Synthesis, characterization and electrochemical behavior of the vanadium pentoxide/cetyl pyridinium chloride hybrid material

In situ and ex situ studies concerning the new hybrid material vanadium pentoxide xerogel in the presence of the cationic surfactant cetyl pyridinium chloride (V(2)O(5)/CPC) are presented. The in situ characterization studies revealed the presence of a lamellar structure for the V(2)O(5)/CPC hybrid material. The intercalation reaction was evidenced on the basis of the increase in the d-spacing as well as the displacement of the infrared bands toward lower energy levels. Electrochemical studies comprising the cyclic voltammetry and the electrochemical impedance spectroscopy techniques showed that the behavior of the hybrid material is considerably influenced by the electrolyte composition. The ion insertion/de-insertion into the V(2)O(5) xerogel structure accompanying the charge transfer process is influenced by the solid-state diffusion process modeled by using the finite-space Warburg element.

Synthesis and electrochemical properties of vanadyl phosphate di-hydrate/polyaniline derivatives hybrid films

Vanadyl phosphate and its hybrid compounds have proven to undergo electrochemical intercalation and de-intercalation of lithium ions, which enables its use as cathode material for Li ion rechargeable batteries. In this context, vanadyl phosphate di-hydrate/polyaniline derivatives hybrid films were synthesized via the exfoliation and reconstruction approach in order to evaluate their potential use as cathode in ion lithium batteries. X-ray diffraction patterns indicate that the lamellar structure of the inorganic matrix is maintained, consistent with the topotactic process. In the scanning electron micrographs, hybrid films exhibit rough surface consisting of warped and cracked crystallites, quite different from vanadyl phosphate di-hydrate square platelets crystallites. Electrochemical evaluation using cyclic voltammetry and charge-discharge galvanostatic techniques shows small differences between the charge and the discharge curves, indicating an irreversibility of the hybrid systems. (C) 2009 Elsevier B.V. All rights reserved.

Fms-like tyrosine kinase 3 ligand administration overcomes a genetically determined dendritic cell deficiency in NOD mice and protects against diabetes development

A dendritic cell (DC) imbalance with a marked deficiency in CD4(-)8(+) DC occurs in non-obese diabetic (NOD) mice, a model of human autoimmune diabetes mellitus. Using a NOD congenic mouse strain, we find that this CD4(-)8(+) DC deficiency is associated with a gene segment on chromosome 4, which also encompasses non-MHC diabetes susceptibility loci. Treatment of NOD mice with fms-like tyrosine kinase 3 ligand (FL) enhances the level of CD4(-)8(+) DC, temporarily reversing the DC subtype imbalance. At the same time, fms-like tryosine kinase 3 ligand treatment blocks early stages of the diabetogenic process and with appropriately timed administration can completely prevent diabetes development. This points to a possible clinical use of FL to prevent autoimmune disease.

Total synthesis of (+/-)-dihydroactinidiolide using selenium-stabilized carbenium ion

A new, short total synthesis of dihydroactinidiolide 1 is described using selenium carbenium ion-promoted carbon-carbon bond formation as the key step. Our synthetic strategy starts with a lactonization reaction between 1,3,3-trimethylcyclohexene 13 and alpha-chloro-alpha-phenylseleno ethyl acetate 14, affording the key intermediate, alpha-phenylseleno-gamma-butyro lactone 15, which reacted via a selenoxide elimination to the target compound 1. (C) 2009 Elsevier Ltd. All rights reserved.

Facilitation of 5-HT(1A)-mediated neurotransmission in dorsal periaqueductal grey matter accounts for the panicolytic-like effect of chronic fluoxetine

Chronic administration of antidepressants such as fluoxetine and imipramine increases the responsiveness of 5-HT(1A) receptors in dorsal periaqueductal grey matter (DPAG), a midbrain area consistently implicated in the pathogenesis of panic disorder. This effect has been related to the clinically relevant anti-panic action of these drugs. In this study we determined whether long-term administration of fluoxetine also affects 5-HT efflux in DPAG. As a comparison, the effect of chronic treatment with the anxiolytic 5-HT(1A) receptor agonist buspirone on DPAG 5-HT levels was assessed. We also investigated whether the inhibitory effect of chronic fluoxetine on escape behaviour in the rat elevated T-maze, considered as a panicolytic-like effect, is counteracted by intra-DPAG injection of the 5-HT(1A) receptor antagonist WAY 100635. Male Wistar rats were treated (1 or 21 d, i.p.) with fluoxetine, buspirone or vehicle, once daily. After treatment, 5-HT in DPAG was measured by in-vivo microdialysis coupled to HPLC. In another study, rats treated (21 d, i.p.) with either fluoxetine or vehicle also received intra-DPAG injection of WAY 100635 or saline 10 min before being tested in the elevated T-maze. Chronic, but not acute, administration of fluoxetine significantly raised extracellular levels of 5-HT in DPAG. Long-term treatment with buspirone was ineffective. In the elevated T-maze, intra-DPAG injection of WAY 100635 fully blocked the anti-escape effect of chronic administration of fluoxetine. Therefore, chronic fluoxetine facilitates 5-HT(1A)-mediated neurotransmission within DPAG and this effect accounts for the panicolytic-like effect of this antidepressant in the elevated T-maze.

