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1.  Neural circuitry coordinating male copulation 
eLife  null;5:e20713.
Copulation is the goal of the courtship process, crucial to reproductive success and evolutionary fitness. Identifying the circuitry underlying copulation is a necessary step towards understanding universal principles of circuit operation, and how circuit elements are recruited into the production of ordered action sequences. Here, we identify key sex-specific neurons that mediate copulation in Drosophila, and define a sexually dimorphic motor circuit in the male abdominal ganglion that mediates the action sequence of initiating and terminating copulation. This sexually dimorphic circuit composed of three neuronal classes – motor neurons, interneurons and mechanosensory neurons – controls the mechanics of copulation. By correlating the connectivity, function and activity of these neurons we have determined the logic for how this circuitry is coordinated to generate this male-specific behavior, and sets the stage for a circuit-level dissection of active sensing and modulation of copulatory behavior.
eLife digest
Idioms and love songs often euphemistically refer to “the birds and the bees”. Yet for neurobiologists interested in uncovering basic facts about sex and reproduction, the fruit fly has proven much more informative.
Male fruit flies court females with a series of “hard-wired” or genetically programmed behaviors. One gene called doublesex generates differences in the anatomy and behavior of males and females in many animal species. In male fruit flies, the doublesex gene is active in roughly 650 neurons, with specific groups of cells controlling distinct steps of the courtship ritual. However, it was not understood how the different steps involved in copulation were coordinated to ensure a successful mating.
Pavlou et al. have now identified a circuit of doublesex-expressing neurons that controls copulation itself. The circuit, which is in the fruit fly’s equivalent of the spinal cord, is made up of three types of neurons: motor neurons, inhibitory interneurons and mechanosensory neurons. The motor neurons coordinate the joining of the male’s genitals with those of the female. The inhibitory interneurons promote the release of the male’s genitals by opposing the motor neurons, while the mechanosensory neurons possibly coordinate the activity of the other neurons to generate the correct sequence of events needed for copulation. Pavlou et al. also showed that the mechanism that controls how the male attaches to and detaches from the female is independent of ejaculation, indicating that the mechanics of copulation are separate from those of reproduction.
A future challenge will be to understand how command centres in the brain combine these signals with sensory feedback to enable males to execute and modify their copulation-related behaviors. Identifying neural circuits that drive behaviors in fruit flies provide insights into the universal principles by which a nervous system can coordinate complex motor behaviors such as walking and flying.
PMCID: PMC5114013  PMID: 27855059
sexual behavior; sexual-dimorphism; copulation; doublesex; D. melanogaster
4.  Chest pain in a patient with a tall R wave in V1 
BMJ Case Reports  2014;2014:bcr2014205923.
An 83-year-old man 2 days postoperative from L3 to L5 laminectomy developed sudden onset of chest pain. Initial ECGs demonstrated a tall R wave in V1 and ST-segment depression in leads V2–V5. A posterior ECG was performed, but failed to demonstrate ST elevations. The patient was initially treated as an non-ST-segment elevation myocardial infarction with weight-based enoxaparin. On further review, the patient's ECG was identified as a STEMI equivalent, and he underwent cardiac catheterisation. He was noted to have a near complete occlusion of the posterior descending branch of the right coronary artery (RCA). Bare-metal stents were placed in the proximal and distal RCA, with restored flow distal to the lesions. The patient was transferred to the intensive care unit for observation, and was noted to develop atrial fibrillation. Rate control was achieved with diltiazem, and the patient was started on dabigatran. Medical therapy including aspirin and clopidogrel was initiated, and the patient was discharged home.
PMCID: PMC4154027  PMID: 25150241
5.  In Vivo Biotinylation of the Toxoplasma Parasitophorous Vacuole Reveals Novel Dense Granule Proteins Important for Parasite Growth and Pathogenesis 
mBio  2016;7(4):e00808-16.
