Electroencephalographic correlates of low-frequency vagus nerve stimulation therapy for Crohn's disease.

Objectives: In the context of the first clinical trial of vagus nerve stimulation (VNS) in Crohn's disease (CD), our main objective was to quantify the acute and chronic effects of VNS on brain activity in CD patients.

Methods: We measured the electroencephalogram (EEG) in 9CD patients under VNS at 10 Hz just before VNS initiation, after 6 weeks and after 12 months of chronic VNS.

Results: Acute VNS induced increased spectral power in delta and theta bands on frontal, temporal and occipital electrodes.

Functional monitoring of peripheral nerves from electrical impedance measurements.

Medical electrical stimulators adapted to peripheral nerves use multicontact cuff electrodes (MCC) to provide selective neural interfaces. However, neuroprostheses are currently limited by their inability to locate the regions of interest to focus. Intended until now either for stimulation or recording, MCC can also be used as a means of transduction to characterize the nerve by impedancemetry.

Chronic vagus nerve stimulation in Crohn's disease: a 6-month follow-up pilot study.

The vagus nerve (VN) is a link between the brain and the gut. The VN is a mixed nerve with anti-inflammatory properties through the activation of the hypothalamic-pituitary-adrenal axis by its afferents and by activating the cholinergic anti-inflammatory pathway through its efferents. We have previously shown that VN stimulation (VNS) improves colitis in rats and that the vagal tone is blunted in Crohn's disease (CD) patients.

Modular architecture of a multi-frequency electrical impedance tomography system: design and implementation.

Electrical impedance tomography (EIT) provides means of imaging the electrical properties distribution of biological tissues and fluids while impedance spectroscopy (IS) allows measuring their frequency response in a more global way. Both require precise and well-integrated instrumentation. In this work, we propose a modular architecture of a multi-frequency EIT (MfEIT) system which has capabilities in implementing both IS and MfEIT.

Impact of Anesthetics on Immune Functions in a Rat Model of Vagus Nerve Stimulation.

Vagus nerve stimulation (VNS) has been successfully performed in animals for the treatment of different experimental models of inflammation. The anti-inflammatory effect of VNS involves the release of acetylcholine by vagus nerve efferent fibers inhibiting pro-inflammatory cytokines (e.g.

Vagus nerve stimulation: from epilepsy to the cholinergic anti-inflammatory pathway.

Background: The brain and the gut communicate bidirectionally through the autonomic nervous system (ANS). The vagus nerve (VN), a major component of the ANS, plays a key role in the neuro-endocrine-immune axis to maintain homeostasia through its afferents (through the activation of the hypothalamic pituitary adrenal axis and the central ANS) and through its efferents (i.e.

Distribution and radiosensitizing effect of cholesterol-coupled Dbait molecule in rat model of glioblastoma.

Background: Glioma is the most aggressive tumor of the brain and the most efficient treatments are based on radiotherapy. However, tumors are often resistant to radiotherapy due to an enhanced DNA repair activity. Short and stabilized DNA molecules (Dbait) have recently been proposed as an efficient strategy to inhibit DNA repair in tumor.

Anti-inflammatory effect of vagus nerve stimulation in a rat model of inflammatory bowel disease.

Vagus nerve stimulation of afferents is used as an adjunctive treatment for drug-resistant epilepsy and depression. In addition, anti-inflammatory properties of vagus nerve stimulation have been reported in various experimental models of inflammation but not in colitis. These effects are thought to be mediated via peripheral release of acetylcholine from the vagus and subsequent activation of macrophages.

Dynamic Causal Modelling and physiological confounds: a functional MRI study of vagus nerve stimulation.

Dynamic Causal Modelling (DCM) has been proposed to estimate neuronal connectivity from functional magnetic resonance imaging (fMRI) using a biophysical model that links synaptic activity to hemodynamic processes. However, it is well known that fMRI is sensitive not only to neuronal activity, but also to many other psychophysiological responses which may be task-related, such as changes in cardio-respiratory activity. They are not explicitly taken into account in the generative models of DCM and their effects on estimated neuronal connectivity are not known.

Comparison of the oxime-induced reactivation of rhesus monkey, swine and guinea pig erythrocyte acetylcholinesterase following inhibition by sarin or paraoxon, using a perfusion model for the real-time determination of membrane-bound acetylcholinesterase activity.

Recently, a dynamically working in vitro model with real-time determination of membrane-bound human acetylcholinesterase (AChE) activity was shown to be a versatile model to investigate oxime-induced reactivation kinetics of organophosphate- (OP) inhibited enzyme. In this assay, AChE was immobilized on particle filters which were perfused with acetylthiocholine, Ellman's reagent and phosphate buffer. Subsequently, AChE activity was continuously analyzed in a flow-through detector.

Therapeutic efficacy of intra-cochlear administration of methylprednisolone after acoustic trauma caused by gunshot noise in guinea pigs.

The therapeutic efficacy of cochlear infusion of methylprednisolone (MP) after an impulse noise trauma (170dB SPL peak) was evaluated in guinea pigs. The compound action potential threshold shifts were measured over a 14 days recovery period after the gunshot exposure. For each animal, one of the cochlea was perfused directly into the scala tympani with MP during 7 days via a mini-osmotic pump, whereas the other cochlea was not pump-implanted.

Spectrum of neural electrical activity in guinea pig cochlea: effects of anaesthesia regimen, body temperature and ambient noise.

Spectral analysis of electric noise recorded from the round window of the cochlea is thought to represent the summed spontaneous activity of the auditory nerve. It has been postulated that it could provide a possible tinnitus index. Because experimental conditions could change this neural activity, the effect of anaesthesia regimen, body temperature and ambient noise on the spectrum of spontaneous neural noise (SNN) were investigated in guinea pig cochlea.

