The objective of this study was to test the hypothesis that when standard artificial media 5-salt culture water (SAM-5S) is used to test sediment toxicity of much lower ionic-strength aquatic ecosystems, the resulting toxicity estimates are lower than if the tests had been conducted in water of comparable ionic strength. Results showed that this concern was unfounded for testing of copper toxicity to Hyalella azteca (H. azteca) in Ottawa River water. Sediment testing is often conducted using a standard water that is prepared in the laboratory. However, this water may have an ionic strength that is different than local water bodies. It follows that laboratory results using the standard water may be unrepresentative. A study was undertaken to assess the copper tolerance of 2 strains of H. azteca in SAM-5S, diluted SAM-5S (similar in electrical conductivity to Ottawa River water), and Ottawa River water. Acute (96 h) copper toxicity tests were conducted with 9–16 day-old H. azteca. For a given water type, the 2 strains of H. azteca yielded comparable responses to copper. The highest copper tolerance was found in Ottawa River water (closely followed by SAM-5S), whereas the lowest copper tolerance was found in diluted SAM-5S. Our results suggest that sediment toxicity is not lowered by the higher ionic strength of SAM-5S and that sediment toxicity tests of Ottawa River sediments, conducted with SAM-5S, can be used to estimate the in situ toxicity of the sediments.
To reduce the compilation times for Field Programmable Gate Arrays, genetic algorithms have been proposed for performing placement. However, the quality of solutions produced by these methods, so far, has been inferior to that produced by other search methods. In this paper, we show how traditional recombination operators, employed by the genetic algorithm when performing placement, fail to produce offspring solutions that are confined to the solution subspace defined by the parent solutions. This violates a fundamental principle that should govern the behavior of the recombination operator. We explore this flaw in detail, and propose a novel recombination operator that yields very statistically significant performance improvements, when tested with standard benchmarks.
Introduction: Nanometre sized UHMWPE particles have recently been isolated from periprosthetic tissues and hip simulator lubricants [1,2]. The biological response to UHMWPE particles of 0.1 μm and above has been well characterised, with particles in the 0.1–1.0 μm size range having the highest biological activity [3]. The purpose of the study was to determine the biological activity of nanometre-sized particles in terms of osteolytic cytokine release from primary human monocytes. Methods: Monocytes were isolated from peripheral blood from 5 healthy donors by density gradient centrifugation over Lymphoprep. Cells were cultured using the agarose gel technique [3] at particle volume (μm3):cell number ratios of 10:1 and 100:1. The particles used were: 1 Polystyrene FITC-conjugated FluoSpheres (FS; Invitrogen) in 20 nm, 40 nm, 0.2 μm and 1.0 μm sizes. 2a Complete Ceridust® 3615 (CD), a low MW polyethylene powder (size range 15 nm – 53 μm). 2b Nanometresized Ceridust® (fractionated by filtration using 10, 1, 0.1, 0.05 & 0.015 μm filters). 3 Clinically relevant GUR 1120 UHMWPE debris produced aseptically using a multidirectional wear rig. All particles were tested for the presence of endotoxin prior to culture with cells. Cells without particles were used as a negative control and 200 ng/ml LPS was used as a positive control. Cell viability was assessed using the ATP Lite assay (Perkin Elmer) and ELISA was used to determine TNF-alpha, IL-1beta, IL-6 and IL-8 release at 3, 6, 12 and 24 h. Results: FluoSpheres and CD had no effect on cell viability at 10 or 100:1. Clinically relevant UHMWPE particles had no effect on cell viability at 10:1, however, at 100:1 significant differences (P Discussion: This study found that all nanometre-sized particles had the potential to provoke inflammatory cytokine release from macrophages. Particle volume and particle size played critical roles in initiating cellular responses. There was a lower particle size limit, with the 20 nm FS showing the lowest activity. Nanometre-sized polyethylene particles (CD) caused elevated TNF-α release, and since it has been shown that nanometre-sized UHMWPE particles are produced in large numbers in vivo [2], the relative contribution of these particles to osteolysis should be considered. The biological response to nanometre-sized clinically relevant UHMWPE particles is currently under investigation.