Toxoplasma gondii is an obligate intracellular parasite that invades host cells and replicates within a unique parasitophorous vacuole. To maintain this intracellular niche, the parasite secretes an array of dense granule proteins (GRAs) into the nascent parasitophorous vacuole. These GRAs are believed to play key roles in vacuolar remodeling, nutrient uptake, and immune evasion while the parasite is replicating within the host cell. Despite the central role of GRAs in the Toxoplasma life cycle, only a subset of these proteins have been identified, and many of their roles have not been fully elucidated. In this report, we utilize the promiscuous biotin ligase BirA* to biotinylate GRA proteins secreted into the vacuole and then identify those proteins by affinity purification and mass spectrometry. Using GRA-BirA* fusion proteins as bait, we have identified a large number of known and candidate GRAs and verified localization of 13 novel GRA proteins by endogenous gene tagging. We proceeded to functionally characterize three related GRAs from this group (GRA38, GRA39, and GRA40) by gene knockout. While Δgra38 and Δgra40 parasites showed no altered phenotype, disruption of GRA39 results in slow-growing parasites that contain striking lipid deposits in the parasitophorous vacuole, suggesting a role in lipid regulation that is important for parasite growth. In addition, parasites lacking GRA39 showed dramatically reduced virulence and a lower tissue cyst burden in vivo. Together, the findings from this work reveal a partial vacuolar proteome of T. gondii and identify a novel GRA that plays a key role in parasite replication and pathogenesis.
Most intracellular pathogens reside inside a membrane-bound vacuole within their host cell that is extensively modified by the pathogen to optimize intracellular growth and avoid host defenses. In Toxoplasma, this vacuole is modified by a host of secretory GRA proteins, many of which remain unidentified. Here we demonstrate that in vivo biotinylation of proximal and interacting proteins using the promiscuous biotin ligase BirA* is a powerful approach to rapidly identify vacuolar GRA proteins. We further demonstrate that one factor identified by this approach, GRA39, plays an important role in the ability of the parasite to replicate within its host cell and cause disease.
PMCID: PMC4981711  PMID: 27486190
6.  Rapid, Multiplexed Characterization of Shiga Toxin-Producing Escherichia coli (STEC) Isolates Using Suspension Array Technology 
Molecular methods have emerged as the most reliable techniques to detect and characterize pathogenic Escherichia coli. These molecular techniques include conventional single analyte and multiplex PCR, PCR followed by microarray detection, pulsed-field gel electrophoresis (PFGE), and whole genome sequencing. The choice of methods used depends upon the specific needs of the particular study. One versatile method involves detecting serogroup-specific markers by hybridization or binding to encoded microbeads in a suspension array. This molecular serotyping method has been developed and adopted for investigating E. coli outbreaks. The major advantages of this technique are the ability to simultaneously serotype E. coli and detect the presence of virulence and pathogenicity markers. Here, we describe the development of a family of multiplex molecular serotyping methods for Shiga toxin-producing E. coli, compare their performance to traditional serotyping methods, and discuss the cost-benefit balance of these methods in the context of various food safety objectives.
PMCID: PMC4873620  PMID: 27242670
E. coli; Shiga toxin; immunoassay; PCR; microbead
7.  Analysis of the immune response of human dendritic cells to Mycobacterium tuberculosis by quantitative proteomics 
Proteome Science  2016;14:5.
The cellular immune response for Mycobacterium tuberculosis (M. tuberculosis) infection remained incompletely understood. To uncover membrane proteins involved in this infection mechanism, an integrated approach consisting of an organic solvent-assisted membrane protein digestion, stable-isotope dimethyl labeling and liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis was used to comparatively profile the membrane protein expression of human dendritic cells upon heat-killed M. tuberculosis (HKTB) treatment.
Organic solvent-assisted trypsin digestion coupled with stable-isotope labeling and LC-MS/MS analysis was applied to quantitatively analyze the membrane protein expression of THP-1 derived dendritic cells. We evaluated proteins that were upregulated in response to HKTB treatment, and applied STRING website database to analyze the correlations between these proteins. Of the investigated proteins, aminopeptidase N (CD13) was found to be largely expressed after HKTB treatment.
By using confocal microscopy and flow cytometry, we found that membranous CD13 expression was upregulated and was capable of binding to live mycobacteria. Treatment dendritic cell with anti-CD13 antibody during M. tuberculosis infection enhanced the ability of T cell activation.
