GLORIA

GEOMAR Library Ocean Research Information Access

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Articles  (22)
  • 2010-2014  (22)
  • 1985-1989
  • 1980-1984
  • 2014  (22)
Document type
Source
Years
  • 2010-2014  (22)
  • 1985-1989
  • 1980-1984
Year
  • 1
    Publication Date: 2014-09-02
    Description: Long-term synaptic potentiation (LTP) is thought to be a key process in cortical synaptic network plasticity and memory formation. Hebbian forms of LTP depend on strong postsynaptic depolarization, which in many models is generated by action potentials that propagate back from the soma into dendrites. However, local dendritic depolarization has been shown to mediate these forms of LTP as well. As pyramidal cells in supragranular layers of the somatosensory cortex spike infrequently, it is unclear which of the two mechanisms prevails for those cells in vivo. Using whole-cell recordings in the mouse somatosensory cortex in vivo, we demonstrate that rhythmic sensory whisker stimulation efficiently induces synaptic LTP in layer 2/3 (L2/3) pyramidal cells in the absence of somatic spikes. The induction of LTP depended on the occurrence of NMDAR (N-methyl-d-aspartate receptor)-mediated long-lasting depolarizations, which bear similarities to dendritic plateau potentials. In addition, we show that whisker stimuli recruit synaptic networks that originate from the posteromedial complex of the thalamus (POm). Photostimulation of channelrhodopsin-2 expressing POm neurons generated NMDAR-mediated plateau potentials, whereas the inhibition of POm activity during rhythmic whisker stimulation suppressed the generation of those potentials and prevented whisker-evoked LTP. Taken together, our data provide evidence for sensory-driven synaptic LTP in vivo, in the absence of somatic spiking. Instead, LTP is mediated by plateau potentials that are generated through the cooperative activity of lemniscal and paralemniscal synaptic circuitry.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Gambino, Frederic -- Pages, Stephane -- Kehayas, Vassilis -- Baptista, Daniela -- Tatti, Roberta -- Carleton, Alan -- Holtmaat, Anthony -- England -- Nature. 2014 Nov 6;515(7525):116-9. doi: 10.1038/nature13664. Epub 2014 Aug 31.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉1] Department of Basic Neurosciences and the Center for Neuroscience, CMU, University of Geneva, 1 rue Michel Servet, 1211 Geneva, Switzerland [2] [3] Institute for Interdisciplinary Neuroscience (IINS), UMR 5297 CNRS and University of Bordeaux, 146 rue Leo-Saignat, 33077 Bordeaux, France. ; 1] Department of Basic Neurosciences and the Center for Neuroscience, CMU, University of Geneva, 1 rue Michel Servet, 1211 Geneva, Switzerland [2]. ; 1] Department of Basic Neurosciences and the Center for Neuroscience, CMU, University of Geneva, 1 rue Michel Servet, 1211 Geneva, Switzerland [2] Lemanic Neuroscience Doctoral School, 1 rue Michel Servet, 1211 Geneva, Switzerland. ; Department of Basic Neurosciences and the Center for Neuroscience, CMU, University of Geneva, 1 rue Michel Servet, 1211 Geneva, Switzerland.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25174710" target="_blank"〉PubMed〈/a〉
    Keywords: Action Potentials ; Animals ; Dendrites/*physiology ; *Long-Term Potentiation ; Male ; Mice ; Mice, Inbred C57BL ; Physical Stimulation ; Receptors, N-Methyl-D-Aspartate/metabolism ; Rhodopsin/metabolism ; Somatosensory Cortex/*cytology/*physiology ; Thalamus/cytology/physiology ; Vibrissae/physiology
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 2
    Publication Date: 2014-07-22
    Description: Background: The cognitive consequences of carbon monoxide (CO) poisoning are well described. However, most studies have been carried out without an ad-hoc group of control subjects. The main aim of this study was to evaluate cognitive and psychiatric outcome after CO exposure during the storm Klaus in the South West of France (January 2009) in a homogeneous group of patients compared to a group of 1:1 paired controls. Methods: Patients and controls were asked to fill out questionnaires about quality of life and cognitive complaints. They then underwent a cognitive assessment derived from the Carbon Monoxide Neuropsychological Screening Battery. Psychiatric assessment was performed using subtests of the Mini International Neuropsychiatric Interview. Results: 38 patients and 38 paired controls were included (mean age 38.8 years) and evaluated 51 days after the poisoning. No difference was found between groups on the cognitive complaint questionnaire but patients had a lower quality of life than controls. Patients showed significantly lower cognitive performance than controls on processing speed, mental flexibility, inhibition and working and verbal episodic memories. Patients were more depressed than controls, and suffered more from post-traumatic stress disorder. Conclusions: We report the first study investigating cognitive and psychiatric outcome in consecutive patients after CO poisoning during a natural disaster, using a group comparison method. CO poisoning during storms needs to be dealt with adequately and clinicians should be aware of its possible consequences.
