69 research outputs found

    Release mechanism of octadecyl rhodamine B chloride from Au nanorods by ultrafast laser pulses

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    We investigated the release of octadecyl rhodamine B chloride (R[subscript 18]) loaded onto cetyltrimethylammonium bromide (CTAB) coated gold nanorods (NR) by pulsed ultrafast laser excitation. R[subscript 18] intercalates into the hydrophobic CTAB bilayer on the NR surface and can exchange on and off the NR with free CTAB micelles in solution. We find that laser excitation accelerates the rate of both R[subscript 18] release from the NR and R[subscript 18] binding to the NR with increasing fluence. However, at laser fluences >220 ÎŒJ/cm[superscript 2] thermal degradation of the R[subscript 18] dominates. We also find that the concentration of CTAB, particularly around the critical micelle concentration, strongly influences the release and binding rates

    Antigen Delivery by Lipid-Enveloped PLGA Microparticle Vaccines Mediated by in Situ Vesicle Shedding

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    Lipid-coated poly(lactide-co-glycolide) microparticles (LCMPs) consist of a solid polymer core wrapped by a surface lipid bilayer. Previous studies demonstrated that immunization with LCMPs surface-decorated with nanograms of antigen elicit potent humoral immune responses in mice. However, the mechanism of action for these vaccines remained unclear, as LCMPs are too large to drain efficiently to lymph nodes from the vaccination site. Here, we characterized the stability of the lipid envelope of LCMPs and discovered that in the presence of serum the lipid coating of the particles spontaneously delaminates, shedding antigen-displaying vesicles. Lipid delamination generated 180 nm liposomes in a temperature- and lipid/serum-dependent manner. Vesicle shedding was restricted by inclusion of high-T[subscript M] lipids or cholesterol in the LCMP coating. Administration of LCMPs bearing stabilized lipid envelopes generated weaker antibody responses than those of shedding-competent LCMPs, suggesting that in situ release of antigen-loaded vesicles plays a key role in the remarkable potency of LCMPs as vaccine adjuvants.National Institutes of Health (U.S.) (AI091693)Bill & Melinda Gates FoundationRagon Institute of MGH, MIT and Harvar

    Nanoparticulate STING agonists are potent lymph node–targeted vaccine adjuvants

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    Cyclic dinucleotides (CDNs) are agonists of stimulator of IFN genes (STING) and have potential as vaccine adjuvants. However, cyclic di-GMP (cdGMP) injected s.c. shows minimal uptake into lymphatics/draining lymph nodes (dLNs) and instead is rapidly distributed to the bloodstream, leading to systemic inflammation. Here, we encapsulated cdGMP within PEGylated lipid nanoparticles (NP-cdGMP) to redirect this adjuvant to dLNs. Compared with unformulated CDNs, encapsulation blocked systemic dissemination and markedly enhanced dLN accumulation in murine models. Delivery of NP-cdGMP increased CD8[superscript +] T cell responses primed by peptide vaccines and enhanced therapeutic antitumor immunity. A combination of a poorly immunogenic liposomal HIV gp41 peptide antigen and NP-cdGMP robustly induced type I IFN in dLNs, induced a greater expansion of vaccine-specific CD4[superscript +] T cells, and greatly increased germinal center B cell differentiation in dLNs compared with a combination of liposomal HIV gp41 and soluble CDN. Further, NP-cdGMP promoted durable antibody titers that were substantially higher than those promoted by the well-studied TLR agonist monophosphoryl lipid A and comparable to a much larger dose of unformulated cdGMP, without the systemic toxicity of the latter. These results demonstrate that nanoparticulate delivery safely targets CDNs to the dLNs and enhances the efficacy of this adjuvant. Moreover, this approach can be broadly applied to other small-molecule immunomodulators of interest for vaccines and immunotherapy.Bill & Melinda Gates FoundationRagon Institute of MGH, MIT and HarvardNational Institutes of Health (U.S.) (AI091693)National Institutes of Health (U.S.) (AI095109)National Cancer Institute (U.S.) (Koch Institute Support (Core) Grant P30-CA14051)National Institutes of Health (U.S.) (Ruth L. Kirschstein National Research Service Award 1F32CA180586)Hertz Foundation (Graduate Fellowship)National Science Foundation (U.S.). Graduate Research Fellowshi

    TMG 1 (2014): Pandemic Disease in the Medieval World: Rethinking the Black Death, ed. Monica Green