Via proteomics data and STRING analysis, we demonstrated that the highly-expressed CD13 is also associated with proteins involved in the antigen presenting process, especially with CD1 proteins. Increasing expression of CD13 on dendritic cells while M. tuberculosis infection and enhancement of T cell activation after CD13 treated with anti-CD13 antibody indicates CD13 positively involved in the pathogenesis of M. tuberculosis.
Electronic supplementary material
The online version of this article (doi:10.1186/s12953-016-0095-8) contains supplementary material, which is available to authorized users.
PMCID: PMC4782377  PMID: 26957948
CD13; M. tuberculosis; Membrane proteomics; Antigen presentation
8.  Prevalence of Traumatic Brain Injury in Early Versus Late-Onset Alzheimer’s Disease 
Traumatic brain injury (TBI) is the most established environmental risk factor for Alzheimer’s disease (AD), but it is unclear if TBI is specifically associated with early-onset AD (EOAD).
To evaluate the relationship between TBI and EOAD (<65 years).
We identified 1,449 EOAD, 4,337 late-onset AD (LOAD), and corresponding EOAD-matched and LOAD-matched normal controls (NC) in the National Alzheimer’s Coordinating Center Uniform (NACC) database and compared the prevalence of any history of TBI as well as measures of cognition, function, behavior, and neuropathology. For validation, we determined TBI prevalence among 115 well-characterized clinic patients with EOAD.
Part A: The prevalence of any TBI in the NACC-database EOAD participants (13.3%) was comparable to that observed in the clinic EOAD patients (13.9%) but significantly higher than in the NACC-database LOAD participants (7.7%; p < 0.0001) and trended to higher compared to EOAD-matched NC (11.1%; logistic regression p = 0.053). Part B: When we compared EOAD patients with documented non-acute and non-residually impairing TBI to EOAD without a documented history of prior TBI, those with TBI had significantly more disinhibition. Part C: Autopsies did not reveal differences in AD neuropathology based on a history of TBI.
These findings suggest, but do not establish, that TBI is a specific risk factor for EOAD and may lead to disinhibition, a feature that often results from the frontal effects of head injury. This study recommends further research on the effects of TBI in EOAD in larger numbers of participants.
PMCID: PMC4753056  PMID: 26401777
Aging; Alzheimer’s disease; concussion; dementia; epidemiology; head injury; memory loss; neurodegeneration; risk factors; traumatic brain injury
9.  The Health Experts onLine at Portsmouth (HELP) system: One-year review of adult and Pediatric Asynchronous Telehealth Consultations 
SAGE Open Medicine  2016;4:2050312115626433.
The Health Experts onLine at Portsmouth teleconsultation system is designed to connect health providers in the Navy Medicine East Region to specialists at Naval Medical Center Portsmouth.
A review of the first year of the Health Experts onLine at Portsmouth system was performed. Data on each teleconsultation were extracted from the Health Experts onLine at Portsmouth system database and analyzed.
From June 2014 to May 2015 there have been 585 teleconsultations. Providers stationed on 36 ships/submarines and at 28 remote military treatment facilities have utilized the Health Experts onLine at Portsmouth system. Over 280 specialists in 34 different specialties were consulted. The median time to first response from a specialist was 6 h and 8 min, with 75% of all consults being addressed within 24 h. Eighteen medevacs were recommended. Thirty-nine potential medevacs were prevented, and 100 potential civilian network deferrals were prevented, resulting in an estimated savings of over US$580,000.
Based on the 1-year metrics, Health Experts onLine at Portsmouth has provided improved access and quality of care to service members and their families throughout the Navy Medicine East Region. It has helped avoid over US$580,000 in unnecessary cost burden. Further review at the 2-year time interval will demonstrate the continued growth and effectiveness of the Health Experts onLine at Portsmouth system.
PMCID: PMC4778083  PMID: 26985390
Telehealth; telemedicine; teleconsult; asynchronous; operational medicine
Neuro-Oncology  2014;16(Suppl 5):v27.