Abstract Recurrence of solid tumors renders patients vulnerable to a distinctly advanced, highly treatment-refractory disease state that has an increased mutational burden and novel oncogenic drivers not detected at initial diagnosis. Improving outcomes for recurrent cancers requires a better understanding of cancer cell populations that expand from the post-therapy, minimal residual disease (MRD) state. We profiled barcoded tumor stem cell populations through therapy at tumor initiation/engraftment, MRD and recurrence in our therapy-adapted, patient-derived xenograft models of glioblastoma (GBM). Tumors showed distinct patterns of recurrence in which clonal populations exhibited either an a priori , pre-existing fitness advantage, or a priori equipotency fitness acquired through therapy. Characterization of the MRD state by single-cell and bulk RNA sequencing revealed a tumor-intrinsic immunomodulatory signature with strong prognostic significance at the transcriptomic level and in proteomic analysis of cerebrospinal fluid (CSF) collected from GBM patients at all stages of disease. Our results provide insight into the innate and therapy-driven dynamics of human GBM, and the prognostic value of interrogating the MRD state in solid cancers.
Abstract Glioblastoma (GBM) is a deadly cancer in which cancer stem cells (CSCs) sustain tumor growth and contribute to therapeutic resistance. Protein arginine methyltransferase 5 (PRMT5) has recently emerged as a promising target in GBM. Using two orthogonal-acting inhibitors of PRMT5 (GSK591 or LLY-283), we show that pharmacological inhibition of PRMT5 suppresses the growth of a cohort of 46 patient-derived GBM stem cell cultures, with the proneural subtype showing greater sensitivity. We show that PRMT5 inhibition causes widespread disruption of splicing across the transcriptome, particularly affecting cell cycle gene products. We identify a GBM splicing signature that correlates with the degree of response to PRMT5 inhibition. Importantly, we demonstrate that LLY-283 is brain-penetrant and significantly prolongs the survival of mice with orthotopic patient-derived xenografts. Collectively, our findings provide a rationale for the clinical development of brain penetrant PRMT5 inhibitors as treatment for GBM.
Ceramics have a history of use in total hip replacement (THR) including early use in hip resurfacing. Improvements in ceramics over the past two decades have resulted in the BIOLOX ® delta material which has a higher fracture resistance, low wear and excellent biocompatibility compared to other orthopaedic biomaterials. Cobalt Chromium Molybdenum (CoCrMo) metal alloy continues to be used in hip resurfacing but is generally limited to use of larger sizes in active males due to a legacy of concerns with metal ion release from discontinued devices and large diameter modular head trunnions. A novel hip resurfacing device (ReCerf ® , MatOrtho Ltd., UK) utilises BIOLOX ® delta, removing CoCrMo metal from the prosthesis. ReCerf ® is based on a clinically successful design from the same manufacturer (ADEPT ® , MatOrtho Ltd., UK) and although BIOLOX ® delta is a clinically proven material in THR, it requires significant testing to prove safety in the clinical environment. Increasing regulations particularly in Europe, has increased the time to market for new devices such as this and whilst the changes are being implemented to ensure the lowest risk for patients, they are also leaving patients unable to access new treatment routes. Ultimately, it is long term clinical outcomes that are required to determine whether the future of resurfacing is in using alternative materials such as ceramic and whether these compare favourably with the established, successful metal designs which have been in clinical use for over 20 years.
Recently, nanometre-sized UHMWPE particles generated from hip and knee replacements have been identified in vitro and in vivo. UHMWPE particles in the 0.1–1.0 μm size range have been shown to be more biologically active than larger particles, provoking an inflammatory response implicated in late aseptic loosening of total joint replacements. The biological activity of nanometre-sized particles has not previously been studied. The biological response to clinically-relevant UHMWPE wear particles including nanometre-sized and micrometre-sized, along with polystyrene particles (FluoSpheres 20 nm, 60 nm, 200 nm and 1.0 μm), and nanometre-sized model polyethylene particles (Ceridust 3615®), was determined in terms of osteolytic cytokine release from primary human peripheral blood mononuclear cells (PBMNCs). Nanometre-sized UHMWPE wear particles, nanometre-sized Ceridust 3615® and 20 nm FluoSpheres had no significant effect on TNF-α, IL-1β, IL-6 and IL-8 release from PBMNCs at a concentration of 100 μm3 particles per cell after 12 and 24 h. The micrometre-size UHMWPE wear particles (0.1–1.0 μm) and 60 nm, 200 nm and 1.0 μm FluoSpheres caused significantly elevated osteolytic cytokine release from PBMNCs. These results indicated that particles below circa 50 nm fail to activate PBMNCs and that particle size, composition and morphology played a crucial role in cytokine release by particle stimulated macrophages.