    Electronic ISSN: 1471-2377
    Topics: Medicine
    Published by BioMed Central
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 3
    Publication Date: 2014-07-02
    Description: This paper presents two digital transmission techniques for long haul ionospheric links. Since 2003 we have studied the HF link between the Antarctic Spanish Base, Juan Carlos I, and Spain and we have described the link in terms of availability, signal to noise ratio (SNR) and delay and Doppler power profile. Based on these previous studies we have developed a test bed to investigate two digital transmission techniques, i.e. Direct Sequence Spread Spectrum and Orthogonal Frequency Division Multiplexing, which can provide a low power, low rate ionospheric data link from Antarctica. Symbol length, bandwidth and constellation are some of the features that are analyzed in this work. Data gathered from the link throughout the 2010/2011 and 2011/2012 Antarctic surveys show that spread spectrum techniques can be used to transmit data at low rate when the channel forecast is poor but when the channel forecast is good multicarrier techniques can be used to transmit sporadic bursts of data at higher rate.
    Print ISSN: 0048-6604
    Electronic ISSN: 1944-799X
    Topics: Geosciences , Physics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 4
    Publication Date: 2014-08-05
    Description: The geophysical observatory in the Antarctic Spanish Station, Juan Carlos I (ASJI), on Livingston Island, has been monitoring the magnetic field in the Antarctic region for more than fifteen years. In 2004, a vertical incidence ionospheric sounder completed the observatory, which brings a significant added value in a region with low density of geophysical data. Although the ASJI is only operative during the austral summer, the geomagnetic station records the data throughout the year. A High Frequency (HF) transmission system was installed in 2004 in order to have the geomagnetic data available during the whole year. As the power supply is very limited when the station is not operative, we had to design a low-power HF transceiver with a very simple antenna, due to environmental aspects. Moreover, the flow of information was unidirectional, so the modulation had to be extremely robust since there is no retransmission in case of error. This led us to study the main parameters of the ionospheric channel and to design new modulations specially adapted to very low signal to noise scenarios with high levels of interference. In this paper, a review of the results of our remote geophysical observatory and associated transmission system in Antarctica during the last decade is presented.
    Electronic ISSN: 2072-4292
    Topics: Architecture, Civil Engineering, Surveying , Geography
    Published by MDPI Publishing
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 5
    Publication Date: 2014-03-12
    Description: Thermal stress affects organism performance differently depending on the ambient temperature to which they are acclimatized, which varies along latitudinal gradients. This study investigated whether differences in physiological responses to temperature are consistent with regional differences in temperature regimes for the stony coral Oculina patagonica . To resolve this question we experimentally assessed how colonies originating from four different locations characterized by 〉3°C variation in mean maximum annual temperature responded to warming from 20 to 32°C. We assessed plasticity in symbiont identity, density, and photosynthetic properties, together with changes in host tissue biomass. Results show that, without changes in the type of symbiont hosted by coral colonies, O. patagonica has limited capacity to acclimatize to future warming. We found little evidence of variation in overall thermal tolerance, or in thermal optima, in response to spatial variation in ambient temperature. Given that the invader O. patagonica is a relatively new member of the Mediterranean coral fauna our results also suggest that coral populations may need to remain isolated for a long period of time for thermal adaptation to potentially take place. Our study indicates that for O. patagonica , mortality associated with thermal stress manifests primarily through tissue breakdown under moderate but prolonged warming (which does not impair symbiont photosynthesis and, therefore, does not lead to bleaching). Consequently, projected global warming is likely to causes repeat incidents of partial and whole colony mortality and might drive a gradual range contraction of Mediterranean corals. This article is protected by copyright. All rights reserved.
    Print ISSN: 1354-1013
    Electronic ISSN: 1365-2486
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Geography
    Published by Wiley-Blackwell
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 6
    Publication Date: 2014-04-11
    Description: Ceftazidime is particularly efficient against Pseudomonas aeruginosa in cystic fibrosis patients. Thus, the spontaneous production of pyridine, which is a toxic product, raises some concern. Our aim was to examine the kinetics of degradation of ceftazidime in portable infusion pumps either at 4°C, 22°C, or 33°C and to propose some recommendations in order to reduce the pyridine exposure. Two administration models were studied in vitro . In model 1, we administered 12 g of ceftazidime infused over 23 h (once-daily infusion) compared to 6 g infused over 11.5 h in model 2 (twice-daily regimen). Samples were collected at 0 h and then every 4 and 2 h after the shaping of portable infusion pumps in models 1 and 2, respectively. Both ceftazidime and pyridine were analyzed using an ultraviolet high-performance liquid chromatograph. Production of pyridine is highly depending on the temperature. The in situ production of pyridine per day of treatment decreases at a ratio close to 1/6 and 1/3 between 33°C and 4°C in models 1 and 2, respectively. Regardless of the conditions, the production of pyridine is significantly lower in model 2, whereas the total delivery amount of ceftazidime is significantly higher at 4°C and 33°C compared to that in model 1. According to a the precautionary principle, these findings lead to three major recommendations: (i) exposing a solution of ceftazidime to over 22°C should be strictly avoided, (ii) a divided dose of 6 g over 11.5 h instead of a once-daily administration is preferred, and (iii) infusion should be administered immediately after reconstitution.