Antidepressant-Like Effects of Medial Prefrontal Cortex Deep Brain Stimulation in Rats

Background: Subcallosal cingulate gyrus (SCG) deep brain stimulation (DBS) is being investigated as a treatment for major depression. We report on the effects of ventromedial prefrontal cortex (vmPFC) DBS in rats, focusing on possible mechanisms involved in an antidepressant-like response in the forced swim test (FST). Methods: The outcome of vmPFC stimulation alone or combined with different types of lesions, including serotonin (5-HT) or nore-pineprhine (NE) depletion, was characterized in the FST. We also explored the effects of DBS on novelty-suppressed feeding, learned helplessness, and sucrose consumption in animals predisposed to helplessness. Results: Stimulation at parameters approximating those used in clinical practice induced a significant antidepressant-like response in the FST. Ventromedial PFC lesions or local muscimol injections did not lead to a similar outcome. However, animals treated with vmPFC ibotenic acid lesions still responded to DBS, suggesting that the modulation of fiber near the electrodes could play a role in the antidepressant-like effects of stimulation. Also important was the integrity of the serotonergic system, as the effects of DBS in the FST were completely abolished in animals bearing 5-HT, but not NE, depleting lesions. In addition, vmPFC stimulation induced a sustained increase in hippocampal 5-HT levels. Preliminary work with other models showed that DBS was also able to influence specific aspects of depressive-like states in rodents, including anxiety and anhedonia, but not helplessness. Conclusions: Our study suggests that vmPFC DES in rats maybe useful to investigate mechanisms involved in the antidepressant effects of SCG DBS.

THE ANTERIOR CINGULATE CORTEX IS A TARGET STRUCTURE FOR THE ANXIOLYTIC-LIKE EFFECTS OF BENZODIAZEPINES ASSESSED BY REPEATED EXPOSURE TO THE ELEVATED PLUS MAZE AND FOS IMMUNOREACTIVITY

Prior experience with the elevated plus maze (EPM) increases the avoidance of rodents to the open arms and impairs the anxiolytic-like effects of benzodiazepines on the traditional behaviors evaluated upon re-exposure to the maze, a phenomenon known as one-trial tolerance. Risk assessment behaviors are also sensitive to benzodiazepines. During re-exposure to the maze, these behaviors reinstate the information-processing initiated during the first experience, and the detection of danger generates stronger open-arm avoidance. The present study investigated whether the benzodiazepine midazolam alters risk assessment behaviors and Fos protein distribution associated with test and retest sessions in the EPM. Naive or maze-experienced Wistar rats received either saline or midazolam (0.5 mg/kg i.p.) and were subjected to the EPM. Midazolam caused the usual effects on exploratory behavior, increasing exploratory activity of naive rats in the open arms and producing no effects on these conventional measures in rats re-exposed to the maze. Risk assessment behaviors, however, were sensitive to the benzodiazepine during both sessions, indicating anxiolytic-like effects of the drug in both conditions. Fos immunohistochemistry showed that midazolam injections were associated with a distinct pattern of action when administered before the test or retest session, and the anterior cingulate cortex, area 1 (Cg1), was the only structure targeted by the benzodiazepine in both situations. Bilateral infusions of midazolam into the Cg1 replicated the behavioral effects of the drug injected systemically, suggesting that this area is critically involved in the anxiolytic-like effects of benzodiazepines, although the behavioral strategy adopted by the animals appears to depend on the previous knowledge of the threatening environment. (C) 2009 IBRO. Published by Elsevier Ltd. All rights reserved.

