433 research outputs found

    High energy gamma ray balloon instrument

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    The High Energy Gamma Ray Balloon Instrument was built in part to verify certain subsystems' performance for the Energetic Gamma Ray Experiment Telescope (EGRET) instrument, the high energy telescope to be carried on the Gamma Ray Observatory. This paper describes the instrument, the performance of some subsystems, and some relevant results

    SAS-B digitized spark chamber gamma ray telescope

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    Systems description of SAS-B gamma ray telescope with multilayer digitized spark chamber for gamma rays with energy exceeding 20 Me

    Submaximal Angioplasty for Symptomatic Intracranial Atherosclerotic Disease: A Meta-Analysis of Peri-Procedural and Long-Term Risk

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    © 2019 by the Congress of Neurological Surgeons. BACKGROUND: Symptomatic intracranial atherosclerotic disease (ICAD) is an important cause of stroke. Although the high periprocedural risk of intracranial stenting from recent randomized studies has dampened enthusiasm for such interventions, submaximal angioplasty without stenting may represent a safer endovascular treatment option. OBJECTIVE: To examine the periprocedural and long-term risks associated with submaximal angioplasty for ICAD based on the available literature. METHODS: All English language studies of intracranial angioplasty for ICAD were screened. Inclusion criteria were as follows: ≥ 5 patients, intervention with submaximal angioplasty alone, and identifiable periprocedural (30-d) outcomes. Analysis was co-nducted to identify the following: 1) periprocedural risk of any stroke (ischemic or hemorrh-agic) or death, and 2) stroke in the territory of the target vessel and fatal stroke beyond 30 d. Mixed effects logistic regression was used to summarize event rates. Funnel plot and rank correlation tests were employed to detect publication bias. The relative risk of periprocedural events from anterior vs posterior circulation disease intervention was also examined. RESULTS: A total of 9 studies with 408 interventions in 395 patients met inclusion criteria. Six of these studies included 113 posterior circulation interventions. The estimated pooled rate for 30-d stroke or death following submaximal angioplasty was 4.9% (95% CI: 3.2%-7.5%), whereas the estimated pooled rate beyond 30 d was 3.7% (95% CI: 2.2%-6.0%). There was no statistical difference in estimated pooled rate for 30-d stroke or death between patients with anterior (4.8%, 95% CI: 2.8%-7.9%) vs posterior (5.3%, 95% CI: 2.4%-11.3%) circulation disease (P \u3e. 99). CONCLUSION: Submaximal angioplasty represents a potentially promising intervention for symptomatic ICAD

    Expanding the toolbox of metabolically stable lipid prodrug strategies

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    Nucleoside- and nucleotide-based therapeutics are indispensable treatment options for patients suffering from malignant and viral diseases. These agents are most commonly administered to patients as prodrugs to maximize bioavailability and efficacy. While the literature provides a practical prodrug playbook to facilitate the delivery of nucleoside and nucleotide therapeutics, small context-dependent amendments to these popular prodrug strategies can drive dramatic improvements in pharmacokinetic (PK) profiles. Herein we offer a brief overview of current prodrug strategies, as well as a case study involving the fine-tuning of lipid prodrugs of acyclic nucleoside phosphonate tenofovir (TFV), an approved nucleotide HIV reverse transcriptase inhibitor (NtRTI) and the cornerstone of combination antiretroviral therapy (cART). Installation of novel lipid terminal motifs significantly reduced fatty acid hepatic ω-oxidation while maintaining potent antiviral activity. This work contributes important insights to the expanding repertoire of lipid prodrug strategies in general, but particularly for the delivery and distribution of acyclic nucleoside phosphonates

    CD4 Depletion in SIV-Infected Macaques Results in Macrophage and Microglia Infection with Rapid Turnover of Infected Cells

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    In rhesus macaques (RMs), experimental depletion of CD4+ T-cells prior to SIV infection results in higher viremia and emergence of CD4-independent SIV-envelopes. In this study we used the rhesus recombinant anti-CD4 antibody CD4R1 to deplete RM CD4+ T-cells prior to SIVmac251 infection and investigate the sources of the increased viral burden and the lifespan of productively infected cells. CD4-depleted animals showed (i) set-point viral load two-logs higher than controls; (ii) macrophages constituting 80% of all SIV vRNA+ cells in lymph node and mucosal tissues; (iii) substantial expansion of pro-inflammatory monocytes; (iv) aberrant activation and infection of microglial cells; and (v) lifespan of productively infected cells significantly longer in comparison to controls, but markedly shorter than previously estimated for macrophages. The net effect of CD4+ T-cell depletion is an inability to control SIV replication and a shift in the tropism of infected cells to macrophages, microglia, and, potentially, other CD4-low cells which all appear to have a shortened in vivo lifespan. We believe these findings have important implications for HIV eradication studies

    A review of technological innovations leading to modern endovascular brain aneurysm treatment

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    Tools and techniques utilized in endovascular brain aneurysm treatment have undergone rapid evolution in recent decades. These technique and device-level innovations have allowed for treatment of highly complex intracranial aneurysms and improved patient outcomes. We review the major innovations within neurointervention that have led to the current state of brain aneurysm treatment

    Grifonin-1: A Small HIV-1 Entry Inhibitor Derived from the Algal Lectin, Griffithsin

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    Background: Griffithsin, a 121-residue protein isolated from a red algal Griffithsia sp., binds high mannose N-linked glycans of virus surface glycoproteins with extremely high affinity, a property that allows it to prevent the entry of primary isolates and laboratory strains of T- and M-tropic HIV-1. We used the sequence of a portion of griffithsin's sequence as a design template to create smaller peptides with antiviral and carbohydrate-binding properties. Methodology/Results: The new peptides derived from a trio of homologous β-sheet repeats that comprise the motifs responsible for its biological activity. Our most active antiviral peptide, grifonin-1 (GRFN-1), had an EC50 of 190.8±11.0 nM in in vitro TZM-bl assays and an EC50 of 546.6±66.1 nM in p24gag antigen release assays. GRFN-1 showed considerable structural plasticity, assuming different conformations in solvents that differed in polarity and hydrophobicity. Higher concentrations of GRFN-1 formed oligomers, based on intermolecular β-sheet interactions. Like its parent protein, GRFN-1 bound viral glycoproteins gp41 and gp120 via the N-linked glycans on their surface. Conclusion: Its substantial antiviral activity and low toxicity in vitro suggest that GRFN-1 and/or its derivatives may have therapeutic potential as topical and/or systemic agents directed against HIV-1
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