Preparation of Developing and Adult Drosophila Brains and Retinae for Live Imaging

The Drosophila brain and visual system are widely utilized model systems to study neuronal development, function and degeneration. Here we show three preparations of the brain and visual system that cover the range from the developing eye disc-brain complex in the developing pupae to individual eye and brain dissection from adult flies. All protocols are optimized for the live culture of the preparations. However, we also present the conditions for fixed tissue immunohistochemistry where applicable. Finally, we show live imaging conditions for these preparations using conventional and resonant 4D confocal live imaging in a perfusion chamber. Together, these protocols provide a basis for live imaging on different time scales ranging from functional intracellular assays on the scale of minutes to developmental or degenerative processes on the scale of many hours

Guidance Receptor Degradation Is Required for Neuronal Connectivity in the Drosophila Nervous System

During Drosophila brain development, a neuron-specific endolysosomal degradation pathway provides a mechanism for continuous guidance receptor turnover and proper connectivity

Unc-4 acts to promote neuronal identity and development of the take-off circuit in the Drosophila CNS

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The Synaptic Vesicle SNARE Neuronal Synaptobrevin Promotes Endolysosomal Degradations and Prevents Neurodegeneration

Soluble NSF attachment protein receptors (SNAREs) are the core proteins in membrane fusion. The neuron-specific synaptic v-SNARE n-syb (neuronal Synaptobrevin) plays a key role during synaptic vesicle exocytosis. In this paper, we report that loss of n-syb caused slow neurodegeneration independent of its role in neurotransmitter release in adult Drosophila melanogaster photoreceptor neurons. In addition to synaptic vesicles, n-Syb localized to endosomal vesicles. Loss of n-syb lead to endosomal accumulations, transmembrane protein degradation defects, and a secondary increase in autophagy. Our evidence suggests a primary defect of impaired delivery of vesicles that contain degradation proteins, including the acidification-activated Cathepsin proteases and the neuron-specific proton pump and V0 adenosine triphosphatase component V100. Overexpressing V100 partially rescued n-syb–dependent degeneration through an acidification-independent endosomal sorting mechanism. Collectively, these findings reveal a role for n-Syb in a neuron-specific sort-and-degrade mechanism that protects neurons from degeneration. Our findings further shed light on which intraneuronal compartments exhibit increased or decreased neurotoxicity

Long-term outcomes of heart failure with preserved or mid-range ejection fraction in the United States

Background: Approximately one-half of all heart failure (HF) consists of heart failure with preserved ejection fraction (HFpEF) or heart failure with mid-range ejection fraction (HFmrEF). Although several recent trials have investigated treatments for HFpEF/HFmrEF, there is limited insight on the long-term clinical trajectory of this population. Objectives: The purpose of this study was to model clinical outcomes in patients with symptomatic (NYHA functional class II-IV) HFpEF/HFmrEF over 10 years. Methods: We developed a Markov model with stable HF, HF hospitalization, and death states to follow a cohort of patients with HFpEF/HFmrEF treated with standard of care (SoC) recommended by the American Heart Association/American College of Cardiology/Heart Failure Society of America. Population characteristics and clinical event probabilities were derived from recent phase 3 HFpEF/HFmrEF trials. We used weighted averages for control and sodium-glucose cotransporter-2 inhibitor outcomes. SoC was informed by baseline treatments reported in clinical trials. Results: In a cohort of U.S. patients with HFpEF/HFmrEF treated with SoC, our model estimated 0.53 cumulative HF hospitalizations per patient over 10 years. Overall, 37% had at least 1 HF hospitalization, and 26% experienced cardiovascular death. The model estimated 6.1 years of life expectancy from age 72 and total cost of care over this time of $123,900. Conclusions: HFpEF/HFmrEF is associated with high rates of HF hospitalization and cardiovascular mortality based on contemporary clinical trials in this population. Furthermore, clinical trial results are likely to be more optimistic than real-world outcomes. Continuing to optimize care and treatment may reduce clinical burden and improve population health

Can majority support save an endangered language? A case study of language attitudes in Guernsey

Many studies of minority language revitalisation focus on the attitudes and perceptions of minorities, but not on those of majority group members. This paper discusses the implications of these issues, and presents research into majority andf minority attitudes towards the endangered indigenous vernacular of Guernsey, Channel Islands. The research used a multi-method approach (questionnaire and interview) to obtain attitudinal data from a representative sample of the population that included politicians and civil servants (209 participants). The findings suggested a shift in language ideology away from the post-second world war ‘culture of modernisation’ and monolingual ideal, towards recognition of the value of a bi/trilingual linguistic heritage. Public opinion in Guernsey now seems to support the maintenance of the indigenous language variety, which has led to a degree of official support. The paper then discusses to what extent this ‘attitude shift’ is reflected in linguistic behaviour and in concrete language planning measures

Regulation of branching dynamics by axon-intrinsic asymmetries in Tyrosine Kinase Receptor signaling

