Dysphagia Alone as a Unique Presentation of Wound Botulism in the Emergency Department: A Case Report.

INTRODUCTION: Wound botulism is a rare and potentially fatal infectious disease, often seen in patients who abuse injection drugs. It classically presents with dysfunction of bilateral cranial nerves followed by proximal and distal motor weakness, which can progress to respiratory failure. CASE REPORT: We report a case of a 31-year-old female who presented to the emergency department for the fifth time with an eight-day history of isolated dysphagia without any other neurologic symptoms. She reported a history of injection drug abuse via "skin popping," was admitted to the hospital, and ultimately diagnosed with wound botulism. CONCLUSION: This case exemplifies the diagnostic pitfalls of rare diseases such as wound botulism and provides insight regarding the diagnosis and treatment of this entity. This case also highlights the unique medical and social challenges emergency physicians face while trying to reliably evaluate patients who abuse controlled substances.

Handheld Ultrasound: Overcoming the Challenge of Difficult Peripheral Intravenous Access in the Emergency Department.

OBJECTIVES: The purpose of this study was to evaluate the performance of a handheld ultrasound device for difficult peripheral intravenous (PIV) access performed by nurses and paramedics in the emergency department (ED). METHODS: This was a retrospective review at an academic medical center. Participants were ED nurses and paramedics with competence in ultrasound-guided PIV placement. Participants were asked to log their use of the handheld device when used on patients deemed to have "difficult" access and complete a questionnaire, which consisted of items related to the effectiveness and ease of use of the device. Data were collected over the course of 1 year. An electronic medical record review was performed to track the success rates and the occurrence of any associated complications throughout the hospital stay. RESULTS: Nurses and paramedics logged a total of 483 cases in which PIV access was attempted with the handheld ultrasound device. Ninety-two percent (95% confidence interval [CI], 89%-94%) of the ultrasound-guided PIV lines attempted were placed successfully. Eighty-four percent (95% CI, 80%-87%) of the lines were placed successfully on the first attempt. In most cases (396 of 483 [82%]), no complications associated with the PIV occurred. A total of 429 questionnaires were completed over the study period. Most of the operators (84%; 95% CI, 80%-87%) stated that the handheld device was adequate to perform ultrasound-guided PIV access. CONCLUSIONS: The handheld ultrasound device performed well in terms of usability and reliability for PIV access.

Pharmacologic Characterization of JNJ-42226314, [1-(4-Fluorophenyl)indol-5-yl]-[3-[4-(thiazole-2-carbonyl)piperazin-1-yl]azetidin-1-yl]methanone, a Reversible, Selective, and Potent Monoacylglycerol Lipase Inhibitor.

The serine hydrolase monoacylglycerol lipase (MAGL) is the rate-limiting enzyme responsible for the degradation of the endocannabinoid 2-arachidonoylglycerol (2-AG) into arachidonic acid and glycerol. Inhibition of 2-AG degradation leads to elevation of 2-AG, the most abundant endogenous agonist of the cannabinoid receptors (CBs) CB1 and CB2. Activation of these receptors has demonstrated beneficial effects on mood, appetite, pain, and inflammation. Therefore, MAGL inhibitors have the potential to produce therapeutic effects in a vast array of complex human diseases. The present report describes the pharmacologic characterization of [1-(4-fluorophenyl)indol-5-yl]-[3-[4-(thiazole-2-carbonyl)piperazin-1-yl]azetidin-1-yl]methanone (JNJ-42226314), a reversible and highly selective MAGL inhibitor. JNJ-42226314 inhibits MAGL in a competitive mode with respect to the 2-AG substrate. In rodent brain, the compound time- and dose-dependently bound to MAGL, indirectly led to CB1 occupancy by raising 2-AG levels, and raised norepinephrine levels in cortex. In vivo, the compound exhibited antinociceptive efficacy in both the rat complete Freund's adjuvant-induced radiant heat hypersensitivity and chronic constriction injury-induced cold hypersensitivity models of inflammatory and neuropathic pain, respectively. Though 30 mg/kg induced hippocampal synaptic depression, altered sleep onset, and decreased electroencephalogram gamma power, 3 mg/kg still provided approximately 80% enzyme occupancy, significantly increased 2-AG and norepinephrine levels, and produced neuropathic antinociception without synaptic depression or decreased gamma power. Thus, it is anticipated that the profile exhibited by this compound will allow for precise modulation of 2-AG levels in vivo, supporting potential therapeutic application in several central nervous system disorders. SIGNIFICANCE STATEMENT: Potentiation of endocannabinoid signaling activity via inhibition of the serine hydrolase monoacylglycerol lipase (MAGL) is an appealing strategy in the development of treatments for several disorders, including ones related to mood, pain, and inflammation. [1-(4-Fluorophenyl)indol-5-yl]-[3-[4-(thiazole-2-carbonyl)piperazin-1-yl]azetidin-1-yl]methanone is presented in this report to be a novel, potent, selective, and reversible noncovalent MAGL inhibitor that demonstrates dose-dependent enhancement of the major endocannabinoid 2-arachidonoylglycerol as well as efficacy in models of neuropathic and inflammatory pain.