Changes in sleep-wake cycle after chronic exposure to uranium in rats.

Uranium is a heavy metal known to induce toxicity in kidneys. It is also known to enter the central nervous system, thus inducing neurophysiological effects, after exposure to relatively high concentrations. The effect of chronic uranium exposure (40 mg l(-1) in drinking water, for 90 days) on electroencephalographic architecture has been studied on freely moving rats using a telemetry technique.

Acute ileal inflammatory cytokine response induced by irradiation is modulated by subdiaphragmatic vagotomy.

Neural involvement plays a role in the genesis of the peripheral inflammatory process that contributes to the irradiation intestinal disorders. However, little is known about the role of vagus nerve in modulating inflammatory process in rat. Here, we have shown that the NF-kappaB activation was consistent with the acute overexpression of pro-inflammatory cytokines (IL- 1beta, TNF-alpha, IL-6) at 3, 6, and 12 h induced by whole-body irradiation (8 Gy).

Rat pro-inflammatory cytokine and cytokine related mRNA quantification by real-time polymerase chain reaction using SYBR green.

Background: Cytokine mRNA quantification is widely used to investigate cytokine profiles, particularly in small samples. Real-time polymerase chain reaction is currently the most reliable method of quantifying low-level transcripts such as cytokine and cytokine receptor mRNAs. This accurate technique allows the quantification of a larger pattern of cytokines than quantification at the protein level, which is limited to a smaller number of proteins.

Acute induction of inflammatory cytokine expression after gamma-irradiation in the rat: effect of an NF-kappaB inhibitor.

Purpose: The pathologic changes within the intestinal muscle layer may be at the origin of the cytokines that account for acute radiation-induced inflammation. We were specifically interested in evaluating the efficacy of an inhibitor of nuclear transcription factor kappa B (NF-kappaB) activation that is involved in regulating cytokine expression.

Methods And Materials: Cytokine expression was analyzed in the ileal muscularis layer by reverse transcriptase-polymerase chain reaction (RT-PCR) at 3 h, 6 h, and 3 days after a 10-Gy gamma whole-body irradiation of rats.

Nitric oxide voltammetric measurements in the rat brain after gamma irradiation.

The effects of a lethal gamma irradiation were investigated on cerebral NO-ergic system by using a voltammetric method in freely moving rats. It is reported that the cortical NO concentration increases right from the end of the radiation exposure (15 Gy) and reaches a maximal magnitude (+120%) 24 h later. A dose-effect relationship from 2 to 15 Gy for gamma-ray exposure has also been observed.

IL-1beta, TNFalpha and IL-6 induction in the rat brain after partial-body irradiation: role of vagal afferents.

Purpose: To evaluate the central nervous system neuroimmune and inflammatory responses during the prodromal phase of the acute irradiation syndrome in rat brains after partial-body exposure (head-protected) and to investigate the potential neural signalling pathways from the irradiated periphery to the non-irradiated brain.

Material And Methods: The study included four groups of rats: one irradiated group and one sham irradiated group, each containing non-vagotomized and vagotomized rats. In vagotomized rat groups, the subdiaphragmatic vagal section surgery was carried out 45 days before the irradiation exposure.

Effects of a thermal injury on brain and blood nitric oxide (NO) content in the rat.

In the present study, the effects of a thermal injury on the nitric oxide (NO)-ergic system was investigated in freely moving rats. Using a voltammetric method allowing direct and in situ NO measurements, a significant decrease in cortical NO concentration was observed during the 24h following burning procedure. Since in the burning procedure halothane was employed, it was verified that this anaesthetic did not induce significant effect on cortical NO level.

Effect of heavy ions on neuro-endocrine regulations.

During American and Russian short and long-term space flights neuroimmune dysregulations have been observed in man and rats for up to three months after the return. During Extra-Vehicular Activity, radiation exposure risk is greater to elicit short and/or long-term deleterious effects on the functional capacity of the neuroimmune system. In order to assess the effects of high LET events on neuroimmune networks, our preliminary ground-based study was to investigate brain inflammatory responses in mouse after low dose radiation exposure with high LET particles (12C, 95MeV/u, 42 mGy).

Subchronic administration of pyridostigmine or huperzine to primates: compared efficacy against soman toxicity.

Organophosphonate (OP) nerve agents, such as soman, are potent irreversible inhibitors of central and peripheral acetylcholinesterases (AChEs). Pre-treatment of OP poisoning relies on the subchronic administration of a reversible AChE inhibitor. In the present limited study, the protective effects against soman toxicity of such compounds, i.

Compared efficacy of diazepam or avizafone to prevent soman-induced electroencephalographic disturbances and neuropathology in primates: relationship to plasmatic benzodiazepine pharmacokinetics.

We performed an experiment to characterize the toxicity of soman in cynomolgus monkeys in which organophosphorus intoxication was followed by treatment with either the current three-drug therapy atropine/pralidoxime/diazepam or a combination of atropine/pralidoxime/avizafone, avizafone being the water soluble prodrug of diazepam. Clinical, electrophysiological, and histological approaches were combined. When benzodiazepines were injected at the similar molar dose of 0.

Review of the value of gacyclidine (GK-11) as adjuvant medication to conventional treatments of organophosphate poisoning: primate experiments mimicking various scenarios of military or terrorist attack by soman.

Today, organophosphorus nerve agents are still considered as potential threats in both military or terrorism situations. These agents act as potent irreversible inhibitors of acetylcholinesterase in both central and peripheral nervous systems. Conventional treatment of organophosphate poisoning includes the combined administration of a cholinesterase reactivator (an oxime), a muscarinic cholinergic receptor antagonist (atropine) and a benzodiazepine anticonvulsant (diazepam).