Many tumour cells show dependence on exogenous serine and dietary serine and glycine starvation can inhibit the growth of these cancers and extend survival in mice. However, numerous mechanisms ...promote resistance to this therapeutic approach, including enhanced expression of the de novo serine synthesis pathway (SSP) enzymes or activation of oncogenes that drive enhanced serine synthesis. Here we show that inhibition of PHGDH, the first step in the SSP, cooperates with serine and glycine depletion to inhibit one-carbon metabolism and cancer growth. In vitro, inhibition of PHGDH combined with serine starvation leads to a defect in global protein synthesis, which blocks the activation of an ATF-4 response and more broadly impacts the protective stress response to amino acid depletion. In vivo, the combination of diet and inhibitor shows therapeutic efficacy against tumours that are resistant to diet or drug alone, with evidence of reduced one-carbon availability. However, the defect in ATF4-response seen in vitro following complete depletion of available serine is not seen in mice, where dietary serine and glycine depletion and treatment with the PHGDH inhibitor lower but do not eliminate serine. Our results indicate that inhibition of PHGDH will augment the therapeutic efficacy of a serine depleted diet.
Essentials
An international collaboration provides a consensus for clinical definitions.
This concerns thrombotic microangiopathies and thrombotic thrombocytopenic purpura (TTP).
The consensus ...defines diagnosis, disease monitoring and response to treatment.
Requirements for ADAMTS‐13 are given.
Summary
Background
Thrombotic thrombocytopenic purpura (TTP) and hemolytic–uremic syndrome (HUS) are two important acute conditions to diagnose. Thrombotic microangiopathy (TMA) is a broad pathophysiologic process that leads to microangiopathic hemolytic anemia and thrombocytopenia, and involves capillary and small‐vessel platelet aggregates. The most common cause is disseminated intravascular coagulation, which may be differentiated by abnormal coagulation. Clinically, a number of conditions present with microangiopathic hemolytic anemia and thrombocytopenia, including cancer, infection, transplantation, drug use, autoimmune disease, and pre‐eclampsia and hemolysis, elevated liver enzymes and low platelet count syndrome in pregnancy. Despite overlapping clinical presentations, TTP and HUS have distinct pathophysiologies and treatment pathways.
Objectives
To present a consensus document from an International Working Group on TTP and associated thrombotic microangiopathies (TMAs).
Methods
The International Working Group has proposed definitions and terminology based on published information and consensus‐based recommendations.
Conclusion
The consensus aims to aid clinical decisions, but also future studies and trials, utilizing standardized definitions. It presents a classification of the causes of TMA, and criteria for clinical response, remission and relapse of congenital and immune‐mediated TTP.
Summary
Accurate and precise potency determination by manufacturers of different types of factor VIII product (plasma‐derived and recombinant FVIII rFVIII) is vital to clinicians and patients using ...FVIII concentrates. A separate, but related, requirement is ascertaining the FVIII activity levels in clinical samples for diagnosing and treating hemophilia A. The one‐stage clotting assay (OSA) and the chromogenic substrate assay (CSA) are the main assays used for these measurements, with both assays being used for potency assignments, and the OSA also being widely used for clinical monitoring. Although the assays can produce concordant results, discrepancies often occur, e.g. when measuring FVIII levels in patients with mild or moderate hemophilia A, or when assaying high‐purity FVIII products. Modifications to rFVIII proteins, such as B‐domain deletion (BDD), and technologies for improving the pharmacokinetic profile of rFVIII may exacerbate assay discrepancies. The CSA appears to be essentially unaffected by these modifications. However, the OSA underestimates the FVIII activity levels and therapeutic potential of some further modified BDD rFVIII products, especially those conjugated to poly(ethylene glycol); the extent of the effects is dependent on the specific OSA reagents used. Although the OSA remains the preferred choice for clinical monitoring in Europe and the USA, an awareness of the limitations of that assay has prompted more laboratories to adopt the CSA.
