Effect of nicotine on serotonin (5-HT) levels in brain of depressed rats

Background: Reduction in brain serotonin (5-HT) levels contributes to depression. Nicotine may have antidepressant properties and smokers self-medicate underlying depression. Epidemiological findings suggest that smokers more often demonstrate depressive symptoms than non-smokers and depressed patients are less likely to cease smoking. Therefore, the study was planned to evaluate the effect of nicotine on serotonin levels in brain of depressed rats.Methods: Antidepressant action of study drugs was evaluated using isolation induced hyperactivity model in rats. Rats were divided into five groups with six rats in each group. Study groups: Vehicle in normal rats 1 ml/kg (subcutaneous); vehicle after isolation 1ml/kg (subcutaneous); imipramine 10 mg/kg (intraperitoneal) for 7 consecutive days; single dose of nicotine 0.4 mg/kg (subcutaneous); single dose of nicotine 0.2 mg/kg (inhalational). Brain serotonin assay was carried out. The statistical significance was determined by ANOVA followed by Tukey test (p<0.05).Results: Serotonin levels (55.93ng/g of brain tissue) in rats after isolation were significantly less than in normal rats (335.87ng/g) (p<0.001). In imipramine treated group, serotonin levels (301.4ng/g) after isolation were highly significant as compared to serotonin levels in vehicle treated group after isolation (p<0.001). Nicotine administered by subcutaneous and inhalational route showed significantly higher brain serotonin levels, i.e. 175ng/g and 254.62ng/g respectively as compared to vehicle treated rats after isolation (p<0.001).Conclusions: Single dose nicotine (inhalational) produced significant antidepressant action comparable to that of seven days’ treatment of standard antidepressant drug imipramine in rats. In rats, nicotine by both routes i.e. subcutaneous and inhalational increased serotonergic activity

Adventive hydrothermal circulation on Stromboli volcano (Aeolian Islands, Italy) revealed by geophysical and geochemical approaches: Implications for general fluid flow models on volcanoes

International audienceOn March 15th 2007 a paroxysmal explosion occurred at the Stromboli volcano. This event generated a large amount of products, mostly lithic blocks, some of which impacted the ground as far as down to 200 m a.s.l., about 1.5 km far away from the active vents. Two days after the explosion, a new vapour emission was discovered on the north-eastern flank of the volcanic edifice, at 560 m a.s.l., just above the area called "Nel Cannestrà". This new vapour emission was due to a block impact. In order to investigate the block impact area to understand the appearance of the vapour emission, we conducted on May 2008 a multidisciplinary study involving Electrical Resistivity Tomography (ERT), Ground Penetrating Radar (GPR), Self-Potential (SP), CO2 soil diffuse degassing and soil temperature surveys. This complementary data set revealed the presence of an anomalous conductive body, probably related to a shallow hydrothermal level, at about 10-15 m depth, more or less parallel to the topography. It is the first time that such a hydrothermal fluid flow, with a temperature close to the water boiling point (76 °C) has been evidenced at Stromboli at this low elevation on the flank of the edifice. The ERT results suggest a possible link between (1) the main central hydrothermal system of Stromboli, located just above the plumbing system feeding the active vents, with a maximum of subsurface soil temperature close to 90 °C and limited by the NeoStromboli summit crater boundary and (2) the investigated area of Nel Cannestrà, at ~ 500 m a.s.l., a buried eruptive fissure active 9 ka ago. In parallel, SP and CO2 soil diffuse degassing measurements suggest in this sector at slightly lower elevation from the block impact crater a magmatic and hydrothermal fluid rising system along the N41° regional fault. A complementary ERT profile, on May 2009, carried out from the NeoStromboli crater boundary down to the block impact crater displayed a flank fluid flow apparently connected to a deeper system. The concept of shallow hydrothermal level have been compared to similar ERT results recently obtained on Mount Etna and La Fossa cone of Vulcano. This information needs to be taken into account in general fluid flow models on volcanoes. In particular, peripheral thermal waters (as those bordering the north-eastern coast of Stromboli) could be contaminated by hydrothermal and magmatic fluids coming from regional faults but also from the summit

Validation of Agent-Based Models in Economics and Finance

Since the survey by Windrum et al. (Journal of Artificial Societies and Social Simulation 10:8, 2007), research on empirical validation of agent-based models in economics has made substantial advances, thanks to a constant flow of high-quality contributions. This Chapter attempts to take stock of such recent literature to offer an updated critical review of the existing validation techniques. We sketch a simple theoretical framework that conceptualizes existing validation approaches, which we examine along three different dimensions: (i) comparison between artificial and real-world data; (ii) calibration and estimation of model parameters; and (iii) parameter space exploration. Finally, we discuss open issues in the field of ABM validation and estimation. In particular, we argue that more research efforts should be devoted toward advancing hypothesis testing in ABM, with specific emphasis on model stationarity and ergodicity

