Ankyrin B promotes developmental spine regulation in the mouse prefrontal cortex.

Postnatal regulation of dendritic spine formation and refinement in cortical pyramidal neurons is critical for excitatory/inhibitory balance in neocortical networks. Recent studies have identified a selective spine pruning mechanism in the mouse prefrontal cortex mediated by class 3 Semaphorins and the L1 cell adhesion molecules, neuron-glia related cell adhesion molecule, Close Homolog of L1, and L1. L1 cell adhesion molecules bind Ankyrin B, an actin-spectrin adaptor encoded by Ankyrin2, a high-confidence gene for autism spectrum disorder. In a new inducible mouse model (Nex1Cre-ERT2: Ank2flox: RCE), Ankyrin2 deletion in early postnatal pyramidal neurons increased spine density on apical dendrites in prefrontal cortex layer 2/3 of homozygous and heterozygous Ankyrin2-deficient mice. In contrast, Ankyrin2 deletion in adulthood had no effect on spine density. Sema3F-induced spine pruning was impaired in cortical neuron cultures from Ankyrin B-null mice and was rescued by re-expression of the 220 kDa Ankyrin B isoform but not 440 kDa Ankyrin B. Ankyrin B bound to neuron-glia related CAM at a cytoplasmic domain motif (FIGQY1231), and mutation to FIGQH inhibited binding, impairing Sema3F-induced spine pruning in neuronal cultures. Identification of a novel function for Ankyrin B in dendritic spine regulation provides insight into cortical circuit development, as well as potential molecular deficiencies in autism spectrum disorder.

Ankyrin B Promotes Developmental Spine Regulation in the Mouse Prefrontal Cortex.

Postnatal regulation of dendritic spine formation and refinement in cortical pyramidal neurons is critical for excitatory/inhibitory balance in neocortical networks. Recent studies have identified a selective spine pruning mechanism in the mouse prefrontal cortex (PFC) mediated by class 3 Semaphorins and the L1-CAM cell adhesion molecules Neuron-glia related CAM (NrCAM), Close Homolog of L1 (CHL1), and L1. L1-CAMs bind Ankyrin B (AnkB), an actin-spectrin adaptor encoded by Ankyrin2 ( ANK2 ), a high confidence gene for autism spectrum disorder (ASD). In a new inducible mouse model (Nex1Cre-ERT2: Ank2 flox : RCE), Ank2 deletion in early postnatal pyramidal neurons increased spine density on apical dendrites in PFC layer 2/3 of homozygous and heterozygous Ank2 -deficient mice. In contrast, Ank2 deletion in adulthood had no effect on spine density. Sema3F-induced spine pruning was impaired in cortical neuron cultures from AnkB-null mice and was rescued by re-expression of the 220 kDa AnkB isoform but not 440 kDa AnkB. AnkB bound to NrCAM at a cytoplasmic domain motif (FIGQY 1231 ), and mutation to FIGQH inhibited binding, impairing Sema3F-induced spine pruning in neuronal cultures. Identification of a novel function for AnkB in dendritic spine regulation provides insight into cortical circuit development, as well as potential molecular deficiencies in ASD.

Injectable and topical local anesthetics for acute dental pain: 2 systematic reviews.

BACKGROUND: Local anesthesia is essential for pain control in dentistry. The authors assessed the comparative effect of local anesthetics on acute dental pain after tooth extraction and in patients with symptomatic irreversible pulpitis. TYPES OF STUDIES REVIEWED: The authors searched MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and the US Clinical Trials registry through November 21, 2020. The authors included randomized controlled trials (RCTs) comparing long- vs short-acting injectable anesthetics to reduce pain after tooth extraction (systematic review 1) and evaluated the effect of topical anesthetics in patients with symptomatic pulpitis (systematic review 2). Pairs of reviewers screened articles, abstracted data, and assessed risk of bias using a modified version of the Cochrane risk of bias 2.0 tool. The authors assessed the certainty of the evidence using the Grading of Recommendations Assessment, Development and Evaluation approach. RESULTS: Fourteen RCTs comparing long- vs short-acting local anesthetics suggest that bupivacaine may decrease the use of rescue analgesia and may not result in additional adverse effects (low certainty evidence). Bupivacaine probably reduces the amount of analgesic consumption compared with lidocaine with epinephrine (mean difference, -1.91 doses; 95% CI, -3.35 to -0.46; moderate certainty) and mepivacaine (mean difference, -1.58 doses; 95% CI, -2.21 to -0.95; moderate certainty). Five RCTs suggest that both benzocaine 10% and 20% may increase the number of people experiencing pain reduction compared with placebo when managing acute irreversible pulpitis (low certainty). PRACTICAL IMPLICATIONS: Bupivacaine may be superior to lidocaine with epinephrine and mepivacaine with regard to time to and amount of analgesic consumption. Benzocaine may be superior to placebo in reducing pain for 20 through 30 minutes after application.

