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Found 10470 matches for

  • Antibodies That Work Again and Again and Again.

    23 July 2018

    In the past few years significant concern has been raised about the quality and reproducibility of antibodies used in numerous scientific publications. In this chapter we discuss some of the biggest contributing factors to the "antibody problem" from both the commercial production side, as well as the end-users side. Specifically we argue that Western blot data should be used to provide a reliable initial indication of antibody quality, as well as a guide to distinguish between multiple offerings for antibodies to the same target. Secondly, we describe a set of best practices for antibody manufacturers to employ that will eliminate most of the variability in polyclonal antibodies. Taken together these proposals provide a way to significantly improve both the quality and the reproducibility of commercial antibodies.

  • Radiation induces acute alterations in neuronal function.

    23 July 2018

    Every year, nearly 200,000 patients undergo radiation for brain tumors. For both patients and caregivers the most distressing adverse effect is impaired cognition. Efforts to protect against this debilitating effect have suffered from inadequate understanding of the cellular mechanisms of radiation damage. In the past it was accepted that radiation-induced normal tissue injury resulted from a progressive reduction in the survival of clonogenic cells. Moreover, because radiation-induced brain dysfunction is believed to evolve over months to years, most studies have focused on late changes in brain parenchyma. However, clinically, acute changes in cognition are also observed. Because neurons are fully differentiated post-mitotic cells, little information exists on the acute effects of radiation on synaptic function. The purpose of our study was to assess the potential acute effects of radiation on neuronal function utilizing ex vivo hippocampal brain slices. The cellular localization and functional status of excitatory and inhibitory neurotransmitter receptors was identified by immunoblotting. Electrophysiological recordings were obtained both for populations of neuronal cells and individual neurons. In the dentate gyrus region of isolated ex vivo slices, radiation led to early decreases in tyrosine phosphorylation and removal of excitatory N-methyl-D-aspartate receptors (NMDARs) from the cell surface while simultaneously increasing the surface expression of inhibitory gamma-aminobutyric acid receptors (GABA(A)Rs). These alterations in cellular localization corresponded with altered synaptic responses and inhibition of long-term potentiation. The non-competitive NMDAR antagonist memantine blocked these radiation-induced alterations in cellular distribution. These findings demonstrate acute effects of radiation on neuronal cells within isolated brain slices and open new avenues for study.

  • Optimized protocol to make phospho-specific antibodies that work.

    23 July 2018

    Phosphoproteins are considered to be among the most important proteins in the body. They are the proteins that regulate almost all cell processes from cell division in cancer to neuronal signal transduction in learning and memory. This review will describe the development of a revolutionary immunochemical technique that produces antibodies that bind to target proteins only when the protein is in the phosphorylated state. These phospho-specific antibodies can thus be used to track the activity of a protein, not simply its level of expression. In this review, we will discuss both the design of the phosphopeptide immunogen and immunization. The affinity purification of the phospho-specific antibody as well as the methods most suitable for characterizing the phosphospecificity of the antibody will be described here. Taken together, these methods will cover the key procedures and protocols required to produce a phospho-specific antibody that works.

  • Cell surface expression of NR1 splice variants and NR2 subunits is modified by prenatal ethanol exposure.

    23 July 2018

    N-methyl-D-aspartate receptor dysfunction has been strongly suggested to link with the abnormalities seen in fetal alcohol syndrome. Thus, the effects of prenatal ethanol exposure on the total expression of NR1 splice variants and the cell surface expression of both NR1 and NR2 subunits in brain were investigated in rats. Western blot studies of membrane homogenates from cerebral cortices at postnatal days 1 through 21 indicate that prenatal ethanol treatment does not alter total NR1 expression or differential expression of NR1 splice variants during development. However, immunoprecipitation studies using PSD95 suggest that both C2'-terminal variants and NR2A subunits at the cortical postsynaptic membrane of postnatal day 21 were significantly reduced after prenatal ethanol treatment. Moreover, C1-terminal variants were decreased in both pair-fed and ethanol-treated groups, while no significant differences in the levels of total NR1 subunits, NR1 splice variants containing the N- or C2-terminal cassettes, or NR2B subunits were observed. Thus, these results suggest that prenatal exposure to ethanol may influence neuronal function by selective regulation of expression of C2'-terminal variants and NR2A subunits at the cell surface.

