Search results for "phage"

Influence of Surface Charge and Polymer Coating on Internalization and Biodistribution of Polyethylene Glycol-Modified Iron Oxide Nanoparticles

2015

International audience; The aim of this study was to investigate the influence of the surface charge and coating of Superparamagnetic Iron Oxide Nanoparticles (SPIONs) on their in vitro and in vivo behaviors. Neutral and negatively-charged PEG-based SPIONs were synthesized and compared to Resovist (R), a carboxydextran-based SPION currently used in clinics. Their cytotoxicity, cell internalization, and potential as contrast agents for magnetic resonance imaging were assessed. Neutral pegylated SPIONs were internalized less readily by the reticuloendothelial system and showed a lower uptake by the liver, compared to negatively-charged SPIONs (with carboxydextran and PEG). These results sugge…

Inference of the Life Cycle of Environmental Phages from Genomic Signature Distances to Their Hosts

2023

The environmental impact of uncultured phages is shaped by their preferred life cycle (lytic or lysogenic). However, our ability to predict it is very limited. We aimed to discriminate between lytic and lysogenic phages by comparing the similarity of their genomic signatures to those of their hosts, reflecting their co-evolution. We tested two approaches: (1) similarities of tetramer relative frequencies, (2) alignment-free comparisons based on exact k = 14 oligonucleotide matches. First, we explored 5126 reference bacterial host strains and 284 associated phages and found an approximate threshold for distinguishing lysogenic and lytic phages using both oligonucleotide-based methods. The an…

Human Macrophage Invasion: Gelatin‐Hyaluronan Click‐Crosslinked Cryogels Elucidate Human Macrophage Invasion Behavior (Adv. Funct. Mater. 28/2021)

2021

Heme oxygenase-1 induction by nitric oxide in RAW 264.7 macrophages is upregulated by a cyclo-oxygenase-2 inhibitor.

2001

Unstimulated RAW 264.7 macrophages express negligible heme oxygenase-1 (HO-1) protein but incubation with the nitric oxide (NO) donor spermine nonoate (SPNO) induced HO-1 and weakly cyclo-oxygenase-2 (COX-2) protein. This effect was potentiated by coincubation with the COX-2 selective inhibitor, SC58125. Cells incubated with SPNO showed a strong increase in HO-1 mRNA levels after 4 h with a significant potentiation in the presence of SC58125, which did not modify HO-1 mRNA stability. The induction of HO-1 by NO and its potentiation by anti-inflammatory agents may play a role in inflammatory and immune responses.

An inherited deficiency of the third component of complement, C3, in guinea pigs

1986

Hereditary deficiency of the third component of complement, C3, is found very seldom in the human. C3 deficiency is associated with severe bacterial infections revealing the central role of C3 in complement activation via the classical or alternative pathway. We describe a new hereditary C3 deficiency in strain 2 guinea pigs. Serum from these animals had a markedly reduced lytic activity in a standard assay for complement-dependent, antibody-mediated cytotoxicity. In functional assays of individual components, the hemolytic activity of the components C4, C2, C5 and of factors B, D and H was in the normal range. The functional C3 titer, and similarly C3 antigenic activity in the serum of the…

Vitamin C blocks inflammatory platelet-activating factor mimetics created by cigarette smoking.

1997

Cigarette smoking within minutes induces leukocyte adhesion to the vascular wall and formation of intravascular leukocyte-platelet aggregates. We find this is inhibited by platelet-activating factor (PAF) receptor antagonists, and correlates with the accumulation of PAF-like mediators in the blood of cigarette smoke-exposed hamsters. These mediators were PAF-like lipids, formed by nonenzymatic oxidative modification of existing phospholipids, that were distinct from biosynthetic PAF. These PAF-like lipids induced isolated human monocytes and platelets to aggregate, which greatly increased their secretion of IL-8 and macrophage inflammatory protein-1alpha. Both events were blocked by a PAF r…

Including Ratio of Platelets to Liver Stiffness Improves Accuracy of Screening for Esophageal Varices That Require Treatment

2021

International audience; Background & aims: Based on platelets and liver stiffness measurements, the Baveno VI criteria (B6C), the expanded B6C (EB6C), and the ANTICIPATE score can be used to rule out varices needing treatment (VNT) in patients with compensated chronic liver disease. We aimed to improve these tests by including data on the ratio of platelets to liver stiffness.Methods: In a retrospective analysis of data from 10 study populations, collected from 2004 through 2018, we randomly assigned data from 2368 patients with chronic liver disease of different etiologies to a derivation population (n = 1579; 15.1% with VNT, 50.2% with viral hepatitis, 28.9% with nonalcoholic fatty liver …

Platelet-localized FXI promotes a vascular coagulation-inflammatory circuit in arterial hypertension

2017

Multicellular interactions of platelets, leukocytes, and the blood vessel wall support coagulation and precipitate arterial and venous thrombosis. High levels of angiotensin II cause arterial hypertension by a complex vascular inflammatory pathway that requires leukocyte recruitment and reactive oxygen species production and is followed by vascular dysfunction. We delineate a previously undescribed, proinflammatory coagulation-vascular circuit that is a major regulator of vascular tone, blood pressure, and endothelial function. In mice with angiotensin II-induced hypertension, tissue factor was up-regulated, as was thrombin-dependent endothelial cell vascular cellular adhesion molecule 1 ex…

Platelets accumulate in lung lesions of tuberculosis patients and inhibit T-cell responses and Mycobacterium tuberculosis replication in macrophages

2021

: Platelets regulate human inflammatory responses that lead to disease. However, the role of platelets in tuberculosis (TB) pathogenesis is still unclear. Here, we show that patients with active TB have a high number of platelets in peripheral blood and a low number of lymphocytes leading to a high platelets to lymphocytes ratio (PL ratio). Moreover, the serum concentration of different mediators promoting platelet differentiation or associated with platelet activation is increased in active TB. Immunohistochemistry analysis shows that platelets localise around the lung granuloma lesions in close contact with T lymphocytes and macrophages. Transcriptomic analysis of caseous tissue of human …

Enhanced platelet thromboxane synthesis and reduced macrophage-dependent fibrinolytic activity related to oxidative stress in oral contraceptive-trea…

1996

Abstract In previous studies conducted in rats and in women, we have shown that oral contraceptive (OC) administration induced a platelet hyperaggregation simultaneously with an increased platelet lipid biosynthesis which might be related to lipid peroxidation. In the present study, we specifically studied the arachidonic acid and the fibrinolytic pathways in relation to the fatty acid composition in female rats treated for 6 weeks with OC (ethinyl estradiol plus lynestrenol). We found that platelets of treated animals were not only hyper-responsive to thrombin and ADP, but also to sodium arachidonate. In addition, the results of the thrombin-induced release of labeled arachidonic acid pre-…