21,369 research outputs found
Antibacterial and Antifungal Efficacy of Medium and Low Weight Chitosan-Shelled Nanodroplets for the Treatment of Infected Chronic Wounds [* V. Allizond is the corresponding author; **A.M. Cuffini and G. Banche are co-last authors]
No full textPurpose: Medium versus low weight (MW vs LW) chitosan-shelled oxygen-loaded nanodroplets (cOLNDs) and oxygen-free nanodroplets (cOFNDs) were comparatively challenged for biocompatibility on human keratinocytes, for antimicrobial activity against four common infectious agents of chronic wounds (CWs) - methicillin-resistant Staphylococcus aureus (MRSA), Streptococcus pyogenes, Candida albicans and C. glabrata - and for their physical interaction with cell walls/membranes. Methods: cNDs were characterized for morphology and physico-chemical properties by microscopy and dynamic light scattering. In vitro oxygen release from cOLNDs was measured through an oximeter. ND biocompatibility and ability to promote wound healing in human normoxic/hypoxic skin cells were challenged by LDH and MTT assays using keratinocytes. ND antimicrobial activity was investigated by monitoring upon incubation with/without MW or LW cOLNDs/cOFNDs either bacteria or yeast growth over time. The mechanical interaction between NDs and microorganisms was also assessed by confocal microscopy. Results: LW cNDs appeared less toxic to keratinocytes than MW cNDs. Based on cell counts, either MW or LW cOLNDs and cOFNDs displayed long-term antimicrobial efficacy against S. pyogenes, C. albicans, and C. glabrata (up to 24 h), whereas a short-term cytostatic effects against MRSA (up to 6 h) was revealed. The internalization of all ND formulations by all four microorganisms, already after 3 h of incubation, was showed, with the only exception to MW cOLNDs/cOFNDs that adhered to MRSA walls without being internalized even after 24 h. Conclusion: cNDs exerted bacteriostatic and fungistatic effects, due to the presence of chitosan in the outer shell and independently of oxygen addition in the inner core. The duration of such effects strictly depends on the characteristics of each microbial species, and not on the molecular weight of chitosan in ND shells. However, LW chitosan was better tolerated by human keratinocytes than MW. For these reasons, the use of LW NDs should be recommended in future research to assess cOLND efficacy for the treatment of infected CWs
Immunomodulating effect of antimicrobial agents on cytokine production by human polymorphonuclear neutrophils
No full textIt has been previously demonstrated that some antimicrobial agents enhance activities of human polymorphonuclear neutrophils (PMNs). The effect on the release of cytokines in an inflammatory context from PMNs by these antibiotics was evaluated. We studied the effect of the release of some cytokines by human PMNs RT-PCR analysis on a clinical strain of Klebsiella pneumoniae by comparing the effect with that observed in the presence of co-amoxiclav, sanfetrinem, clarithromycin, prulifloxacin and tobramycin. All the drugs tested were capable of modulating PMN synthesis in vitro of pro-inflammatory cytokines IL-8, IL-1β, TNF-α and IL-6, but not that of anti-inflammatory cytokine IL-10. The degree of their stimulatory or inhibitory potency varied with the cytokine examined. © 2003 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved
Protecting Animals 36: Author Witi Ihimaera
No full textIn this very special episode of Knowing Animals I am joined by beloved New Zealand author Witi Ihimaera. Witi has written many books featuring nonhuman animals. He offers us a non-colonial lens through which to think about the human/nonhuman relationship
I Think I Am Philip K. Dick
No full textFor years, noted writer Laurence A. Rickels often found himself compared to novelist Philip K. Dickthough in fact Rickels had never read any of the science fiction writers work. When he finally read his first Philip K. Dick novel, while researching for his recent book The Devil Notebooks , it prompted a prolonged immersion in Dicks writing as well as a recognition of Rickelss own long-documented intellectual pursuits. The result of this engagement is I Think I Am: Philip K. Dick , a profound thought experiment that charts the wide relevance of the pulp sci-fi author and paranoid visionary. I Think I Am: Philip K. Dick explores the science fiction authors meditations on psychic reality and psychosis, Christian mysticism, Eastern religion, and modern spiritualism. Covering all of Dicks science fiction, Rickels corrects the lack of scholarly interest in the legendary Californian author and, ultimately, makes a compelling case for the philosophical and psychoanalytic significance of Philip K. Dicks popular and influential science fiction.Intro -- Contents -- Introjection -- Part I -- Endopsychic Allegories -- Schreber Guardian -- Belief System Surveillance -- Part II -- Deeper Problems -- Veil of Tears -- Go West -- Dick Manfred -- Timing -- Glimmung -- Part III -- Spiritualism Analogy -- Imitating the Dead -- Indexical Layer -- Ilse -- Hammers and Things -- Crucifictions -- Over There -- Martyrology -- Can't Live, Can't Live -- Lola -- Umwelt, Mitwelt, and Eigenwelt -- Outer Race -- The German Introject -- Part IV -- Materialism, Idealism, and Cybernetics -- Startling Stories -- A Couple of Years -- Android Empathy -- Homunculus and Robot -- ALL OF YOU ARE DEAD. I AM ALIVE. -- Go with the Flow -- Part V -- Room for Thought -- Caduceus -- Jump -- Still -- A Wake -- Spätwerk -- Let the Dead Be -- Play Bally -- Das Hund -- Notes -- BibliographyFor years, noted writer Laurence A. Rickels often found himself compared to novelist Philip K. Dickthough in fact Rickels had never read any of the science fiction writers work. When he finally read his first Philip K. Dick novel, while researching for his recent book The Devil Notebooks , it prompted a prolonged immersion in Dicks writing as well as a recognition of Rickelss own long-documented intellectual pursuits. The result of this engagement is I Think I Am: Philip K. Dick , a profound thought experiment that charts the wide relevance of the pulp sci-fi author and paranoid visionary. I Think I Am: Philip K. Dick explores the science fiction authors meditations on psychic reality and psychosis, Christian mysticism, Eastern religion, and modern spiritualism. Covering all of Dicks science fiction, Rickels corrects the lack of scholarly interest in the legendary Californian author and, ultimately, makes a compelling case for the philosophical and psychoanalytic significance of Philip K. Dicks popular and influential science fiction.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
Innovative titanium alloy surfaces able to promote bone integration and avoid bacterial contamination
No full textIntroduction: An ideal surface for orthopedic implants should improve cellular adhesion and reduce bacterial one. A proper stimulation of the cell activity is the last request to the new biomaterials, intended for bone substitution and osseointegration. In this regard, the scientific literature suggests that the surface modification on a nanoscale is a major source of innovation. Furthermore, numerous solutions have been proposed to face the problem of the bacterial contamination and to prevent the development of prosthetic infections. The considered solutions are based on inorganic antibacterial agents, such as silver (Ag) copper or zinc, which have been introduced to overcome the growing problem of bacterial resistance to antibiotics.
The aim of the present research work is the development of innovative antibacterial and bioactive titanium alloy (Ti6Al4V) surfaces, able to promote fast and physiological bone integration and avoid bacterial contamination.
Materials and methods
Ti6Al4V disks were surface modified by means of a patented process that foresees a first etching in diluted hydrofluoric acid and a subsequent controlled oxidation in hydrogen peroxide, added with Ag.The surface topography and chemical composition of modified surfaces were characterized by means of Field Emission Scanning Electron Microscopy, X-ray Photoelectron Spectroscopy (XPS) and Fourier Transformed Infrared Spectroscopy (FT-IR). In vitro bioactivity was investigated by soaking samples in Simulated Body Fluid (SBF) and Ag release was quantified in double distilled water. The modified surface antibacterial activity was tested against Staphylococcus aureus ATCC 29213 by means of inhibition halo on agar medium and quantitative bacterial adhesion assays by using a sonication protocol to dislodge adherent microorganisms.
Results
Modified Ti6Al4V samples present a titanium oxide layer with a peculiar nanotexture that can be described as a nanometric sponge. Ag nanoparticles are embedded in this surface layer by the addition of an Ag precursor in the hydrogen peroxide bath. XPS analyses indicate that Ag is in the metallic form. Ag nanoparticles are responsible of Ag ion release in water: the released Ag amount is higher than what required to have an antibacterial action and lower that the cytotoxic limit reported in the literature. The results of antibacterial tests confirm these data and reveal an effective antibacterial behaviour of modified surfaces against S. aureus. Moreover a reduced bacterial adhesion has been observed on nanotextured surfaces compared to the polished ones. The modified surfaces are rich in hydroxyls groups (FT-IR and XPS evidence) and they are able to induce hydroxyapatite precipitation after immersion in SBF.
