Influence of Operational Strategies for the Recovery of Magnesium Hydroxide from Brines at a Pilot Scale.

The continuous depletion of minerals caused by land mining and the increase in their demand have pushed the development of novel sustainable technological processes for mineral recovery from unconventional sources. In this context, magnesium (Mg) has gained considerable attention for its peculiar properties and high relevance of its compounds, such as magnesium hydroxide, Mg(OH)2. In the present work, the influence of several operating conditions on the Mg(OH)2 precipitation process was thoroughly investigated by adopting a novel multiple feed-plug flow reactor. The influence of (i) initial Mg2+ concentrations in the feed stream; (ii) brine and alkaline flow rates; and (iii) the product recycling strategy (seeded crystallization) was considered. The results marked the possibility of improving sedimentation and filterability properties of Mg(OH)2 suspensions by adopting the recycling strategy to overcome industrial issues associated with the production of Mg(OH)2 suspensions using NaOH solutions.

Micro-imaging of Brain Cancer Radiation Therapy Using Phase-contrast Computed Tomography.

PURPOSE: Experimental neuroimaging provides a wide range of methods for the visualization of brain anatomic morphology down to subcellular detail. Still, each technique-specific detection mechanism presents compromises among the achievable field-of-view size, spatial resolution, and nervous tissue sensitivity, leading to partial sample coverage, unresolved morphologic structures, or sparse labeling of neuronal populations and often also to obligatory sample dissection or other sample invasive manipulations. X-ray phase-contrast imaging computed tomography (PCI-CT) is an experimental imaging method that simultaneously provides micrometric spatial resolution, high soft-tissue sensitivity, and ex vivo full organ rodent brain coverage without any need for sample dissection, staining or labeling, or contrast agent injection. In the present study, we explored the benefits and limitations of PCI-CT use for in vitro imaging of normal and cancerous brain neuromorphology after in vivo treatment with synchrotron-generated x-ray microbeam radiation therapy (MRT), a spatially fractionated experimental high-dose radiosurgery. The goals were visualization of the MRT effects on nervous tissue and a qualitative comparison of the results to the histologic and high-field magnetic resonance imaging findings. METHODS AND MATERIALS: MRT was administered in vivo to the brain of both healthy and cancer-bearing rats. At 45 days after treatment, the brain was dissected out and imaged ex vivo using propagation-based PCI-CT. RESULTS: PCI-CT visualizes the brain anatomy and microvasculature in 3 dimensions and distinguishes cancerous tissue morphology, necrosis, and intratumor accumulation of iron and calcium deposits. Moreover, PCI-CT detects the effects of MRT throughout the treatment target areas (eg, the formation of micrometer-thick radiation-induced tissue ablation). The observed neurostructures were confirmed by histologic and immunohistochemistry examination and related to the micro-magnetic resonance imaging data. CONCLUSIONS: PCI-CT enabled a unique 3D neuroimaging approach for ex vivo studies on small animal models in that it concurrently delivers high-resolution insight of local brain tissue morphology in both normal and cancerous micro-milieu, localizes radiosurgical damage, and highlights the deep microvasculature. This method could assist experimental small animal neurology studies in the postmortem evaluation of neuropathology or treatment effects.

Immuno-pharmacological characterization of group II metabotropic glutamate receptors controlling glutamate exocytosis in mouse cortex and spinal cord.

BACKGROUND AND PURPOSE: We recently proposed the existence of mGlu3 -preferring autoreceptors in spinal cord terminals and of mGlu2 -preferring autoreceptors in cortical terminals. This study aims to verify our previous conclusions and to extend their pharmacological characterization. EXPERIMENTAL APPROACH: We studied the effect of LY566332, an mGlu2 receptor positive allosteric modulator (PAM), and of LY2389575, a selective mGlu3 receptor negative allosteric (NAM) modulator, on the mGlu2/3 agonist LY379268-mediated inhibition of glutamate exocytosis [measured as KCl-evoked release of preloaded [3 H]-D-aspartate]. The mGlu2 PAM BINA and the mGlu3 NAM ML337, as well as selective antibodies recognizing the N-terminal of the receptor proteins, were used to confirm the pharmacological characterization of the native receptors. KEY RESULTS: Cortical synaptosomes possess LY566332-sensitive autoreceptors that are slightly, although significantly, susceptible to LY2389575. In contrast, LY566332-insensitive and LY2389575-sensitive autoreceptors are present in spinal cord terminals. BINA and ML337 mimicked LY566332 and LY2389575, respectively, in controlling LY379268-mediated inhibition of glutamate exocytosis from both cortical and spinal cord synaptosomes. Incubation of cortical synaptosomes with anti-mGlu2 antibody prevented the LY379268-induced inhibition of glutamate exocytosis, and this response was partially reduced by the anti-mGlu3 antibody. Incubation of spinal cord synaptosomes with the anti-mGlu3 antibody abolished LY379268-mediated reduction of glutamate exocytosis from these terminals, while the anti-mGlu2 antibody was inactive. Western blot analysis and confocal microscopy data were largely consistent with these functional observations. CONCLUSIONS AND IMPLICATIONS: We confirmed that mGlu3 -preferring autoreceptors exist in spinal cord terminals. Differently, cortical glutamatergic terminals possess mGlu2 /mGlu3 heterodimers, whose inhibitory effect is largely mediated by mGlu2 receptors.