In vivo Characterization of a Selective, Orally Available, and Brain Penetrant Small Molecule GPR139 Agonist.

Recently, our group along with another demonstrated that GPR139 can be activated by L-phenylalanine (L-Phe) and L-tryptophan (L-Trp) at physiologically relevant concentrations. GPR139 is discretely expressed in brain, with highest expression in medial habenula. Not only are the endogenous ligands catecholamine/serotonin precursors, but GPR139 expressing areas can directly/indirectly regulate the activity of catecholamine/serotonin neurons. Thus, GPR139 appears expressed in an interconnected circuit involved in mood, motivation, and anxiety. The aim of this study was to characterize a selective and brain penetrant GPR139 agonist (JNJ-63533054) in relevant in vivo models. JNJ-63533054 was tested for its effect on c-fos activation in the habenula and dorsal striatum. In vivo microdialysis experiments were performed in freely moving rats to measure basal levels of serotonin or dopamine (DA) in prefrontal cortex (mPFC) and nucleus accumbens (NAc). Finally, the compound was profiled in behavioral models of anxiety, despair, and anhedonia. The agonist (10-30 mg/kg, p.o.) did not alter c-fos expression in medial habenula or dorsal striatum nor neurotransmitter levels in mPFC or NAc. JNJ-63533054 (10 mg/kg p.o.) produced an anhedonic-like effect on urine sniffing, but had no significant effect in tail suspension, with no interaction with imipramine, no effect on naloxone place aversion, and no effect on learned helplessness. In the marble burying test, the agonist (10 mg/kg p.o.) produced a small anxiolytic-like effect, with no interaction with fluoxetine, and no effect in elevated plus maze (EPM). Despite GPR139 high expression in medial habenula, an area with connections to limbic and catecholaminergic/serotoninergic areas, the GPR139 agonist had no effect on c-fos in medial habenula. It did not alter catecholamine/serotonin levels and had a mostly silent signal in in vivo models commonly associated with these pathways. The physiological function of GPR139 remains elusive.

In vivo Calcium Imaging Reveals That Cortisol Treatment Reduces the Number of Place Cells in Thy1-GCaMP6f Transgenic Mice.

The hippocampus, a structure essential for spatial navigation and memory undergoes anatomical and functional changes during chronic stress. Here, we investigate the effects of chronic stress on the ability of place cells to encode the neural representation of a linear track. To model physiological conditions of chronic stress on hippocampal function, transgenic mice expressing the genetically encoded calcium indicator GCaMP6f in CA1 pyramidal neurons were chronically administered with 40 µg/ml of cortisol for 8 weeks. Cortisol-treated mice exhibited symptoms typically observed during chronic stress, including diminished reward seeking behavior and reduced adrenal gland and spleen weights. In vivo imaging of hippocampal cellular activity during linear track running behavior revealed a reduced number of cells that could be recruited to encode spatial position, despite an unchanged overall number of active cells, in cortisol-treated mice. The properties of the remaining place cells that could be recruited to encode spatial information, however, was unperturbed. Bayesian decoders trained to estimate the mouse's position on the track using single neuron activity data demonstrated reduced performance in a cue richness-dependent fashion in cortisol-treated animals. The performance of decoders utilizing data from the entire neuronal ensemble was unaffected by cortisol treatment. Finally, to test the hypothesis that an antidepressant drug could prevent the effects of cortisol, we orally administered a group of mice with 10 mg/kg citalopram during cortisol administration. Citalopram prevented the cortisol-induced decrease in single-neuron decoder performance but failed to significantly prevent anhedonia and the cortisol-induced reduction in the proportion place cells. The dysfunction observed at the single-neuron level indicates that chronic stress may impair the ability of the hippocampus to encode individual neural representations of the mouse's spatial position, a function pivotal to forming an accurate navigational map of the mouse's external environment; however, the hippocampal ensemble as a whole is resilient to any cortisol-induced insults to single neuronal place cell function on the linear track.