Effects of microinjections of apomorphine and haloperidol into the inferior colliculus on the latent inhibition of the conditioned emotional response

Electrical or chemical stimulation of the inferior colliculus (IC) induces fear-like behaviors. More recently, consistent evidence has shown that electrical stimulation of the central nucleus of the IC supports Pavlovian conditioning and latent inhibition (Li). LI is characterized by retardation in conditioning and also by an impaired ability to ignore irrelevant stimuli, after a non-reinforced pre-exposure to the conditioned stimulus. LI has been proposed as a behavioral model of cognitive abnormalities seen in schizophrenia. The aim of the present study was to determine whether dopaminergic mechanisms in the IC are involved in LI of the conditioned emotional response (CER). To induce LI, a group of rats was pre-exposed (PE) to six tones in two sessions, while rats that were not pre-exposed (NPE) had two sessions without tone presentations. The conditioning consisted of two tone presentations to the animal, followed immediately by a foot shock. PE and NPE rats received IC microinjections of physiological saline, the dopaminergic agonist apomorphine (9.0 mu g/0.5 mu L/side), or the dopaminergic antagonist haloperidol (0.5 mu g/0.5 mu L/side) before both pre-exposure and conditioning. During the test, the PE rats that received saline or haloperidol had a lower suppression of the licking response compared to NPE rats that received vehicle or haloperidol, indicating that latent inhibition was induced. There was no significant difference in the suppression ratio in rats that received apomorphine injections into the IC, indicating reduced latent inhibition. These results suggest that dopamine-mediated mechanisms of the IC are involved in the development of LI. (C) 2008 Elsevier Inc. All rights reserved.

Anxiety-like symptoms induced by morphine withdrawal may be due to the sensitization of the dorsal periaqueductal grey

Withdrawal from morphine leads to the appearance of extreme anxiety accompanied of several physical disturbances, most of them linked to the activation of brainstem regions such as the locus coeruleus, ventral tegmental area, hypothalamic nuclei and periaqueductal grey (PAG). As anxiety remains one of the main components of morphine withdrawal the present study aimed to evaluating the influence of the dorsal aspects of the PAG on the production of this state, since this structure is well-known to be involved in defensive behaviour elicited by anxiety-evoking stimuli. Different groups of animals were submitted to 10 days of i.p. morphine injections, challenged 2 h after with an i.p. injection of naloxone (0.1 mg/kg), and submitted to the plus-maze, open-field and light-dark transition tests. The effects of morphine withdrawal on anxiety-induced Fos immunolabelling were evaluated in four animals that passed by the light-dark transition test randomly chosen for Fos-protein analysis. Besides the PAG, Fos neural expression was conducted in other brain regions involved in the expression of anxiety-related behaviours. Our results showed that morphine withdrawn rats presented enhanced anxiety accompanied of few somatic symptoms. Increased Fos immunolabelling was noted in brain regions well-known to modulate these states as the prelimbic cortex, nucleus accumbens, amygdala and paraventricular hypothalamus. Increased Fos labelling was also observed in the ventral and dorsal aspects of the PAG, a region involved in anxiety-related processes suggesting that this region could be a common neural substrate enlisted during anxiety evoked by dangerous stimuli as well as those elicited by opiate withdrawal. (c) 2008 Elsevier Inc. All rights reserved,

Serotonin-1A receptors in the dorsal periaqueductal gray matter mediate the panicolytic-like effect of pindolol and paroxetine combination in the elevated T-maze

The beta-adrenergic blocker and 5-HT(1A) receptor antagonist pindolol has been combined with selective serotonin reuptake inhibitors (SSRIs) in patients with depressive and anxiety disorders to shorten the onset of the clinical action and/or increase the proportion of responders. The results of a previous study have shown that pindolol potentiates the panicolytic effect of paroxetine in rats submitted to the elevated T-maze (ETM). Since reported evidence has implicated the 5-HT(1A) receptors of the dorsal periaqueductal gray matter (DPAG) in the panicolytic effect of antidepressants, rats treated with pindolol (5.0 mg/kg, i.p.) and paroxetine (1.5 mg/kg, i.p.) received a previous intra-DPAG injection of the selective 5-HT(1A) antagonist, WAY-100635 (0.4 mu g) and were submitted to the ETM. Pretreatment with WAY-100635 reversed the increase in escape latency, a panicolytic effect, determined by the pindolol-paroxetine combination. These results implicate the 5-HT(1A) receptors of the DPAG in the panicolytic effect of the pindolol-paroxetine combination administered systemically. They also give further preclinical support for the use of this drug combination in the treatment of panic disorder. (C) 2011 Elsevier Ireland Ltd. All rights reserved.

