Nitric oxide resets kisspeptin-excited GnRH neurons via PIP2 replenishment.

Fertility relies upon pulsatile release of gonadotropin-releasing hormone (GnRH) that drives pulsatile luteinizing hormone secretion. Kisspeptin (KP) neurons in the arcuate nucleus are at the center of the GnRH pulse generation and the steroid feedback control of GnRH secretion. However, KP evokes a long-lasting response in GnRH neurons that is hard to reconcile with periodic GnRH activity required to drive GnRH pulses. Using calcium imaging, we show that 1) the tetrodotoxin-insensitive calcium response evoked by KP relies upon the ongoing activity of canonical transient receptor potential channels maintaining voltage-gated calcium channels in an activated state, 2) the duration of the calcium response is determined by the rate of resynthesis of phosphatidylinositol 4,5-bisphosphate (PIP2), and 3) nitric oxide terminates the calcium response by facilitating the resynthesis of PIP2 via the canonical pathway guanylyl cyclase/3',5'-cyclic guanosine monophosphate/protein kinase G. In addition, our data indicate that exposure to nitric oxide after KP facilitates the calcium response to a subsequent KP application. This effect was replicated using electrophysiology on GnRH neurons in acute brain slices. The interplay between KP and nitric oxide signaling provides a mechanism for modulation of the refractory period of GnRH neurons after KP exposure and places nitric oxide as an important component for tonic GnRH neuronal pulses.

Flavonoid quercetin and its glucuronide and sulfate conjugates bind to 67-kDa laminin receptor and prevent neuronal cell death induced by serum starvation.

Quercetin, a dietary flavonoid, has been shown to protect against various neurodegenerative diseases with mechanisms largely unknown. After oral administration, quercetin is rapidly conjugated, and the aglycone is not detectable in the plasma and brain. However, its glucuronide and sulfate conjugates are present only at low nanomolar concentrations in the brain. Since quercetin and its conjugates have limited antioxidant capability at low nanomolar concentrations, it is crucial to determine whether they induce neuroprotection by binding to high-affinity receptors. Previously we found that (-)-epigallocatechin-3-gallate (EGCG), a polyphenol from green tea, induces neuroprotection by binding to the 67-kDa laminin receptor (67LR). Therefore, in this study, we determined whether quercetin and its conjugates bind 67LR to induce neuroprotection and compared their ability with EGCG. Based on the quenching of intrinsic tryptophan fluorescence of peptide G (residues 161-180 in 67LR), we found quercetin, quercetin-3-O-glucuronide, and quercetin-3-O-sulfate bind to this peptide with a high affinity comparable to EGCG. Molecular docking using the crystal structure of 37-kDa laminin receptor precursor supported the high-affinity binding of all these ligands to the site corresponding to peptide G. A pretreatment with quercetin (1-1000 nM) did not effectively protect Neuroscreen-1 cells from death induced by serum starvation. Contrarily, a pretreatment with low concentrations (1-10 nM) of quercetin conjugates better protected these cells than quercetin and EGCG. The 67LR-blocking antibody substantially prevented neuroprotection by all these agents, suggesting the role of 67LR in this process. Collectively, these studies reveal that quercetin induces neuroprotection primarily through its conjugates via high affinity binding to 67LR.

Managing opioid waste, cost, and opportunity for drug diversion in the emergency department.