INTRODUCTION: Pseudoprogression (PsP) is a radiologic phenomenon in which treatment results in disruption of the blood brain barrier resulting in areas of contrast enhancement that is indistinguishable from true tumor progression. In glioblastoma, PsP occurs more frequently in tumors with MGMT promoter methylation and is associated with a better prognosis. We investigated whether the two recurrent genetic alterations, 1p/19q codeletions and IDH1 R132H mutation, which have prognostic significance in oligodendrogliomas (OG) and oligoastrocytomas (OA), are associated with PsP. METHODS: Institutional review board approval was granted to query a pathologic database for grade II and III OG/OA and to perform IDH1 R132H immunohistochemistry on archival material. 139 patient cases were identified, in which serial imaging was performed, records were available for review, and the tumors were treated with fractionated radiotherapy. IDH1 R132H immunohistochemistry was performed on archival material from these cases when available and their charts were reviewed for clinical data. RESULTS: PsP occurred less frequently in OG/OAs with 1p/19q codeletions (8% of tumors) than tumors without 1p/19q codeletions (27% of tumors) with an odds ratio of 0.168 and 95% CI of 0.050-0.562 when adjusting for covariables by multivariate modeling. Within the cohort without 1p/19q codeletions, the development of PsP in OG/OA was independently associated with worse survival when compared to tumors without early contrast enhancement following treatment (p = 0.0059). Additionally, within this cohort without 1p/19q codeletions, 50% of the tumors with PsP were negative for IDH1 R132H mutation by immunohistochemistry, compared to 26% negativity among tumors without early contrast enhancement. CONCLUSIONS: In this study, we are the first to show that PsP occurs more frequently in OG/OA with a worse prognosis and that PsP may have an inverse association with 1p/19q codeletions and IDH1 R132H mutation.
PMCID: PMC4217886
11.  Overdrive pacing in a patient with incessant torsades de pointes 
BMJ Case Reports  2013;2013:bcr2013200146.
A 75-year-old man presented to the emergency department (ED) for syncope and was found to have intermittent runs of torsades de pointes (TdP). The patient had a medical history significant for disseminated coccidiomycosis and was on prophylactic fluconazole. Forty-eight hours prior to presentation, the patient had intractable nausea and vomiting and was unable to take anything orally. He eventually presented to the ED with severe hypokalaemia and hypomagnesaemia with repeat symptomatic runs of TdP, which required overdrive transvenous pacing. During the patient’'s admission, his electrolytes were aggressively replete. Fluconazole was discontinued, and prior to discharge, the patient recovered fully with ECGs showing a normalisation of the QT interval.
PMCID: PMC3822076  PMID: 24121811
12.  Engineering the gut microbiota to treat hyperammonemia 
The Journal of Clinical Investigation  2015;125(7):2841-2850.
Increasing evidence indicates that the gut microbiota can be altered to ameliorate or prevent disease states, and engineering the gut microbiota to therapeutically modulate host metabolism is an emerging goal of microbiome research. In the intestine, bacterial urease converts host-derived urea to ammonia and carbon dioxide, contributing to hyperammonemia-associated neurotoxicity and encephalopathy in patients with liver disease. Here, we engineered murine gut microbiota to reduce urease activity. Animals were depleted of their preexisting gut microbiota and then inoculated with altered Schaedler flora (ASF), a defined consortium of 8 bacteria with minimal urease gene content. This protocol resulted in establishment of a persistent new community that promoted a long-term reduction in fecal urease activity and ammonia production. Moreover, in a murine model of hepatic injury, ASF transplantation was associated with decreased morbidity and mortality. These results provide proof of concept that inoculation of a prepared host with a defined gut microbiota can lead to durable metabolic changes with therapeutic utility.
PMCID: PMC4563680  PMID: 26098218
13.  Influence of Obesity on Efficacy and Toxicity of Induction Chemotherapy in Patients with Newly Diagnosed Acute Myeloid Leukemia 
Leukemia & lymphoma  2012;54(3):541-546.