Targeting of highly conserved Dengue virus sequences with anti-Dengue virus trans-splicing group I introns

<p>Abstract</p> <p>Background</p> <p>Dengue viruses (DENV) are one of the most important viral diseases in the world with approximately 100 million infections and 200,000 deaths each year. The current lack of an approved tetravalent vaccine and ineffective insecticide control measures warrant a search for alternatives to effectively combat DENV. The <it>trans</it>-splicing variant of the <it>Tetrahymena thermophila </it>group I intron catalytic RNA, or ribozyme, is a powerful tool for post-transcriptional RNA modification. The nature of the ribozyme and the predictability with which it can be directed makes it a powerful tool for modifying RNA in nearly any cell type without the need for genome-altering gene therapy techniques or dependence on native cofactors.</p> <p>Results</p> <p>Several anti-DENV Group I <it>trans</it>-splicing introns (αDENV-GrpIs) were designed and tested for their ability to target DENV-2 NGC genomes <it>in situ</it>. We have successfully targeted two different uracil bases on the positive sense genomic strand within the highly conserved 5'-3' cyclization sequence (CS) region common to all serotypes of DENV with our αDENV-GrpIs. Our ribozymes have demonstrated ability to specifically <it>trans</it>-splice a new RNA sequence downstream of the targeted site <it>in vitro </it>and in transfected insect cells as analyzed by firefly luciferase and RT-PCR assays. The effectiveness of these αDENV-GrpIs to target infecting DENV genomes is also validated in transfected or transformed Aedes mosquito cell lines upon infection with unattenuated DENV-2 NGC.</p> <p>Conclusions</p> <p>Analysis shows that our αDENV-GrpIs have the ability to effectively <it>trans</it>-splice the DENV genome <it>in situ</it>. Notably, these results show that the αDENV-GrpI 9v1, designed to be active against all forms of Dengue virus, effectively targeted the DENV-2 NGC genome in a sequence specific manner. These novel αDENV-GrpI introns provide a striking alternative to other RNA based approaches for the transgenic suppression of DENV in transformed mosquito cells and tissues.</p

BIOCIDAL ACTIVITY OF BACILLUS THURINGIENSIS H-14 TOXIN ON THREE SPECIES OF MOSQUITOES

Comparative toxicity of Bacillus thuringiensis israelensis H-14, commercial product in aqueous and granular formulations, were studied on the three species of mosquitoes, Anopheles stephansi, Culex quinquefasciatus and Aedes aegypti. It was observed that both the formulations were equally effective against these three species. Further biological studies on the pesticide resistant and susceptible strains of Ae. aegypti showed that the toxin was highly effective on the larvae irespective of their pesticide susceptibility status. In the light of these observations the use of bio-pesticides for the control of these vector mosquitoes is discussed

<span style="font-size: 21.0pt;mso-bidi-font-size:14.0pt;font-family:"Times New Roman","serif"">Highly-substrate active isoenzyme acetylcholinesterase-II, in rosy eye mutant of <i><span style="font-size:21.0pt;mso-bidi-font-size:14.0pt;font-family:"Times New Roman","serif"">Aedes aegypti </span></i><span style="font-size:21.0pt;mso-bidi-font-size:14.0pt; font-family:"Times New Roman","serif"">mosquito </span></span>

807-810<span style="font-size: 15.0pt;mso-bidi-font-size:8.0pt;font-family:" times="" new="" roman","serif""="">Insecticide bioassays were carried out on larvae and adults of rosy eye mutant and wildtype strains of A. <span style="font-size:15.5pt;mso-bidi-font-size:8.5pt; font-family:" times="" new="" roman","serif""="">aegypti. Both the strains were equally susceptible to DDT, malathion and deltamethrin. Biochemical assays showed an increase in acetylcholinesterase enzyme (AChE) activity in all the stages of mutant strain with both the substrates i.e. acetylthiocholine iodide and S-butyrylthiocholine iodide. However, there was no difference in the percent inhibition of enzyme activity with propoxur in these two strains. Polyacrylamide gel electrophoresis performed in native conditions on the homogenates of adults of rosy eye mosquitoes showed that AChE-II allele was highly active with the substrate acetylthiocholine iodide as compared to wildtype strain. Frequency of the highly active AChE-II allele in the mutant strain was about 68%, whereas it was about 5% in the wildtype strain. </span