INTRODUCTION: Management of pain is a component of 80% of all emergency department (ED) visits, and intravenous (IV) opioids are most commonly used to treat moderate to severe pain. Since the dose of stock vials is rarely purchased based on provider ordering patterns, there is often a discrepancy between ordered doses and the dose of the stock vial, leading to waste. Here, waste is defined as the difference between the dose of the stock vials used to fill an order and the ordered dose. Drug waste is problematic as it increases the chance of administering the incorrect dose, it is a source of lost revenue, and in the context of opioids, it increases the opportunity for drug diversion. In this study, we sought to utilize real-world data to describe the magnitude of morphine and hydromorphone waste in the studied EDs. We also applied scenario analyses based on provider ordering patterns to simulate the effects of cost versus opioid waste minimization when making purchasing decisions for the dose of stock vial of each opioid. METHODS: This was an observational analysis of IV morphine and hydromorphone orders across three EDs within a health care system between December 1, 2014 and November 30, 2015. In the primary analysis we measured total waste and cost of all ordered hydromorphone and morphine, and we created logistic regression models for each opioid to estimate the odds that a given ordered dose would create waste. In the secondary scenario analysis we determined the total waste created and total cost to satisfy all written orders for both opioids with respect to prioritizing minimizing waste versus cost. RESULTS: Among a total of 34,465 IV opioid orders, 7866 (35%) of morphine orders created 21,767 mg of waste, and 10,015 (85%) of hydromorphone orders created 11,689 mg of waste. Larger dose orders were associated with a smaller likelihood of waste in both morphine and hydromorphone due to the doses of stock vials available. In the waste optimization scenario, relative to the base scenario, total waste, which included waste from both morphine and hydromorphone, was reduced by 97% and cost was reduced by 11%. In the cost optimization scenario, cost was reduced by 28% but waste increased by 22%. CONCLUSION: As hospitals continue to seek strategies to reduce costs and mitigate the harms of opioid diversion amidst the opioid epidemic, this study shows that optimizing the dose of the stock vial to minimize waste using provider ordering patterns, could mitigate risk while also reducing cost. Limitations included the use of data from EDs within a single health system, drug shortages that affected stock vial availability, and finally, the actual cost of stock vials, used for cost calculations, can differ based on a variety of factors.

Cyclic-AMP induces Nogo-A receptor NgR1 internalization and inhibits Nogo-A-mediated collapse of growth cone.

The promotion of axonal regeneration is required for functional recovery from stroke and various neuronal injuries. However, axonal regeneration is inhibited by diverse axonal growth inhibitors, such as Nogo-A. Nogo-66, a C-terminal domain of Nogo-A, binds to the Nogo-A receptor 1 (NgR1) and induces the collapse of growth cones and inhibits neurite outgrowth. NgR1 is also a receptor for additional axonal growth inhibitors, suggesting it is an important target for the prevention of axonal growth inhibition. By using the indirect immunofluorescence method, we show for the first time that a cell-permeable cAMP analog (dibutyryl-cAMP) induced a rapid decrease in the cell surface expression of NgR1 in Neuroscreen-1 (NS-1) cells. The biotinylation method revealed that cAMP indeed induced internalization of NgR1 within minutes. Other intracellular cAMP-elevating agents, such as forskolin, which directly activates adenylyl cyclase, and rolipram, which inhibits cyclic nucleotide phosphodiesterase, also induced this process. This internalization was found to be reversible and influenced by intracellular levels of cAMP. Using selective activators and inhibitors of protein kinase A (PKA) and the exchange protein directly activated by cAMP (Epac), we found that NgR1 internalization is independent of PKA, but dependent on Epac. The decrease in cell surface expression of NgR1 desensitized NS-1 cells to Nogo-66-induced growth cone collapse. Therefore, it is likely that besides axonal growth inhibitors affecting neurons, neurons themselves also self-regulate their sensitivity to axonal growth inhibitors, as influenced by intracellular cAMP/Epac. This normal cellular regulatory mechanism may be pharmacologically exploited to overcome axonal growth inhibitors, and enhance functional recovery after stroke and neuronal injuries.

Applying advanced analytics to guide emergency department operational decisions: A proof-of-concept study examining the effects of boarding.

BACKGROUND: Emergency Department (ED) leaders are increasingly confronted with large amounts of data with the potential to inform and guide operational decisions. Routine use of advanced analytic methods may provide additional insights. OBJECTIVES: To examine the practical application of available advanced analytic methods to guide operational decision making around patient boarding. METHODS: Retrospective analysis of the effect of boarding on ED operational metrics from a single site between 1/2015 and 1/2017. Times series were visualized through decompositional techniques accounting for seasonal trends, to determine the effect of boarding on ED performance metrics and to determine the impact of boarding "shocks" to the system on operational metrics over several days. RESULTS: There were 226,461 visits with the mean (IQR) number of visits per day was 273 (258-291). Decomposition of the boarding count time series illustrated an upward trend in the last 2-3 quarters as well as clear seasonal components. All performance metrics were significantly impacted (p<0.05) by boarding count, except for overall Press Ganey scores (p<0.65). For every additional increase in boarder count, overall length-of-stay (LOS) increased by 1.55min (0.68, 1.50). Smaller effects were seen for waiting room LOS and treat and release LOS. The impulse responses indicate that the boarding shocks are characterized by changes in the performance metrics within the first day that fade out after 4-5days. CONCLUSION: In this study regarding the use of advanced analytics in daily ED operations, time series analysis provided multiple useful insights into boarding and its impact on performance metrics.

