Concussions in the National Basketball Association: Analysis of Incidence, Return to Play, and Performance From 1999 to 2018.

Background: The effect of concussions on professional athletes has been investigated in many sports. However, few studies have evaluated concussions in National Basketball Association (NBA) players. Hypothesis: We hypothesized that concussion incidence has increased, yet the return-to-play (RTP) rate will remain high following the institution of the NBA concussion policy (NBACP). We also hypothesized that the incidence of repeat concussions will be similar to first occurrences and that player performance and game availability will not be significantly affected by sustaining a concussion. Study Design: Descriptive epidemiology study. Methods: Publicly available records were searched to identify all concussions from NBA seasons 1999-2000 to 2017-2018. Player demographics and information regarding career history were tabulated. Incidence of concussion and RTP timing were evaluated before and after institution of the NBACP (2011). Minutes per game and game score per minute were evaluated pre- versus postconcussion. Player availability and performance were also compared with an age-, body mass index-, position-, and experience-matched control group of players who did not sustain a concussion. Results: A total of 189 concussions were reported in the NBA from 1999 to 2018, with a mean +/- SD incidence of 9.7 +/- 7.3 concussions per season. Following implementation of the NBACP, incidence significantly increased from 5.7 +/- 2.8 to 16.7 +/- 7.5 concussions per season (P = .007). All players returned to play following first-time concussion after missing 7.7 +/- 8.6 days and 3.5 +/- 4.1 games. RTP time was not significantly different after implementation of the NBACP (games missed, P = .24; days missed, P = .27), and there was no difference in concussion-free time interval (P = .29). Game score per minute and minutes per game were not significantly affected by sustaining a concussion (both P \u3e .05). Conclusion: Concussion incidence in NBA players is approximately 17 instances per season since the 2011 institution of a league-wide concussion policy. The number of reported concussions significantly increased following the policy, in line with trends seen in other professional sports leagues. Players have retained a high rate of RTP after 3 to 4 missed games. Player performance and availability are not affected by sustaining a concussion following successful RTP

Detection of nitric oxide release from single neurons in the pond snail, Lymnaea stagnalis

Multiple 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

Using 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

Hilbert transform of voltammetric data

The 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

Inhibitory neuromuscular transmission to ileal longitudinal muscle predominates in neonatal guinea pigs

BACKGROUND: Inhibitory neurotransmission to the longitudinal muscle is more prominent in the neonatal than in the adult guinea pig small intestine. METHODS: Inhibitory neuromuscular transmission was investigated using in vitro ileal longitudinal muscle myenteric plexus (LMMP) preparations made from neonatal (≤ 48 h postnatal) and adult (~ 4 weeks postnatal) guinea pigs. KEY RESULTS: Amperometric measurements of nicotine induced nitric oxide release (measured as an oxidation current) from myenteric ganglia revealed larger currents in neonatal (379 ± 24 pA) vs. adult (119 ± 39 pA, P < 0.05) tissues. Nicotine-induced oxidation currents were blocked by the nitric oxide synthase (NOS) inhibitor, nitro-L-arginine (NLA, 100 µM). Nicotine-induced, NLA-sensitive oxidation currents could be detected in the tertiary plexus of neonatal but not adult tissues. Immunohistochemistry demonstrated stronger NOS immunoreactivity in neonatal compared to adult myenteric ganglia. Western blot studies revealed higher levels of NOS in neonatal compared to adult LMMP. Cell counts revealed that the total number of myenteric neurons in the small intestine was greater in adults than in neonatal guinea pigs, however the ratio of NOS:Calbindin neurons was significantly higher in neonatal compared to adult tissues. CONCLUSIONS: NO signaling to the longitudinal muscle is stronger in neonatal compared to adult guinea pig ileum. NOS-containing neurons are diluted postnatally by cholinergic and other, as yet unidentified neuronal subtypes

Subsecond voltammetric separation between dopamine and serotonin in the presence of ascorbate

Although 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/