459 research outputs found
Decreases in the serotonin content of a pair of identified neurones can explain the effects of p-chlorophenylalanine on the feeding behaviour of the pond snail, Lymnaea stagnalis
No full text3D printable conductive materials for the fabrication of electrochemical sensors:A mini review
Full text linkThe review presents recent developments in the use of conductive materials that can be printed using additive manufacturing (3D printing), enabling the development of mass-produced electrochemical sensors of varying geometries. This review will highlight some key electroanalytical applications of 3D-printed electrochemical sensors and discuss their potential future capabilities
Scutt_et_al_TADS_Supplementary_material – Supplemental material for Does the 5-HT<sub>1A</sub> rs6295 polymorphism influence the safety and efficacy of citalopram therapy in the oldest old?
No full textSupplemental material, Scutt_et_al_TADS_Supplementary_material for Does the 5-HT1A rs6295 polymorphism influence the safety and efficacy of citalopram therapy in the oldest old? by Greg Scutt, Andrew Overall, Railton Scott, Bhavik Patel, Lamia Hachoumi, Mark Yeoman and Juliet Wright in Therapeutic Advances in Drug Safety</p
Synapse-specific changes in serotonin signalling contribute to age-related changes in the feeding behaviour of the pond snail, Lymnaea
Full text linkThis study utilised the pond snail, Lymnaea to examine the contribution that alterations in serotonergic signalling make to age-related changes in feeding. Age-related decreases in 5-HIAA levels in feeding ganglia were positively correlated with a decrease in the number of sucrose-evoked bites and negatively correlated with an increase in inter-bite interval, implicating alterations in serotonergic signalling in the aged phenotype. Analysis of the serotonergic cerebral giant cell (CGC) input to the protraction motor neurone (B1) demonstrated that fluoxetine (10–100 nM) increased the amplitude/duration of the evoked EPSP in both young and middle aged but not in old neurones, suggesting an age-related attenuation of the serotonin transporter. 5-HT evoked a concentration-dependent increase in the amplitude/duration of B1 EPSP, which was greater in old neurones compared to both young and middle aged. Conversely, the 5-HT-evoked depolarisation and conditional bursting of the swallow motor neurone (B4) were attenuated in old neurones, functions critical for a full feeding rhythm. The CGCs' ability to excite B1 was blocked by cinanserin but not by methysergide. Conversely, the CGC to B4 connection was completely blocked by methysergide and only partially by cinanserin suggesting that age-related changes may be receptor-specific. In summary, synapse-specific attenuation of the CGC-B4 connection and enhancement of the CGC-B1 connection would slow the swallow phase and maintain protraction, consistent with behavioural observation
Hilbert transform of voltammetric data
No full textThe use of the fast Fourier transform (FFT) assumes stationarity and, in many applications, linearity; assumptions that are often invalid in the analysis of voltammetric data. Empirical mode decomposition followed by the Hilbert transform offers an alternative mode of analysis that can overcome these difficulties. The validity of the Hilbert transform for the analysis of non-linear signals merits application to electrochemistry which, to our knowledge, has not been carried out before. Preliminary results, for three well-characterised redox processes: (i) a thermodynamically reversible electron transfer; (ii) formation of a passivating layer; (iii) growth of an oxide layer on an electrode surface, suggest that it can provide useful and novel insights into electrochemical processes. A less well-characterised process, the adsorption of 5-hydroxytryptamine (5-HT) oxidation products on the surface of a glassy carbon electrode, is also investigated using the Hilbert transfor
Subsecond voltammetric separation between dopamine and serotonin in the presence of ascorbate
No full textAlthough voltammetry has proved an important tool for unraveling the dynamics of specific neurotransmitter molecules during the past decade, it has been very difficult to monitor more than one neurotransmitter simultaneously. In this work, we present a voltammetric methodology that allows discrimination between dopamine and serotonin, two important neurotransmitter molecules with very similar electrochemical properties, in the presence of high concentrations of ascorbate. We combined the application of a novel large-amplitude/high-frequency voltage excitation with signal processing techniques valid for the analysis of nonstationary and nonlinear phenomena. This allows us to minimize the contribution from capacitance and preserve the faradaic features of the voltammetric response providing us with excellent voltammetric detail. Using appropriate voltage excitation parameters and defining specific regions in the voltage space, so-called voltage windows, we can measure the concentrations of dopamine and serotonin separately or independently in mixed solutions even in the presence of high concentrations of ascorbate. Because of the enhanced voltammetric detail of this new technique, it is also possible to explore effects attributed to interfacial phenomena such as adsorption/desorption and electrode fouling.<br/