Resveratrol and its metabolites elicit neuroprotection via high-affinity binding to the laminin receptor at low nanomolar concentrations.

Resveratrol prevents various neurodegenerative diseases in animal models despite reaching only low nanomolar concentrations in the brain after oral administration. In this study, based on the quenching of intrinsic tryptophan fluorescence and molecular docking, we found that trans-resveratrol, its conjugates (glucuronide and sulfate), and dihydro-resveratrol (intestinal microbial metabolite) bind with high affinities (Kd, 0.2-2 nm) to the peptide G palindromic sequence (near glycosaminoglycan-binding motif) of the 67-kDa laminin receptor (67LR). Preconditioning with low concentrations (0.01-10 nm) of these polyphenols, especially resveratrol-glucuronide, protected neuronal cells from death induced by serum withdrawal via activation of cAMP-mediated signaling pathways. This protection was prevented by a 67LR-blocking antibody, suggesting a role for this cell-surface receptor in neuroprotection by resveratrol metabolites.

Pediatric trauma surgery in Iraq and Afghanistan: Mortality, indicators, and most common operating room interventions from 2007 to 2016.

BACKGROUND: The wars in Afghanistan and Iraq produced thousands of pediatric casualties, using substantial military medical resources. We sought to describe characteristics of pediatric casualties who underwent operative intervention in Iraq and Afghanistan. METHODS: This is a retrospective analysis of pediatric casualties treated by US Forces in the Department of Defense Trauma Registry with at least one operative intervention during their course. We report descriptive, inferential statistics, and multivariable modeling to assess associations for receiving an operative intervention and survival. We excluded casualties who died on arrival to the emergency department. RESULTS: During the study period, there were a total of 3,439 children in the Department of Defense Trauma Registry, of which 3,388 met inclusion criteria. Of those, 2,538 (75%) required at least 1 operative intervention totaling 13,824 (median, 4; interquartile range, 2-7; range, 1-57). Compared with nonoperative casualties, operative casualties were older and male and had a higher proportion of explosive and firearm injuries, higher median composite injury severity scores, higher overall blood product administration, and longer intensive care hospitalizations. The most common operative procedures were related to abdominal, musculoskeletal, and neurosurgical trauma; burn management; and head and neck. When adjusting for confounders, older age (unit odds ratio, 1.04; 1.02-1.06), receiving a massive transfusion during their initial 24 hours (6.86, 4.43-10.62), explosive injuries (1.43, 1.17-1.81), firearm injuries (1.94, 1.47-2.55), and age-adjusted tachycardia (1.45, 1.20-1.75) were all associated with going to the operating room. Survival to discharge on initial hospitalization was higher in the operative cohort (95% vs. 82%, p < 0.001). When adjusting for confounders, operative intervention was associated with improved mortality (odds ratio, 7.43; 5.15-10.72). CONCLUSION: Most children treated in US military/coalition treatment facilities required at least one operative intervention. Several preoperative descriptors were associated with casualties' likelihood of operative interventions. Operative management was associated with improved mortality. LEVEL OF EVIDENCE: Prognostic and Epidemiological; Level III.

The Dopamine D4 Receptor Regulates Gonadotropin-Releasing Hormone Neuron Excitability in Male Mice.

Gonadotropin-releasing hormone (GnRH)-secreting neurons control fertility. The release of GnRH peptide regulates the synthesis and release of both luteinizing hormone (LH) and Follicle stimulation hormone (FSH) from the anterior pituitary. While it is known that dopamine regulates GnRH neurons, the specific dopamine receptor subtype(s) involved remain unclear. Previous studies in adult rodents have reported juxtaposition of fibers containing tyrosine hydroxylase (TH), a marker of catecholaminergic cells, onto GnRH neurons and that exogenous dopamine inhibits GnRH neurons postsynaptically through dopamine D1-like and/or D2-like receptors. Our microarray data from GnRH neurons revealed a high level of Drd4 transcripts [i.e., dopamine D4 receptor (D4R)]. Single-cell RT-PCR and immunocytochemistry confirmed GnRH cells express the Drd4 transcript and protein, respectively. Calcium imaging identified changes in GnRH neuronal activity during application of subtype-specific dopamine receptor agonists and antagonists when GABAergic and glutamatergic transmission was blocked. Dopamine, dopamine with D1/5R-specific or D2/3R-specific antagonists or D4R-specific agonists decreased the frequency of calcium oscillations. In contrast, D1/5R-specific agonists increased the frequency of calcium oscillations. The D4R-mediated inhibition was dependent on Gαi/o protein coupling, while the D1/5R-mediated excitation required Gαs protein coupling. Together, these results indicate that D4R plays an important role in the dopaminergic inhibition of GnRH neurons.