Increased body mass index (BMI) is associated with increased risk of treatment-related complications and inferior overall survival in children and adolescents with AML. The growing proportion of the general population who are obese raises the dilemma of whether the pharmacokinetic differences in obese patients necessitate chemotherapy dosage adjustments. This also poses the question of whether obese patients experience differing outcomes or toxicities with chemotherapy.
We are retrospectively evaluating the association between percentage of ideal body weight (IBW) and complete remission (CR) among newly diagnosed, previously untreated AML patients. We also describe secondary objectives including associations between IBW and overall survival (OS), platelet and neutrophil recovery, and incidence of grade 3-4 hematologic and nonhematologic toxic effects. Additionally, we characterize the dosing strategies used for induction chemotherapy in obese patients with AML at a single institution.
This is a retrospective study of obesity and its impact on outcome in 63 newly diagnosed, previously untreated adults with AML receiving standard induction chemotherapy with 7 + 3 from 2006 to 2010.
The median percentage of ideal body weight was 121% (range 86-246%). Thirty-five percent of patients were obese (≥ 130% IBW). Controlling for history of prior malignancies, FLT3-ITD status, and NPM1, obesity was not associated with CR (odds ratio [OR] = 0.97, p=0.88), OS (hazard ratio=0.48, p=0.52), platelet recovery by 30 days (OR=1.14, p=0.52), or neutrophil recovery by 30 days (OR=1.12, p=0.60). Among obese patients, CR rates were not significantly different comparing patients not dose adjusted to patients with obesity-related adjustments (CR=86% vs. 67%, p=0.55)
In this study population, obesity was not an independent prognostic factor of outcome or toxicity. Empiric dose reductions based on obesity did not result is significantly different CR rates.
PMCID: PMC4451200  PMID: 22852586
acute myeloid leukemia; obesity; outcome
14.  Codeletions at 1p and 19q predict a lower risk of pseudoprogression in oligodendrogliomas and mixed oligoastrocytomas 
Neuro-Oncology  2013;16(1):123-130.
Pseudoprogression (PsP) occurs at a higher rate in glioblastoma multiforme with a methylated MGMT promoter—a subset with increased sensitivity to chemoradiotherapy and better overall prognosis. In oligodendroglioma (OG) and oligoastrocytoma (OA), presence of 1p/19q codeletions is highly predictive of response to treatment and is often associated with the methylated MGMT promoter; hence, this study queries whether the presence of 1p/19q codeletions in OG/OA correlates with a higher rate of PsP following therapy.
A retrospective analysis was performed on all OG/OA in a database of patients with brain tumors who underwent resection of their tumor since 1998. Eighty-eight cases (37 with and 51 without 1p/19q codeletions) met inclusion criteria, and their patient data were analyzed to determine whether the presence of 1p/19q codeletions was associated with PsP and survival.
OG/OA (World Health Organization grades II and III) with 1p/19q codeletions had a significantly improved survival (P = .041). Multivariate analysis found that PsP occurred less frequently in OG/OA with 1p/19q codeletions compared with tumors without codeletions (odds ratio, 0.047; 95% confidence interval, 0.005–0.426; P = .0066). The rate of PsP was 19% for the entire cohort, 31% for tumors without codeletions, and 3% for tumors with codeletions. When early posttreatment contrast enhancement developed in tumors with 1p/19q codeletions, it occurred exclusively in tumors that were histologically OA and not OG.
Codeletions of 1p/19q are a marker of good prognosis but are unexpectedly associated with a lower likelihood of PsP. PsP does not correlate with sensitivity to treatment and improved survival in OG/OA.
PMCID: PMC3870829  PMID: 24285548
oligodendroglioma; oligoastrocytoma; pseudoprogression; 1p/19q codeletions; p53.
15.  Multivessel spontaneous coronary artery dissection treated with staged percutanous coronary intervention in a non-postpartum female 
BMJ Case Reports  2012;2012:bcr2012007274.