Effects of Self-Assembled Materials Prepared from V(2)O(5) for Lithium Ion Electroinsertion

Self-assembled materials consisting of V(2)O(5), polyallylamine (PAR) and silver nanoparticles (AgNPs) were obtained by the layer-by-layer (LbL) method, aiming at their application as electrodes for lithium-ion batteries and electrochromic devices. The method employed herein allowed for linear growth of visually homogeneous films composed of V(2)O(5), V(2)O(5)/PAH, and V(2)O(5)/PAH/AgNP with 15 bilayers. According to the Fourier transform infrared spectra, interaction between the oxygen atom of the vanadyl group and the amino group should be responsible for the growth of these films. This interaction also enabled establishment of an electrostatic shield between the lithium ions and the sites with higher negative charge, thereby raising the ionic mobility and consequently increasing the energy storage capacity and reducing the response time. According to the site-saturation model and the electrochemical and spectroelectrochemical results, the presence of PAH in the self-assembled host matrix decreased the number of V(2)O(5) electroactive sites. Thus, AgNPs were stabilized in PAR and inserted into the nanoarchitecture, so as to enhance the specific capacity. This should provide new conducting pathways and connect isolated V(2)O(5) particles in the host matrix. Therefore, new nanoarchitectures for specific interactions were formed spontaneously and chosen as examples in this work, aiming to demonstrate the potentiality of the adopted self-assembled method for enhancing the charge transport rate into the host matrices. The obtained materials displayed suitable properties for use as electrodes in lithium batteries and electrochromic devices.

Structural and Biochemical Correlates of Na(+), K(+)-ATPase Driven Ion Uptake Across the Posterior Gill Epithelium of the True Freshwater Crab, Dilocarcinus pagei (Brachyura, Trichodactylidae)

To better comprehend the structural and biochemical underpinnings of ion uptake across the gills of true freshwater crabs, we performed an ultrastructural, ultracytochemical and morphometric investigation, and kinetically characterized the Na(+), K(+)-ATPase, in posterior gill lamellae of Dilocarcinus pagei. Ultrastructurally, the lamellar epithelia are markedly asymmetrical: the thick, mushroom-shaped, proximal ionocytes contain elongate mitochondria (41% cell volume) associated with numerous (approximate to 14 mu m(2) membrane per mu m(3) cytoplasm), deep invaginations that house the Na(+), K(+)-ATPase, revealed ultracytochemically. Their apical surface is amplified (7.5 mu m(2) mu m(-2)) by stubby evaginations whose bases adjoin mitochondria below the subcuticular space. The apical membrane of the thin, distal ionocytes shows few evaginations (1.6 mu m(2) mu m(-2)), each surrounding a mitochondrion, abundant in the cytoplasm below the subcuticular space; basolateral invaginations and mitochondria are few. Fine basal cytoplasmic bridges project across the hemolymph space, penetrating into the thick ionocytes, suggesting ion movement between the epithelia. Microsomal Na(+), K(+)-ATPase specific activity resembles marine crabs but is approximate to 5-fold less than in species from fluctuating salinities, and freshwater shrimps, suggesting ion loss compensation by strategies other than Na(+) uptake. Enzyme apparent K(+) affinity attains 14-fold that of marine crabs, emphasizing the relevance of elevated K(+) affinity to the conquest of fresh water. Western blotting and biphasic ouabain inhibition disclose two alpha-subunit isoforms comprising distinct functional isoenzymes. While enzyme activity is not synergistically stimulated by NH(4)(+) and K(+), each increases affinity for the other, possibly assuring appropriate intracellular K(+) concentrations. These findings reveal specific structural and biochemical adaptations that may have allowed the establishment of the Brachyura in fresh water. J. Exp. Zool. 313A:508-523, 2010. (C) 2010 Wiley-Liss, Inc.

Management of brachial plexus region tumours and tumour-like conditions: relevant diagnostic and surgical features in a consecutive series of eighteen patients

Tumours of the brachial plexus region are rare and most publications are case reports or studies with a small series of patients. The aim of this study is to present our experience in managing these lesions. We review 18 patients with tumours in the brachial plexus region submitted to surgical treatment in a 6 year period, including their clinical presentation, neuro-imaging data, surgical findings and outcome. The tumours comprised a heterogeneous group of lesions, including schwannomas, neurofibromas, malignant peripheral nerve sheath tumour (MPNST), sarcomas, metastases, desmoids and an aneurysmal bone cyst. The most common presentation was an expanding lump (83.33%). Eleven tumours were benign and 7 were malignant. Neurofibromatosis was present in only 2 patients (11.11%). Gross total resection was achieved in 14 patients and sub-total resection in the others. Only 3 patients presented with new post-operative motor deficits. The incidence of complications was low (16.5 %). The majority of tumours were benign and most of them could be excised with a low incidence of additional deficits. Some of the malignant tumours could be controlled by surgery plus adjuvant therapy, but this category is still associated with high morbidity and mortality rates.