Utilizing Miniature Fluorescence Microscopy to Image Hippocampal Place Cell Ensemble Function in Thy1.GCaMP6f Transgenic Mice.

Imaging neuronal activity in awake behaving mice with miniature fluorescence microscopes requires the implementation of a variety of procedures. Surgeries are performed to gain access to the cell population of interest and to implant microscope components. After a recovery period, mice are trained to exhibit a desired behavior. Finally, neuronal activity is imaged and synchronized with that behavior. To take full advantage of the technology, selection of the calcium indicator and experimental design must be carefully considered. In this article, we explain the procedures and considerations that are critical for obtaining high-quality calcium imaging data. As an example, we describe how to utilize miniature fluorescence microscopy to image hippocampal place cell activity during linear track running in Thy1.GCaMP6f transgenic mice. © 2018 by John Wiley & Sons, Inc.

Drone Transport of Chemistry and Hematology Samples Over Long Distances.

OBJECTIVES: We addressed the stability of biological samples in prolonged drone flights by obtaining paired chemistry and hematology samples from 21 adult volunteers in a single phlebotomy event-84 samples total. METHODS: Half of the samples were held stationary, while the other samples were flown for 3 hours (258 km) in a custom active cooling box mounted on the drone. After the flight, 19 chemistry and hematology tests were performed. RESULTS: Seventeen analytes had small or no bias, but glucose and potassium in flown samples showed an 8% and 6.2% bias, respectively. The flown samples (mean, 24.8°C) were a mean of 2.5°C cooler than the stationary samples (mean, 27.3°C) during transportation to the flight field as well as during the flight. CONCLUSIONS: The changes in glucose and potassium are consistent with the magnitude and duration of the temperature difference between the flown and stationary samples. Long drone flights of biological samples are feasible but require stringent environmental controls to ensure consistent results.

Prospective evaluation of the learning curve for ultrasound-guided peripheral intravenous catheter placement.

INTRODUCTION: It is unclear how many ultrasound-guided peripheral intravenous catheters (USG PIVC) one must place to become proficient at the procedure. The objective of this study was to determine the learning curve associated with PIVC placement and determine how many attempts are required for non-physician learners to reach proficiency. METHODS: This is a prospective observational study. Emergency department (ED) nurses and paramedics with competence in traditional PIVC placement underwent a USG PIVC placement training program. Their success or failure in placing USG PIVCs as part of patient care on ED patients with difficult IV access was monitored. Number of attempts (defined as one skin puncture) was recorded and success was defined as the ability to aspirate blood and flush saline. The probability of success over time was analyzed. Proficiency was defined a priori as 70% probability of success. RESULTS: Thirty-three providers with 1077 PIV access attempts on 796 patients over 1000 unique patient ED encounters were included in the study. Overall success rate for all providers was 88.24% (86.3%-90.2%). LOcally WEighted Scatter-plot Smoother (Lowess) smoothing and mixed effects logistic regression analysis both determined that a learner's probability of success would be greater than 70% after four USG PIVCs have been placed. Post hoc analysis for a more stringent 88% success rate resulted in 15 and 26 required attempts, respectively. DISCUSSION: After placement of four USG PIVCs, new learners of the procedure are capable of a greater than 70% success rate. A success rate of greater than 88% is achieved after 15 to 26 attempts.

Direct Imaging of Hippocampal Epileptiform Calcium Motifs Following Kainic Acid Administration in Freely Behaving Mice.