We present a case of a 43-year-old woman who presented with a non-ST elevation myocardial infarction. During her first cardiac catheterisation, she was diagnosed with a chronic total occlusion of the right coronary artery and a flow limiting dissection of her middle left anterior descending artery. The dissection of the left anterior descending artery was stented with two overlapping everolimus-eluting stents. There were no complications from this percutaneous coronary intervention. On the following day, the patient continued to have persistent chest pain and returned to the catheterisation laboratory. It was then found that the patient had a total occlusion of the right coronary artery secondary to dissection. This was also stented with three everolimus-eluting stents with excellent clinical and angiographic results. It is important to consider spontaneous multivessel coronary dissections which can be treated successfully with percutaneous coronary intervention.
PMCID: PMC4544694  PMID: 23220437
16.  Sparse, Decorrelated Odor Coding in the Mushroom Body Enhances Learned Odor Discrimination 
Nature neuroscience  2014;17(4):559-568.
Sparse coding may be a general strategy of neural systems to augment memory capacity. In Drosophila, sparse odor coding by the Kenyon cells of the mushroom body is thought to generate a large number of precisely addressable locations for the storage of odor-specific memories. However, it remains untested how sparse coding relates to behavioral performance. Here we demonstrate that sparseness is controlled by a negative feedback circuit between Kenyon cells and the GABAergic anterior paired lateral (APL) neuron. Systematic activation and blockade of each leg of this feedback circuit show that Kenyon cells activate APL and APL inhibits Kenyon cells. Disrupting the Kenyon cell-APL feedback loop decreases the sparseness of Kenyon cell odor responses, increases inter-odor correlations, and prevents flies from learning to discriminate similar, but not dissimilar, odors. These results suggest that feedback inhibition suppresses Kenyon cell activity to maintain sparse, decorrelated odor coding and thus the odor-specificity of memories.
PMCID: PMC4000970  PMID: 24561998
17.  Prevalence of Hemolysin Genes and Comparison of ehxA Subtype Patterns in Shiga Toxin-Producing Escherichia coli (STEC) and Non-STEC Strains from Clinical, Food, and Animal Sources 
Applied and Environmental Microbiology  2013;79(20):6301-6311.
Shiga toxin-producing Escherichia coli (STEC) belonging to certain serogroups (e.g., O157 and O26) can cause serious conditions like hemolytic-uremic syndrome (HUS), but other strains might be equally pathogenic. While virulence factors, like stx and eae, have been well studied, little is known about the prevalence of the E. coli hemolysin genes (hlyA, ehxA, e-hlyA, and sheA) in association with these factors. Hemolysins are potential virulence factors, and ehxA and hlyA have been associated with human illness, but the significance of sheA is unknown. Hence, 435 E. coli strains belonging to 62 different O serogroups were characterized to investigate gene presence and phenotypic expression of hemolysis. We further investigated ehxA subtype patterns in E. coli isolates from clinical, animal, and food sources. While sheA and ehxA were widely distributed, e-hlyA and hlyA were rarely found. Most strains (86.7%) were hemolytic, and significantly more hemolytic (95%) than nonhemolytic strains (49%) carried stx and/or eae (P < 0.0001). ehxA subtyping, as performed by using PCR in combination with restriction fragment length polymorphism analysis, resulted in six closely related subtypes (>94.2%), with subtypes A/D being eae-negative STECs and subtypes B, C, E, and F eae positive. Unexpectedly, ehxA subtype patterns differed significantly between isolates collected from different sources (P < 0.0001), suggesting that simple linear models of exposure and transmission need modification; animal isolates carried mostly subtypes A/C (39.3%/42.9%), food isolates carried mainly subtype A (81.9%), and clinical isolates carried mainly subtype C (66.4%). Certain O serogroups correlated with particular ehxA subtypes: subtype A with O104, O113, and O8; B exclusively with O157; C with O26, O111, and O121.