The Askaryan Radio Array (ARA) is an ultrahigh energy (UHE, > 1017 eV) neutrino detector designed to observe neutrinos by searching for the radio waves emitted by the relativistic products of ...neutrino-nucleon interactions in Antarctic ice. In this paper, we present constraints on the diffuse flux of ultrahigh energy neutrinos between 1016 and 1021 eV resulting from a search for neutrinos in two complementary analyses, both analyzing four years of data (2013–2016) from the two deep stations (A2, A3) operating at that time. We place a 90% CL upper limit on the diffuse all flavor neutrino flux at 1018 eV of EF(E) = 5.6 × 10−16 cm−2 s−1 sr−1. This analysis includes four times the exposure of the previous ARA result and represents approximately 1 / 5 th the exposure expected from operating ARA until the end of 2022.
Essentials
AFSTYLA exhibits ≈50% underestimation in activity when the one‐stage (OS) assay is utilized.
A field study compared the performance of AFSTYLA with Advate in factor VIII activity assays.
...AFSTYLA activity can be monitored with both the chromogenic substrate and the OS assay.
The consistent OS underestimation allows for a conversion factor to be applied to OS results.
Summary
Introduction
AFSTYLA (antihemophilic factor recombinant single chain) is a novel B‐domain truncated recombinant factor VIII (rFVIII). For AFSTYLA, an approximate 50% discrepancy was observed between results of the one‐stage (OS) and chromogenic substrate (ChS) FVIII activity assays. An investigation was undertaken to test whether there is a linear relationship between ChS and OS assay results that would allow reliable clinical interpretation of results independent of the assay method used.
Aims
To provide confidence in future clinical monitoring, this field study investigated the performance of AFSTYLA and a full‐length rFVIII (Advate®) in FVIII activity assays routinely performed in clinical laboratories.
Methods
The comparison of AFSTYLA and Advate was performed in an international, multicenter and blinded field study of simulated post‐infusion samples. The study documented the extent of variability between methods and laboratories and characterized the relationship between the ChS and OS assays.
Results
Results from 23 laboratories demonstrate that intra and interlaboratory variability in OS assays were similar for both products. When comparing within the OS assay format, there was a similar and reagent‐correlated variability in response to different activators for both AFSTYLA and Advate. The OS underestimation was highly predictable and consistent across the complete range of FVIII plasma concentrations.
Conclusion
Post‐infusion plasma AFSTYLA levels can be monitored in patients by the OS and ChS assays. The consistent and predictable difference between the two assay formats provides clinicians with adequate guidance on how to interpret the results of the OS assay using a single conversion factor.
We demonstrate the first successful growth of large-area (200 × 200 μm2) bilayer, Bernal stacked, epitaxial graphene (EG) on atomically flat, 4H-SiC (0001) step-free mesas (SFMs) . The use of SFMs ...for the growth of graphene resulted in the complete elimination of surface step-bunching typically found after EG growth on conventional nominally on-axis SiC (0001) substrates. As a result heights of EG surface features are reduced by at least a factor of 50 from the heights found on conventional substrates. Evaluation of the EG across the SFM using the Raman 2D mode indicates Bernal stacking with low and uniform compressive lattice strain of only 0.05%. The uniformity of this strain is significantly improved, which is about 13-fold decrease of strain found for EG grown on conventional nominally on-axis substrates. The magnitude of the strain approaches values for stress-free exfoliated graphene flakes. Hall transport measurements on large area bilayer samples taken as a function of temperature from 4.3 to 300 K revealed an n-type carrier mobility that increased from 1170 to 1730 cm2 V–1 s–1, and a corresponding sheet carrier density that decreased from 5.0 × 1012 cm–2 to 3.26 × 1012 cm–2. The transport is believed to occur predominantly through the top EG layer with the bottom layer screening the top layer from the substrate. These results demonstrate that EG synthesized on large area, perfectly flat on-axis mesa surfaces can be used to produce Bernal-stacked bilayer EG having excellent uniformity and reduced strain and provides the perfect opportunity for significant advancement of epitaxial graphene electronics technology.
Summary
Essentials
Performance of the one‐stage clotting (OSC) assay varies with the clotting activator used.
Recombinant FIX‐albumin fusion protein (rIX‐FP) was reliably monitored with most OSC ...reagents.
rIX‐FP shows comparable reagent‐dependent variability to other rFIX products in the OSC assay.