Prolonged exposure to abnormally high calcium concentrations is thought to be a core mechanism underlying hippocampal damage in epileptic patients; however, no prior study has characterized calcium activity during seizures in the live, intact hippocampus. We have directly investigated this possibility by combining whole-brain electroencephalographic (EEG) measurements with microendoscopic calcium imaging of pyramidal cells in the CA1 hippocampal region of freely behaving mice treated with the pro-convulsant kainic acid (KA). We observed that KA administration led to systematic patterns of epileptiform calcium activity: a series of large-scale, intensifying flashes of increased calcium fluorescence concurrent with a cluster of low-amplitude EEG waveforms. This was accompanied by a steady increase in cellular calcium levels (>5 fold increase relative to the baseline), followed by an intense spreading calcium wave characterized by a 218% increase in global mean intensity of calcium fluorescence (n = 8, range [114-349%], p < 10(-4); t-test). The wave had no consistent EEG phenotype and occurred before the onset of motor convulsions. Similar changes in calcium activity were also observed in animals treated with 2 different proconvulsant agents, N-methyl-D-aspartate (NMDA) and pentylenetetrazol (PTZ), suggesting the measured changes in calcium dynamics are a signature of seizure activity rather than a KA-specific pathology. Additionally, despite reducing the behavioral severity of KA-induced seizures, the anticonvulsant drug valproate (VA, 300 mg/kg) did not modify the observed abnormalities in calcium dynamics. These results confirm the presence of pathological calcium activity preceding convulsive motor seizures and support calcium as a candidate signaling molecule in a pathway connecting seizures to subsequent cellular damage. Integrating in vivo calcium imaging with traditional assessment of seizures could potentially increase translatability of pharmacological intervention, leading to novel drug screening paradigms and therapeutics designed to target and abolish abnormal patterns of both electrical and calcium excitation.

Discovery and Characterization of AMPA Receptor Modulators Selective for TARP-γ8.

Members of the α-amino-3-hydroxyl-5-methyl-4-isoxazole-propionic acid (AMPA) subtype of ionotropic glutamate receptors mediate the majority of fast synaptic transmission within the mammalian brain and spinal cord, representing attractive targets for therapeutic intervention. Here, we describe novel AMPA receptor modulators that require the presence of the accessory protein CACNG8, also known as transmembrane AMPA receptor regulatory protein γ8 (TARP-γ8). Using calcium flux, radioligand binding, and electrophysiological assays of wild-type and mutant forms of TARP-γ8, we demonstrate that these compounds possess a novel mechanism of action consistent with a partial disruption of the interaction between the TARP and the pore-forming subunit of the channel. One of the molecules, 5-[2-chloro-6-(trifluoromethoxy)phenyl]-1,3-dihydrobenzimidazol-2-one (JNJ-55511118), had excellent pharmacokinetic properties and achieved high receptor occupancy following oral administration. This molecule showed strong, dose-dependent inhibition of neurotransmission within the hippocampus, and a strong anticonvulsant effect. At high levels of receptor occupancy in rodent in vivo models, JNJ-55511118 showed a strong reduction in certain bands on electroencephalogram, transient hyperlocomotion, no motor impairment on rotarod, and a mild impairment in learning and memory. JNJ-55511118 is a novel tool for reversible AMPA receptor inhibition, particularly within the hippocampus, with potential therapeutic utility as an anticonvulsant or neuroprotectant. The existence of a molecule with this mechanism of action demonstrates the possibility of pharmacological targeting of accessory proteins, increasing the potential number of druggable targets.

High incidence of post-operative infection after 'sinus tarsi' approach for treatment of intra-articular fractures of the calcaneus: a 5 year experience in an academic level one trauma center.

BACKGROUND: The optimal management of displaced intra-articular calcaneal fractures remains a topic of debate among trauma surgeons. The purpose of this study was to assess the safety of the sinus tarsi approach in regard to the incidence of deep infection and amputation following open reduction and internal fixation intra-articular calcaneal fractures. METHODS: We conducted a retrospective chart review of all patients with displaced intra-articular calcaneus fractures treated with internal fixation through the sinus tarsi approach in a five year period. All surgeries were performed in a single level one trauma center by a single orthopedic trauma fellowship trained surgeon. RESULTS: Seventeen patients with an average age of 36.6 ± 13.6 years (range 12-61 years) met the inclusion criteria. The time between injury and surgery was on average 6.1 days (range 1-22 days). Average follow up was 116 ± 78.2 days (range 3-276 days). Two patients (11.7%) had diabetes mellitus. None of the patients required amputation. Three patients (17.6%) developed deep infection and underwent subsequent formal irrigation and debridement, two of these requiring multiple repeat surgeries in addition to hardware removals. Negative pressure wound therapy and long term antibiotics via peripherally inserted central catheter (PICC) were necessary in these three patients with wound infections. CONCLUSION: The sinus tarsi approach for intra fixation intra-articular calcaneal fractures is safe as compared to the traditional extensile approach in regard to flap necrosis and amputation. However, the rate of deep infection was higher than previously described in the literature.

Pattern and not magnitude of neural activity determines dendritic spine stability in awake mice.

