Stimulation of delta opioid receptors located in substantia nigra reticulata but not globus pallidus or striatum restores motor activity in 6‐hydroxydopamine lesioned rats: new insights into the role of delta receptors in parkinsonism

The delta opioid peptide (DOP) receptor has been proposed as a target in the symptomatic therapy of Parkinson’s disease. However, the circuitry underlying the antiparkinsonian action of DOP receptor agonists and their site of action have never been adequately investigated. Systemic administration of the DOP receptor agonist (+)‐4‐[(αR)‐α‐(2S,5R)‐allyl‐2,5‐dimethyl‐1‐piperazinyl)‐3‐methoxy‐benzyl]‐N‐N‐diethylbenzamide (SNC‐80) attenuated akinesia/bradykinesia and improved motor activity in 6‐hydroxydopamine hemilesioned rats. Opposite effects were produced by the selective DOP receptor antagonist naltrindole (NTD), suggesting that endogenous enkephalins tonically sustain movement under parkinsonian conditions. Microdialysis revealed that SNC‐80 reduced GABA release in globus pallidus (GP) while NTD elevated it. Moreover, SNC‐80 reduced GABA and glutamate release in substantia nigra reticulata (SNr) whereas NTD reduced GABA without affecting glutamate release. The bar test coupled to microdialysis showed that perfusion with NTD in SNr but not GP or striatum prevented the antiakinetic effect of systemic SNC‐80 and its neurochemical correlates. Consistently, microinjections of SNC‐80 into SNr or bicuculline in GP attenuated parkinsonian‐like symptoms while SNC‐80 microinjections in GP or striatum were ineffective. This study demonstrates that nigral DOP receptors mediate antiparkinsonian actions of SNC‐80 and challenges the common view that DOP receptor agonists solely attenuate parkinsonism via pallidal mechanisms.     

Segmentation des IRM cérébrales par une variante bootstrapée du HMRF-EM : étude préliminaire sur fantômes

This paper deals with global statistical unsupervised magnetic resonance image (MRI) segmentation based on a Markovian model combined with the family of mixture identification algorithms EM (Hidden Markov Random Field [HMRF-EM]) and using the Bootstrap sampling, which allows a greater respect to the data independence assumption and a reduction of algorithmic complexity. This leads not only to a flexibility in the control of running time but also an improvement in the classification quality relatively to the performance shown by an earlier version of the bootstrapped HMRF-EM.     

Study of the Optical and Thermoplasmonics Properties of Gold Nanoparticle Embedded in Al2O3 Matrix

Plasmonics - In this paper, the optical and thermoplasmonics properties of nanocomposites consisting of spherical gold nanoparticles (AuNPs) integrated in $${Al}_{2}{O}_{3}$$ matrix are determined...     

Lethal neurotoxicity in mice of the basic domains of HIV and SIV Rev proteins. Study of these regions by circular dichroism

We have recently reported a basic domain-mediated neurotoxic activity of HIV-1 Tat [1991, J. Virol. 65, 961-965]. Here we have tested the neurotoxicity in vivo of several Rev-related synthetic peptides and found that only those mimicking the basic regions of Rev from HIV-1, HIV-2 and SIV were lethal to mice. In contrast, the homologous domain of HTLV-1 Rex was found to be inactive for lethal activity. Analysis of the tropism of these peptides for phospholipids has demonstrated a direct interaction of the basic domain-containing peptides, except Rex, with acidic--but not neutral--phospholipids. As determined by circular dichroism, a possible correlation between the conformation of the basic regions and the toxicity is discussed.     

Improving the Sensitivity of the Plasmon-Based Sensor by Asymmetric Nanoarray

Plasmonics - In this work, we investigate the effect of the symmetry in 2D arrays of gold nanoparticle on the sensitivity to the refractive index change. We demonstrate a generalized result that an...     

Thymoquinone attenuates lead‐induced nephropathy in rats

Kidney hazards from lead (Pb) exposure are one of the fastest growing areas of concern in toxicology today. The thymoquinone (TQ) renoprotective effect against Pb‐induced nephropathy has not previously been studied. Therefore, adult male Wistar rats were treated with Pb (2000 ppm of Pb acetate in drinking water) and/or TQ (5 mg/kg/day,  per os). All treatments were applied for 5 weeks. The results indicated that Pb exposure produced metal deposition, histopathological changes, functional impairment (significant elevation in plasma urea, uric acid, and creatinine levels), total antioxidant status decrease, and lipid peroxidation stimulation in the kidneys. Interestingly, TQ supplementation remarkably improved the Pb‐induced renal adverse effects without significantly reducing the tissue metal accumulation. In conclusion, our data indicate for the first time a protective effect of TQ against Pb‐induced nephropathy, most likely through an antioxidant mechanism. On this basis, TQ deserves more consideration and further examination as a potential therapeutic option.     

Studies of the polysaccharides from sunflower heads

Extraction of sunflower heads with ammonium oxalate afforded water-soluble pectin material and water-insoluble glycoprotein material, the carbohydrate portion of which consisted of galacturonic acid and xylose residues; the pectin material defied fractionation with cetylpyridinium chloride. Extraction with hydrochloric acid (pH 1.5) afforded water-soluble and water-insoluble polysaccharide materials. The former, when fractionated with cetylpyridinium chloride, gave a glycoprotein, the carbohydrate moiety of which was composed of galacturonic acid, galactose (major), glucose, arabinose, and xylose, and also a rhamnan. The latter was a glycoprotein, the carbohydrate portion of which consisted of galactose (major), glucose, xylose, and rhamnose residues. Extraction of the sunflower heads with water also gave glycoprotein material, which was fractionated by paper electrophoresis into a glyco-protein, the carbohydrate moiety ofwhich was composed of galacturonic acid (minor), galactose, glucose, xylose, arabinose, and rhamnose (major) residues, and a heteropolysaccharide composed of galactose (major), glucose, xylose, and arabinose residues.