Doublecortin-Like Kinase 1 Facilitates Dendritic Spine Growth of Pyramidal Neurons in Mouse Prefrontal Cortex.

The L1 cell adhesion molecule NrCAM (Neuron-glia related cell adhesion molecule) functions as a co-receptor for secreted class 3 Semaphorins to prune subpopulations of dendritic spines on apical dendrites of pyramidal neurons in the developing mouse neocortex. The developing spine cytoskeleton is enriched in actin filaments, but a small number of microtubules have been shown to enter the spine apparently trafficking vesicles to the membrane. Doublecortin-like kinase 1 (DCLK1) is a member of the Doublecortin (DCX) family of microtubule-binding proteins with serine/threonine kinase activity. To determine if DCLK1 plays a role in spine remodeling, we generated a tamoxifen-inducible mouse line (Nex1Cre-ERT2: DCLK1flox/flox: RCE) to delete microtubule binding isoforms of DCLK1 from pyramidal neurons during postnatal stages of spine development. Homozygous DCLK1 conditional mutant mice exhibited decreased spine density on apical dendrites of pyramidal neurons in the prefrontal cortex (layer 2/3). Mature mushroom spines were selectively decreased upon DCLK1 deletion but dendritic arborization was unaltered. Mutagenesis and binding studies revealed that DCLK1 bound NrCAM at the conserved FIGQY1231 motif in the NrCAM cytoplasmic domain, a known interaction site for the actin-spectrin adaptor Ankyrin. These findings demonstrate in a novel mouse model that DCLK1 facilitates spine growth and maturation on cortical pyramidal neurons in the mouse prefrontal cortex.

Neurocan Inhibits Semaphorin 3F Induced Dendritic Spine Remodeling Through NrCAM in Cortical Neurons.

Neurocan is a chondroitin sulfate proteoglycan present in perineuronal nets, which are associated with closure of the critical period of synaptic plasticity. During postnatal development of the neocortex dendritic spines on pyramidal neurons are initially overproduced; later they are pruned to achieve an appropriate balance of excitatory to inhibitory synapses. Little is understood about how spine pruning is terminated upon maturation. NrCAM (Neuron-glial related cell adhesion molecule) was found to mediate spine pruning as a subunit of the receptor complex for the repellent ligand Semaphorin 3F (Sema3F). As shown here in the postnatal mouse frontal and visual neocortex, Neurocan was localized at both light and electron microscopic level to the cell surface of cortical pyramidal neurons and was adjacent to neuronal processes and dendritic spines. Sema3F-induced spine elimination was inhibited by Neurocan in cortical neuron cultures. Neurocan also blocked Sema3F-induced morphological retraction in COS-7 cells, which was mediated through NrCAM and other subunits of the Sema3F holoreceptor, Neuropilin-2, and PlexinA3. Cell binding and ELISA assays demonstrated an association of Neurocan with NrCAM. Glycosaminoglycan chain interactions of Neurocan were required for inhibition of Sema3F-induced spine elimination, but the C-terminal sushi domain was dispensable. These results describe a novel mechanism wherein Neurocan inhibits NrCAM/Sema3F-induced spine elimination.

Response to Comments on "Designing river flows to improve food security futures in the Lower Mekong Basin".

Sabo et al presented an empirically derived algorithm defining the socioecological response of the Tonle Sap Dai fishery in the Cambodian Mekong to basin-scale variation in hydrologic flow regime. Williams suggests that the analysis leading to the algorithm is flawed because of the large distance between the gauge used to measure water levels (hydrology) and the site of harvest for the fishery. Halls and Moyle argue that Sabo et al's findings are well known and contend that the algorithm is not a comprehensive assessment of sustainability. We argue that Williams' critique stems from a misunderstanding about our analysis; further clarification of the analysis is provided. We regret not citing more of the work indicated by Halls and Moyle, yet we note that our empirical analysis provides additional new insights into Mekong flow-fishery relationships.

