Search results for "LSA"
showing 10 items of 832 documents
Mitochondrial basis of the anti-arrhythmic action of lidocaine and modulation by the n-6 to n-3 PUFA ratio of cardiac phospholipids
2012
The aim of this study was to evaluate the involvement of mitochondria in the mechanism of the anti-arrhythmic lidocaine. Rats were fed with a diet containing either n-6 polyunsaturated fatty acids (PUFAs, SSO group) or an equimolecular mixture of n-3 and n-6 PUFAs (FO group) for 8 weeks. The hearts were perfused according to the working mode using a medium with or without lidocaine 5 μM. They were then subjected to local ischemia (20 min) and reperfusion (30 min). Dietary n-3 PUFAs triggered the expected decrease in the n-6/n-3 PUFA ratio of cardiac phospholipids. Reperfusing the ischemic area favored the incidence of severe arrhythmias. Lidocaine treatment abolished almost completely reper…
Furosemide interactions with brain GABAA receptors
1997
1. The loop diuretic furosemide is known to antagonize the function of gamma-aminobutyric acid type A (GABAA) receptors. The purpose of the present study was to examine the direct interaction of furosemide with the GABAA receptors by autoradiography and ligand binding studies with native rat and human receptors and with recombinant receptors composed of rat subunits. 2. Autoradiography with [35S]-t-butylbicyclophosphorothionate ([35S]-TBPS) as a ligand indicated that furosemide (0.1-1 mM) reversed the 5 microM GABA-induced inhibition of binding only in the cerebellar granule cell layer of rat brain sections. In all other regions studied, notably also in the hippocampal and thalamic areas, f…
Long-term pulse profile study of the Be/X-ray pulsar SAX J2103.5+4545
2007
Aims. We present the first long-term pulse profile study of the X-ray pulsar SAX J2103.5+4545. Our main goal is to study the pulse shape correlation either with luminosity, time or energy. Methods. This Be/X-ray binary system was observed from 1999 to 2004 by RXTE PCA, and by INTEGRAL from 2002 to 2005, during the Performance and Verification (PV) phase and the Galactic Plane Scan survey (GPS). X-ray pulse profiles were obtained in different energy ranges. The long-term spectral variability of this source is studied. The long-term flux, frequency and spin-up rate histories are computed. A new set of orbital parameters are also determined. Results. The pulse shape is complex and highly varia…
Influence of carbenoxolone on the anticonvulsant efficacy of conventional antiepileptic drugs against audiogenic seizures in DBA/2 mice
2004
Carbenoxolone, the succinyl ester of glycyrrhetinic acid, is an inhibitor of 11beta-hydroxy steroid dehydrogenase and gap junctional intercellular communication. It is currently used in clinical treatment of ulcer diseases. Systemic administration of carbenoxolone (1-40 mg/kg, intraperitoneally (i.p.)) was able to produce a dose-dependent decrease in DBA/2 audiogenic seizure severity score. Glycyrrhizin, an analogue of carbenoxolone inactive at the gap-junction level, was unable to affect audiogenic seizures at doses up to 30 mg/kg. In combination with conventional antiepileptic drugs, carbenoxolone, 0.5 mg/kg, i.p., which per se did not significantly affect the occurrence of audiogenic sei…
Temperature dependence of the toxic effects of phenytoin on peripheral neuromuscular function of the rat tail.
1990
We studied the acute effects of a single dose of phenytoin (250 mg/kg) on peripheral neuromuscular function. The evoked muscle action potentials of the dorsal segmental muscles in the rat tail, and the conduction velocity of the dorsal nerve trunk which innervates them, were measured before and after the intraperitoneal injection of phenytoin. The experiments were performed at different temperatures, 27 (physiological tail temperature), 36 and 37 degrees C (physiological central temperature) in different groups of animals. The amplitudes of the evoked muscle action potentials in the treated groups showed no significant modifications at 27 degrees C, at 36 degrees C a small nonsignificant de…
Antiepileptic drug use in nursing home residents: a cross-sectional, regional study.
2006
Summary The use of antiepileptic drugs (AED), their primary indication, comorbid conditions, and concomitant medications were collected from 565 nursing homes (NH) residents of six NH located around the city of Mainz, Germany representing 5.05% of all NH residents in the area. Data were collected from the electronic pharmacy files and by reviewing all available medical records. Average age was 82.2±2.4 years, 85.5% were women. Of 565 NH residents 28 (4.96%) received AED therapy, of which in 17 (63%) AED were prescribed for a seizure-related diagnosis. In 76.5% seizure types were unspecified and a distinction in focal and generalized epilepsy was made in only 23.5% of patients. Three patient…
Prevention of the acute neurotoxic effects of phenytoin on rat peripheral nerve by H7, an inhibitor of protein kinase C.
1992
Abstract The neurotoxic effects of a single dose of phenytoin (150 mg/kg body weight) alone or 30 min after H7 (a protein kinase C inhibitor) injection (20 mg/kg body weight) were investigated in terms of peripheral neuromuscular function and Na + ,K + -ATPase activity of the sciatic nerve. This intraperitoneal injection of phenytoin induced complete blockade of muscle action potentials in the dorsal segmental muscles of the rat tail evoked by electric stimulation of the caudal nerve and a 40% decrease in the Na + ,K + -ATPase activity of the rat sciatic nerve when compared with control values, measured as the difference between total and ouabain-insensitive ATPase activity. Prior administr…
Search for multiwavelength emission from the binary millisecond pulsar PSR J1836-2354A in the globular cluster M22
2019
We present a multi-band search for X-ray, optical and $\gamma$-ray emission of the radio binary millisecond pulsar J1836-2354A, hosted in the globular cluster M22. X-ray emission is significantly detected in two Chandra observations, performed in 2005 and 2014, at a luminosity of $\sim$2-3$\times$10$^{30}$ erg s$^{-1}$, in the 0.5-8 keV energy range. The radio and the X-ray source positions are found consistent within 1$\sigma$ error box. No detection is found in archival XMM-Newton and Swift/XRT observations, compatible with the Chandra flux level. The low statistics prevents us to assess if the X-ray source varied between the two observations. The X-ray spectrum is consistent with a power…
Prolonged sub-luminous state of the new transitional pulsar candidate CXOU J110926.4-650224
2019
We report on a multi-wavelength study of the unclassified X-ray source CXOU J110926.4-650224 (J1109). We identified the optical counterpart as a blue star with a magnitude of $\sim$20.1 (3300-10500 $\require{mediawiki-texvc} \AA$). The optical emission was variable on timescales from hundreds to thousands of seconds. The spectrum showed prominent emission lines with variable profiles at different epochs. Simultaneous XMM-Newton and NuSTAR observations revealed a bimodal distribution of the X-ray count rates on timescales as short as tens of seconds, as well as sporadic flaring activity. The average broad-band (0.3-79 keV) spectrum was adequately described by an absorbed power law model with…
The Role Of General Relativity in the Evolution of Low-Mass X-ray Binaries
2005
We study the evolution of Low Mass X-ray Binaries (LMXBs) and of millisecond binary radio pulsars (MSPs), with numerical simulations that keep into account the evolution of the companion, of the binary system and of the neutron star. According to general relativity, when energy is released, the system loses gravitational mass. Moreover, the neutron star can collapse to a black hole if its mass exceeds a critical limit, that depends on the equation of state. These facts have some interesting consequences: 1) In a MSP the mass-energy is lost with a specific angular momentum that is smaller than the one of the system, resulting in a positive contribution to the orbital period derivative. If th…