Antibody-mediated phagocytosis contributes to the anti-tumor activity of the therapeutic antibody daratumumab in lymphoma and multiple myeloma

Daratumumab (DARA) is a human CD38-specific IgG1 antibody that is in clinical development for the treatment of multiple myeloma (MM). The potential for IgG1 antibodies to induce macrophage-mediated phagocytosis, in combination with the known presence of macrophages in the tumor microenvironment in MM and other hematological tumors, led us to investigate the contribution of antibody-dependent, macrophage-mediated phagocytosis to DARA''s mechanism of action. Live cell imaging revealed that DARA efficiently induced macrophage-mediated phagocytosis, in which individual macrophages rapidly and sequentially engulfed multiple tumor cells. DARA-dependent phagocytosis by mouse and human macrophages was also observed in an in vitro flow cytometry assay, using a range of MM and Burkitt''s lymphoma cell lines. Phagocytosis contributed to DARA''s anti-tumor activity in vivo, in both a subcutaneous and an intravenous leukemic xenograft mouse model. Finally, DARA was shown to induce macrophage-mediated phagocytosis of MM cells isolated from 11 of 12 MM patients that showed variable levels of CD38 expression. In summary, we demonstrate that phagocytosis is a fast, potent and clinically relevant mechanism of action that may contribute to the therapeutic activity of DARA in multiple myeloma and potentially other hematological tumors.     

Characterisation of a thermostable and proteolysis resistant phytase from Penicillium polonicum MF82 associated with the marine sponge Phorbas sp.

Abstract

Phytases are widely used in human and animal nutrition, aquaculture, soil amendment, and in the production of lower myo-inositol phosphates for clinical purposes. Some of these applications, especially feed industry require robust enzymes. Since the marine environments are less studied compared to terrestrial environments, we evaluated the extracellular phytase activity of 110 marine derived filamentous fungal (MDFF) strains previously isolated from sponge and sediment samples of the Turkey. MDFF strains were qualitatively screened for their extracellular phytase activities and P. polonicum MF82 phytase was further characterized following partial purification. Optimum pH and temperature were determined as 5.5 and 60?°C respectively. A significant relative phytase activity was observed in the presence of urea and acetone. However, there was no phytase activity followed by the treatment with Triton X-100 and Tween 80. Characterization studies revealed that P. polonicum MF82 phytase has superior properties for industrial use including wide pH and temperature range for activity, high optimum activity temperature, high thermal and pH stability, resistance to many enzyme inhibitors including various heavy metals, denaturants, detergents, proteases and organic solvents. Phytase extracellularly produced by P. polonicum MF82 strain presents a good candidate for commercial applications. This study demonstrates that the MDFF strains are prolific sources for phytase and presents the first report about the production and characterization of the phytase from a marine-derived P. polonicum strain.     

Effects of organophosphate insecticides on mechanical properties of rat aorta

The present study was carried out to search whether organophosphate pesticides affect the mechanical properties of the thoracic aorta. Wistar female rats (aged 6-8 weeks) were assigned randomly to a control group and groups treated with either dichlorvos or chlorpyriphos for 90 days at a dose of 5 mg/kg/day. After that period, animals were killed and thoracic aorta strips in longitudinal direction were isolated. The stress, strain and elastic modulus were obtained from the strips. Our results showed that chronic administration of chlorpyriphos and dichlorvos caused downward shift of the stress-strain relations compared to the control curve. The elastic modulus-stress curve revealed distinct characteristics in the low and high stress regions. A power function was used to simulate the low stress region while a line was fit to the high stress region. Curve fitting procedure illustrated that both pesticides influenced mainly the high stress region, but they had diverse effects at the low stress region. The results also imply that chlorpyriphos and dichlorvos decrease the strength of the aorta and therefore might influence the response of the aorta to mechanical loading induced by blood pressure.     

A MEMS-based spiral channel dielectrophoretic chromatography system for cytometry applications

In this paper design, fabrication, and evaluation of an easy-to-use and low cost dielectrophoretic quantizer are introduced. The device works with standard tools in a biomedical laboratory: a stereo microscope with CCD camera and a voltage supply. A novel spiral microchannel geometry together with the coaxial electrode configuration is established. The device works with a droplet of sample, eliminating microfluidic connections, and external syringes. The proposed geometry decreases the footprint, therefore reduces the device cost, without compromizing the separation and quantization performances. Coaxial electrode geometry enables continuous electric-field application with simple voltage supplies. The devices are fabricated using a simple 3-mask process, and experiments are realized with 1 and 10 μm polystyrene beads. The results show that 1 μm particles have an average speed of 4.57 μm/s with 1.06 μm/s SD, and 10 μm particles have an average speed of 544 μm/s with 105 μm/s SD. The speed variation coefficient for 1 and 10 μm beads can be calculated as 23 and 19%, respectively. The size accuracy of the device is ± 10%, while the resolution is 20%, i.e., particles with radii different from each other by 20% can be separated. Hence, moderate separation performance with minimized cost and standard laboratory equipment is enabled.     