    Print ISSN: 0066-4804
    Electronic ISSN: 1098-6596
    Topics: Biology , Medicine
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 7
    Publication Date: 2014-11-15
    Description: The classic model of tumor suppression implies that malignant transformation requires full “two-hit” inactivation of a tumor-suppressor gene. However, more recent work in mice has led to the proposal of a “continuum” model that involves more fluid concepts such as gene dosage-sensitivity and tissue specificity. Mutations in the tumor-suppressor gene von Hippel-Lindau (VHL) are associated with a complex spectrum of conditions. Homozygotes or compound heterozygotes for the R200W germline mutation in VHL have Chuvash polycythemia, whereas heterozygous carriers are free of disease. Individuals with classic, heterozygous VHL mutations have VHL disease and are at high risk of multiple tumors (e.g., CNS hemangioblastomas, pheochromocytoma, and renal cell carcinoma). We report here an atypical family bearing two VHL gene mutations in cis (R200W and R161Q), together with phenotypic analysis, structural modeling, functional, and transcriptomic studies of these mutants in comparison with classical mutants involved in the different VHL phenotypes. We demonstrate that the complex pattern of disease manifestations observed in VHL syndrome is perfectly correlated with a gradient of VHL protein (pVHL) dysfunction in hypoxia signaling pathways. Thus, by studying naturally occurring familial mutations, our work validates in humans the “continuum” model of tumor suppression. Cancer Res; 74(22); 6554–64. ©2014 AACR.
    Print ISSN: 0008-5472
    Electronic ISSN: 1538-7445
    Topics: Medicine
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 8
    Publication Date: 2014-08-12
    Description: Hyperpolarized [1, 13 C]pyruvate was injected rapidly into haemolysates in which hydrolysis of nicotinamide adenine dinucleotide (phosphate) (NAD(P))/NAD(P)H had been inhibited with nicotinamide. Haemolysates provide a stable glycolytic system in which membrane permeability is not a flux-controlling step, and they enable the concentration of NADH to be adjusted experimentally while keeping the rest of the sample with the same composition as that of the cytoplasm of the cell (albeit diluted twofold at the time of injection of the [1, 13 C]pyruvate). We showed that the maximum amplitude of the 13 C NMR signal from the [1, 13 C] L -lactate, produced from [1, 13 C]pyruvate, and the time at which it occurred was dependent on NADH concentration, as predicted by enzyme-kinetic analysis. The main feature of such curves was dictated by the immediacy of the supply of the co-substrate of lactate dehydrogenase (LDH, EC 1.1.1.27), and we posit that this also pertains in vivo in various tissues including neoplasms. By constructing an appropriate mathematical model and by using a Markov-chain Monte Carlo approach, we fitted experimental data to estimate LDH and NADH concentrations. Experiments carried out with only endogenous NADH present enabled the estimation of its effective concentration in human RBCs; the ability to make this estimate is a special feature of the rapid-dissolution dynamic nuclear polarization method. We found an endogenous NADH concentration in human RBCs two to four times higher than previously reported. Copyright © 2014 John Wiley & Sons, Ltd. We measured lactate dehydrogenase and NADH concentrations in human erythrocytes by using 13 C NMR rapid-dissolution dynamic nuclear polarization. A detailed enzyme kinetic model was used in the description of the experimental system, and a Markov-chain Monte Carlo procedure yielded estimates of parameter values. We report new estimates of concentrations of LDH and NADH in human erythrocytes; the former was about three times lower than previously reported while the latter was about three times higher.
    Print ISSN: 0952-3480
    Electronic ISSN: 1099-1492
    Topics: Medicine
    Published by Wiley-Blackwell
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 9
    Publication Date: 2014-08-28
    Description: We investigate by near-forward Raman scattering a presumed reinforcement of the (A-C,B-C)-mixed phonon-polariton of a A 1-x B x C zincblende alloy when entering its longitudinal optical-like ( LO -like) regime near the Brillouin zone centre Γ, as predicted within the formalism of the linear dielectric response. A choice system to address such issue is ZnSe 0.68 S 0.32 due to the moderate dispersion of its refractive index in the visible range, a sine qua non condition to bring the phonon-polariton insight near Γ. The LO- like reinforcement regime is actually accessed by using the 633.0 nm laser excitation, testified by the strong emergence of the (Zn-Se,Zn-S)-mixed phonon-polariton at ultimately small scattering angles.
    Print ISSN: 0021-8979
    Electronic ISSN: 1089-7550
    Topics: Physics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 10
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...