduced anthrahydroquinone-2,6-disulfonate (AH2QDS), (ii) resting Geobacter metallireducens strain GS-15, and (iii) a combined system containing AQDS and GS-15. Approximately 97.0% of the adsorbed RDX was transformed in each of these experimental systems by 90 h. Chemically reduced AQDS (AH2QDS) transformed 99.2% of adsorbed RDX; formaldehyde was produced rapidly and was stoichiometric (3 mol HCHO per mol RDX). Geobacter metallireducens also reduced RDX with and without AQDS present. This is the first study to demonstrate biological transformation of RDX adsorbed to GAC. Formaldehyde increased and then decreased in biological systems, suggesting a previously unreported capacity for G. metallireducens to oxidize formaldehyde, which was confirmed with resting cell suspensions. These data suggest the masses of GAC waste currently produced by activated carbon at RDX remediation sites can be minimized, decreasing the carbon footprint of the treatment technology. Alternatively, this strategy may be used to develop a Bio-GAC system for ex situ RDX treatment.

Concussions in Kids

MedlinePlus

... nights, and no sleepovers. Rest also involves a mental time out. No using a computer, cell phone, or ... a place for exercise at…Social PhobiaRead Article >>Mental HealthSocial ... Living Travel Occupational Health First Aid and Injury Prevention Crisis ...

Mouth and neck radiation - discharge

MedlinePlus

... to doing. Try to get more sleep at night. Rest during the day when you can. Take a few weeks off ... neck - discharge; Head and neck cancer - radiation; Squamous cell cancer - mouth and neck radiation; Mouth and neck ...

Analysis of Dibenzothiophene Desulfurization in a Recombinant Pseudomonas putida Strain▿

PubMed Central

Calzada, Javier; Zamarro, María T.; Alcón, Almudena; Santos, Victoria E.; Díaz, Eduardo; García, José L.; Garcia-Ochoa, Felix

2009-01-01

Biodesulfurization was monitored in a recombinant Pseudomonas putida CECT5279 strain. DszB desulfinase activity reached a sharp maximum at the early exponential phase, but it rapidly decreased at later growth phases. A model two-step resting-cell process combining sequentially P. putida cells from the late and early exponential growth phases was designed to significantly increase biodesulfurization. PMID:19047400

Method of forming densified edge seals for fuel cell components

DOEpatents

DeCasperis, Anthony J.; Roethlein, Richard J.; Breault, Richard D.

1981-01-01

A porous fuel cell component, such as an electrode substrate, has a densified edge which forms an improved gas seal during operation when soaked with electrolyte. The edges are made from the same composition as the rest of the component and are made by compressing an increased thickness of this material along the edges during the fabrication process.

Enzymatic Recovery of Elemental Palladium by Using Sulfate-Reducing Bacteria

PubMed Central

Lloyd, Jon R.; Yong, Ping; Macaskie, Lynne E.

1998-01-01

Worldwide usage of platinum group metals is increasing, prompting new recovery technologies. Resting cells of Desulfovibrio desulfuricans reduced soluble Pd2+ to elemental, cell-bound Pd0 supported by pyruvate, formate, or H2 as the electron donor without biochemical cofactors. Pd reduction was O2 insensitive, opening the way for recycling and recovery of Pd under oxic conditions. PMID:9797331

Macromolecular assembly of the adaptor SLP-65 at intracellular vesicles in resting B cells.

PubMed

Engelke, Michael; Pirkuliyeva, Sona; Kühn, Julius; Wong, Leo; Boyken, Janina; Herrmann, Nadine; Becker, Stefan; Griesinger, Christian; Wienands, Jürgen

2014-08-19

The traditional view of how intracellular effector proteins are recruited to the B cell antigen receptor (BCR) complex at the plasma membrane is based on the occurrence of direct protein-protein interactions, as exemplified by the recruitment of the tyrosine kinase Syk (spleen tyrosine kinase) to phosphorylated motifs in BCR signaling subunits. By contrast, the subcellular targeting of the cytosolic adaptor protein SLP-65 (Src homology 2 domain-containing leukocyte adaptor protein of 65 kD), which serves as a proximal Syk substrate, is unclear. We showed that SLP-65 activation required its association at vesicular compartments in resting B cells. A module of ~50 amino acid residues located at the amino terminus of SLP-65 anchored SLP-65 to the vesicles. Nuclear magnetic resonance spectroscopy showed that the SLP-65 amino terminus was structurally disordered in solution but could bind in a structured manner to noncharged lipid components of cellular membranes. Our finding that preformed vesicular signaling scaffolds are required for B cell activation indicates that vesicles may deliver preassembled signaling cargo to sites of BCR activation. Copyright © 2014, American Association for the Advancement of Science.

Production of twin /Λ-hypernuclei from Ξ- hyperon capture at rest

NASA Astrophysics Data System (ADS)

Ichikawa, A.; Ahn, J. K.; Akikawa, H.; Aoki, S.; Arai, K.; Bahk, S. Y.; Baik, K. M.; Bassalleck, B.; Chung, J. H.; Chung, M. S.; Hoshino, K.; Ieiri, M.; Imai, K.; Iwata, Y. H.; Iwata, Y. S.; Kanda, H.; Kaneko, M.; Kawai, T.; Kim, C. O.; Kim, J. Y.; Kim, S. J.; Kim, S. H.; Kondo, Y.; Kouketsu, T.; Lee, Y. L.; McNabb, J. W. C.; Mitsuhara, M.; Nagase, Y.; Nagoshi, C.; Nakazawa, K.; Noumi, H.; Ogawa, S.; Okabe, H.; Oyama, K.; Park, H. M.; Park, I. G.; Parker, J.; Ra, Y. S.; Rhee, J. T.; Rusek, A.; Shibuya, H.; Sim, K. S.; Saha, P. K.; Seki, D.; Sekimoto, M.; Song, J. S.; Takahashi, H.; Takahashi, T.; Takeutchi, F.; Tanaka, H.; Tanida, K.; Tojo, J.; Torii, H.; Torikai, S.; Ushida, N.; Yamamoto, K.; Yasuda, N.; Yang, J. T.; Yoon, C. J.; Yoon, C. S.; Yosoi, M.; Yoshida, T.; Zhu, L.

2001-02-01

A hybrid emulsion experiment was carried out to study double-strangeness nuclei produced via Ξ- hyperon capture at rest with the expectation of ten times larger statistics than previous experiments. We have analyzed 5% of the total emulsion and found one ``twin-hypernuclei'' event involving the emission of two single-/Λ hypernuclei and a nuclear fragment from a Ξ- hyperon stopping point. The event is interpreted as the decay of a Ξ-+14N atomic system to 5ΛHe+5ΛHe+4He+neutron. The species of the Ξ--atom and the fragmentation products are uniquely identified for the first time for twin-hypernuclei events. Combined with the results from a past hybrid-emulsion experiment, one double-/Λ hypernucleus and three twin-hypernuclei events have been found from Ξ- captures on light emulsion nuclei. The ratio of the detected rate of double-/Λ hypernuclei to that of twin-hypernuclei is compared with theoretical estimates.

Functional characterization of a regulatory human T-cell subpopulation increasing during autologous MLR.

PubMed Central

Cosulich, M E; Risso, A; Canonica, G W; Bargellesi, A

1986-01-01

The present study was undertaken to investigate the heterogeneity of helper T cells in humans using two different monoclonal antibodies: 5/9 and MLR4. The former identifies 15-20% of resting T lymphocytes from peripheral blood and corresponds to an anti-helper/inducer T cell. The second antibody, MLR4, recognizes 5% of total T lymphocytes and partially overlaps with the 5/9+ T cells. In order to investigate functional differences within the 5/9+ cells, we separated two different subsets (5/9+ MLR+ and 5/9+ MLR4-) by a rosetting technique. Although both subsets provide help for Ig synthesis in a PWM-stimulated culture, only the 5/9+ MLR4- fraction gave a proliferative response in both autologous and allogeneic MLR and to soluble protein antigens. The effect of radiation on the ability of the two subsets to provide help for Ig synthesis showed that the 5/9+ MLR4+ subset is highly radiation-sensitive, while 5/9+ MLR- is relatively radiation-resistant. In a further series of experiments, 5/9+ MLR4+ cells isolated after activation in an autologous MLR but not by Con A, were no longer able to induce T-cell differentiation but now showed a strong suppressor effect. The 5/9+ MLR4- subset separated from the same cultures did not display any suppressor function. These data demonstrate in fresh PBL the existence of a radiation-sensitive regulatory subset exerting a helper activity, and which acquires suppressor activity after activation in autologous MLR. PMID:2936679

ABDOMINAL PAIN IN ADULT SICKLE CELL DISEASE PATIENTS: A NIGERIAN EXPERIENCE

PubMed Central

Akingbola, T.S.; Kolude, B.; Aneni, E.C.; Raji, A.A.; Iwara, K.U.; Aken’Ova, Y.A.; Soyannwo, O.A.