Perineuronal Net Protein Neurocan Inhibits NCAM/EphA3 Repellent Signaling in GABAergic Interneurons.

Perineuronal nets (PNNs) are implicated in closure of critical periods of synaptic plasticity in the brain, but the molecular mechanisms by which PNNs regulate synapse development are obscure. A receptor complex of NCAM and EphA3 mediates postnatal remodeling of inhibitory perisomatic synapses of GABAergic interneurons onto pyramidal cells in the mouse frontal cortex necessary for excitatory/inhibitory balance. Here it is shown that enzymatic removal of PNN glycosaminoglycan chains decreased the density of GABAergic perisomatic synapses in mouse organotypic cortical slice cultures. Neurocan, a key component of PNNs, was expressed in postnatal frontal cortex in apposition to perisomatic synapses of parvalbumin-positive interneurons. Polysialylated NCAM (PSA-NCAM), which is required for ephrin-dependent synapse remodeling, bound less efficiently to neurocan than mature, non-PSA-NCAM. Neurocan bound the non-polysialylated form of NCAM at the EphA3 binding site within the immunoglobulin-2 domain. Neurocan inhibited NCAM/EphA3 association, membrane clustering of NCAM/EphA3 in cortical interneuron axons, EphA3 kinase activation, and ephrin-A5-induced growth cone collapse. These studies delineate a novel mechanism wherein neurocan inhibits NCAM/EphA3 signaling and axonal repulsion, which may terminate postnatal remodeling of interneuron axons to stabilize perisomatic synapses in vivo.

OSIRIS-REx Contamination Control Strategy and Implementation.

OSIRIS-REx will return pristine samples of carbonaceous asteroid Bennu. This article describes how pristine was defined based on expectations of Bennu and on a realistic understanding of what is achievable with a constrained schedule and budget, and how that definition flowed to requirements and implementation. To return a pristine sample, the OSIRIS-REx spacecraft sampling hardware was maintained at level 100 A/2 and <180 ng/cm2 of amino acids and hydrazine on the sampler head through precision cleaning, control of materials, and vigilance. Contamination is further characterized via witness material exposed to the spacecraft assembly and testing environment as well as in space. This characterization provided knowledge of the expected background and will be used in conjunction with archived spacecraft components for comparison with the samples when they are delivered to Earth for analysis. Most of all, the cleanliness of the OSIRIS-REx spacecraft was achieved through communication among scientists, engineers, managers, and technicians.

Designing river flows to improve food security futures in the Lower Mekong Basin.

Rivers provide unrivaled opportunity for clean energy via hydropower, but little is known about the potential impact of dam-building on the food security these rivers provide. In tropical rivers, rainfall drives a periodic flood pulse fueling fish production and delivering nutrition to more than 150 million people worldwide. Hydropower will modulate this flood pulse, thereby threatening food security. We identified variance components of the Mekong River flood pulse that predict yield in one of the largest freshwater fisheries in the world. We used these variance components to design an algorithm for a managed hydrograph to explore future yields. This algorithm mimics attributes of discharge variance that drive fishery yield: prolonged low flows followed by a short flood pulse. Designed flows increased yield by a factor of 3.7 relative to historical hydrology. Managing desired components of discharge variance will lead to greater efficiency in the Lower Mekong Basin food system.

Metabolic Reprogramming of Host Cells by Virulent Francisella tularensis for Optimal Replication and Modulation of Inflammation.

A shift in macrophage metabolism from oxidative phosphorylation to aerobic glycolysis is a requirement for activation to effectively combat invading pathogens. Francisella tularensis is a facultative intracellular bacterium that causes an acute, fatal disease called tularemia. Its primary mechanism of virulence is its ability to evade and suppress inflammatory responses while replicating in the cytosol of macrophages. The means by which F. tularensis modulates macrophage activation are not fully elucidated. In this study, we demonstrate that virulent F. tularensis impairs production of inflammatory cytokines in primary macrophages by preventing their shift to aerobic glycolysis, as evidenced by the downregulation of hypoxia inducible factor 1α and failure to upregulate pfkfb3 We also show that Francisella capsule is required for this process. In addition to modulating inflammatory responses, inhibition of glycolysis in host cells is also required for early replication of virulent Francisella Taken together, our data demonstrate that metabolic reprogramming of host cells by F. tularensis is a key component of both inhibition of host defense mechanisms and replication of the bacterium.