PMCID: PMC3811216  PMID: 23934487
18.  A functional equivalent of endoplasmic reticulum and Golgi in axons for secretion of locally synthesized proteins 
Subcellular localization of protein synthesis provides a means to regulate the protein composition in far reaches of a cell. This localized protein synthesis gives neuronal processes autonomy to rapidly respond to extracellular stimuli. Locally synthesized axonal proteins enable neurons to respond to guidance cues and can help to initiate regeneration after injury. Most studies of axonal mRNA translation have concentrated on cytoplasmic proteins. While ultrastructural studies suggest that axons do not have rough endoplasmic reticulum or Golgi apparatus, mRNAs for transmembrane and secreted proteins localize to axons. Here, we show that growing axons with protein synthetic activity contain ER and Golgi components needed for classical protein synthesis and secretion. Isolated axons have the capacity to traffic locally synthesized proteins into secretory pathways and inhibition of Golgi function attenuates translation-dependent axonal growth responses. Finally, the capacity for secreting locally synthesized proteins in axons appears to be increased by injury.
PMCID: PMC3794446  PMID: 19022387
Axonal protein synthesis; Secretory pathway; Rough endoplasmic reticulum; Golgi apparatus; mRNA localization; Axon guidance
19.  Different Kenyon Cell Populations Drive Learned Approach and Avoidance in Drosophila 
Neuron  2013;79(5):945-956.
In Drosophila, anatomically discrete dopamine neurons that innervate distinct zones of the mushroom body (MB) assign opposing valence to odors during olfactory learning. Subsets of MB neurons have temporally unique roles in memory processing, but valence-related organization has not been demonstrated. We functionally subdivided the αβ neurons, revealing a value-specific role for the ∼160 αβ core (αβc) neurons. Blocking neurotransmission from αβ surface (αβs) neurons revealed a requirement during retrieval of aversive and appetitive memory, whereas blocking αβc only impaired appetitive memory. The αβc were also required to express memory in a differential aversive paradigm demonstrating a role in relative valuation and approach behavior. Strikingly, both reinforcing dopamine neurons and efferent pathways differentially innervate αβc and αβs in the MB lobes. We propose that conditioned approach requires pooling synaptic outputs from across the αβ ensemble but only from the αβs for conditioned aversion.
•Differential representation of memory valence in Drosophila mushroom body neurons•αβ core neurons are specifically required for conditioned approach behavior•Relative aversive learning requires rewarding dopaminergic reinforcement•Distinct circuits drive learned aversion and approach
Perisse et al. demonstrate that discrete mushroom body neuron populations drive learned approach and avoidance behaviors in the fruit fly. Aversive and appetitive memories for the same odor are therefore represented in different neural ensembles.
PMCID: PMC3765960  PMID: 24012007
20.  Odor Discrimination in Drosophila: From Neural Population Codes to Behavior 
Neuron  2013;79(5):932-944.
Taking advantage of the well-characterized olfactory system of Drosophila, we derive a simple quantitative relationship between patterns of odorant receptor activation, the resulting internal representations of odors, and odor discrimination. Second-order excitatory and inhibitory projection neurons (ePNs and iPNs) convey olfactory information to the lateral horn, a brain region implicated in innate odor-driven behaviors. We show that the distance between ePN activity patterns is the main determinant of a fly’s spontaneous discrimination behavior. Manipulations that silence subsets of ePNs have graded behavioral consequences, and effect sizes are predicted by changes in ePN distances. ePN distances predict only innate, not learned, behavior because the latter engages the mushroom body, which enables differentiated responses to even very similar odors. Inhibition from iPNs, which scales with olfactory stimulus strength, enhances innate discrimination of closely related odors, by imposing a high-pass filter on transmitter release from ePN terminals that increases the distance between odor representations.
•Distances between excitatory PN (ePN) signals predict innate odor discrimination•Silencing ePN subsets has distance-specific behavioral consequences•Inhibitory PNs (iPNs) increase the contrast between similar odor representations•iPNs act by high-pass filtering transmitter release from ePNs
Studying olfaction in Drosophila, Parnas et al. relate neuronal population activity to odor discrimination. The distance between projection neuron signals determines spontaneous discrimination, whereas inhibitory projection neurons improve performance by stretching this distance.
PMCID: PMC3765961  PMID: 24012006
21.  Function and regulation of local axonal translation 
An increasing body of evidence indicates that local axonal translation is required for growing axons to respond appropriately to guidance cues and other stimuli. Recent studies suggest that asymmetrical synthesis of cytoskeletal proteins mediates growth cone turning and that local translation and retrograde transport of transcription factors mediate neuronal survival. Axonal translation is regulated partly by selective axonal localization of mRNAs and by translation initiation factors and RNA-binding proteins. We discuss possible rationales for local axonal translation, including distinct properties of nascent proteins, precise localization, and axonal autonomy.