2011-01-01

Background: Abdominal pain is a relatively frequent occurrence in sickle cell disease. The aetiology of abdominal pain in sickle cell disease is often difficult to diagnose clinically. Despite the frequent occurrence, diagnostic dilemma, and the need for an accurate, early diagnosis, abdominal pain in sickle cell disease has not been rigorously studied. Objective: We therefore sought to describe the different presentations and patterns of abdominal pain in persons with sickle cell disease. Methods: A prospective case series of 20 patients was done in which data was collected on demographic characteristics, hemoglobin electrophoresis patterns, a description of the abdominal pain including sites, severity, and type of pain, packed cell volume and the provisional and final diagnosis. Results: Haemoglobin S patients were 17 in number constituting eightyfive percent (85%) of our study population whilst the rest 3 were Hb S+C. Most patients (70%) had one site of abdominal pain. The pain was mainly colicky or tightening, moderate to severe in nature and, in some cases, associated with vomiting. We did not find any significant difference between the steady state PCV and the PCV during the acute abdominal pain episodes. The final diagnosis showed that only 38.8% of the patients had vasoocclusive crises and the reliability index between the provisional diagnosis and the final diagnosis was 67%. Conclusion: Abdominal pain in sickle cell disease may present in different ways and it is important to recognize that the possible diagnoses are numerous. Not all cases are due to vasoocclusive crises. Early diagnosis and prompt treatment can be life saving. PMID:25161492

The exercise-induced biochemical milieu enhances collagen content and tensile strength of engineered ligaments.

PubMed

West, Daniel W D; Lee-Barthel, Ann; McIntyre, Todd; Shamim, Baubak; Lee, Cassandra A; Baar, Keith

2015-10-15

Exercise stimulates a dramatic change in the concentration of circulating hormones, such as growth hormone (GH), but the biological functions of this response are unclear. Pharmacological GH administration stimulates collagen synthesis; however, whether the post-exercise systemic milieu has a similar action is unknown. We aimed to determine whether the collagen content and tensile strength of tissue-engineered ligaments is enhanced by serum obtained post-exercise. Primary cells from a human anterior cruciate ligament (ACL) were used to engineer ligament constructs in vitro. Blood obtained from 12 healthy young men 15 min after resistance exercise contained GH concentrations that were ∼7-fold greater than resting serum (P < 0.001), whereas IGF-1 was not elevated at this time point (P = 0.21 vs. rest). Ligament constructs were treated for 7 days with medium supplemented with serum obtained at rest (RestTx) or 15 min post-exercise (ExTx), before tensile testing and collagen content analysis. Compared with RestTx, ExTx enhanced collagen content (+19%; 181 ± 33 vs. 215 ± 40 μg per construct P = 0.001) and ligament mechanical properties - maximal tensile load (+17%, P = 0.03 vs. RestTx) and ultimate tensile strength (+10%, P = 0.15 vs. RestTx). In a separate set of engineered ligaments, recombinant IGF-1, but not GH, enhanced collagen content and mechanics. Bioassays in 2D culture revealed that acute treatment with post-exercise serum activated mTORC1 and ERK1/2. In conclusion, the post-exercise biochemical milieu, but not recombinant GH, enhances collagen content and tensile strength of engineered ligaments, in association with mTORC1 and ERK1/2 activation. © 2015 The Authors. The Journal of Physiology © 2015 The Physiological Society.

T cells which proliferate in response to concanavalin A include cells which proliferate in mixed leucocyte reactions.

PubMed

Watanabe, T; Fathman, C G; Coutinho, A

1977-09-01

Selection in long-term culture of alloreactive T cells, by successive in vitro restimulation with semi-allogeneic cells, results in primed responder cell populations which maintain full proliferative reactivity to allogeneic cells as well as to the T cell mitogens concanavalin A (Con A) and phytohemagglutinin (PHA) but are depleted of cells which can effect target cell destruction in either a specific or nonspecific manner. Con A-induced T cell blasts (selected by velocity sedimentation) can revert to small resting lymphocytes in the presence of inert "filler" cells. Con A blasts which have reverted, readily proliferate in response to Con A or allogeneic stimulator cells but are largely depleted of effector killer cells and PHA-responsive cells.

Dynamics and certain mechanisms in the changes of the skeletal-muscular system of man under bedrest conditions

NASA Technical Reports Server (NTRS)

Oganov, V. G.

1977-01-01

Bed rest conditions evaluated varied in the longitudinal axis of the body, perpendicular to the vector gravitational forces, and the cranial portion of the body inclined from the horizontal. The duration of bed rest fluctuated in various experiments from 30 to 182 days. The state of muscle and neuromuscular system was judged on the basis of the recording of various functional indices, as well as by certain results of morphological and biochemical studies and data from the study of motor functions.

How Visual Is the Visual Cortex? Comparing Connectional and Functional Fingerprints between Congenitally Blind and Sighted Individuals.

PubMed

Wang, Xiaoying; Peelen, Marius V; Han, Zaizhu; He, Chenxi; Caramazza, Alfonso; Bi, Yanchao

2015-09-09

Classical animal visual deprivation studies and human neuroimaging studies have shown that visual experience plays a critical role in shaping the functionality and connectivity of the visual cortex. Interestingly, recent studies have additionally reported circumscribed regions in the visual cortex in which functional selectivity was remarkably similar in individuals with and without visual experience. Here, by directly comparing resting-state and task-based fMRI data in congenitally blind and sighted human subjects, we obtained large-scale continuous maps of the degree to which connectional and functional "fingerprints" of ventral visual cortex depend on visual experience. We found a close agreement between connectional and functional maps, pointing to a strong interdependence of connectivity and function. Visual experience (or the absence thereof) had a pronounced effect on the resting-state connectivity and functional response profile of occipital cortex and the posterior lateral fusiform gyrus. By contrast, connectional and functional fingerprints in the anterior medial and posterior lateral parts of the ventral visual cortex were statistically indistinguishable between blind and sighted individuals. These results provide a large-scale mapping of the influence of visual experience on the development of both functional and connectivity properties of visual cortex, which serves as a basis for the formulation of new hypotheses regarding the functionality and plasticity of specific subregions. Significance statement: How is the functionality and connectivity of the visual cortex shaped by visual experience? By directly comparing resting-state and task-based fMRI data in congenitally blind and sighted subjects, we obtained large-scale continuous maps of the degree to which connectional and functional "fingerprints" of ventral visual cortex depend on visual experience. In addition to revealing regions that are strongly dependent on visual experience (early visual cortex and posterior fusiform gyrus), our results showed regions in which connectional and functional patterns are highly similar in blind and sighted individuals (anterior medial and posterior lateral ventral occipital temporal cortex). These results serve as a basis for the formulation of new hypotheses regarding the functionality and plasticity of specific subregions of the visual cortex. Copyright © 2015 the authors 0270-6474/15/3512545-15$15.00/0.

Comparison of the lateral retention forces on sessile and pendant water drops on a solid surface

NASA Astrophysics Data System (ADS)

de la Madrid, Rafael; Whitehead, Taylor; Irwin, George M.

2015-06-01

We present a simple experiment that demonstrates how a water drop hanging from a Plexiglas surface (pendant drop) experiences a lateral retention force that is comparable to, and in some cases larger than, the lateral retention force on a drop resting on top of the surface (sessile drop). The experiment also affords a simple demonstration of the Coriolis effect in two dimensions.

Exploring the interaction of physical exercise load and pattern recall performance in female handball players.

PubMed

Schapschröer, M; Baker, J; Schorer, J

2016-06-01

Studies examining experts' superiority within domain-specific structured pattern recall tasks have typically had athletes perform them at rest, which is far different from how they are executed in their sport. The aim of this study was to investigate whether performing these tasks under different physical exercise intensities influenced pattern recall results of experts, advanced and novices. In two experiments, 68 participants (experiment 1: n = 33; experiment 2: n = 35) were tested using a handball-specific pattern recall task both at rest and during physical exercise. Physical exercises of 60 % heart rate reserve (constant workload: experiment 1) and of 86.5-90 % HRmax (handball-specific interval load: experiment 2) were induced. Results of both experiments revealed significant group differences with experts recalling patterns more accurately than novices but no significant within-subject differences for the two conditions and no interaction between both factors. Our findings replicate prior research concerning perceptual-cognitive expertise in structured specific pattern recall tasks. However, the lack of intergroup differences between the two conditions or interactions was surprising, suggesting sport-specific pattern recall skill is robust to changes in exercise stimuli. Future work is needed to further examine the impact of "physiological specificity" on perceptual-cognitive expertise.

Liquid level sensing device

DOEpatents

Tokarz, Richard D.

1983-01-01

A liquid level sensing device comprising a load cell supporting a column or stack of segments freely resting on one another. The density of each element is substantially identical to that of the surrounding liquid. The elements are freely guided within a surrounding tube. As each element is exposed above the liquid level, its weight will be impressed through the column to the load cell, thereby providing a signal at the load cell directly proportional to the liquid level elevation.

Bepridil exacerbates glutamate-induced deterioration of calcium homeostasis and cultured nerve cell injury.

PubMed

Storozhevykh, T P; Sorokina, E G; Vinskaya, N P; Pinelis, V G; Vergun, O V; Fayuk, D A; Sobolevskiy, A I; Khodorov, B I

1996-12-01

Application of 50 microM bepridil (BPD) to cultured nerve cells did not greatly affect the resting cytoplasmic Ca2+ concentration ([Ca2+]i) but caused its pronounced increase both during prolonged glutamate (GLU, 100 microM) treatment and, especially, in the postglutamate period in case of partial [Ca2+]i recovery. In contrast, in cells exhibiting a high [Ca2+]i plateau in the postglutamate period, BPD application either did not cause any additional elevation of [Ca2+]i or caused a very small increase. Under identical conditions replacement of external Na+ by Li+ or N-methyl-D-glucamine (NMDG) either did not change [Ca2+]i or produced a very small increase, strongly indicating that the BPD-evoked Ca2+ responses could not be explained solely by Na+/Ca2+ exchange inhibition but resulted from some other BPD effects. Indeed, in experiments with Rhodamine 123-loaded neurons it has been shown that 50 microM BPD induced prominent mitochondrial depolarization which is known to abolish the mitochondrial Ca2+ uptake. Finally it was revealed that BPD application to the cell culture either in the period of a prolonged (15 min) GLU action or, especially, in the postglutamate period greatly exacerbated delayed neuronal death, apparently due to a complex inhibitory action of the drug on both Ca2+ buffering and Ca2+ extrusion systems.