  • Presynaptic and postsynaptic mechanisms of long-term potentiation.

    23 July 2018

  • Ethanol sensitivity and subunit composition of NMDA receptors in cultured striatal neurons.

    23 July 2018

    Assessment of ethanol (EtOH) sensitivity was combined with analysis of N-methyl-D-aspartate (NMDA) NR1-NR2 subunit composition in primary cultured striatal neurons. Subunit composition was determined by western blot analysis; assessment of ifenprodil and spermine sensitivity during whole-cell patch-clamp recordings. From 3-21 days in culture, NR2B was the only NR2 subunit detected using NR2 subunit specific antibodies; NMDA-induced currents were strongly inhibited by the NR2B-selective antagonist ifenprodil. Two populations of neurons were identified at all ages in culture: those in which NMDA-induced current was or was not potentiated by 100 microM spermine. This suggested that the striatal neurons expressed functional NMDARs which lacked or contained the NR1 N-terminal cassette. The EtOH sensitivity did not differ between these two populations of neurons nor did it change with age in culture at all concentrations of EtOH studied. Human embryonic kidney (HEK) 293 cells containing NR1-1a or NR1-1b with either the NR2A or NR2B subunits did not differ in their EtOH sensitivity. Thus, it would appear that the presence or absence of the N-terminal cassette does not affect the EtOH sensitivity of recombinant NMDARs and native NMDARs expressed in cultured striatal neurons.

  • Long-term enhancement of excitability and the regulation of glutamate receptors by protein kinases.

    23 July 2018

  • Protein phosphorylation in isolated human adipocytes-adrenergic control of the phosphorylation of hormone-sensitive lipase.

    23 July 2018

    The effect of adrenergic agents on protein phosphorylation in human adipocytes was examined. Freshly isolated human fat cells were incubated with 32PO4 in order to label intracellular ATP, then treated with a variety of adrenergic and other pharmacologic agents. Treatment with the beta-adrenergic agonist isoproterenol led to a significant increase in phosphate content of at least five protein bands (Mr 52, 53, 63, 67, 84 kDa). The increase in phosphorylation was partially inhibited by the alpha-2 agonist clonidine. Epinephrine, a combined alpha and beta agonist, was less effective at increasing phosphate content of the proteins than was isoproterenol. Neither insulin nor the alpha-1 agonist phenylephrine had any discernible effect on the pattern of protein phosphorylation. The 84 kDa phosphorylated peptide band appears to contain hormone-sensitive lipase, a key enzyme in the lipolytic pathway which is activated by phosphorylation. These results are somewhat different than previously reported results for rat adipocytes, and represent the first report of overall pattern and adrenergic modulation of protein phosphorylation in human adipocytes.

  • Studies of the physiological role of specific neuronal phosphoproteins.

    23 July 2018

    Studies in the last five years have provided conclusive evidence that protein phosphorylation is involved in the regulation of neuronal function. Direct evidence from microinjection experiments has shown that four distinct classes of protein kinases modulate physiological processes in neurons. In addition, a large number of substrates for these proteins have been identified in neurons. Three of these phosphoproteins have been discussed here: first, synapsin I, a substrate protein present in nerve terminals, the phosphorylation of which appears to regulate neurotransmitter release from those nerve terminals; second, the acetylcholine receptor, the phosphorylation of which regulates its rate of desensitization in the presence of acetylcholine; and, finally, DARPP-32, the phosphorylation of which converts it into a very potent phosphatase inhibitor that may be involved in the regulation by the neuromodulator dopamine of the effects of the neurotransmitter glutamate. These studies of specific phosphoproteins suggest that the identification and characterization of additional neuronal phosphoproteins should lead to the clarification of additional molecular mechanisms by which signal transduction is carried out in nerve cells.

  • Synapsin I, a phosphoprotein associated with synaptic vesicles: possible role in regulation of neurotransmitter release.