Axonal branching allows a neuron to connect to several targets, increasing neuronal circuit complexity. While axonal branching is well described, the mechanisms that control it remain largely unknown. We find that in the Drosophila CNS branches develop through a process of excessive growth followed by pruning. In vivo high-resolution live imaging of developing brains as well as loss and gain of function experiments show that activation of Epidermal Growth Factor Receptor (EGFR) is necessary for branch dynamics and the final branching pattern. Live imaging also reveals that intrinsic asymmetry in EGFR localization regulates the balance between dynamic and static filopodia. Elimination of signaling asymmetry by either loss or gain of EGFR function results in reduced dynamics leading to excessive branch formation. In summary, we propose that the dynamic process of axon branch development is mediated by differential local distribution of signaling receptors

Ultraviolet Spectroscopy and TARDIS Models of the Broad-lined Type-Ic Supernova 2014ad

Few published ultraviolet (UV) spectra exist for stripped-envelope supernovae, and none to date for broad-lined Type Ic supernovae (SN Ic-bl). These objects have extremely high ejecta velocities and are the only supernova type directly linked to gamma-ray bursts (GRBs). Here we present two epochs of HST/STIS spectra of the SN Ic-bl 2014ad, the first UV spectra for this class. We supplement this with 26 new epochs of ground-based optical spectra, augmenting a rich spectral time series. The UV spectra do not show strong features, likely due to high opacity, and are consistent with broadened versions of other SN Ic spectra observed in the UV. We measure Fe II 5169 Angstrom velocities and show that SN 2014ad has even higher ejecta velocities than most SNe Ic both with and without observed GRBs. We construct models of the SN 2014ad UV+optical spectra using TARDIS, a 1D Monte-Carlo radiative-transfer spectral synthesis code. The models fit the data well at multiple epochs in the optical but underestimate the flux in the UV. We find that high densities at high velocities are needed to reproduce the spectra, with $\sim$3 M$_\odot$ of material at $v >$ 22,000 km s$^{-1}$, assuming spherical symmetry. Our nebular line fits suggest a steep density profile at low velocities. Together, these results imply a higher total ejecta mass than estimated from previous light curve analysis and expected from theory. This may be reconciled by a flattening of the density profile at low velocity and extra emission near the center of the ejecta.Comment: 25 pages, 14 figures, submitted to AAS Journal

Risk algorithm using serial biomarker measurements doubles the number of screen-detected cancers compared with a single-threshold rule in the United Kingdom collaborative trial of ovarian cancer screening

PURPOSE: Cancer screening strategies have commonly adopted single-biomarker thresholds to identify abnormality. We investigated the impact of serial biomarker change interpreted through a risk algorithm on cancer detection rates. PATIENTS AND METHODS: In the United Kingdom Collaborative Trial of Ovarian Cancer Screening, 46,237 women, age 50 years or older underwent incidence screening by using the multimodal strategy (MMS) in which annual serum cancer antigen 125 (CA-125) was interpreted with the risk of ovarian cancer algorithm (ROCA). Women were triaged by the ROCA: normal risk, returned to annual screening; intermediate risk, repeat CA-125; and elevated risk, repeat CA-125 and transvaginal ultrasound. Women with persistently increased risk were clinically evaluated. All participants were followed through national cancer and/or death registries. Performance characteristics of a single-threshold rule and the ROCA were compared by using receiver operating characteristic curves. RESULTS: After 296,911 women-years of annual incidence screening, 640 women underwent surgery. Of those, 133 had primary invasive epithelial ovarian or tubal cancers (iEOCs). In all, 22 interval iEOCs occurred within 1 year of screening, of which one was detected by ROCA but was managed conservatively after clinical assessment. The sensitivity and specificity of MMS for detection of iEOCs were 85.8% (95% CI, 79.3% to 90.9%) and 99.8% (95% CI, 99.8% to 99.8%), respectively, with 4.8 surgeries per iEOC. ROCA alone detected 87.1% (135 of 155) of the iEOCs. Using fixed CA-125 cutoffs at the last annual screen of more than 35, more than 30, and more than 22 U/mL would have identified 41.3% (64 of 155), 48.4% (75 of 155), and 66.5% (103 of 155), respectively. The area under the curve for ROCA (0.915) was significantly (P = .0027) higher than that for a single-threshold rule (0.869). CONCLUSION: Screening by using ROCA doubled the number of screen-detected iEOCs compared with a fixed cutoff. In the context of cancer screening, reliance on predefined single-threshold rules may result in biomarkers of value being discarded

Modeling the Prospective Relationships of Impairment, Injury Severity, and Participation to Quality of Life Following Traumatic Brain Injury

Identifying reliable predictors of positive adjustment following traumatic brain injury (TBI) remains an important area of inquiry. Unfortunately, much of available research examines direct relationships between predictor variables and outcomes without attending to the contextual relationships that can exist between predictor variables. Relying on theoretical models of well-being, we examined a theoretical model of adjustment in which the capacity to engage in intentional activities would be prospectively associated with greater participation, which in turn would predict subsequent life satisfaction and perceived health assessed at a later time. Structural equation modeling of data collected from 312 individuals (226 men, 86 women) with TBI revealed that two elements of participation—mobility and occupational activities—mediated the prospective influence of functional independence and injury severity to optimal adjustment 60 months following medical discharge for TBI. The model accounted for 21% of the variance in life satisfaction and 23% of the variance in self-rated health. Results indicate that the effects of functional independence and injury severity to optimal adjustment over time may be best understood in the context of participation in meaningful, productive activities. Implications for theoretical models of well-being and for clinical interventions that promote adjustmentafter TBI are discussed