Spontaneous calcium waves in Bergman glia increase with age and hypoxia and may reduce tissue oxygen.

PubMed

Mathiesen, Claus; Brazhe, Alexey; Thomsen, Kirsten; Lauritzen, Martin

2013-02-01

Glial calcium (Ca(2+)) waves constitute a means to spread signals between glial cells and to neighboring neurons and blood vessels. These waves occur spontaneously in Bergmann glia (BG) of the mouse cerebellar cortex in vivo. Here, we tested three hypotheses: (1) aging and reduced blood oxygen saturation alters wave activity; (2) glial Ca(2+) waves change cerebral oxygen metabolism; and (3) neuronal and glial wave activity is correlated. We used two-photon microscopy in the cerebellar cortexes of adult (8- to 15-week-old) and aging (48- to 80-week-old) ketamine-anesthetized mice after bolus loading with OGB-1/AM and SR101. We report that the occurrence of spontaneous waves is 20 times more frequent in the cerebellar cortex of aging as compared with adult mice, which correlated with a reduction in resting brain oxygen tension. In adult mice, spontaneous glial wave activity increased on reducing resting brain oxygen tension, and ATP-evoked glial waves reduced the tissue O(2) tension. Finally, although spontaneous Purkinje cell (PC) activity was not associated with increased glia wave activity, spontaneous glial waves did affect intracellular Ca(2+) activity in PCs. The increased wave activity during aging, as well as low resting brain oxygen tension, suggests a relationship between glial waves, brain energy homeostasis, and pathology.

The high energy demand of neuronal cells caused by passive leak currents is not a waste of energy.

PubMed

Berndt, Nikolaus; Holzhütter, Hermann-Georg

2013-11-01

It is estimated that maintenance of the resting potential of neurons consumes between 15% (in gray matter) and 44% (in fully myelinated white matter) of the brain's total energy budget [1]. This poses the intriguing question why evolution has not strived to lower the permeability of passive ion channels to cut the high resting-state energy budget of the brain. Based on a conceptual mathematical model of neuronal ion currents and action potential (AP) firing we demonstrate that a neuron endowed with small leak currents and correspondingly low energy consumption by the Na(+)/K(+)-ATPase in the resting state may indeed recapitulate all features of normal AP firing. However, the activation and inactivation of such a "low-energy-cost neuron" turns out to be extremely sensitive to small fluctuation of Na(+) currents associated with Na(+)-dependent secondary-active transport that is indispensable for the metabolic integrity of the cell and neurotransmitter recycling. We provide evidence that sufficiently large leak currents function as important stabilizers of the membrane potential and thus are required to allow robust AP firing. Our simulations suggest that the energy demand of the Na(+)/K(+)-ATPase needed to counterbalance passive leak currents cannot be significantly dropped below observed values.

Effects of concanavalin A on chondrocyte hypertrophy and matrix calcification.

PubMed

Yan, W; Pan, H; Ishida, H; Nakashima, K; Suzuki, F; Nishimura, M; Jikko, A; Oda, R; Kato, Y

1997-03-21

Resting chondrocytes do not usually undergo differentiation to the hypertrophic stage and calcification. However, incubating these cells with concanavalin A resulted in 10-100-fold increases in alkaline phosphatase activity, binding of 1,25(OH)2-vitamin D3, type X collagen synthesis, 45Ca incorporation into insoluble material, and calcium content. On the other hand, other lectins tested (including wheat germ agglutinin, lentil lectin, pea lectin, phytohemagglutinin-L, and phytohemagglutinin-E) marginally affected alkaline phosphatase activity, although they activate lymphocytes. Methylmannoside reversed the effect of concanavalin A on alkaline phosphatase within 48 h. Concanavalin A did not increase alkaline phosphatase activity in articular chondrocyte cultures. In resting chondrocyte cultures, succinyl concanavalin A was as potent as concanavalin A in increasing alkaline phosphatase activity, the incorporation of [35S]sulfate, D-[3H]glucosamine, and [3H]serine into proteoglycans, and the incorporation of [3H]serine into protein, although concanavalin A, but not succinyl concanavalin A, induced a rapid change in the shape of the cells from flat to spherical. These findings suggest that concanavalin A induces a switch from the resting, to the growth-plate stage, and that this action of concanavalin A is not secondary to changes in the cytoskeleton. Chondrocytes exposed to concanavalin A may be useful as a novel model of endochondral bone formation.

The T-Allele of TCF7L2 rs7903146 Associates With a Reduced Compensation of Insulin Secretion for Insulin Resistance Induced by 9 Days of Bed Rest

PubMed Central

Alibegovic, Amra C.; Sonne, Mette P.; Højbjerre, Lise; Hansen, Torben; Pedersen, Oluf; van Hall, Gerrit; Holst, Jens J.; Stallknecht, Bente; Dela, Flemming; Vaag, Allan

2010-01-01

OBJECTIVE The aim of this study was to determine whether the type 2 diabetes–associated T-allele of transcription factor 7-like 2 (TCF7L2) rs7903146 associates with impaired insulin secretion to compensate for insulin resistance induced by bed rest. RESEARCH DESIGN AND METHODS A total of 38 healthy young Caucasian men were studied before and after bed rest using the hyperinsulinemic-euglycemic clamp technique combined with indirect calorimetry preceded by an intravenous glucose tolerance test. The TCF7L2 rs7903146 was genotyped using allelic discrimination performed with an ABI 7900 system. The genetic analyses were done assuming a dominant model of inheritance. RESULTS The first-phase insulin response (FPIR) was significantly lower in carriers of the T-allele compared with carriers of the CC genotype before bed rest, with and without correction for insulin resistance. The incremental rise of FPIR in response to insulin resistance induced by bed rest was lower in carriers of the T-allele (P < 0.001). Fasting plasma glucagon levels were significantly lower in carriers of the T-allele before and after bed rest. While carriers of the CC genotype developed increased hepatic insulin resistance, the TCF7L2 rs7903146 did not influence peripheral insulin action or the rate of lipolysis before or after bed rest. CONCLUSIONS Healthy carriers of the T-allele of TCF7L2 rs7903146 exhibit a diminished increase of insulin secretion in response to intravenous glucose to compensate for insulin resistance as induced by bed rest. Reduced paracrine glucagon stimulation may contribute to the impairment of β-cell function in the carriers TCF7L2 rs7903146 T-allele associated with increased risk of type 2 diabetes. PMID:20107109

Differentiating closed-loop cortical intention from rest: building an asynchronous electrocorticographic BCI.

PubMed

Williams, Jordan J; Rouse, Adam G; Thongpang, Sanitta; Williams, Justin C; Moran, Daniel W

2013-08-01

Recent experiments have shown that electrocorticography (ECoG) can provide robust control signals for a brain-computer interface (BCI). Strategies that attempt to adapt a BCI control algorithm by learning from past trials often assume that the subject is attending to each training trial. Likewise, automatic disabling of movement control would be desirable during resting periods when random brain fluctuations might cause unintended movements of a device. To this end, our goal was to identify ECoG differences that arise between periods of active BCI use and rest. We examined spectral differences in multi-channel, epidural micro-ECoG signals recorded from non-human primates when rest periods were interleaved between blocks of an active BCI control task. Post-hoc analyses demonstrated that these states can be decoded accurately on both a trial-by-trial and real-time basis, and this discriminability remains robust over a period of weeks. In addition, high gamma frequencies showed greater modulation with desired movement direction, while lower frequency components demonstrated greater amplitude differences between task and rest periods, suggesting possible specialized BCI roles for these frequencies. The results presented here provide valuable insight into the neurophysiology of BCI control as well as important considerations toward the design of an asynchronous BCI system.

Differentiating closed-loop cortical intention from rest: building an asynchronous electrocorticographic BCI

NASA Astrophysics Data System (ADS)

Williams, Jordan J.; Rouse, Adam G.; Thongpang, Sanitta; Williams, Justin C.; Moran, Daniel W.

2013-08-01

Objective. Recent experiments have shown that electrocorticography (ECoG) can provide robust control signals for a brain-computer interface (BCI). Strategies that attempt to adapt a BCI control algorithm by learning from past trials often assume that the subject is attending to each training trial. Likewise, automatic disabling of movement control would be desirable during resting periods when random brain fluctuations might cause unintended movements of a device. To this end, our goal was to identify ECoG differences that arise between periods of active BCI use and rest. Approach. We examined spectral differences in multi-channel, epidural micro-ECoG signals recorded from non-human primates when rest periods were interleaved between blocks of an active BCI control task. Main Results. Post-hoc analyses demonstrated that these states can be decoded accurately on both a trial-by-trial and real-time basis, and this discriminability remains robust over a period of weeks. In addition, high gamma frequencies showed greater modulation with desired movement direction, while lower frequency components demonstrated greater amplitude differences between task and rest periods, suggesting possible specialized BCI roles for these frequencies. Significance. The results presented here provide valuable insight into the neurophysiology of BCI control as well as important considerations toward the design of an asynchronous BCI system.