Regional collaborative home-based palliative care and health care outcomes among adults with heart failure

BackgroundInnovative models of collaborative palliative care are urgently needed to meet gaps in end-of-life care among people with heart failure. We sought to determine whether regionally organized, collaborative, home-based palliative care that involves cardiologists, primary care providers and palliative care specialists, and that uses shared decision-making to promote goal- and need-concordant care for patients with heart failure, was associated with a greater likelihood of patients dying at home than in hospital.MethodsWe conducted a population-based matched cohort study of adults who died with chronic heart failure across 2 large health regions in Ontario, Canada, between 2013 and 2019. The primary outcome was location of death. Secondary outcomes included rates of health care use, including unplanned visits to the emergency department, hospital admissions, hospital lengths of stay, admissions to the intensive care unit, number of visits with primary care physicians or cardiologists, number of home visits by palliative care physicians or nurse practitioners, and number of days spent at home.ResultsPatients who received regionally organized, collaborative, home-based palliative care (n = 245) had a 48% lower associated risk of dying in hospital (relative risk 52%, 95% confidence interval 44%–66%) compared with the matched cohort (n = 1172) who received usual care, with 101 (41.2%) and 917 (78.2%) patients, respectively, dying in hospital (number needed to treat = 3). Additional associated benefits of the collaborative approach included higher rates of clinician home visits, longer time to first hospital admission, shorter hospital stays and more days spent at home.InterpretationAdoption of a model of regionally organized, collaborative, home-based palliative care that uses shared decision-making may improve end-of-life outcomes for people with chronic heart failure.

Innovative models of collaborative, interdisciplinary palliative care that use shared decision-making to promote goal- and need-concordant care are urgently needed to meet rising demand among people with heart failure.^1,2 Between 2010 and 2015, 75% of people with heart failure in Ontario died in hospital, despite 70% of people preferring an out-of-hospital death and 90% preferring end-of-life health care delivery at home.^3–5 Most people also prioritize improvements in quality of life at the end of life over extension of life.⁶ Admission to hospital near the end of life is often perceived as undesirable and may result in the provision of unwanted care, whereas home visits near the end of life tend to focus on comfort and are associated with higher rates of death at home.^4,5,7,8 These preferences are recognized at a system level, such that avoidance of unwanted health care and at-home death are considered quality indicators for end-of-life care.^9–11 However, delivering high-quality care for people with heart failure who are near the end of their life is challenging because of their unpredictable illness course and limited capacity of specialist palliative care.^4,12–14Many studies, including a recent meta-analysis, have shown that home-based palliative care is associated with improved quality of life and symptoms, reduced health care use and a higher likelihood of a home death among people with heart failure. ^{4,8,12,13,15,16} However, only 32% of people with heart failure received home-based palliative care near the end of life in Ontario.^4,8 Several randomized controlled trials explored the effects of collaborative care models for people with heart failure; ^12–16 the results were mixed regarding quality of life, symptoms and health care use.^13,17–21 Some trials reported that palliative care resulted in improvements in quality of life and reductions in burdensome symptoms and hospital admissions, whereas others reported no change in these outcomes.¹³ Most studies were single centre and none evaluated a model of regional organization and in-person home visits as a scalable approach.Given the need to address end-of-life care gaps for people with heart failure, we sought to determine whether regionally organized, collaborative, home-based palliative care (CHPC) — involving cardiology, primary care and palliative care — was associated with increased rates of out-of-hospital death among adults who died with heart failure.     

Improved salt tolerance of melon (Cucumis melo L.) by the addition of proline and potassium nitrate

A pot experiment was carried out under glasshouse conditions with melon (Cucumis melo) cv. “Tempo F1” in a mixture of peat, perlite and sand (1:1:1) to investigate the effects of external proline and potassium nitrate applications to salinity-treated (150 mM) plants with respect to fruit yield, plant growth, some physiological parameters and ion uptake. Treatments were—(i) control (C): plants receiving nutrient solution, (ii) salinity treatment, as for control plus 150 mM NaCl. Salinity treatment was combined with or without either 5 mM supplementary KNO₃ or 10 mM proline. The salt treatment (150 mM NaCl) led to significant decreases in plant growth, fruit yield, relative water content (RWC), stomatal density, uptake of Ca²⁺, K⁺ and N, and chlorophyll a and b contents, accompanied by significant increases in Na⁺ uptake, proline concentration and membrane permeability. Supplementary KNO₃ and proline treatments significantly ameliorated the adverse effects of salinity on plant growth, fruit yield and the physiological parameters examined. This could be attributed to the effects of all the external supplements in maintaining membrane permeability, and increasing concentrations of Ca²⁺, N and K⁺ in the leaves of plants subjected to salt stress.     

Compensation of Missing Wedge Effects with Sequential Statistical Reconstruction in Electron Tomography

Electron tomography (ET) of biological samples is used to study the organization and the structure of the whole cell and subcellular complexes in great detail. However, projections cannot be acquired over full tilt angle range with biological samples in electron microscopy. ET image reconstruction can be considered an ill-posed problem because of this missing information. This results in artifacts, seen as the loss of three-dimensional (3D) resolution in the reconstructed images. The goal of this study was to achieve isotropic resolution with a statistical reconstruction method, sequential maximum a posteriori expectation maximization (sMAP-EM), using no prior morphological knowledge about the specimen. The missing wedge effects on sMAP-EM were examined with a synthetic cell phantom to assess the effects of noise. An experimental dataset of a multivesicular body was evaluated with a number of gold particles. An ellipsoid fitting based method was developed to realize the quantitative measures elongation and contrast in an automated, objective, and reliable way. The method statistically evaluates the sub-volumes containing gold particles randomly located in various parts of the whole volume, thus giving information about the robustness of the volume reconstruction. The quantitative results were also compared with reconstructions made with widely-used weighted backprojection and simultaneous iterative reconstruction technique methods. The results showed that the proposed sMAP-EM method significantly suppresses the effects of the missing information producing isotropic resolution. Furthermore, this method improves the contrast ratio, enhancing the applicability of further automatic and semi-automatic analysis. These improvements in ET reconstruction by sMAP-EM enable analysis of subcellular structures with higher three-dimensional resolution and contrast than conventional methods.