Evaluation in pre-diagnosis samples discounts ICAM-1 and TIMP-1 as biomarkers for earlier diagnosis of pancreatic cancer.

Circulating intercellular adhesion molecule-1 (ICAM-1) and tissue inhibitor of metalloproteinases-1 (TIMP-1) have been widely proposed as potential diagnostic biomarkers for pancreatic ductal adenocarcinoma (PDAC). We report on serum protein levels prior to clinical presentation of pancreatic cancer. Serum ICAM-1 and TIMP-1 were measured by ELISA in two case­control sets: 1) samples from patients diagnosed with pancreatic cancer (n = 40), chronic pancreatitis (n = 20), benign jaundice due to gall stones (n = 20) and healthy subjects (n = 20); 2) a preclinical set from the UK Collaborative Trial of Ovarian Cancer Screening biobank of samples collected from 27 post-menopausal women 0­12 months prior to diagnosis of pancreatic cancer and controls matched for date of donation and centre. Levels of ICAM-1 and TIMP-1 were significantly elevated in set 1 in PDAC patients with jaundice compared to PDAC patients without jaundice and both proteins were elevated in patients with jaundice due to gall stones. Neither protein was elevated in samples taken 0­12 months prior to PDAC diagnosis compared to non-cancer control samples. In conclusion, evaluation in pre-diagnosis samples discounts ICAM-1 and TIMP-1 as biomarkers for earlier diagnosis of pancreatic cancer. Failure to account for obstructive jaundice may have contributed to the previous promise of these candidate biomarkers. BIOLOGICAL SIGNIFICANCE: Pancreatic cancer is usually diagnosed when at an advanced stage which greatly limits therapeutic options. Biomarkers that could facilitate earlier diagnosis are urgently sought.

iTRAQ reveals candidate pancreatic cancer serum biomarkers: influence of obstructive jaundice on their performance.

BACKGROUND: The aims of our study were to identify serum biomarkers that distinguish pancreatic cancer (pancreatic ductal adenocarcinoma, PDAC) patients from benign pancreatic disease patients and healthy subjects, and to assess the effects of jaundice on biomarker performance. METHODS: Isobaric tags for relative and absolute quantification were used to compare pooled serum and pancreatic juice samples from a test set of 59 and 25 subjects, respectively. Validation was undertaken in 113 independent subjects. RESULTS: Candidate proteins Complement C5, inter-α-trypsin inhibitor heavy chain H3, α1-ß glycoprotein and polymeric immunoglobulin receptor were elevated in cancer, as were the reference markers CA19-9 and Reg3A. Biliary obstruction had a significant effect on the performance of the markers, in particular within the PDAC group where the presence of jaundice was associated with a significant increase in the levels of all six proteins (P<0.01). Consequently, in the absence of jaundice, proteins showed reduced sensitivity for PDAC patients over benign subjects and healthy controls (HCs). Similarly, in the presence of jaundice, markers showed reduced specificity for PDAC patients over benign subjects with jaundice. Combining markers enabled improved sensitivity for non-jaundiced PDAC patients over HCs and improved specificity for jaundiced PDAC patients over jaundiced benign disease subjects. CONCLUSIONS: The presence-absence of jaundice in the clinical scenario severely impacts the performance of biomarkers for PDAC diagnosis and has implications for their clinical translation.

Mixed lymphovenous oedema with leg ulceration: a case study.

Necrotizing skin infections, although rare, have proven difficult to manage and treat in a wide range of patient groups. The risks of extensive tissue necrosis, systemic sepsis and potentially organ failure make this disease one which health-care professionals must be aware of. Treatment involves rapid debridement and intensive therapy including broad-spectrum antibiotics. Appropriate wound care is essential as is a great deal of psychological support for the patient and relatives. This article also highlights some of the risk factors which may pre-dispose a patient to infection.

Disseminated histoplasmosis and AIDS at the University Hospital of the West Indies. A case report.