The mitochondrial uniporter controls fight or flight heart rate increases.

PubMed

Wu, Yuejin; Rasmussen, Tyler P; Koval, Olha M; Joiner, Mei-Ling A; Hall, Duane D; Chen, Biyi; Luczak, Elizabeth D; Wang, Qiongling; Rokita, Adam G; Wehrens, Xander H T; Song, Long-Sheng; Anderson, Mark E

2015-01-20

Heart rate increases are a fundamental adaptation to physiological stress, while inappropriate heart rate increases are resistant to current therapies. However, the metabolic mechanisms driving heart rate acceleration in cardiac pacemaker cells remain incompletely understood. The mitochondrial calcium uniporter (MCU) facilitates calcium entry into the mitochondrial matrix to stimulate metabolism. We developed mice with myocardial MCU inhibition by transgenic expression of a dominant-negative (DN) MCU. Here, we show that DN-MCU mice had normal resting heart rates but were incapable of physiological fight or flight heart rate acceleration. We found that MCU function was essential for rapidly increasing mitochondrial calcium in pacemaker cells and that MCU-enhanced oxidative phoshorylation was required to accelerate reloading of an intracellular calcium compartment before each heartbeat. Our findings show that MCU is necessary for complete physiological heart rate acceleration and suggest that MCU inhibition could reduce inappropriate heart rate increases without affecting resting heart rate.

[G-protein potentiates the activation of TNF-alpha on calcium-activated potassium channel in ECV304].

PubMed

Lin, L; Zheng, Y; Qu, J; Bao, G

2000-06-01

Observe the effect of tumor necrosis factor-alpha (TNF-alpha) on calcium-activated potassium channel in ECV304 and the possible involvement of G-protein mediation in the action of TNF-alpha. Using the cell-attached configuration of patch clamp technique. (1) the activity of high-conductance calcium-activated potassium channel (BKca) was recorded. Its conductance is (202.54 +/- 16.62) pS; (2) the activity of BKca was potentiated by 200 U/ml TNF-alpha; (3) G-protein would intensify this TNF-alpha activation. TNF-alpha acted on vascular endothelial cell ECV304 could rapidly activate the activity of BKca. Opening of BKca resulted in membrane hyper-polarization which could increase electro-chemical gradient for the resting Ca2+ influx and open leakage calcium channel, thus resting cytoplasmic free Ca2+ concentration could be elevated. G-protein may exert an important regulation in this process.

Plasma catecholamine concentrations in rainbow trout (Salmo gairdneri) at rest and after anesthesia and surgery

USGS Publications Warehouse

Gingerich, W.H.; Drottar, K.R.

1989-01-01

The effects of surgery and anesthesia on concentrations of plasma epinephrine (E), norepinephrine (NE), and dopamine (DA) were investigated in rainbow trout fitted with dorsal aorta cannulae. Baseline catecholamines (CA) concentrations, established in resting rainbow trout, were 1.55 ± 0.90 ϱmol/ml (X ± SD) for E, 2.07 ± 1.26 for NE, and 1.33 ± 0.87 for DA. These values were based on the pooled analyses of five individual fish taken over seven different sampling periods. The E:NE ratio in resting fish was always less than 1.0. In a second experiment, fish were subjected to dorsal aorta cannulation and sequential blood samples were taken immediately after surgery, and 6, 24, and 48 hr later. Plasma E concentrations were 36 times greater than baseline values in the first sample; NE was 15 times greater and DA was 41 times greater. After surgery, plasma concentrations of all CAs fell rapidly but values were still higher than baseline 6 hr after surgery, then were near baseline at 24 and 48 hr after surgery. The E:NE ratio was about 3.0 immediately after surgery, dropped to 1.8 at 6 hr, and was about 1.0 at 24 and 48 hr. In a third experiment, plasma CAs were determined in a group of five animals anesthetized with tricaine methanesulfonate (100 mg/ml) to advanced anesthesia, and then allowed to recover in flowing well water over a 12-hr observation period. Plasma E and NE concentrations in the fish during early anes-thesia (1.14 ± 0.14 min) were not significantly different from preanesthesia values. During advanced anesthesia (2.31 ± 0.21 min), values for E and NE were significantly greater and continued to be elevated during the 12-hr recovery period. The E:NE ratio exceeded 1.0 during advanced anesthesia and for the rest of the experiment.

Resting Lightly on Mother Earth: The Aboriginal Experience in Urban Educational Settings.

ERIC Educational Resources Information Center

Ward, Angela; Bouvier, Rita

This book examines the differential educational experiences of Aboriginal peoples in urban centers--primarily in Canada, but also in Australia and the United States. Major themes of the book are maintenance of individual and collective Aboriginal identity, the impact on that identity of disconnection from the land, spirituality as the key to…

Aesthetic Experience in the World of Visual Culture

ERIC Educational Resources Information Center

Moore, Ronald

2004-01-01

This article draws attention to three important aesthetic ideas--ideas which have become, in the early twenty-first century, so widely endorsed in Western culture that they have become the stock platform of much theorizing and teaching about our experience of art and its relation to the rest of life. All of these ideas sprang from Beat thought in…

Policies to Reduce High-Tenured Displaced Workers' Earnings Losses through Retraining. Discussion Paper 2011-11

ERIC Educational Resources Information Center

Jacobson, Louis S.; LaLonde, Robert J.; Sullivan, Daniel G.

2011-01-01

High-tenured displaced workers often experience significant earnings losses that persist for the rest of their working lives. A well-targeted training initiative has the potential to substantially reduce permanent earnings losses for those displaced workers who have the academic preparation, work experience, and interest to complete high-return…

Encouraging Cognitive Connections and Creativity in the Music Classroom

ERIC Educational Resources Information Center

Peterson, Christopher W.; Madsen, Clifford K.

2010-01-01

The ability to apply knowledge rests at the core of the educational experience and is an important aspect of all teaching. In music education, many experiences are structured so information gained can be related to another activity, but such transfer can be difficult. When students learn to transfer information and knowledge to new situations,…

Computing the stability of steady-state solutions of mathematical models of the electrical activity in the heart.

PubMed

Tveito, Aslak; Skavhaug, Ola; Lines, Glenn T; Artebrant, Robert

2011-08-01

Instabilities in the electro-chemical resting state of the heart can generate ectopic waves that in turn can initiate arrhythmias. We derive methods for computing the resting state for mathematical models of the electro-chemical process underpinning a heartbeat, and we estimate the stability of the resting state by invoking the largest real part of the eigenvalues of a linearized model. The implementation of the methods is described and a number of numerical experiments illustrate the feasibility of the methods. In particular, we test the methods for problems where we can compare the solutions with analytical results, and problems where we have solutions computed by independent software. The software is also tested for a fairly realistic 3D model. Copyright © 2011 Elsevier Ltd. All rights reserved.

The impacts of rest breaks and stretching exercises on lower back pain among commercial truck drivers in Iran.

PubMed

Ghasemi, Mohammad; Khoshakhlagh, Amir Hossein; Ghanjal, Ali; Yazdanirad, Saeid; Laal, Fereydoon

2018-06-07

This study aimed to determine the impacts of rest breaks and stretching exercises on lower back pain (LBP) in commercial truck drivers. This quasi-experiment was carried out on 92 truck drivers suffering from chronic LBP. Subjects were categorized into three groups (stretching exercises and rest breaks, rest breaks only and reference). Pain severity and related disability were measured at the beginning of the survey and after 6 and 12 weeks. The latter was assessed using the Oswestry low back pain disability questionnaire (OLBPDQ) and the Roland Morris questionnaire (RMQ). At the end of the intervention, the mean pain scores in the three groups were 2.72 ± 1.44, 4.11 ± 0.86 and 4.90 ± 1.31 respectively (p < 0.001). The OLBPDQ scores in group 1 (stretches and resting time breaks) were significantly lower than those in group 2 (rest break) (p = 0.009). The RMQ scores showed a significant reduction in group 1 compared with the other two groups (p = 0.001). Drivers in group 2 improved more significantly than those in group 3 regarding visual analog scale pain score (p = 0.049), OLBPDQ score (p = 0.024) and RMQ score (p = 0.011). This study provided converging results that supplementary exercises during break periods consistently help to minimize LBP and disability.

Measuring vascular reactivity with resting-state blood oxygenation level-dependent (BOLD) signal fluctuations: A potential alternative to the breath-holding challenge?

PubMed

Jahanian, Hesamoddin; Christen, Thomas; Moseley, Michael E; Pajewski, Nicholas M; Wright, Clinton B; Tamura, Manjula K; Zaharchuk, Greg

2017-07-01

Measurement of the ability of blood vessels to dilate and constrict, known as vascular reactivity, is often performed with breath-holding tasks that transiently raise arterial blood carbon dioxide (P a CO 2 ) levels. However, following the proper commands for a breath-holding experiment may be difficult or impossible for many patients. In this study, we evaluated two approaches for obtaining vascular reactivity information using blood oxygenation level-dependent signal fluctuations obtained from resting-state functional magnetic resonance imaging data: physiological fluctuation regression and coefficient of variation of the resting-state functional magnetic resonance imaging signal. We studied a cohort of 28 older adults (69 ± 7 years) and found that six of them (21%) could not perform the breath-holding protocol, based on an objective comparison with an idealized respiratory waveform. In the subjects that could comply, we found a strong linear correlation between data extracted from spontaneous resting-state functional magnetic resonance imaging signal fluctuations and the blood oxygenation level-dependent percentage signal change during breath-holding challenge ( R 2  = 0.57 and 0.61 for resting-state physiological fluctuation regression and resting-state coefficient of variation methods, respectively). This technique may eliminate the need for subject cooperation, thus allowing the evaluation of vascular reactivity in a wider range of clinical and research conditions in which it may otherwise be impractical.

