57 research outputs found

    Towards Integrability of Topological Strings I: Three-forms on Calabi-Yau manifolds

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    The precise relation between Kodaira-Spencer path integral and a particular wave function in seven dimensional quadratic field theory is established. The special properties of three-forms in 6d, as well as Hitchin's action functional, play an important role. The latter defines a quantum field theory similar to Polyakov's formulation of 2d gravity; the curious analogy with world-sheet action of bosonic string is also pointed out.Comment: 31 page

    Oral octreotide capsules for the treatment of acromegaly: comparison of 2 phase 3 trial results

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    Purpose Results are presented from 2 to 3 trials investigating oral octreotide capsules (OOC) as an alternative to injectable somatostatin receptor ligands (iSRLs) in the treatment of acromegaly. Methods CH-ACM-01 was an open-label trial (N = 155) and CHIASMA OPTIMAL was a double-blind placebo-controlled (DPC) trial (N = 56), both investigating OOC as maintenance therapy for patients with acromegaly who were biochemical responders receiving iSRLs. Results Baseline characteristics in both trials reflected those expected of patients with acromegaly responding to treatment and were similar between trials, despite differences in inclusion criteria. OOC demonstrated a consistent degree of biochemical response across trials, with 65% of patients in CH-ACM-01 maintaining response during the core period and 64% of patients in CHIASMA OPTIMAL at the end of the DPC. Mean insulin-like growth factor I (IGF-I) levels remained within inclusion criteria at the end of treatment in both trials. Of 110 patients entering the fixed-dose phase in CH-ACM-01, 80% maintained or improved acromegaly symptoms from baseline to the end of treatment. Over 85% of patients in both trials elected to continue into the extension phases. OOC were found to be well tolerated across both trials, and no dose-related adverse events were observed. Conclusions OOC demonstrated remarkably consistent results for biochemical response, durability of response, and preference to continue with oral treatment across these 2 complementary landmark phase 3 trials, despite differences in the design of each.Diabetes mellitus: pathophysiological changes and therap

    DNA repair modulates the vulnerability of the developing brain to alkylating agents

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    Neurons of the developing brain are especially vulnerable to environmental agents that damage DNA (i.e., genotoxicants), but the mechanism is poorly understood. The focus of the present study is to demonstrate that DNA damage plays a key role in disrupting neurodevelopment. To examine this hypothesis, we compared the cytotoxic and DNA damaging properties of the methylating agents methylazoxymethanol (MAM) and dimethyl sulfate (DMS) and the mono- and bifunctional alkylating agents chloroethylamine (CEA) and nitrogen mustard (HN2), in granule cell neurons derived from the cerebellum of neonatal wild type mice and three transgenic DNA repair strains. Wild type cerebellar neurons were significantly more sensitive to the alkylating agents DMS and HN2 than neuronal cultures treated with MAM or the half-mustard CEA. Parallel studies with neuronal cultures from mice deficient in alkylguanine DNA glycosylase (Aag[superscript −/−]) or O6-methylguanine methyltransferase (Mgmt[superscript −/−]), revealed significant differences in the sensitivity of neurons to all four genotoxicants. Mgmt−/− neurons were more sensitive to MAM and HN2 than the other genotoxicants and wild type neurons treated with either alkylating agent. In contrast, Aag[superscript −/−] neurons were for the most part significantly less sensitive than wild type or Mgmt[superscript −/−] neurons to MAM and HN2. Aag[superscript −/−] neurons were also significantly less sensitive than wild type neurons treated with either DMS or CEA. Granule cell development and motor function were also more severely disturbed by MAM and HN2 in Mgmt[superscript −/−] mice than in comparably treated wild type mice. In contrast, cerebellar development and motor function were well preserved in MAM-treated Aag[superscript −/−] or MGMT-overexpressing (Mgmt[superscript Tg+]) mice, even as compared with wild type mice suggesting that AAG protein increases MAM toxicity, whereas MGMT protein decreases toxicity. Surprisingly, neuronal development and motor function were severely disturbed in Mgmt[superscript Tg+] mice treated with HN2. Collectively, these in vitro and in vivo studies demonstrate that the type of DNA lesion and the efficiency of DNA repair are two important factors that determine the vulnerability of the developing brain to long-term injury by a genotoxicant.United States. Army Medical Research and Materiel Command (Contract/Grant/Intergovernmental Project Order DAMD 17-98-1-8625)United States. National Institutes of Health (grants CA075576)United States. National Institutes of Health (RO1 C63193)United States. National Institutes of Health (P30 CA043703

    The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

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    INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

    Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

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    Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

    Aspergillus species producing ochratoxin A: isolation from vineyard soils and infection of Semillon bunches in Australia

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    The definitive version is available at www.blackwell-synergy.comAimsThe incidence of toxigenicity among Australian isolates of Aspergillus niger and Aspergillus carbonarius was assessed. Aspergillus rot and concomitant production of ochratoxin A (OA) in bunches inoculated with A. carbonarius were also investigated.Methods and resultsAspergillus niger and A. carbonarius were isolated from vineyard soils. Aspergillus niger was more widespread than A. carbonarius, and two restriction fragment length polymorphism types of A. niger, N and T, were present. Three of 113 A. niger isolates and all 33 A. carbonarius isolates produced OA. Aspergillus carbonarius was inoculated onto Semillon bunches with and without damage in the month before harvest. Damaged berries at greater than 12.3 (o) Bx were particularly susceptible to Aspergillus rot and production of OA, which was concentrated in severely mouldy berries.ConclusionsOA in Australian grapes results mainly from infection of berries by A. carbonarius. It is concentrated in discoloured, shrivelled berries. The potential for Aspergillus rot and OA production appears to commence after veraison and increase with berry damage and ripeness.Significance and impact of the studyMinimizing damage to grapes between veraison and harvest significantly reduces Aspergillus rot and OA formation. Monitoring the extent of Aspergillus rot in bunches infected with toxigenic Aspergillus spp. may give some indication of OA contamination

    Durable biochemical response and safety with oral octreotide capsules in acromegaly

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    ObjectiveThe objective of this study is to report results from the open-label extension (OLE) of the OPTIMAL trial of oral octreotide capsules (OOC) in adults with acromegaly, evaluating the long-term durability of therapeutic response. DesignThe study design is an OLE of a double-blind placebo-controlled (DPC) trial. MethodsPatients completing the 36-week DPC period on the study drug (OOC or placebo) or meeting predefined withdrawal criteria were eligible for OLE enrollment at 60 mg/day OOC dose, with the option to titrate to 40 or 80 mg/day. The OLE is ongoing; week 48 results are reported. ResultsForty patients were enrolled in the OLE, 20 each having received OOC or placebo, with 14 and 5 patients completing the DPC period as responders, respectively. Ninety percent of patients completing the DPC period on OOC and 70% of those completing on placebo completed 48 weeks of the OLE. Maintenance of response in the OLE (i.e. insulin-like growth factor I (IGF1) <= 1.0 x upper limit of normal (ULN)) was achieved by 92.6% of patients who responded to OOC during the DPC period. Mean IGF1 levels were maintained between the end of the DPC period (0.91 x ULN; 95% CI: 0.784, 1.045) and week 48 of the OLE (0.90 x ULN; 95% CI: 0.750, 1.044) for those completing the DPC period on OOC. OOC safety was consistent with previous findings, with no increased adverse events (AEs) associated with the higher dose and improved gastrointestinal tolerability observed over time. ConclusionsPatients with acromegaly maintained long-term biochemical response while receiving OOC, with no new AEs observed with prolonged OOC exposure
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