Detection of nitric oxide release from single neurons in the pond snail, Lymnaea stagnalis
No full textMultiple film-coated nitric oxide sensors have been fabricated using Nafion and electropolymerized polyeugenol or o-phenylenediamine on 30-?m carbon fiber disk electrodes. This is a rare study that utilizes disk electrodes rather than the widely used protruding tip microelectrodes in order to measure from a biological environment. These electrodes have been used to evaluate the differences in nitric oxide release between two different identified neurons in the pond snail, Lymnaea stagnalis. These results show the first direct measurements of nitric oxide release from individual neurons. The electrodes are very sensitive to nitric oxide with a detection limit of 2.8 nM and a sensitivity of 9.46 nA ?M-1. The sensor was very selective against a variety of neurochemical interferences such as ascorbic acid, uric acid, and catecholamines and secondary oxidation products such as nitrite. Nitric oxide release was measured from the cell bodies of two neurons, the cerebral giant cell (CGC) and the B2 buccal motor neuron, in the intact but isolated CNS. A high-Ca2+/high-K+ stimulus was capable of evoking reproducible release. For a given stimulus, the B2 neuron released more nitric oxide than the CGC neuron; however, both cells were equally suppressed by the NOS inhibitor l-NAM
Simple and rapid determination of serotonin and catecholamines in biological tissue using high-performance liquid chromatography with electrochemical detection
No full textUsing the CNS of Lymnaea stagnalis a method is described for the rapid analysis of neurotransmitters and their metabolites using high performance liquid chromatography coupled with electrochemical detection. Tissue samples were homogenised in ice-cold 0.1 M perchloric acid and centrifuged. Using a C18 microbore column the mobile phase was maintained at a flow rate of 100 ?l/min and consisted of sodium citrate buffer (pH 3.2)–acetonitrile (82.5:17.5, v/v) with 2 mM decane-sulfonic acid sodium salt. The potential was set at +750 mV versus Ag|AgCl reference electrode at a sensitivity of 50 nA full scale deflection. The detection limit for serotonin was 11.86 ng ml?1 for a 5 ?l injection. Preparation of tissue samples in mobile phase reduced the response to dopamine and serotonin compared with perchloric acid. In addition it was found that the storage of tissue samples at ?20 °C caused losses of dopamine and serotonin. As a result of optimising the sample preparation and mobile phase the total time of analysis was substantially reduced resulting in a sample preparation and assay time of 15–20 min
DS_10.1177_0363546519860522 – Supplemental material for Injury Surveillance in Major League Soccer: A 4-Year Comparison of Injury on Natural Grass Versus Artificial Turf Field
No full textSupplemental material, DS_10.1177_0363546519860522 for Injury Surveillance in Major League Soccer: A 4-Year Comparison of Injury on Natural Grass Versus Artificial Turf Field by Sean P. Calloway, David M. Hardin, Matthew D. Crawford, J. Michael Hardin, Lawrence J. Lemak, Eric Giza, Brian Forsythe, Yining Lu, Bhavik H. Patel, Daryl C. Osbahr, Michael B. Gerhardt, Bert R. Mandelbaum and William W. Baldwin in The American Journal of Sports Medicine</p
Systematic review and meta-analysis investigating the diagnostic yield of dual-energy CT for renal mass assessment
No full textOBJECTIVE. The objective of our study was to perform a systematic review and meta-analysis to evaluate the diagnostic accuracy of dual-energy CT (DECT) for renal mass evaluation. MATERIALS AND METHODS. In March 2018, we searched MEDLINE, Cochrane Database of Systematic Reviews, Embase, and Web of Science databases. Analytic methods were based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Pooled estimates for sensitivity, specificity, and diagnostic odds ratios were calculated for DECT-based virtual monochromatic imaging (VMI) and iodine quantification techniques as well as for conventional attenuation measurements from renal mass CT protocols. I 2 was used to evaluate heterogeneity. The methodologic quality of the included studies and potential bias were assessed using items from the Quality Assessment Tool for Diagnostic Accuracy Studies 2 (QUADAS-2). RESULTS. Of the 1043 articles initially identified, 13 were selected for inclusion (969 patients, 1193 renal masses). Cumulative data of sensitivity, specificity, and summary diagnostic odds ratio for VMI were 87% (95% CI, 80–92%; I 2 , 92.0%), 93% (95% CI, 90–96%; I 2 , 18.0%), and 183.4 (95% CI, 30.7–1093.4; I 2 , 61.6%), respectively. Cumulative data of sensitivity, specificity, and summary diagnostic odds ratio for iodine quantification were 99% (95% CI, 97–100%; I 2 , 17.6%), 91% (95% CI, 89–94%; I 2 , 84.2%), and 511.5 (95% CI, 217–1201; I 2 , 0%). No significant differences in AUCs were found when comparing iodine quantification to conventional attenuation measurements (p = 0.79). CONCLUSION. DECT yields high accuracy for renal mass evaluation. Determination of iodine content with the iodine quantification technique shows diagnostic accuracy similar to conventional attenuation measurements from renal mass CT protocols. The iodine quantification technique may be used to characterize incidental renal masses when a dedicated renal mass protocol is not available
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