The combined effects of single-nucleotide polymorphisms, tobacco products, and ethanol on normal resting blood mononuclear cells.

PubMed

Cederblad, Lena; Thunberg, Ulf; Engström, Mats; Castro, Juan; Rutqvist, Lars Erik; Laytragoon-Lewin, Nongnit

2013-05-01

Tobacco and ethanol consumption are crucial factors in the development of various diseases including cancer. In this investigation, we evaluated the combined effects of a number of single nucleotide polymorphisms (SNPs), with ethanol and tobacco products on healthy individuals. Pure nicotine, cigarette smoke extract, and Swedish snuff (snus) extract were used. The effects were examined by means of in vitro cell cycle progression and cell death of peripheral blood mononuclear cells (PBMCs) obtained from healthy donors. After 3 days, in vitro, resting PBMCs entered the S and G2 stage in the presence of 100 µM nicotine. The PBMCs only proceeded to S stage, in the presence of 0.2% ethanol. The nicotine- and ethanol-induced normal cell cycle progression correlated to a number of SNPs in the IL12RB2, Rad 52, XRCC2, P53, CCND3, and ABCA1 genes. Certain SNPs in Caspases 8, IL12RB2, Rad 52, MMP2, and MDM2 genes appeared to significantly influence the effects of EtOH-, snus-, and snus + EtOH-induced cell death. Importantly, the highest degree of cell death was observed in the presence of smoke + EtOH. The amount of cell death under this treatment condition also correlated to specific SNPs, located in the MDM2, ABCA1, or GASC1 genes. Cigarette smoke in combination with ethanol strongly induced massive cell death. Long-term exposure to smoke and ethanol could provoke chronic inflammation, and this could be the initiation of disease including the development of cancer at various sites.

Vascular Uptake of Six Rehydration Drinks at Rest and Exercise

NASA Technical Reports Server (NTRS)

Greenleaf, J. E.; Geelen, G.; Jackson, C. G. R.; Saumet, J.-L.; Juhos, L. T.; Keil, L. C.; Fegan-Meyer, D.; Dearborn, A.; Hinghofer-Szalkay, H.; Whittam, J. H.

1996-01-01

A report presents data on the effectiveness of each of six rehydration fluids in restoring total body water and plasma volume in human subjects during rest and exercise. One of the six fluids was water sweetened with aspartame: the others were water containing various amounts of sodium chloride and/or sodium citrate, plus various amounts of aspartame and/or other carbohydrates. In one experiment, five men who had previously dehydrated themselves for 24 hours drank one of the rehydration fluids, then sat for 70 minutes. Pretest plasma volumes were measured and changes in plasma volumes were calculated. This procedure was repeated at weekly intervals until all six rehydration fluids had been tested. Another similar experiment involved four men who exercised on a cycle ergometer for 70 minutes in the supine position after drinking the fluids.

Stimulus-Elicited Connectivity Influences Resting-State Connectivity Years Later in Human Development: A Prospective Study.

PubMed

Gabard-Durnam, Laurel Joy; Gee, Dylan Grace; Goff, Bonnie; Flannery, Jessica; Telzer, Eva; Humphreys, Kathryn Leigh; Lumian, Daniel Stephen; Fareri, Dominic Stephen; Caldera, Christina; Tottenham, Nim

2016-04-27

Although the functional architecture of the brain is indexed by resting-state connectivity networks, little is currently known about the mechanisms through which these networks assemble into stable mature patterns. The current study posits and tests the long-term phasic molding hypothesis that resting-state networks are gradually shaped by recurring stimulus-elicited connectivity across development by examining how both stimulus-elicited and resting-state functional connections of the human brain emerge over development at the systems level. Using a sequential design following 4- to 18-year-olds over a 2 year period, we examined the predictive associations between stimulus-elicited and resting-state connectivity in amygdala-cortical circuitry as an exemplar case (given this network's protracted development across these ages). Age-related changes in amygdala functional connectivity converged on the same regions of medial prefrontal cortex (mPFC) and inferior frontal gyrus when elicited by emotional stimuli and when measured at rest. Consistent with the long-term phasic molding hypothesis, prospective analyses for both connections showed that the magnitude of an individual's stimulus-elicited connectivity unidirectionally predicted resting-state functional connectivity 2 years later. For the amygdala-mPFC connection, only stimulus-elicited connectivity during childhood and the transition to adolescence shaped future resting-state connectivity, consistent with a sensitive period ending with adolescence for the amygdala-mPFC circuit. Together, these findings suggest that resting-state functional architecture may arise from phasic patterns of functional connectivity elicited by environmental stimuli over the course of development on the order of years. A fundamental issue in understanding the ontogeny of brain function is how resting-state (intrinsic) functional networks emerge and relate to stimulus-elicited functional connectivity. Here, we posit and test the long-term phasic molding hypothesis that resting-state network development is influenced by recurring stimulus-elicited connectivity through prospective examination of the developing human amygdala-cortical functional connections. Our results provide critical insight into how early environmental events sculpt functional network architecture across development and highlight childhood as a potential developmental period of heightened malleability for the amygdala-medial prefrontal cortex circuit. These findings have implications for how both positive and adverse experiences influence the developing brain and motivate future investigations of whether this molding mechanism reflects a general phenomenon of brain development. Copyright © 2016 the authors 0270-6474/16/364772-14$15.00/0.

Stimulus-Elicited Connectivity Influences Resting-State Connectivity Years Later in Human Development: A Prospective Study

PubMed Central

Gee, Dylan Grace; Goff, Bonnie; Flannery, Jessica; Telzer, Eva; Humphreys, Kathryn Leigh; Lumian, Daniel Stephen; Fareri, Dominic Stephen; Caldera, Christina; Tottenham, Nim

2016-01-01

Although the functional architecture of the brain is indexed by resting-state connectivity networks, little is currently known about the mechanisms through which these networks assemble into stable mature patterns. The current study posits and tests the long-term phasic molding hypothesis that resting-state networks are gradually shaped by recurring stimulus-elicited connectivity across development by examining how both stimulus-elicited and resting-state functional connections of the human brain emerge over development at the systems level. Using a sequential design following 4- to 18-year-olds over a 2 year period, we examined the predictive associations between stimulus-elicited and resting-state connectivity in amygdala-cortical circuitry as an exemplar case (given this network's protracted development across these ages). Age-related changes in amygdala functional connectivity converged on the same regions of medial prefrontal cortex (mPFC) and inferior frontal gyrus when elicited by emotional stimuli and when measured at rest. Consistent with the long-term phasic molding hypothesis, prospective analyses for both connections showed that the magnitude of an individual's stimulus-elicited connectivity unidirectionally predicted resting-state functional connectivity 2 years later. For the amygdala-mPFC connection, only stimulus-elicited connectivity during childhood and the transition to adolescence shaped future resting-state connectivity, consistent with a sensitive period ending with adolescence for the amygdala-mPFC circuit. Together, these findings suggest that resting-state functional architecture may arise from phasic patterns of functional connectivity elicited by environmental stimuli over the course of development on the order of years. SIGNIFICANCE STATEMENT A fundamental issue in understanding the ontogeny of brain function is how resting-state (intrinsic) functional networks emerge and relate to stimulus-elicited functional connectivity. Here, we posit and test the long-term phasic molding hypothesis that resting-state network development is influenced by recurring stimulus-elicited connectivity through prospective examination of the developing human amygdala-cortical functional connections. Our results provide critical insight into how early environmental events sculpt functional network architecture across development and highlight childhood as a potential developmental period of heightened malleability for the amygdala-medial prefrontal cortex circuit. These findings have implications for how both positive and adverse experiences influence the developing brain and motivate future investigations of whether this molding mechanism reflects a general phenomenon of brain development. PMID:27122035

Preconditioned mesenchymal stem cells treat myasthenia gravis in a humanized preclinical model

PubMed Central

Sudres, Muriel; Maurer, Marie; Robinet, Marieke; Bismuth, Jacky; Truffault, Frédérique; Girard, Diane; Dragin, Nadine; Attia, Mohamed; Fadel, Elie; Santelmo, Nicola; Sicsic, Camille; Brenner, Talma

2017-01-01

Myasthenia gravis (MG) with anti–acetylcholine receptor (AChR) Abs is an autoimmune disease characterized by severe defects in immune regulation and thymic inflammation. Because mesenchymal stem cells (MSCs) display immunomodulatory features, we investigated whether and how in vitro–preconditioned human MSCs (cMSCs) could treat MG disease. We developed a new humanized preclinical model by subcutaneously grafting thymic MG fragments into immunodeficient NSG mice (NSG-MG model). Ninety percent of the animals displayed human anti-AChR Abs in the serum, and 50% of the animals displayed MG-like symptoms that correlated with the loss of AChR at the muscle endplates. Interestingly, each mouse experiment recapitulated the MG features of each patient. We next demonstrated that cMSCs markedly improved MG, reducing the level of anti-AChR Abs in the serum and restoring AChR expression at the muscle endplate. Resting MSCs had a smaller effect. Finally, we showed that the underlying mechanisms involved (a) the inhibition of cell proliferation, (b) the inhibition of B cell–related and costimulatory molecules, and (c) the activation of the complement regulator DAF/CD55. In conclusion, this study shows that a preconditioning step promotes the therapeutic effects of MSCs via combined mechanisms, making cMSCs a promising strategy for treating MG and potentially other autoimmune diseases. PMID:28405609