    23 July 2018

    The data presented here provide evidence that the study of neuronal phosphoproteins can lead to the identification of previously unknown proteins and that these proteins may play important roles in neuronal communication. Specifically, in the case of synapsin I, direct evidence has been obtained that this phosphoprotein is involved in regulating neurotransmitter release. A tentative explanation of the results obtained in the micro-injection studies is as follows: synapsin I, in the dephosphostate, is bound to the cytoplasmic surface of synaptic vesicles and inhibits the ability of the vesicle to interact with the plasma membrane; increases in intracellular calcium activate calmodulin kinase II which in turn phosphorylates synapsin I and the phosphorylated synapsin I dissociates from the synaptic vesicle thus removing a constraint on the release of neurotransmitter. Clearly, more studies need to be done to rigorously test this hypothesis. Nevertheless these studies of synapsin I suggest that the study of previously unknown phosphoproteins will lead to the elucidation of previously unknown regulatory processes in neurons.

  • Volunteers needed for a study investigating the effects of mental exercises

    22 January 2018

    You would be invited to the Department of Psychiatry (Warneford Hospital) for two study sessions. Both sessions would take approximately 60 to 90 minutes. Between the sessions you would be assigned a brief mental exercise (taking approximately 10 minutes per day) that you carry out for 7 days. After this training period, your performance on a range of computerized psychological tasks will be assessed.

  • Dynamics of perceptual decision making

    17 April 2018

    During this study you will learn and perform a task that involves judging the direction of motion of clouds of moving dots. You will participate in a maximum of 4 sessions; first you will learn how to do the task on a computer. Then you will do 1-2 sessions performing the task while we record your brain activity using magnetoencephalography (MEG). MEG is a safe neuro-imaging technique that records the weak magnetic fields produced by the synchronised firing of neurons in the brain. MEG sessions will last up to 2 hours. Finally, we will make a 3D image of your brain using magnetic resonance imaging (MRI) which we will use to localise the neural generators of the MEG signals.

  • VOLUNTEERS NEEDED FOR ONE-TO-ONE INTERVIEW ON BRAIN HEALTH

    14 March 2018

    We are conducting a research study to investigate people’s perceptions of the brain and brain health (Ethics Approval Reference: R56033/RE001). The study is led by the EU-funded Lifebrain consortium (www.lifebrain.uio.no).

  • Can non-drug antidepressant treatments influence the way the human brain processes information?

    28 September 2017

    Ethics Approval Reference: R48997/RE003

  • Healthy volunteers needed for emotional processing study

    12 June 2018

    Volunteers should be right handed, have no history of a psychological disorder such as depression, anxiety, or an eating disorder, no previous participation in a study using computerised tasks with emotional faces, and no participation in a drug study within the last 3 months. Central University Research Ethics Committee number: R57219/RE001

  • Are spiders a problem for you? Interested in taking part in a research study?

    12 June 2018

  • The effect of losartan on fear learning

    6 September 2017

    We are looking for healthy volunteers aged 18-40 years and fluent in English to take part in a study investigating how a single dose of the medication losartan affects learning and information processing, using a simple computer task. Losartan is currently used to treat high blood pressure. However, we think that it may also enhance the effectiveness of psychological therapies such as Cognitive-Behaviour Therapy. The study involves three appointments of about 5 hours in total.

  • VOLUNTEERS NEEDED FOR MAGNETIC RESONANCE STUDIES OF THE BRAIN

    2 July 2018

    MRI is a type of brain scan that allows us to see how the brain is organised and performs tasks like decision making. The scan is safe and does not involve any needles or injections. Who are we looking for? Fluent English-speaking men or women aged 18-45, who are not pregnant, with a range of symptoms of depression. You will be asked questions about your medical history to check your suitability for an MRI scan.

  • Volunteers needed for Dementia Prevention Study: European Prevention of Alzheimer’s Dementia (EPAD)

    11 April 2018

    The European Prevention of Alzheimer’s Dementia (EPAD study) aims to address the urgent need for new treatments designed to prevent Alzheimer’s Dementia. The main study objectives are to: 1. Learn and understand better the factors involved in developing Alzheimer’s dementia. 2. To develop new treatments more quickly which are hoped to prevent Alzheimer’s dementia.

  • Ebselen as an add-on treatment in hypo/mania

    31 October 2017

    Lithium can stabilise the highs and lows of mood but requires careful monitoring. We are interested in a new lithium-like medicine called ebselen which might help improve recovery from acute hypo/manic episodes. The study involves adding ebselen to your usual medication during an acute episode of hypo/mania.