cAMP-induced decrease in cell-surface laminin receptor and cellular prion protein attenuates amyloid-ß uptake and amyloid-ß-induced neuronal cell death.

Previous studies have shown that amyloid-ß oligomers (AßO) bind with high affinity to cellular prion protein (PrPC ). The AßO-PrPC complex binds to cell-surface co-receptors, including the laminin receptor (67LR). Our current studies revealed that in Neuroscreen-1 cells, 67LR is the major co-receptor involved in the cellular uptake of AßO and AßΟ-induced cell death. Both pharmacological (dibutyryl-cAMP, forskolin and rolipram) and physiological (pituitary adenylate cyclase-activating polypeptide) cAMP-elevating agents decreased cell-surface PrPC and 67LR, thereby attenuating the uptake of AßO and the resultant neuronal cell death. These cAMP protective effects are dependent on protein kinase A, but not dependent on the exchange protein directly activated by cAMP. Conceivably, cAMP protects neuronal cells from AßO-induced cytotoxicity by decreasing cell-surface-associated PrPC and 67LR.

Prehospital Battlefield Casualty Intervention Decision Cognitive Study.

INTRODUCTION: Airway compromise is the third most common cause of preventable battlefield death. Surgical cricothyroidotomy (SC) is recommended by Tactical Combat Casualty Care (TCCC) guidelines when basic airway maneuvers fail. This is a descriptive analysis of the decision-making process of prehospital emergency providers to perform certain airway interventions. METHODS: We conducted a scenario-based survey using two sequential video clips of an explosive injury event. The answers were used to conduct descriptive analyses and multivariable logistic regression models to estimate the association between the choice of intervention and training factors. RESULTS: There were 254 respondents in the survey, 176 (69%) of them were civilians and 78 (31%) were military personnel. Military providers were more likely to complete TCCC certification (odds ratio [OR]: 13.1; confidence interval [CI]: 6.4-26.6; P-value < 0.001). The SC was the most frequently chosen intervention after each clip (29.92% and 22.10%, respectively). TCCC-certified providers were more likely to choose SC after viewing the two clips (OR: 1.9; CI: 1.2-3.2; P-value: 0.009), even after controlling for relevant factors (OR: 2.3; CI: 1.1-4.8; P-value: 0.033). CONCLUSIONS: Military providers had a greater propensity to be certified in TCCC, which was found to increase their likelihood to choose the SC in early prehospital emergency airway management.

Genetics of vestibulopathy and migraine.

PURPOSE OF REVIEW: Our understanding of the genetics of vestibular loss lags far behind advances in the genetics of hearing loss, in large part because a basic awareness of hearing is a universal human experience, in those without congenital deafness, whereas public awareness of vestibular function is virtually nonexistent. This review highlights the challenges brought on by this disparity and recent advances in genetics, which provide hope for improved diagnosis and treatment of vestibular loss. RECENT FINDINGS: Linkage analysis has resulted in mapping of genetic loci for familial vestibulopathies with normal hearing and migraine. Targeted gene therapy provides hope for those with permanent vestibular loss. SUMMARY: Recent discoveries emphasize the need for better ascertainment of vestibular loss in general clinical practice.

Effect of disorder on slow light velocity in optical slow-wave structures.

Slow-wave optical structures such as coupled photonic crystal cavities, coupled microresonators, and similar coupled-resonator optical waveguides are being proposed for slowing light because of the nature of their dispersion relationship. Since the group velocity becomes small, slow light and enhanced light-matter interaction may be observed at the edges of the waveguiding band. We derive a model of the effects of disorder on slow light in such structures, obtaining a relationship between the root-mean-square variation in the coupling coefficients and how slow the light is at the band edge.