586 research outputs found

    The Recognition of Hypothalamo-Neurohypophysial Functions by Developing T Cells

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    Neuropeptide signals and specific neuropeptide receptors have been described in the thymus supporting the concept of a close dialogue between the neuroendocrine and the immune systems at the level of early T-cell differentiation. In this paper, we review recent data about neurohypophysial (NHP)-related peptides detected in the thymus from different species. We suggest that we are dealing in fact with other member(s) of the NHP hormone family, which seems to exert its activity locally through a novel model of cell-to-cell signaling, that of cryptocrine communication. This model involves exchange of signals between thymic epithelial cells and developing thymocytes. The NHP-related peptides have been shown to trigger thymocyte proliferation and could induce immune tolerance of this highly conserved neuroendocrine family

    Beta-blocker migraine prophylaxis affects the excitability of the visual cortex as revealed by transcranial magnetic stimulation

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    The objective of this study is to assess effects of beta-blocker migraine prophylaxis on cortical excitability determined by transcranial magnetic stimulation (TMS). Phosphene and motor thresholds (PT, MT) were investigated in 29 patients with migraine, in 15 of them prior to and following preventive medication with metoprolol and in 14 patients without prophylaxis. Following prophylaxis headache frequency significantly decreased (p = 0.005) and mean PT were significantly increased (51.5 ± 7.5 vs. 63.6 ± 8.4%) compared to patients without preventive treatment (53.7 ± 5.3 vs. 52.3 ± 6.3%; p = 0.040). Mean MT did not significantly differ either between groups or due to treatment. In the group of all patients, a significant inverse correlation between headache frequency and the level of PT was found (R = −0.629; p < 0.01). There was, however, no significant correlation in the subgroups of patients. We conclude that (a) clinical efficacy of beta-blocker treatment in migraine could be (at least partly) linked to its ability to modulate the excitability of the visual cortex and (b) the PT determined by TMS appears suitable to assess the effects of prophylaxis on cortical excitability in the individual patient. This may be useful in clinical trials investigating migraine preventive drugs

    A One-Pot, 3 Component, Domino Heck-aza-Michael Approach to Libraries of Functionalized 1, 1-Dioxido-1, 2-benzisothiazoline-2-acetic acids

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    This document is the Accepted Manuscript version of a Published Work that appeared in final form in Journal of Combinatorial Chemistry, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see http://doi.org/10.1021/cc900025e.A sequential three-component synthesis of functionalized benzisothiazoline-3-acetic acid 1,1- dioxides utilizing a domino Heck-aza-Michael pathway is reported. This one-pot procedure rapidly assembles functionalized benzylsulfonamides, which undergo a palladium-catalyzed, domino, Heckaza- Michael transformation in an experimentally straightforward manner. This attractive protocol has been utilized to synthesize three combinatorial sub-libraries (I-III) comprising a total of 95 compounds in high purities (≥95% for 75 compounds), yield and quantities

    Isotope or mass encoding of combinatorial libraries

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    Background: Combinatorial chemistry using solid-phase synthesis is a rapidly developing technology that can result in a significant reduction in the time required to find and optimize lead compounds. The application of this approach to traditional medicinal chemistry has led to the construction of libraries of small organic molecules on resin beads. A major difficulty in developing large combinatorial libraries is the lack of a facile encoding and decoding methodology to identify active compounds.Results: Several encoding schemes are described which use the ability of mass spectrometry to ascertain isotopic distributions. Molecular tags are attached to resin beads in parallel or on the linker used for chemical library synthesis. The tags are encoded via a controlled ratio of a number of stable isotopes on the tagging molecules, and range from a single to a complex isotopic distribution.Conclusions: A novel coding scheme is described that is useful for the generation of large encoded combinatorial libraries. The code can be cleaved after assay and analyzed by mass spectrometry in an automated fashion. An important element of the combinatorial discovery process is the ability to extract the structure-activity relationship (SAR) information made available by library screening. The speed and sensitivity of the mass-encoding scheme has the potential to determine the full SAR for a given library