PMCID: PMC3687333  PMID: 18508259
22.  Outsourcing CREB translation to axons to survive 
Nature cell biology  2008;10(2):115-118.
Nerve growth factor induces sensory neuron survival via retrograde signalling from the axon to the cell body. Local translation of the transcription factor CREB in the axon, followed by its transport to the nucleus, is involved in this process.
PMCID: PMC3682635  PMID: 18246035
23.  Radiologic Evaluation of Right Ventricular Outflow Tract Myxomas 
Texas Heart Institute Journal  2013;40(1):68-70.
A 22-year-old man was referred for palpitations. On transthoracic echocardiography, he was found to have a right ventricular outflow tract mass. Further cardiac imaging was conducted by means of transesophageal echocardiography, computed tomography, and cardiac magnetic resonance. Complete surgical resection of the tumor was achieved, and pathologic examination revealed the lesion to be a myxoma.
Cardiac tumors located in the right ventricular outflow tract are rare and can present unusual diagnostic and therapeutic challenges. Cardiac computed tomography and magnetic resonance are becoming more widely available and can be useful adjuncts in the management of such tumors.
PMCID: PMC3568267  PMID: 23466872
Heart neoplasms; magnetic resonance imaging; myxoma/diagnosis/surgery; tomography, X-ray computed; ventricular outflow tract, right
24.  Mast cells and neutrophils release IL-17 through extracellular trap formation in psoriasis1 
IL-17 and IL-23 are absolutely central to psoriasis pathogenesis as drugs targeting either cytokine are highly effective treatments for this disease. The efficacy of these drugs has been attributed to blocking the function of IL-17-producing T cells and their IL-23-induced expansion. However, we demonstrate that mast cells and neutrophils, not T cells, are the predominant cell types that contain IL-17 in human skin. IL-17+ mast cells and neutrophils are found at higher densities than IL-17+ T cells in psoriasis lesions and frequently release IL-17 in the process of forming specialized structures called extracellular traps (MCETs and NETs, respectively). Furthermore, we find that IL-23 and IL-1β can induce MCET formation and degranulation of human mast cells. Release of IL-17 from innate immune cells may be central to the pathogenesis of psoriasis, representing a fundamental mechanism by which the IL-23-IL-17 axis mediates host defense and autoimmunity.
PMCID: PMC3119764  PMID: 21606249
25.  Netting neutrophils induce endothelial damage, infiltrate tissues and expose immunostimulatory molecules in systemic lupus erythematosus* 
An abnormal neutrophil subset has been identified in the PBMC fractions from lupus patients. We have proposed that these “low density granulocytes” (LDGs) play an important role in lupus pathogenesis by damaging endothelial cells and synthesizing increased levels of proinflammatory cytokines and type I interferons. To directly establish LDGs as a distinct neutrophil subset, their gene array profiles were compared to those of autologous normal density neutrophils and control neutrophils. LDGs significantly overexpress mRNA of various immunostimulatory bactericidal proteins and alarmins, relative to lupus and control neutrophils. In contrast, gene profiles of lupus normal density neutrophils do not differ from those of controls. LDGs have heightened capacity to synthesize extracellular traps (NETs) which display increased externalization of bactericidal, immunostimulatory proteins and autoantigens, including LL-37, IL-17, and double-stranded DNA (dsDNA). Through NETosis, LDGs have increased capacity to kill endothelial cells and to stimulate IFN-α synthesis by pDCs. Affected skin and kidneys from lupus patients are infiltrated by netting neutrophils, which expose LL-37 and ds-DNA. Tissue NETosis is associated with increased anti-dsDNA in sera. These results expand the potential pathogenic roles of aberrant lupus neutrophils and suggest that dysregulation of NET formation and its subsequent responses may play a prominent deleterious role.
PMCID: PMC3119769  PMID: 21613614

Results 1-25 (35)