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    The plague organism (Yersinia pestis) killed an estimated 40% to 60% of all people when it spread rapidly through the Middle East, North Africa, and Europe in the fourteenth century: an event known as the Black Death. Previous research has shown, especially for Western Europe, how population losses then led to structural economic, political, and social changes. But why and how did the pandemic happen in the first place? When and where did it begin? How was it sustained? What was its full geographic extent? And when did it really end? Pandemic Disease in the Medieval World is the first book to synthesize the new evidence and research methods that are providing fresh answers to these crucial questions. It was only in 2011, thanks to ancient DNA recovered from remains unearthed in London’s East Smithfield cemetery, that the full genome of the plague pathogen was identified. This single-celled organism probably originated 3000-4000 years ago and has caused three pandemics in recorded history: the Justinianic (or First) Plague Pandemic, around 541-750; the Black Death (Second Plague Pandemic), conventionally dated to the 1340s; and the Third Plague Pandemic, usually dated from around 1894 to the 1930s. This ground-breaking book brings together scholars from the humanities and social and physical sci­ences to address the question of how recent work in genetics, zoology, and epi­de­miology can enable a rethinking of the Black Death\u27s global reach and its larger historical significance. It forms the inaugural double issue of The Medieval Globe, a new journal sponsored by the Program in Medieval Studies at the University of Illinois at Urbana-Champaign. This issue of The Medieval Globe is published with the support of the World History Center at the University of Pittsburgh.https://scholarworks.wmich.edu/medieval_globe/1000/thumbnail.jp

    Liposomal vaccines incorporating molecular adjuvants and intrastructural T-cell help promote the immunogenicity of HIV membrane-proximal external region peptides

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    An HIV vaccine capable of inducing high and durable levels of broadly neutralizing antibodies has thus far proven elusive. A promising antigen is the membrane-proximal external region (MPER) from gp41, a segment of the viral envelope recognized by a number of broadly neutralizing antibodies. Though an attractive vaccine target due to the linear nature of the epitope and its highly conserved sequence, MPER peptides are poorly immunogenic and may require display on membranes to achieve a physiological conformation matching the native virus. Here we systematically explored how the structure and composition of liposomes displaying MPER peptides impacts the strength and durability of humoral responses to this antigen as well as helper T-cell responses in mice. Administration of MPER peptides anchored to the surface of liposomes induced MPER-specific antibodies whereas MPER administered in oil-based emulsion adjuvants or alum did not, even when combined with Toll-like receptor agonists. High-titer IgG responses to liposomal MPER required the inclusion of molecular adjuvants such as monophosphoryl lipid A. Anti-MPER humoral responses were further enhanced by incorporating high-Tm lipids in the vesicle bilayer and optimizing the MPER density to a mean distance of ∌10–15 nm between peptides on the liposomes' surfaces. Encapsulation of helper epitopes within the vesicles allowed efficient “intrastructural” T-cell help, which promoted IgG responses to MPER while minimizing competing B-cell responses against the helper sequence. These results define several key properties of liposome formulations that promote durable, high-titer antibody responses against MPER peptides, which will be a prerequisite for a successful MPER-targeting vaccine.Bill & Melinda Gates FoundationNational Institutes of Health (U.S.) (AI091693

    The whole genome sequence of the Mediterranean fruit fly, Ceratitis capitata (Wiedemann), reveals insights into the biology and adaptive evolution of a highly invasive pest species

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    The Mediterranean fruit fly (medfly), Ceratitis capitata, is a major destructive insect pest due to its broad host range, which includes hundreds of fruits and vegetables. It exhibits a unique ability to invade and adapt to ecological niches throughout tropical and subtropical regions of the world, though medfly infestations have been prevented and controlled by the sterile insect technique (SIT) as part of integrated pest management programs (IPMs). The genetic analysis and manipulation of medfly has been subject to intensive study in an effort to improve SIT efficacy and other aspects of IPM control

    Relevance of Stereotyped B-Cell Receptors in the Context of the Molecular, Cytogenetic and Clinical Features of Chronic Lymphocytic Leukemia