Actin® FS and kaolin‐based reagents underestimated rIX‐FP activity by around 50% in the OSC assay.
Summary
Background
Measuring factor IX activity (FIX:C) with one‐stage clotting (OSC) assays, based on the activated partial thromboplastin time (APTT), is the current mainstay of diagnostic techniques for hemophilia B. Assessing the performance of new recombinant FIX (rFIX) products in OSC assays is essential, as APTT reagents from different manufacturers yield different potency estimates for rFIX.
Objectives
To evaluate the extent to which choice of reagent composition influences rFIX potency measurements of recombinant FIX–albumin fusion protein (rIX‐FP, IDELVION) activity in OSC assays.
Methods
rIX‐FP was added to FIX‐deficient plasma, and FIX:C was assessed centrally and locally in a multicenter international field study with a variety of commercial OSC APTT reagents. Paired sample analysis of clinical samples was performed to compare values of FIX:C from local and central laboratories. In‐house bioanalytical investigations with spiked samples were conducted to compare the APTT‐reagent dependent variability of rIX‐FP with unmodified rFIX and rFIX Fc fusion protein (rFIXFc).
Results
Central and local assessments of FIX:C from 10 countries and 21 participating centers showed comparable results to those from the central laboratory across the majority of 18 different APTT reagents from both clinical and spiked samples. There was a consistent underestimation of rIX‐FP activity of ≈ 50% with OSC assays using Actin FS or kaolin‐based APTT reagents. In the bioanalytical study, rIX‐FP showed comparable variability in OSC assays to unmodified rFIX and rFIXFc.
Conclusions
rIX‐FP activity can be accurately measured by the use of OSC assays with the majority of commercial reagents. Actin FS or kaolin‐based reagents will probably lead to a 50% underestimation of activity.
Immersion‐mode ice‐nucleating particle (INP) concentrations from an off‐road diesel engine were measured using a continuous‐flow diffusion chamber at −30°C. Both petrodiesel and biodiesel were ...utilized, and the exhaust was aged up to 1.5 photochemically equivalent days using an oxidative flow reactor. We found that aged and unaged diesel exhaust of both fuels is not likely to contribute to atmospheric INP concentrations at mixed‐phase cloud conditions. To explore this further, a new limit‐of‐detection parameterization for ice nucleation on diesel exhaust was developed. Using a global‐chemical transport model, potential black carbon INP (INPBC) concentrations were determined using a current literature INPBC parameterization and the limit‐of‐detection parameterization. Model outputs indicate that the current literature parameterization likely overemphasizes INPBC concentrations, especially in the Northern Hemisphere. These results highlight the need to integrate new INPBC parameterizations into global climate models as generalized INPBC parameterizations are not valid for diesel exhaust.
Key Points
Diesel and biodiesel exhaust do not produce significant ice‐nucleating particle concentrations
Photochemical aging does not increase ice‐nucleating particle concentrations in diesel exhaust
Current parameterizations may overemphasize black carbon ice‐nucleating particle concentrations globally
Metal films deposited on graphene are known to influence its electronic properties, but little is known about graphene's interactions with very low work function rare earth metals. Here we report on ...the work functions of a wide range of metals deposited on n-type epitaxial graphene (EG) as measured by Kelvin Probe Force Microscopy (KPFM). We compare the behaviors of rare earth metals (Pr, Eu, Er, Yb, and Y) with commonly used noble metals (Cr, Cu, Rh, Ni, Au, and Pt). The rare earth films oxidize rapidly, and exhibit unique behaviors when on graphene. We find that the measured work function of the low work function group is consistently higher than predicted, unlike the noble metals, which is likely due to rapid oxidation during measurement. Some of the low work function metals interact with graphene; for example, Eu exhibits bonding anomalies along the metal-graphene perimeter. We observe no correlation between metal work function and photovoltage, implying the metal-graphene interface properties are a more determinant factor. Yb emerges as the best choice for future applications requiring a low-work function electrical contact on graphene. Yb films have the strongest photovoltage response and maintains a relatively low surface roughness, ~5 nm, despite sensitivity to oxidation.
PDF