Towards an Ecological Understanding of Dinoflagellate Cyst Functions

PubMed Central

Bravo, Isabel; Figueroa, Rosa Isabel

2014-01-01

The life cycle of many dinoflagellates includes at least one nonflagellated benthic stage (cyst). In the literature, the different types of dinoflagellate cysts are mainly defined based on morphological (number and type of layers in the cell wall) and functional (long- or short-term endurance) differences. These characteristics were initially thought to clearly distinguish pellicle (thin-walled) cysts from resting (double-walled) dinoflagellate cysts. The former were considered short-term (temporal) and the latter long-term (resting) cysts. However, during the last two decades further knowledge has highlighted the great intricacy of dinoflagellate life histories, the ecological significance of cyst stages, and the need to clarify the functional and morphological complexities of the different cyst types. Here we review and, when necessary, redefine the concepts of resting and pellicle cysts, examining both their structural and their functional characteristics in the context of the life cycle strategies of several dinoflagellate species. PMID:27694774

Bloom syndrome in sibs: first reports of hepatocellular carcinoma and Wilms tumor with documented anaplasia and nephrogenic rests.

PubMed

Jain, D; Hui, P; McNamara, J; Schwartz, D; German, J; Reyes-Múgica, M

2001-01-01

The triad of small body size, immunodeficiency, and sun-sensitive facial erythema characterizes the phenotype Bloom syndrome (BS), a rare autosomal recessive disorder with a striking predisposition to multiple types of cancers that arise earlier than expected in the general population. Here we report two sibs with BS. The older, a 15-year-old-girl, developed a hepatocellular carcinoma, a neoplasm not yet reported in association with BS. Her younger brother developed an anaplastic Wilms tumor (WT) associated with nephrogenic rests at the age of 31/2 years, and this was followed by a myelodysplastic syndrome. Complex cytogenetic abnormalities were identified in all three neoplasms. These examples expand the spectrum of malignancies occurring in BS to include liver cell neoplasms, and confirm the association of nephrogenic rests with WT, even in the setting of BS.

Focal Gray Matter Plasticity as a Function of Long Duration Head-down Tilt Bed Rest

NASA Technical Reports Server (NTRS)

Koppelmans, Vincent; Erdeniz, Burak; DeDios, Yiri; Wood, Scott; Reuter-Lorenz, Patricia; Kofman, Igor; Bloomberg, Jacob; Mulavara, Ajitkumar; Seidler, Rachael

2014-01-01

Long duration spaceflight (i.e., 22 days or longer) has been associated with changes in sensorimotor systems, resulting in difficulties that astronauts experience with posture control, locomotion, and manual control. The microgravity environment is an important causal factor for spaceflight induced sensorimotor changes. Whether these sensorimotor changes may be related to structural and functional brain changes is yet unknown. However, increased intracranial pressure that by itself has been related to microgravity-induced bodily fluid shifts: [1] has been associated with white matter microstructural damage, [2] Thus, it is possible that spaceflight may affect brain structure and thereby cognitive functioning. Long duration head-down tilt bed rest has been suggested as an exclusionary analog to study microgravity effects on the sensorimotor system, [3] Bed rest mimics microgravity in body unloading and bodily fluid shifts. In consideration of the health and performance of crewmembers both in- and post-flight, we are conducting a prospective longitudinal 70-day bed rest study as an analog to investigate the effects of microgravity on brain structure, and [4] Here we present results of the first eight subjects.

Aging and free surface flow of a thixotropic fluid

NASA Astrophysics Data System (ADS)

Huynh, H. T.; Roussel, N.; Coussot, P.

2005-03-01

Free surface flows of thixotropic fluids such as paints, self-compacting concrete, or natural mudflows are of noticeable practical interest. Here we study the basic characteristics of the uniform flow of a layer of thixotropic fluid under gravity. A theoretical approach relying on a simple thixotropy constitutive equation shows that after some time at rest over a small slope angle the fluid layer should start to flow rather abruptly beyond a new, larger, critical slope angle. The theory also predicts that the critical time at which the layer velocity should significantly increase is proportional to the duration of the preliminary rest and tends to infinity when the new slope approaches the critical slope. Experiments carried out with different suspensions show that the qualitative trends of the flows are in very good agreement with the theoretical predictions, except that the critical time for flow start appears to be proportional to a power 0.6 of the time of rest whereas the theory predicts a linear dependence. We show that this indicates a restructuration process at rest differing from the restructuration process under flow.

Physical fitness modulates incidental but not intentional statistical learning of simultaneous auditory sequences during concurrent physical exercise.

PubMed

Daikoku, Tatsuya; Takahashi, Yuji; Futagami, Hiroko; Tarumoto, Nagayoshi; Yasuda, Hideki

2017-02-01

In real-world auditory environments, humans are exposed to overlapping auditory information such as those made by human voices and musical instruments even during routine physical activities such as walking and cycling. The present study investigated how concurrent physical exercise affects performance of incidental and intentional learning of overlapping auditory streams, and whether physical fitness modulates the performances of learning. Participants were grouped with 11 participants with lower and higher fitness each, based on their Vo 2 max value. They were presented simultaneous auditory sequences with a distinct statistical regularity each other (i.e. statistical learning), while they were pedaling on the bike and seating on a bike at rest. In experiment 1, they were instructed to attend to one of the two sequences and ignore to the other sequence. In experiment 2, they were instructed to attend to both of the two sequences. After exposure to the sequences, learning effects were evaluated by familiarity test. In the experiment 1, performance of statistical learning of ignored sequences during concurrent pedaling could be higher in the participants with high than low physical fitness, whereas in attended sequence, there was no significant difference in performance of statistical learning between high than low physical fitness. Furthermore, there was no significant effect of physical fitness on learning while resting. In the experiment 2, the both participants with high and low physical fitness could perform intentional statistical learning of two simultaneous sequences in the both exercise and rest sessions. The improvement in physical fitness might facilitate incidental but not intentional statistical learning of simultaneous auditory sequences during concurrent physical exercise.

Spatially distributed effects of mental exhaustion on resting-state FMRI networks.

PubMed

Esposito, Fabrizio; Otto, Tobias; Zijlstra, Fred R H; Goebel, Rainer

2014-01-01

Brain activity during rest is spatially coherent over functional connectivity networks called resting-state networks. In resting-state functional magnetic resonance imaging, independent component analysis yields spatially distributed network representations reflecting distinct mental processes, such as intrinsic (default) or extrinsic (executive) attention, and sensory inhibition or excitation. These aspects can be related to different treatments or subjective experiences. Among these, exhaustion is a common psychological state induced by prolonged mental performance. Using repeated functional magnetic resonance imaging sessions and spatial independent component analysis, we explored the effect of several hours of sustained cognitive performances on the resting human brain. Resting-state functional magnetic resonance imaging was performed on the same healthy volunteers in two days, with and without, and before, during and after, an intensive psychological treatment (skill training and sustained practice with a flight simulator). After each scan, subjects rated their level of exhaustion and performed an N-back task to evaluate eventual decrease in cognitive performance. Spatial maps of selected resting-state network components were statistically evaluated across time points to detect possible changes induced by the sustained mental performance. The intensive treatment had a significant effect on exhaustion and effort ratings, but no effects on N-back performances. Significant changes in the most exhausted state were observed in the early visual processing and the anterior default mode networks (enhancement) and in the fronto-parietal executive networks (suppression), suggesting that mental exhaustion is associated with a more idling brain state and that internal attention processes are facilitated to the detriment of more extrinsic processes. The described application may inspire future indicators of the level of fatigue in the neural attention system.

Sensor Level Functional Connectivity Topography Comparison Between Different References Based EEG and MEG.

PubMed

Huang, Yunzhi; Zhang, Junpeng; Cui, Yuan; Yang, Gang; Liu, Qi; Yin, Guangfu

2018-01-01

Sensor-level functional connectivity topography (sFCT) contributes significantly to our understanding of brain networks. sFCT can be constructed using either electroencephalography (EEG) or magnetoencephalography (MEG). Here, we compared sFCT within the EEG modality and between EEG and MEG modalities. We first used simulations to look at how different EEG references-including the Reference Electrode Standardization Technique (REST), average reference (AR), linked mastoids (LM), and left mastoid references (LR)-affect EEG-based sFCT. The results showed that REST decreased the reference effects on scalp EEG recordings, making REST-based sFCT closer to the ground truth (sFCT based on ideal recordings). For the inter-modality simulation comparisons, we compared each type of EEG-sFCT with MEG-sFCT using three metrics to quantize the differences: Relative Error (RE), Overlap Rate (OR), and Hamming Distance (HD). When two sFCTs are similar, RE and HD are low, while OR is high. Results showed that among all reference schemes, EEG-and MEG-sFCT were most similar when the EEG was REST-based and the EEG and MEG were recorded simultaneously. Next, we analyzed simultaneously recorded MEG and EEG data from publicly available face-recognition experiments using a similar procedure as in the simulations. The results showed (1) if MEG-sFCT is the standard, REST-and LM-based sFCT provided results closer to this standard in the terms of HD; (2) REST-based sFCT and MEG-sFCT had the highest similarity in terms of RE; (3) REST-based sFCT had the most overlapping edges with MEG-sFCT in terms of OR. This study thus provides new insights into the effect of different reference schemes on sFCT and the similarity between MEG and EEG in terms of sFCT.