    Does visual cortex lactate increase following photic stimulation in migraine without aura patients? A functional 1H-MRS study

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    Proton magnetic resonance spectroscopy (1H-MRS) has been used in a number of studies to assess noninvasively the temporal changes of lactate (Lac) in the activated human brain. Migraine neurobiology involves lack of cortical habituation to repetitive stimuli and a mitochondrial component has been put forward. Our group has recently demonstrated a reduction in the high-energy phosphates adenosine triphosphate (ATP) and phosphocreatine (PCr) in the occipital lobe of migraine without aura (MwoA) patients, at least in a subgroup, in a phosphorus MRS (31P-MRS) study. In previous studies, basal Lac levels or photic stimulation (PS)-induced Lac levels were found to be increased in patients with migraine with aura (MwA) and migraine patients with visual symptoms and paraesthesia, paresia and/or dysphasia, respectively. The aim of this study was to perform functional 1H-MRS at 3 T in 20 MwoA patients and 20 control subjects. Repetitive visual stimulation was applied using MR-compatible goggles with 8 Hz checkerboard stimulation during 12 min. We did not observe any significant differences in signal integrals, ratios and absolute metabolite concentrations, including Lac, between MwoA patients and controls before PS. Lac also did not increase significantly during and following PS, both for MwoA patients and controls. Subtle Lac changes, smaller than the sensitivity threshold (i.e. estimated at 0.1–0.2 μmol/g at 3 T), cannot be detected by MRS. Our study does, however, argue against a significant switch to non-aerobic glucose metabolism during long-lasting PS of the visual cortex in MwoA patients

    Abnormal cortical responses to somatosensory stimulation in medication-overuse headache

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    BACKGROUND: Medication-overuse headache (MOH) is a frequent, disabling disorder. Despite a controversial pathophysiology convincing evidence attributes a pivotal role to central sensitization. Most patients with MOH initially have episodic migraine without aura (MOA) characterized interictally by an absent amplitude decrease in cortical evoked potentials to repetitive stimuli (habituation deficit), despite a normal initial amplitude (lack of sensitization). Whether central sensitization alters this electrophysiological profile is unknown. We therefore sought differences in somatosensory evoked potential (SEP) sensitization and habituation in patients with MOH and episodic MOA. METHODS: We recorded median-nerve SEPs (3 blocks of 100 sweeps) in 29 patients with MOH, 64 with MOA and 42 controls. Episodic migraineurs were studied during and between attacks. We measured N20-P25 amplitudes from 3 blocks of 100 sweeps, and assessed sensitization from block 1 amplitude, and habituation from amplitude changes between the 3 sequential blocks. RESULTS: In episodic migraineurs, interictal SEP amplitudes were normal in block 1, but thereafter failed to habituate. Ictal SEP amplitudes increased in block 1, then habituated normally. Patients with MOH had larger-amplitude block 1 SEPs than controls, and also lacked SEP habituation. SEP amplitudes were smaller in triptan overusers than in patients overusing nonsteroidal anti-inflammatory drugs (NSAIDs) or both medications combined, lowest in patients with the longest migraine history, and highest in those with the longest-lasting headache chronification. CONCLUSIONS: In patients with MOH, especially those overusing NSAIDs, the somatosensory cortex becomes increasingly sensitized. Sensory sensitization might add to the behavioral sensitization that favors compulsive drug intake, and may reflect drug-induced changes in central serotoninergic transmission

    The treatment of migraines and tension-type headaches with intravenous and oral niacin (nicotinic acid): systematic review of the literature

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    BACKGROUND: Migraine and tension-type headaches impose a tremendous economic drain upon the healthcare system. Intravenous and oral niacin has been employed in the treatment of acute and chronic migraine and tension-type headaches, but its use has not become part of contemporary medicine, nor have there been randomized controlled trials further assessing this novel treatment. We aimed to systematically review the evidence of using intravenous and/or oral niacin as a treatment for migraine headaches, tension-type headaches, and for headaches of other etiologic types. METHODS: We searched English and non-English language articles in the following databases: MEDLINE (1966–February 2004), AMED (1995–February 2004) and Alt HealthWatch (1990–February 2004). RESULTS: Nine articles were found to meet the inclusion criteria and were included in this systematic review. Hypothetical reasons for niacin's effectiveness include its vasodilatory properties, and its ability to improve mitochondrial energy metabolism. Important side effects of niacin include flushing, nausea and fainting. CONCLUSION: Although niacin's mechanisms of action have not been substantiated from controlled clinical trials, this agent may have beneficial effects upon migraine and tension-type headaches. Adequately designed randomized trials are required to determine its clinical implications