The stability of dendritic spines in the neocortex is profoundly influenced by sensory experience, which determines the magnitude and pattern of neural firing. By optically manipulating the temporal structure of neural activity in vivo using channelrhodopsin-2 and repeatedly imaging dendritic spines along these stimulated neurons over a period of weeks, we show that the specific pattern, rather than the total amount of activity, determines spine stability in awake mice.

Genetic deletion of trkB.T1 increases neuromuscular function.

Neurotrophin-dependent activation of the tyrosine kinase receptor trkB.FL modulates neuromuscular synapse maintenance and function; however, it is unclear what role the alternative splice variant, truncated trkB (trkB.T1), may have in the peripheral neuromuscular axis. We examined this question in trkB.T1 null mice and demonstrate that in vivo neuromuscular performance and nerve-evoked muscle tension are significantly increased. In vitro assays indicated that the gain-in-function in trkB.T1(-/-) animals resulted specifically from an increased muscle contractility, and increased electrically evoked calcium release. In the trkB.T1 null muscle, we identified an increase in Akt activation in resting muscle as well as a significant increase in trkB.FL and Akt activation in response to contractile activity. On the basis of these findings, we conclude that the trkB signaling pathway might represent a novel target for intervention across diseases characterized by deficits in neuromuscular function.

Heterogeneity in synaptic vesicle release at neuromuscular synapses of mice expressing synaptopHluorin.

Mammalian neuromuscular junctions are useful model synapses to study the relationship between synaptic structure and function, although these have rarely been studied together at the same synapses. To do this, we generated transgenic lines of mice in which the thy1.2 promoter drives expression of synaptopHluorin (spH) as a means of optically measuring synaptic vesicle distribution and release. SpH is colocalized with other synaptic vesicle proteins in presynaptic terminals and does not alter normal synaptic function. Nerve stimulation leads to readily detectable and reproducible fluorescence changes in motor axon terminals that vary with stimulus frequency and, when compared with electrophysiological recordings, are reliable indicators of neurotransmitter release. Measurements of fluorescence intensity changes reveal a surprising amount of heterogeneity in synaptic vesicle release throughout individual presynaptic motor axon terminals. Some discrete terminal regions consistently displayed a greater rate and extent of release than others, regardless of stimulation frequency. The amount of release at a particular site is highly correlated to the relative abundance of synaptic vesicles there, indicating that a relatively constant fraction of the total vesicular pool, approximately 30%, is released in response to activity. These studies reveal previously unknown relationships between synaptic structure and function at mammalian neuromuscular junctions and demonstrate the usefulness of spH expressing mice as a tool for studying neuromuscular synapses in adults, as well as during development and diseases that affect neuromuscular synaptic function.

Dysmyelinated lower motor neurons retract and regenerate dysfunctional synaptic terminals.

Axonal degeneration is the major cause of permanent neurological disability in individuals with inherited diseases of myelin. Axonal and neuronal changes that precede axonal degeneration, however, are not well characterized. We show here that dysmyelinated lower motor neurons retract and regenerate dysfunctional presynaptic terminals, leading to severe neurological disability before axonal degeneration. In addition, dysmyelination led to a decreased synaptic quantal content, an indicator of synaptic dysfunction. The amplitude and rise time of miniature endplate potentials were also increased, but these changes were primarily consistent with an increase in the passive membrane properties of the transgenic muscle fibers. Maintenance of synaptic connections should be considered as a therapeutic target for slowing progression of neurological disability in primary diseases of myelin.

Activity-dependent elimination of neuromuscular synapses.

At developing neuromuscular synapses in vertebrates, different motor axon inputs to muscle fibers compete for maintenance of their synapses. Competition results in progressive changes in synaptic structure and strength that lead to the weakening and loss of some inputs, a process that has been called synapse elimination. At the same time, a single input is strengthened and maintained throughout adult life, consistently recruiting muscle fibers to contract even at rapid firing rates. Work over the last decade has led to an understanding of some of the cell biological mechanisms that underlie competition and how these culminate in synapse elimination. We discuss current ideas about how activity modulates neuromuscular synaptic competition, how competition leads to synapse loss, and how these processes are modulated by cell-cell signaling. A common feature of competition at neuromuscular as well as CNS synapses is that temporally correlated activity seems to slow or prevent competition, while uncorrelated activity seems to trigger or enhance competition. Important questions that remain to be addressed include how patterns of motor neuron activity affect synaptic strength, what is the temporal relationship between changes in synaptic strength and structure, and what cellular signals mediate synapse loss. Answers to these questions will expand our understanding of the mechanisms by which activity edits synaptic structure and function, writing permanent changes in neural circuitry.