Disseminated histoplasmosis is rare in Jamaica. However, with the increase in the number of immunocompromised patients in the population, the prevalence of this infection is likely to increase. We present a case of disseminated histoplasmosis in a 16-year-old girl with the acquired immune deficiency syndrome who presented to the Paediatric Infectious Diseases Service of the University Hospital of the West Indies, with cervical lymphadenitis progressing to ulcers and abscesses showing granulomatous inflammation likely to be of fungal aetiology. She later presented to the Emergency Room, with respiratory and gastrointestinal symptoms and was admitted to hospital, disoriented and with a persistent fever. She developed nuchal rigidity while in hospital and was anaemic, leukopaenic and thrombocytopaenic. She died of gastrointestinal bleed ten days post admission. She was the oldest known survivor of mother-to-child-transmission of human immunodeficiency virus in Jamaica. The slow growing fungus, Histoplasma capsulatum, was isolated from the patient's blood three weeks after the specimen was sent to the laboratory.

Disseminated histoplasmosis and AIDS at the University Hospital of the West Indies. A case report

Disseminated histoplasmosis is rare in Jamaica. However, with the increase in the number of immunocompromised patients in the population, the prevalence of this infection is likely to increase. We present a case of disseminated histoplasmosis in a 16-year-old girl with the acquired immune deficiency syndrome who presented to the Paediatric Infectious Diseases Service of the University Hospital of the West Indies, with cervical lymphadenitis progressing to ulcers and abscesses showing granulomatous inflammation likely to be of fungal aetiology. She later presented to the Emergency Room, with respiratory and gastrointestinal symptoms and was admitted to hospital, disoriented and with a persistent fever. She developed nuchal rigidity while in hospital and was anaemic, leukopaenic and thrombocytopaenic. She died of gastrointestinal bleed ten days post admission. She was the oldest known survivor of mother-to-child-transmission of human immunodeficiency virus in Jamaica. The slow growing fungus, Histoplasma capsulatum, was isolated from the patient's blood three weeks after the specimen was sent to the laboratory

Parental health beliefs and compliance with prophylactic penicillin administration in children with sickle cell disease.

PURPOSE: Prophylactic penicillin is effective in preventing severe invasive pneumococcal infection in children with sickle cell disease. In some families, compliance has been problematic. The aims of this study were to monitor compliance and to assess the efficacy of the Health Belief Model (HBM) in predicting compliance. METHODS: Fifty mothers of children with sickle cell disease, ages 6 to 60 months, participated in the study. On enrollment, mothers completed surveys assessing their health beliefs regarding sickle cell disease and infections. Compliance was assessed through self-reporting by the mothers and through review of local pharmacy records of penicillin refills. RESULTS: Sixty percent of the mothers reported that they were highly compliant with obtaining the prescribed 14-day refills. Pharmacy records indicated that only 12% actually adhered to this schedule. The self-reports were significantly related to compliance ratings; mothers who admitted less than optimal compliance averaged 42 days between refills, compared with 19 days for mothers who reported good compliance. Varying perceptions identified through the HBM accounted for approximately 30% of the variance in compliance rates. The perceived burdens of picking up the refills and remembering to administer the medication were the most significant factors. CONCLUSIONS: Educational efforts alone are not sufficient to ensure compliance with penicillin prophylaxis. Routinely monitoring compliance through pharmacy records, reviewing parental beliefs about sickle cell disease and infections, and exploring barriers to treatment will promote dialogue about the importance of strict compliance with this relatively simple yet life-saving prophylaxis.

"Let the Circle be Unbroken" helps African-Americans prevent teen pregnancy.

PIP: Strategies must be developed to address the high rate of adolescent pregnancy among Blacks in the US and the adverse consequences of premature parenting. A number of programs and strategies have been developed and are being implemented in various sites across the US. The "Let the Circle Be Unbroken: Rites of Passage" program is an effort to incorporate an Afrocentric conceptual model into a prevention program. It involves adapting socialization processes often observed in African cultures, which openly acknowledge the need to formally help adolescents during their transition from childhood to adulthood. That socialization process tends to be a cultural experience which requires that ideology, education, training, and culture be taught before an activity or celebration marking the successful transition from one stage of development to another. The "Rites of Passage" approach follows these basic premises to teach adolescents the knowledge and skills needed to become responsible community members and spiritually mature adults. It is specifically designed to help young people build self-esteem; enhance self-image; develop leadership skills, cultural awareness, and appreciation; and make healthy, productive, and self-affirming life choices.^ieng