    Revisiting the β-lactams for tuberculosis therapy with a compound-compound synthetic lethality approach

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    The suboptimal effectiveness of β-lactam antibiotics against Mycobacterium tuberculosis has hindered the utility of this compound class for tuberculosis treatment. However, the results of treatment with a second-line regimen containing meropenem plus a β-lactamase inhibitor were found to be encouraging in a case study of extensively drug-resistant tuberculosis (M. C. Payen, S. De Wit, C. Martin, R. Sergysels, et al., Int J Tuberc Lung Dis 16:558-560, 2012, https://doi.org/10.5588/ijtld.11.0414). We hypothesized that the innate resistance of M. tuberculosis to β-lactams is mediated in part by noncanonical accessory proteins that are not considered the classic targets of β-lactams and that small-molecule inhibitors of those accessory targets might sensitize M. tuberculosis to β-lactams. In this study, we screened an NIH small-molecule library for the ability to sensitize M. tuberculosis to meropenem. We identified six hit compounds, belonging to either the N-arylindole or benzothiophene chemotype. Verification studies confirmed the synthetic lethality phenotype for three of the N-arylindoles and one benzothiophene derivative. The latter was demonstrated to be partially bioavailable via oral administration in mice. Structure-activity relationship studies of both structural classes identified analogs with potent antitubercular activity, alone or in combination with meropenem. Transcriptional profiling revealed that oxidoreductases, MmpL family proteins, and a 27-kDa benzoquinone methyltransferase could be the targets of the N-arylindole potentiator. In conclusion, our compound-compound synthetic lethality screening revealed novel small molecules that were capable of potentiating the action of meropenem, presumably via inhibition of the innate resistance conferred by β-lactam accessory proteins. β-Lactam compound-compound synthetic lethality may be an alternative approach for drug-resistant tuberculosis

    Search for non-relativistic Magnetic Monopoles with IceCube

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    The IceCube Neutrino Observatory is a large Cherenkov detector instrumenting 1km31\,\mathrm{km}^3 of Antarctic ice. The detector can be used to search for signatures of particle physics beyond the Standard Model. Here, we describe the search for non-relativistic, magnetic monopoles as remnants of the GUT (Grand Unified Theory) era shortly after the Big Bang. These monopoles may catalyze the decay of nucleons via the Rubakov-Callan effect with a cross section suggested to be in the range of 1027cm210^{-27}\,\mathrm{cm^2} to 1021cm210^{-21}\,\mathrm{cm^2}. In IceCube, the Cherenkov light from nucleon decays along the monopole trajectory would produce a characteristic hit pattern. This paper presents the results of an analysis of first data taken from May 2011 until May 2012 with a dedicated slow-particle trigger for DeepCore, a subdetector of IceCube. A second analysis provides better sensitivity for the brightest non-relativistic monopoles using data taken from May 2009 until May 2010. In both analyses no monopole signal was observed. For catalysis cross sections of 1022(1024)cm210^{-22}\,(10^{-24})\,\mathrm{cm^2} the flux of non-relativistic GUT monopoles is constrained up to a level of Φ901018(1017)cm2s1sr1\Phi_{90} \le 10^{-18}\,(10^{-17})\,\mathrm{cm^{-2}s^{-1}sr^{-1}} at a 90% confidence level, which is three orders of magnitude below the Parker bound. The limits assume a dominant decay of the proton into a positron and a neutral pion. These results improve the current best experimental limits by one to two orders of magnitude, for a wide range of assumed speeds and catalysis cross sections.Comment: 20 pages, 20 figure
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