Tissue Engineered Skeletal Myofibers can Directly "Sense" Gravitational Force Changes

NASA Technical Reports Server (NTRS)

Vandenburgh, Herman H.; Shansky, J.; DelTatto, M.; Lee, Peter; Meir, J.

1999-01-01

Long-term manned space flight requires a better understanding of skeletal muscle atrophy resulting from microgravity. Atrophy most likely results from changes at both the systemic level (e.g. decreased circulating growth hormone, increased circulating glucocorticoids) and locally (e.g. decreased myofiber resting tension). Differentiated skeletal myofibers in tissue culture have provided a model system over the last decade for gaining a better understanding of the interactions of exogenous growth factors, endogenous growth factors, and muscle fiber tension in regulating protein turnover rates and muscle cell growth. Tissue engineering these cells into three dimensional bioartificial muscle (BAM) constructs has allowed us to extend their use to Space flight studies for the potential future development of countermeasures. Embryonic avian muscle cells were isolated and BAMs tissue engineered as described previously. The myoblasts proliferate and fuse into aligned postmitotic myofibers after ten to fourteen days in vitro. A cylindrical muscle-like structure containing several thousand myofibers is formed which is approximately 30 mm in length, 2-3 mm in diameter, and attached at each end. For the Space Shuttle experiments, the BAMs were transferred to 55 mL bioreactor cartridges (6 BAMs/cartridge). At Kennedy Space Center, the cartridges were mounted in two Space Tissue Loss (STL) Modules (three to four cartridges per Module) and either maintained as ground controls or loaded in a Mid-Deck locker of the Space Shuttle. The BAM cartridges were continuously perfused during the experiment at 1.5 mL/ min with tissue culture medium. Eighteen BAMs were flown for nine days on Mission STS66 while eighteen BAMs served as ground controls. The complete experiment was repeated on Mission STS77 with twenty four BAMs in each group. BAMs could be maintained in a healthy state for at least 30 days in the perfusion bioreactor cartridges. The BAM muscle fibers directly detected both the loss of gravity and the reloading effects of 1 x g. While total cellular metabolism and total protein degradation rates were not altered during 9 to 10 days in Space, protein synthesis rates were significantly reduced and resulted in significant myofiber atrophy compared to ground controls. One g reloading of the flight muscle cells post-flight significantly increased protein synthesis rates and the synthesis rates of myosin heavy chain, fibronectin, and collagen. Tissue cultured muscle cells can directly "sense" changes in gravity and provide a valid model to begin the study of countermeasures. Based on our ground based experiments, and the experiments of others, growth hormone and/or insulin-like growth factors are attractive protein therapeutics which may assisting attenuating skeletal muscle wasting in space. Our laboratory is developing a new cell-based delivery system for this and other potential therapeutic factors for attenuating muscle and bone wasting.

Adult Human Gingival Epithelial Cells as a Source for Whole-tooth Bioengineering

PubMed Central

Angelova Volponi, A.; Kawasaki, M.; Sharpe, P.T.

2013-01-01

Teeth develop from interactions between embryonic oral epithelium and neural-crest-derived mesenchyme. These cells can be separated into single-cell populations and recombined to form normal teeth, providing a basis for bioengineering new teeth if suitable, non-embryonic cell sources can be identified. We show here that cells can be isolated from adult human gingival tissue that can be expanded in vitro and, when combined with mouse embryonic tooth mesenchyme cells, form teeth. Teeth with developing roots can be produced from this cell combination following transplantation into renal capsules. These bioengineered teeth contain dentin and enamel with ameloblast-like cells and rests of Malassez of human origin. PMID:23458883

Exhaustive submaximal endurance and resistance exercises induce temporary immunosuppression via physical and oxidative stress

PubMed Central

Jin, Chan-Ho; Paik, Il-Young; Kwak, Yi-Sub; Jee, Yong-Seok; Kim, Joo-Young

2015-01-01

Regular running and strength training are the best ways to improve aerobic capacity and develop the size of skeletal muscles. However, uncontrolled physical activities can often lead to an undertraining or over-training syndrome. In particular, overtraining causes persistent fatigue and reduces physical performance due to changes in the various physiological and immunological factors. In this study, we gave an exhaustive submaximal endurance or resistance exercise to participants and investigated the relationship between physical stress (cortisol level in blood), oxidative stress (intracellular ROS accumulation), and adaptive immune response (CD4:CD8 ratio). Materials and Methods Ten male volunteers were recruited, and performed a submaximal endurance or resistance exercise with 85% of VO2max or 1-repetition maximum until exhaustion. Blood samples were collected at rest, and at 0 and 30 min after the exercise. Cortisol levels, oxidative stress, and immune cell phenotypes in peripheral blood were evaluated. Cortisol levels in the sera increased after the exhaustive endurance and resistance exercises and such increments were maintained through the recovery. Intra-cellular ROS levels also increased after the exhaustive endurance and resistance exercises. The ratio of CD4+ T cells to CD8+ T cells after each type of submaximal exercise decreased compared with that at the resting stage, and returned to the resting level at 30 min after the exercise. In this study, an exhaustive endurance or a resistance exercise with submaximal intensity caused excessive physical stress, intra-cellular oxidative stress, and post-exercise immunosuppression. This result suggests that excessive physical stress induced temporary immune dysfunction via physical and oxidative stress. PMID:26331134

Cocoa procyanidins and human cytokine transcription and secretion.

PubMed

Mao, T; Van De Water, J; Keen, C L; Schmitz, H H; Gershwin, M E

2000-08-01

We examined whether cocoa, in its isolated procyanidin fractions (monomer through decamer), would modulate cytokine production at the levels of transcription and protein secretion in both resting and phytohemagglutinin (PHA)-stimulated peripheral blood mononuclear cells (PBMC). In resting cells, interleukin (IL)-1beta and IL-4 gene expression from cocoa-treated cells varied markedly among the subjects tested. However, at the protein level, the larger fractions (pentamer through decamer) stimulated a dramatic increase in IL-1beta concentration (up to ninefold) with increasing degree of polymerization. Similarly, these larger fractions augmented IL-4 concentration by as much as 2 pg/ml, whereas the control displayed levels nearly undetectable. In the presence of PHA, gene expression also seemed to be most affected by the larger procyanidin fractions. The pentameric through decameric fractions increased IL-1 beta expression by 7-19% compared with PHA control, whereas the hexameric through decameric fractions significantly inhibited PHA-induced IL-4 transcription in the range of 71-86%. This observation at the transcription level for IL-1 beta was reflected at the protein level in PHA-stimulated PBMC. Significant reductions in mitogen-induced IL-4 production were also seen at the protein level with the hexamer, heptamer and octamer. Individual oligomeric cocoa fractions were unstimulatory for IL-2 in resting PBMC. However, when induced with PHA, the pentamer, hexamer and heptamer fractions caused a 61-73% inhibition in IL-2 gene expression. This study offers additional data for the consideration of the health benefits of dietary polyphenols from a wide variety of foods, including those benefits associated specifically with cocoa and chocolate consumption.

Reactivation of latent HIV-1 by new semi-synthetic ingenol esters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pandeló José, Diego; Bartholomeeusen, Koen; Delveccio da Cunha, Rodrigo

The ability of HIV to establish long-lived latent infection is mainly due to transcriptional silencing of viral genome in resting memory T lymphocytes. Here, we show that new semi-synthetic ingenol esters reactivate latent HIV reservoirs. Amongst the tested compounds, 3-caproyl-ingenol (ING B) was more potent in reactivating latent HIV than known activators such as SAHA, ingenol 3,20-dibenzoate, TNF-α, PMA and HMBA. ING B activated PKC isoforms followed by NF-κB nuclear translocation. As virus reactivation is dependent on intact NF-κB binding sites in the LTR promoter region ING B, we have shown that. ING B was able to reactivate virus transcriptionmore » in primary HIV-infected resting cells up to 12 fold and up to 25 fold in combination with SAHA. Additionally, ING B promoted up-regulation of P-TEFb subunits CDK9/Cyclin T1. The role of ING B on promoting both transcription initiation and elongation makes this compound a strong candidate for an anti-HIV latency drug combined with suppressive HAART. - Highlights: • 3-caproyl-ingenol (ING B) reactivates latent HIV better than SAHA, ingenol 3,20-dibenzoate, TNF-α, PMA and HMBA. • ING B promotes PKC activation and NF-kB translocation to the nucleus. • ING B activates virus transcription of B and non-B subtypes of HIV-1. • ING B activates HIV transcription in infected primary resting CD4+ T cells. • ING B induces higher levels of P-TEFb components in human primary cells.« less

The significance of measuring monocyte tissue factor activity in patients with breast and colorectal cancer

PubMed Central

Lwaleed, B A; Chisholm, M; Francis, J L

1999-01-01

Monocytes express tissue factor (mTF) in several conditions including cancer where levels may be valuable in assessing tumour presence and progression. Using a two-stage kinetic chromogenic assay (KCA), mTF levels were measured in controls [normal subjects (n = 60) and patients undergoing hernia repair or cholecystectomy (n = 60)], in patients with benign and malignant disease of the breast (n = 83) and of the large bowel (n = 62). This was performed under fresh (resting) conditions and after incubation for 6 h without (unstimulated) and with (stimulated) Escherichia coli endotoxin. The malignant groups showed higher mTF levels than each of the three controls for resting (P < 0.05 breast, P < 0.05 colorectal) unstimulated (P < 0.05 breast, P < 0.05 colorectal) and stimulated cells (P < 0.001 breast, P < 0.01 colorectal). Similarly, the benign inflammatory groups had higher mTF levels than controls for resting (P < 0.05 colorectal), unstimulated (P < 0.05 colorectal) and stimulated cells (P < 0.01 breast, P < 0.01 colorectal). There was no significant difference between malignant and benign inflammatory groups in each organ. mTF levels showed an increase corresponding to that of histological tumour progression and were higher in non-surviving patients. In conclusion, mTF levels are raised in malignant and inflammatory disease compared to controls and patients with non-inflammatory conditions. Stimulated cells give better discrimination between the groups and may be of value in identifying high risk individuals. mTF levels showed an association with tumour grade or stage and the patients' survival time. © 1999 Cancer Research Campaign PMID:10390009

Receptor-heteromer mediated regulation of endocannabinoid signaling in activated microglia. Role of CB1 and CB2 receptors and relevance for Alzheimer's disease and levodopa-induced dyskinesia.