Conclusions
In this study, a nanotextured titanium oxide layer rich in hydroxyl groups and embedded with Ag nanoparticles has been obtained. Modified surfaces are bioactive by inducing hydroxyapatite precipitation in SBF, release Ag ions and present an antibacterial action against S. aureus. Considering the reported results, the obtained innovative Ti6Al4V surfaces are promising for orthopaedic applications to induce fast and physiological bone integration and to reduce the incidence of prosthetic infections
Liftings for noncomplete probability spaces
No full textThe current state of knowledge concerning liftings for noncomplete probability spaces is discussed. This is a somewhat expanded version of the author's talk given at the 1991 Summer Conference on General Topology and Applications in Honor of Mary Ellen Rudin and Her Work.PT: S; CR: BURKE MR, IN PRESS P AM MATH S BURKE MR, 1991, ISRAEL J MATH, V73, P33 BURKE MR, 1992, ISRAEL J MATH, V79, P289 CARLSON T, THEOREM LIFTING CHRISTENSEN JPR, 1974, TOPOLOGY BOREL STRUC FREMLIN DH, 1989, HDB BOOLEAN ALGEBRAS, P877 INOESCUTULCEA A, 1966, 5TH P BERK S MATH ST, V2 IONESCUTULCEA A, 1967, CONTRIBUTIONS PROB 1, P63 IONESCUTULCEA A, 1969, TOPICS THEORY LIFTIN JECH TJ, 1978, SET THEORY JOHNSON RA, 1980, P AM MATH SOC, V80, P234 JUST W, IN PRESS T AM MATH S KUPKA J, 1983, INDIANA U MATH J, V32, P717 LOSERT V, 1983, LNM, V1080, P95 MAHARAM D, 1958, P AM MATH SOC, V9, P987 SHELAH S, 1983, ISRAEL J MATH, V45, P90 TALAGRAND M, 1982, P AM MATH SOC, V84, P379 VONNEUMANN J, 1931, CRELLES J MATH, V165, P109; NR: 18; TC: 0; J9: ANN N Y ACAD SCI; PG: 4; GA: BZ86BSource type: Electronic(1
Improvement of clinical response in allergic rhinitis patients treated with an oral immunostimulating bacterial lysate: in vivo immunological effects
No full textIN VITRO DALBAVANCIN ACTIVITY AGAINST CLINICAL ISOLATES OF STAPHYLOCOCCUS SPP. AND SUBSEQUENT INTERACTION WITH HUMAN PHAGOCYTES
No full textIntroduction: Dalbavancin is a semisynthetic long-acting lipoglycopeptide antibiotic recently approved in the United States by the Federal
Drug Administration (FDA) for treatment of adult patients with acute bacterial skin and skin structure infections caused by susceptible Gram-positive bacteria. Among the Gram-positive bacteria, dalbavancin has a broad spectrum of action against most microorganisms, including those resistant to other antimicrobial families. The aims of this study were to evaluate the activity of dalbavancin against Staphylococcus aureus and Staphylococcus epidermidis clinical strains and to determine the straightforward performance of dalbavancin
upon the binomial antibiotic resistant/susceptible bacterium and host defenses, to establish its potential immunomodulating activity. Materials and Methods: Twenty-five isolates of methicillin-susceptible S. aureus (MSSA), 25 isolates of methicillin-resistant S. aureus
(MRSA), 25 isolates of methicillin-resistant and teicoplanin susceptible S. epidermidis (MRSE-TeicoS), 25 isolates of methicillin-resistant and
teicoplanin resistant S. epidermidis (MRSE-Teico R) were collected from various clinical sources and studied. Minimum inhibitory concentrations (MICs) of dalbavancin were determined by broth microdilution according to Clinical and Laboratory Standards Institute guidelines. Additionally the human polymorphonuclear cells (PMNs) functional activity [(microbicidal activity and cytokine release profile (TNF-α, IL-1β, IL-10)] was investigated by incubating MRSA and phagocytes for 30, 60, 90 and 120 minutes with dalbavancin at MIC level.
Results: Dalbavancin demonstrated in vitro activity against all isolates tested with MICs ≤ 0.12 μg/ mL, the FDA susceptible breakpoint for S. aureus. The normal MIC distribution among S. aureus (both MSSA and MRSA) and S. epidermidis (both MRSE-Teico S and MRSE-Teico R) isolates was between 0.03-0.12 μg/mL, with a clear modal MIC of 0.06 μg/mL for MSSA, MRSA and MRSE-Teico S, and 0.12 μg/mL for MRSE-Teico R. Moreover, the data on PMN activity showed that dalbavancin at MIC concentration had effect on both MRSA intracellular killing and cytokine release, in comparison with dalbavancin-free controls, for the entire period of observation.
Conclusions: The need for new agents with potent activity against staphylococci is acute due to increased resistance to most common currently available antibiotics. Our results confirm and extent previous literature data on the antistaphylococcal activity of dalbavancin: it has activity not only in fighting staphylococcal resistant strains, but also in influencing PMN microbicidal activity. These data
support the continued clinical study of dalbavancin in infections where staphylococci are prevalent
The AM Canum Venaticorum binary SDSS J173047.59+554518.5
No full textThe AM Canum Venaticorum (AM CVn) binaries are a rare group of hydrogen-deficient, ultrashort period, mass-transferring white dwarf binaries and are possible progenitors of Type Ia supernovae. We present time-resolved spectroscopy of the recently discovered AM CVn binary SDSS J173047.59+554518.5. The average spectrum shows strong double-peaked helium emission lines, as well as a variety of metal lines, including neon; this is the second detection of neon in an AM CVn binary, after the much brighter system GP Com. We detect no calcium in the accretion disc, a puzzling feature that has been noted in many of the longer period AM CVn binaries. We measure an orbital period, from the radial velocities of the emission lines, of 35.2 ± 0.2 min, confirming the ultracompact binary nature of the system. The emission lines seen in SDSS J1730 are very narrow, although double-peaked, implying a low-inclination, face-on accretion disc; using the measured velocities of the line peaks, we estimate i ≤ 11°. This low inclination makes SDSS J1730 an excellent system for the identification of emission lines
Vitamin E blended UHMWPE has the potential to reduce bacterial adhesive ability [*G.Banche and P. Bracco contributed equally to this work; ** AM Cuffini is the corresponding author]
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