The Experts below are selected from a list of 3060 Experts worldwide ranked by ideXlab platform

K Kwiatek - One of the best experts on this subject based on the ideXlab platform.

H W Ockerman - One of the best experts on this subject based on the ideXlab platform.

Mark E Meyerhoff - One of the best experts on this subject based on the ideXlab platform.

  • thromboresistant anti biofilm catheters via electrochemically modulated nitric oxide release
    Bioelectrochemistry, 2015
    Co-Authors: Alessandro Colletta, Dipankar Koley, Jianfeng Wu, Chuanwu Xi, Terry C Major, Robert H Bartlett, Mark E Meyerhoff
    Abstract:

    Abstract Inexpensive nitric oxide (NO) release strategies to prevent thrombosis and bacterial infections are desirable for implantable medical devices. Herein, we demonstrate the utility of electrochemically modulated NO release from a catheter model using an inner copper wire working electrode and an inorganic Nitrite Salt solution reservoir. These catheters generate NO surface fluxes of > 1.0 × 10 − 10  mol min − 1  cm − 2 for more than 60 h. Catheters with an NO flux of 1.1 × 10 − 10  mol min − 1  cm − 2 are shown to significantly reduce surface thrombus formation when implanted in rabbit veins for 7 h. Further, the ability of these catheters to exhibit anti-biofilm properties against bacterial species commonly causing bloodstream and urinary catheter infections is examined. Catheters releasing NO continuously during the 2 d growth of Staphylococcus aureus exhibit a 6 log-unit reduction in viable surface bacteria. We also demonstrate that catheters generating NO for only 3 h at a flux of 1.0 × 10 − 10  mol min − 1  cm − 2 lower the live bacterial counts of both 2 d and 4 d pre-formed Escherichia coli biofilms by > 99.9%. Overall, the new electrochemical NO-release devices could provide a cost-effective strategy to greatly enhance the biocompatibility and antimicrobial properties of intravascular and urinary catheters, as well as other implantable medical devices.

  • electromodulated release of nitric oxide through polymer material from reservoir of inorganic Nitrite Salt
    RSC Advances, 2012
    Co-Authors: Lajos Hofler, Dipankar Koley, Mark E Meyerhoff
    Abstract:

    Herein, we report a new approach to electromodulate the release of NO at physiological levels through polymeric materials from a stable Nitrite electrolyte reservoir, with potential application in controlling biofilm formation and clotting on intravascular catheters. The NO flux can be turned ‘on’ and ‘off’ electrochemically, on demand.

  • catalytic generation of nitric oxide from Nitrite at the interface of polymeric films doped with lipophilic cu ii complex a potential route to the preparation of thromboresistant coatings
    Biomaterials, 2004
    Co-Authors: Bong Kyun Oh, Mark E Meyerhoff
    Abstract:

    Abstract A novel approach potentially useful for the development of more thromboresistant polymeric materials is examined. The method is based on the catalytic generation of nitric oxide (NO) via Cu(I) mediated reduction of Nitrite ions. Preliminary solution phase studies demonstrate that ascorbate or thiolate anions can generate Cu(I) from Cu(II) with subsequent catalytic conversion of any Nitrite ions present to NO by the unstable Cu(I) species. Incorporation of this same chemistry within a hydrophobic polymeric material requires immobilizing Cu(II) ions into a polymeric phase via use of a lipophilic Cu(II) chelating ligand (dibenzo [e,k]-2,3,8,9-tetraphenyl-1,4,7,10-tetraaza-cyclododeca-1,3,7,9-tetraene (DTTCT)). It is shown that this complex can be reduced to its Cu(I) form by appropriate reducing equivalents present in the bathing solution. The resulting Cu(I) complex can then reduce Nitrite to NO with the NO generation occurring at the polymer/solution interface at physiological pH. Data from chemiluminescence experiments indicate that the flux of NO at the polymer surface is comparable to that of endothelial cells (⩾1×10 −10  mol/cm 2  min) when 0.5 m m Nitrite/1 m m ascorbate are present in the bathing solution. Potentially more useful NO generation can be achieved by doping the polymer film with the Cu(II) complex along with a lipophilic quaternary ammonium Nitrite Salt. In this case reducing equivalents within the aqueous phase enable the Nitrite derived from the polymer to be converted into NO by the Cu(II/I) ligand complex. Films of this type are shown to generate NO for at least 6 h in PBS buffer with fluxes on the order of 1.5×10 −10  mol/cm 2  min. Physiologically relevant levels of NO release are also shown to exist at the polymer interface when films are soaked in fresh plasma as well as undiluted whole blood, indicating that endogenous reducing equivalents present in blood can efficiently reduce the Cu(II)-ligand within the polymer film. The prospects of using these new NO releasing films to devise more biocompatible polymeric coatings for biomedical applications are discussed.