PubMed

Navarro, Gemma; Borroto-Escuela, Dasiel; Angelats, Edgar; Etayo, Íñigo; Reyes-Resina, Irene; Pulido-Salgado, Marta; Rodríguez-Pérez, Ana I; Canela, Enric I; Saura, Josep; Lanciego, José Luis; Labandeira-García, José Luis; Saura, Carlos A; Fuxe, Kjell; Franco, Rafael

2018-01-01

Endocannabinoids are important regulators of neurotransmission and, acting on activated microglia, they are postulated as neuroprotective agents. Endocannabinoid action is mediated by CB 1 and CB 2 receptors, which may form heteromeric complexes (CB 1 -CB 2 Hets) with unknown function in microglia. We aimed at establishing the expression and signaling properties of cannabinoid receptors in resting and LPS/IFN-γ-activated microglia. In activated microglia mRNA transcripts increased (2 fold for CB 1 and circa 20 fold for CB 2 ), whereas receptor levels were similar for CB 1 and markedly upregulated for CB 2 ; CB 1 -CB 2 Hets were also upregulated. Unlike in resting cells, CB 2 receptors became robustly coupled to G i in activated cells, in which CB 1 -CB 2 Hets mediated a potentiation effect. Hence, resting cells were refractory while activated cells were highly responsive to cannabinoids. Interestingly, similar results were obtained in cultures treated with ß-amyloid (Aß 1-42 ). Microglial activation markers were detected in the striatum of a Parkinson's disease (PD) model and, remarkably, in primary microglia cultures from the hippocampus of mutant β-amyloid precursor protein (APP Sw,Ind ) mice, a transgenic Alzheimer's disease (AD) model. Also of note was the similar cannabinoid receptor signaling found in primary cultures of microglia from APP Sw,Ind and in cells from control animals activated using LPS plus IFN-γ. Expression of CB 1 -CB 2 Hets was increased in the striatum from rats rendered dyskinetic by chronic levodopa treatment. In summary, our results showed sensitivity of activated microglial cells to cannabinoids, increased CB 1 -CB 2 Het expression in activated microglia and in microglia from the hippocampus of an AD model, and a correlation between levodopa-induced dyskinesia and striatal microglial activation in a PD model. Cannabinoid receptors and the CB 1 -CB 2 heteroreceptor complex in activated microglia have potential as targets in the treatment of neurodegenerative diseases. Copyright © 2017 Elsevier Inc. All rights reserved.

Transportation stress and the incidence of exertional rhabdomyolysis in emus (Dromaius novaehollandiae).

PubMed

Menon, Deepa G; Bennett, Darin C; Schaefer, Allan L; Cheng, Kimberly M

2014-02-01

Many emu farms are located in areas lacking processing facilities that can handle these birds. Thus, long-distance shipping of birds to an abattoir is necessary. Two experiments were conducted, wherein emus were transported in a modified horse trailer for 6 h to an abattoir. Changes in the indices of stress and metabolic homeostasis (hematology, serum biochemistry, enzymes, and body temperature and weight) were used to evaluate the physiological response to transport. The activities of enzymes alanine aminotransferase, aspartate aminotransferase, and creatine kinase increased significantly (P < 0.001) from pretransport to slaughter, indicating muscle cell wall damages. The body temperature of emus was significantly (P < 0.001) increased from 37.0 to 39.6°C after transport in experiment 1 and from 37.2 to 38.9°C in experiment 2. Transport resulted in significant weight loss in both experiments (P < 0.001; 2.1 ± 0.2 kg vs. 0.6 ± 0.2 kg) and posttransport resting at lairage led to slight regaining (P < 0.01) of BW. Oral administration of supplements before and after transport was effective in protecting against muscle damage and faster recovery of BW losses during lairage. The clinical findings were suggestive of the incidence of exertional rhabdomyolysis and thus underlined the need for careful handling and improved transport conditions of emus.

Human mesenchymal stromal cells transiently increase cytokine production by activated T cells before suppressing T-cell proliferation: effect of interferon-γ and tumor necrosis factor-α stimulation.

PubMed

Cuerquis, Jessica; Romieu-Mourez, Raphaëlle; François, Moïra; Routy, Jean-Pierre; Young, Yoon Kow; Zhao, Jing; Eliopoulos, Nicoletta

2014-02-01

Mesenchymal stromal cells (MSCs) suppress T-cell proliferation, especially after activation with inflammatory cytokines. We compared the dynamic action of unprimed and interferon (IFN)-γ plus tumor necrosis factor (TNF)-α-pretreated human bone marrow-derived MSCs on resting or activated T cells. MSCs were co-cultured with allogeneic peripheral blood mononuclear cells (PBMCs) at high MSC-to-PBMC ratios in the absence or presence of concomitant CD3/CD28-induced T-cell activation. The kinetic effects of MSCs on cytokine production and T-cell proliferation, cell cycle and apoptosis were assessed. Unprimed MSCs increased the early production of IFN-γ and interleukin (IL)-2 by CD3/CD28-activated PBMCs before suppressing T-cell proliferation. In non-activated PBMC co-cultures, low levels of IL-2 and IL-10 synthesis were observed with MSCs in addition to low levels of CD69 expression by T cells and no T-cell proliferation. MSCs also decreased apoptosis in resting and activated T cells and inhibited the transition of these cells into the sub-G0/G1 and the S phases. With inhibition of indoleamine 2,3 dioxygenase, MSCs increased CD3/CD28-induced T-cell proliferation. After priming with IFN-γ plus TNF-α, MSCs were less potent at increasing cytokine production by CD3/CD28-activated PBMCs and more effective at inhibiting T-cell proliferation but had preserved anti-apoptotic functions. Unprimed MSCs induce a transient increase in IFN-γ and IL-2 synthesis by activated T cells. Pre-treatment of MSCs with IFN-γ plus TNF-α may increase their effectiveness and safety in vivo. Copyright © 2014 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.

Differential Alterations in Excitatory and Inhibitory Networks Involving Dentate Granule Cells Following Chronic Treatment with Distinct Classes of NMDAR Antagonists in Hippocampal Slice Cultures

DTIC Science & Technology

2010-03-08

1992; Jung and McNaughton, 1993); (2) low incidence of recurrent excitatory synapses between granule cells (Molnar and Nadler, 1999; Okazaki et al...neurons, dentate granule cells have a relatively more negative resting membrane potential and exhibit low-frequency firing (Staley et al., 1992; Jung ...inhibition plays a dual role in brain function and possibly seizure occurrence through balancing excitation and synchronizing neuronal firing. An

Optimized conditions for primary culture of pituitary cells from the Atlantic cod (Gadus morhua). The importance of osmolality, pCO₂, and pH.

PubMed

Hodne, Kjetil; von Krogh, Kristine; Weltzien, Finn-Arne; Sand, Olav; Haug, Trude M

2012-09-01

Protocols for primary cultures of teleost cells are commonly only moderately adjusted from similar protocols for mammalian cells, the main adjustment often being of temperature. Because aquatic habitats are in general colder than mammalian body temperatures and teleosts have gills in direct contact with water, pH and buffer capacity of blood and extracellular fluid are different in fish and mammals. Plasma osmolality is generally higher in marine teleosts than in mammals. Using Atlantic cod (Gadus morhua) as a model, we have optimized these physiological parameters to maintain primary pituitary cells in culture for an extended period without loosing key properties. L-15 medium with adjusted osmolality, adapted to low pCO(2) (3.8mm Hg) and temperature (12°C), and with pH 7.85, maintained the cells in a physiologically sounder state than traditional culture medium, significantly improving cell viability compared to the initial protocol. In the optimized culture medium, resting membrane potential and response to releasing hormone were stable for at least two weeks, and the proportion of cells firing action potentials during spawning season was about seven times higher than in the original culture medium. The cells were moderately more viable when the modified medium was supplemented with newborn calf serum or artificial serum substitute. Compared to serum-free L-15 medium, expression of key genes (lhb, fshb, and gnrhr2a) was better maintained in medium containing SSR, whereas NCS tended to decrease the expression level. Although serum-free medium is adequate for many applications, serum supplement may be preferable for experiments dependent on membrane integrity. Copyright © 2012 Elsevier Inc. All rights reserved.