Sports massage with ozonised oil or non-ozonised oil: Comparative effects on recovery parameters after maximal effort in cyclists.

OBJECTIVES: To study the effects of passive rest (PR) and sports massage with (SMOZO) and without (SM) ozonised oil on sports performance psycho-physiological indices in competitive amateur cyclists after 3 pre-fatiguing Wingate cycle and post-recovery ramp tests. DESIGN: An intra-subjects experimental design with repeated measures. SETTING: Department of Human Anatomy and Physiology, University of Padua. PARTICIPANTS: Fifteen male competitive cyclists (age: 27 ± 3.5 years, body weight: 77.6 ± 8.3 kg, height: 178 ± 7.7 cm) were studied. MAIN OUTCOME MEASURES: Subjects' power output (P), heart rate (HR), Visual Analogue Scale (VAS) score and blood lactate (BL) clearance in response to PR, SMOZO and SM recoveries were compared. RESULTS: There were no significant differences in cyclists' heart rate patterns in the three experimental conditions (p > 0.05). After SMOZO recovery, athletes showed a higher Pmax (p < 0.05) and a lower perceived fatigue VAS score (p < 0.033) in the ramp test. Blood lactate decreased more at T2 (mid-time point of treatment) and T3 (final time point of treatment) than T1 (beginning of treatment) compared to SM and PR conditions. CONCLUSIONS: These findings suggest that use of ozonised oil during sports massage increases blood lactate removal, improves performance and reduces the perception of fatigue in cyclists from 3 Wingate tests.

N-Acetyl-cysteine causes analgesia by reinforcing the endogenous activation of type-2 metabotropic glutamate receptors.

BACKGROUND: Pharmacological activation of type-2 metabotropic glutamate receptors (mGlu2 receptors) causes analgesia in experimental models of inflammatory and neuropathic pain. Presynaptic mGlu2 receptors are activated by the glutamate released from astrocytes by means of the cystine/glutamate antiporter (System x(c)(-) or Sx(c)(-)). We examined the analgesic activity of the Sx(c)(-) activator, N-acetyl-cysteine (NAC), in mice developing inflammatory or neuropathic pain. RESULTS: A single injection of NAC (100 mg/kg, i.p.) reduced nocifensive behavior in the second phase of the formalin test. NAC-induced analgesia was abrogated by the Sxc- inhibitor, sulphasalazine (8 mg/kg, i.p.) or by the mGlu2/3 receptor antagonist, LY341495 (1 mg/kg, i.p.). NAC still caused analgesia in mGlu3(-/-) mice, but was inactive in mGlu2(-/-) mice. In wild-type mice, NAC retained the analgesic activity in the formalin test when injected daily for 7 days, indicating the lack of tolerance. Both single and repeated injections of NAC also caused analgesia in the complete Freund's adjuvant (CFA) model of chronic inflammatory pain, and, again, analgesia was abolished by LY341495. Data obtained in mice developing neuropathic pain in response to chronic constriction injury (CCI) of the sciatic nerve were divergent. In this model, a single injection of NAC caused analgesia that was reversed by LY341495, whereas repeated injections of NAC were ineffective. Thus, tolerance to NAC-induced analgesia developed in the CCI model, but not in models of inflammatory pain. The CFA and CCI models differed with respect to the expression levels of xCT (the catalytic subunit of Sx(c)(-)) and activator of G-protein signaling type-3 (AGS3) in the dorsal portion of the lumbar spinal cord. CFA-treated mice showed no change in either protein, whereas CCI mice showed an ipislateral reduction in xCT levels and a bilateral increase in AGS3 levels in the spinal cord. CONCLUSIONS: These data demonstrate that pharmacological activation of Sxc- causes analgesia by reinforcing the endogenous activation of mGlu2 receptors. NAC has an excellent profile of safety and tolerability when clinically used as a mucolytic agent or in the management of acetaminophen overdose. Thus, our data encourage the use of NAC for the experimental treatment of inflammatory pain in humans.

Metabotropic glutamate receptors in the thalamocortical network: strategic targets for the treatment of absence epilepsy.

Metabotropic glutamate (mGlu) receptors are positioned at synapses of the thalamocortical network that underlie the development of spike-and-wave discharges (SWDs) associated with absence epilepsy. The modulatory role of individual mGlu receptor subtypes on excitatory and inhibitory synaptic transmission in the cortico-thalamo-cortical circuitry makes subtype-selective mGlu receptor ligands potential candidates as novel antiabsence drugs. Some of these compounds are under clinical development for the treatment of numerous neurologic and psychiatric disorders, and might be soon available for clinical studies in patients with absence seizures refractory to conventional medications. Herein we review the growing evidence that links mGlu receptors to the pathophysiology of pathologic SWDs moving from the anatomic localization and function of distinct mGlu receptor subtypes in the cortico-thalamo-cortical network to in vivo studies in mouse and rat models of absence epilepsy.