E Fulladosa - One of the best experts on this subject based on the ideXlab platform.

  • physicochemical characterisation of restructured fenalar and safety implications of Salt and Nitrite reduction
    Food Control, 2021
    Co-Authors: E Collbrasas, Aricia Possas, P Berg, V Grabež, Bjorg Egelandsdal, S Bovercid, E Fulladosa
    Abstract:

    Abstract There is a new trend to produce dry-cured ham from lamb in shorter times by boning the ham before Salting to later obtain restructured hams that are easier to dry and slice. However, little information about the physicochemical characteristics of Norwegian Fenalars during the process or the safety implications of their elaboration procedures is reported in the literature. The aim of this study was to characterize the colour, texture and physicochemical properties of restructured Fenalars when using Standard Salting (SS), Salt Reduced (SR) and a Non-Nitrite Salt Reduced (NNSR) treatments. Microbiological safety implications of the elaboration process when using the different Salting treatments were also assessed using predictive microbiology. To do so, sixty Fenalars were elaborated using a Standard Salting (SS), a Salt reduced (SR) and a Non-Nitrite Salt Reduced (NNSR) treatments. Physicochemical characterization (instrumental colour and texture and Zinc Protoporphyrin content) was performed at the end of the process using thirty Fenalars. The rest of the Fenalars were used to characterize the product through the elaboration process (pH and aw) for the evaluation of microbiological hazards when using the different Salting treatments using predictive microbiology. Results showed a significant increase in softness when reducing Salt content and a decrease of redness when no Nitrite was used, attributed to the formation of ZnPP content instead of nitrosylmyoglobin. In terms of risk assessment, the decrease of aw through the elaboration process reduced the growth capacity of all the microorganisms evaluated. However, microbiological safety implications in Salt reduced Fenalars are important, especially when no Nitrite was added, because the considerable increase of growth potential of L. monocytogenes. The increase of growth potential of proteolytic C. botulinum is very little and no relevant effect of Nitrite on growth potential of S. aureus was observed. Predictive microbiology and optimization of the process to enhance ZnPP formation can help to ensure safety and quality of Salt reduced restructured Fenalars without additives.

Jorgen Lerfall - One of the best experts on this subject based on the ideXlab platform.

  • sodium Nitrite Salt curing and effects on carotenoid and n nitrosoamines in marine foods
    Processing and Impact on Active Components in Food, 2015
    Co-Authors: Jorgen Lerfall
    Abstract:

    The use of sodium Nitrite in marine food is controversial and it is strictly regulated. At present, Nitrite-curing is prohibited in most countries with some exceptions (e.g., salmonids in the USA). Nitrite-curing of salmonids improves the fillet color due to formation of a nitroso-heme complex. However, retention of carotenoids throughout processing is mostly affected by Salting method applied, whereas only minor effects of added Nitrite are reported. Addition of Nitrite as a food additive can induce formation of N-nitrosoamines in the product or endogenously. No studies have yet reported increased levels of N-nitrosoamines in salmonid fillets treated with Nitrite as compared to fillets treated without. However, one should be more vigilant not to add Nitrite to marine species which contain significant levels of secondary amines. In addition, small amounts of Nitrite may also be formed during processing of fish products which allows small amounts of N-nitrosoamines to be formed naturally.

  • use of sodium Nitrite in Salt curing of atlantic salmon salmo salar l impact on product quality
    Food Chemistry, 2011
    Co-Authors: Jorgen Lerfall, Marianne Osterlie
    Abstract:

    Abstract Quality changes during processing and quality differences in smoked fillets of Atlantic salmon (4–5 kg) Salted with Nitrite Salt compared to table Salted fillets were measured. Quality parameters from right-side fillets dry Salted with Nitrite Salt were compared with the respective left-side fillets treated the same way with table Salt. Ten raw right-side fillets were analysed and used as raw material reference. Use of Nitrite Salt in Salt-curing of smoked salmon affected colour to a more reddish hue, tended to increase carotenoid stability and displayed positive effects on NaCl diffusivity. Only slight weight changes and change in texture properties were revealed. The use of Nitrite Salt displayed no adverse effects like increased content of N-nitrosoamines in smoked products. In fact, significant lower contents of N-nitrosoamines were found in Nitrite Salted smoked fillets compared to smoked fillets Salted with table Salt. Relatively high amounts of residual Nitrite in Nitrite-treated fillets seem to be the most prominent adverse effect caused by the use of Nitrite Salt in Salt-curing of smoked Atlantic salmon.