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    Highly homologous B-cell receptors, characterized by non-random combinations of immunoglobulin heavy-chain variable (IGHV) genes and heavy-chain complementarity determining region-3 (HCDR3), are expressed in a recurrent fraction of patients affected by chronic lymphocytic leukemia (CLL). We investigated the IGHV status of 1131 productive IG rearrangements from a panel of 1126 CLL patients from a multicenter Italian study group, and correlated the presence and class of HCDR3 stereotyped subsets with the major cytogenetic alterations evaluated by FISH, molecular prognostic factors, and the time to first treatment (TTFT) of patients with early stage disease (Binet A). Stereotyped HCDR3 sequences were found in 357 cases (31.7%), 231 of which (64.7%) were unmutated. In addition to the previously described subsets, 31 new putative stereotypes subsets were identified. Significant associations between different stereotyped HCDR3 sequences and molecular prognostic factors, such as CD38 and ZAP-70 expression, IGHV mutational status and genomic abnormalities were found. In particular, deletion of 17p13 was significantly represented in stereotype subset #1. Notably, subset #1 was significantly correlated with a substantially reduced TTFT compared to other CLL groups showing unmutated IGHV, ZAP-70 or CD38 positivity and unfavorable cytogenetic lesions including del(17)(p13). Moreover, subset #2 was strongly associated with deletion of 13q14, subsets #8 and #10 with trisomy 12, whereas subset #4 was characterized by the prevalent absence of the common cytogenetic abnormalities. Our data from a large and representative panel of CLL patients indicate that particular stereotyped HCDR3 sequences are associated with specific cytogenetic lesions and a distinct clinical outcome

    Effects of hospital facilities on patient outcomes after cancer surgery: an international, prospective, observational study

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    Background Early death after cancer surgery is higher in low-income and middle-income countries (LMICs) compared with in high-income countries, yet the impact of facility characteristics on early postoperative outcomes is unknown. The aim of this study was to examine the association between hospital infrastructure, resource availability, and processes on early outcomes after cancer surgery worldwide.Methods A multimethods analysis was performed as part of the GlobalSurg 3 study-a multicentre, international, prospective cohort study of patients who had surgery for breast, colorectal, or gastric cancer. The primary outcomes were 30-day mortality and 30-day major complication rates. Potentially beneficial hospital facilities were identified by variable selection to select those associated with 30-day mortality. Adjusted outcomes were determined using generalised estimating equations to account for patient characteristics and country-income group, with population stratification by hospital.Findings Between April 1, 2018, and April 23, 2019, facility-level data were collected for 9685 patients across 238 hospitals in 66 countries (91 hospitals in 20 high-income countries; 57 hospitals in 19 upper-middle-income countries; and 90 hospitals in 27 low-income to lower-middle-income countries). The availability of five hospital facilities was inversely associated with mortality: ultrasound, CT scanner, critical care unit, opioid analgesia, and oncologist. After adjustment for case-mix and country income group, hospitals with three or fewer of these facilities (62 hospitals, 1294 patients) had higher mortality compared with those with four or five (adjusted odds ratio [OR] 3.85 [95% CI 2.58-5.75]; p<0.0001), with excess mortality predominantly explained by a limited capacity to rescue following the development of major complications (63.0% vs 82.7%; OR 0.35 [0.23-0.53]; p<0.0001). Across LMICs, improvements in hospital facilities would prevent one to three deaths for every 100 patients undergoing surgery for cancer.Interpretation Hospitals with higher levels of infrastructure and resources have better outcomes after cancer surgery, independent of country income. Without urgent strengthening of hospital infrastructure and resources, the reductions in cancer-associated mortality associated with improved access will not be realised

    Mapping genomic loci implicates genes and synaptic biology in schizophrenia

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    Schizophrenia has a heritability of 60-80%1, much of which is attributable to common risk alleles. Here, in a two-stage genome-wide association study of up to 76,755 individuals with schizophrenia and 243,649 control individuals, we report common variant associations at 287 distinct genomic loci. Associations were concentrated in genes that are expressed in excitatory and inhibitory neurons of the central nervous system, but not in other tissues or cell types. Using fine-mapping and functional genomic data, we identify 120 genes (106 protein-coding) that are likely to underpin associations at some of these loci, including 16 genes with credible causal non-synonymous or untranslated region variation. We also implicate fundamental processes related to neuronal function, including synaptic organization, differentiation and transmission. Fine-mapped candidates were enriched for genes associated with rare disruptive coding variants in people with schizophrenia, including the glutamate receptor subunit GRIN2A and transcription factor SP4, and were also enriched for genes implicated by such variants in neurodevelopmental disorders. We identify biological processes relevant to schizophrenia pathophysiology; show convergence of common and rare variant associations in schizophrenia and neurodevelopmental disorders; and provide a resource of prioritized genes and variants to advance mechanistic studies

    The James Webb Space Telescope Mission

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    Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least 4m4m. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the 6.5m6.5m James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 years, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space Telescope Overview, 29 pages, 4 figure
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