scholarly journals Carbon Nanotube/Poly(dimethylsiloxane) Composite Materials to Reduce Bacterial Adhesion

Antibiotics ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 434 ◽  
Author(s):  
Márcia R. Vagos ◽  
Marisa Gomes ◽  
Joana M. R. Moreira ◽  
Olívia S. G. P. Soares ◽  
Manuel F. R. Pereira ◽  
...  
Keyword(s):  
Urinary Tract ◽  
Composite Materials ◽  
Bacterial Adhesion ◽  
Electrical Conductance ◽  
Model Organism ◽  
Flow Chamber ◽  
Parallel Plate Flow Chamber ◽  
Biomedical Field ◽  
Enhanced Properties ◽  
Pre Treatment

Different studies have shown that the incorporation of carbon nanotubes (CNTs) into poly(dimethylsiloxane) (PDMS) enables the production of composite materials with enhanced properties, which can find important applications in the biomedical field. In the present work, CNT/PDMS composite materials have been prepared to evaluate the effects of pristine and chemically functionalized CNT incorporation into PDMS on the composite’s thermal, electrical, and surface properties on bacterial adhesion in dynamic conditions. Initial bacterial adhesion was studied using a parallel-plate flow chamber assay performed in conditions prevailing in urinary tract devices (catheters and stents) using Escherichia coli as a model organism and PDMS as a control due to its relevance in these applications. The results indicated that the introduction of the CNTs in the PDMS matrix yielded, in general, less bacterial adhesion than the PDMS alone and that the reduction could be dependent on the surface chemistry of CNTs, with less adhesion obtained on the composites with pristine rather than functionalized CNTs. It was also shown CNT pre-treatment and incorporation by different methods affected the electrical properties of the composites when compared to PDMS. Composites enabling a 60% reduction in cell adhesion were obtained by CNT treatment by ball-milling, whereas an increase in electrical conductivity of seven orders of magnitude was obtained after solvent-mediated incorporation. The results suggest even at low CNT loading values (1%), these treatments may be beneficial for the production of CNT composites with application in biomedical devices for the urinary tract and for other applications where electrical conductance is required.

scholarly journals Inhibition of Staphylococcus aureusAdherence to Collagen under Dynamic Conditions

1999 ◽  
Vol 67 (2) ◽  
pp. 589-594 ◽  
Author(s):  
Nehal Mohamed ◽  
Mark A. Teeters ◽  
Joseph M. Patti ◽  
Magnus Höök ◽  
Julia M. Ross
Keyword(s):  
Bacterial Adhesion ◽  
Polyclonal Antibodies ◽  
Type Ii Collagen ◽  
Flow Chamber ◽  
Adhesion Assay ◽  
Parallel Plate Flow Chamber ◽  
Bacterial Arthritis ◽  
Dynamic Conditions ◽  
Shear Rates ◽  
Recombinant Fragments

ABSTRACT Staphylococcus aureus is the most common etiological agent of bacterial arthritis and acute osteomyelitis and has been shown to bind to type II collagen under static and dynamic conditions. We have previously reported the effect of shear on the adhesion ofS. aureus Phillips to collagen and found that this process is shear dependent (Z. Li, M. Höök, J. M. Patti, and J. M. Ross, Ann. Biomed. Eng. 24[Suppl. 1]:S–55). In this study, we used recombinant collagen adhesin fragments as well as polyclonal antibodies generated against adhesin fragments in attempts to inhibit bacterial adhesion. A parallel-plate flow chamber was used in a dynamic adhesion assay, and quantification of adhesion was accomplished by phase contrast video microscopy coupled with digital image processing. We report that both recombinant fragments studied, M19 and M55, and both polyclonal antibodies studied, α-M17 and α-M55, inhibit adhesion to varying degrees and that these processes are shear dependent. The M55 peptide and α-M55 cause much higher levels of inhibition than M19 and α-M17, respectively, at all wall shear rates studied. Our results demonstrate the importance of using a dynamic system in the assessment of inhibitory strategies and suggest the possible use of M55 and α-M55 in clinical applications to prevent infections caused by S. aureus adhesion to collagen.

VCAM-1 is more effective than MAdCAM-1 in supporting eosinophil rolling under conditions of shear flow

Blood ◽  
2000 ◽  
Vol 95 (2) ◽  
pp. 592-601 ◽  
Author(s):  
P. Sriramarao ◽  
Richard G. DiScipio ◽  
Ronald R. Cobb ◽  
Myron Cybulsky ◽  
Greg Stachnick ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Parallel Plate ◽  
Cell Adhesion Molecule ◽  
Flow Chamber ◽  
Β1 Integrin ◽  
Vascular Cell Adhesion ◽  
Parallel Plate Flow Chamber ◽  
Vascular Cell

The ability of the 4 integrin counterligands vascular cell adhesion molecule (VCAM)-1 or mucosal addressin (MAd)CAM-1 to support eosinophil rolling or firm adhesion under conditions of physiologic flow has not been delineated. Using a parallel plate flow chamber in vitro and intravital microscopy in vivo, we demonstrate that eosinophil rolling and adhesion on VCAM-1 is mediated by both 4β1 and 4β7 integrins. Eosinophils rolled equally efficiently on both VCAM-1 2 domain and VCAM-1 7 domain, suggesting that the N-terminal 2 domains of VCAM-1 are sufficient to support eosinophil rolling under conditions of flow. Furthermore, activation of the eosinophil β1 integrin with monoclonal antibody (mAb) 8A2 resulted in both resistance to shear stress–induced detachment from VCAM-1 in vitro and in stable arrest of rolling eosinophils on interleukin (IL)-1β–stimulated venules in vivo. Eosinophils rolled less efficiently on MAdCAM-1– than on VCAM-1–coated coverslips under conditions of flow. However, eosinophils firmly adhered as efficiently to MAdCAM-1 as to VCAM-1. Overall, these results demonstrate that both VCAM-1 and MAdCAM-1 can support eosinophil firm adhesion under conditions of flow. In contrast, VCAM-1 is significantly more efficient than MAdCAM-1 in supporting eosinophil rolling under conditions of flow.

scholarly journals The effect of urinary tract calculosis to levels of low molecular inhibitors of crystallization in the urine

2006 ◽  
Vol 134 (1-2) ◽  
pp. 40-43
Author(s):  
Dragica Milenkovic ◽  
Natasa Lalic
Keyword(s):  
Urinary Tract ◽  
Shock Waves ◽  
Stone Formation ◽  
Upper Urinary Tract ◽  
Therapeutic Procedure ◽  
Residual Stone ◽  
Extracorporeal Shock Waves ◽  
Urinary Levels ◽  
Urinary Tract Stones ◽  
Pre Treatment

The incidence of urinary tract calculosis continuously progresses. The triggering event in the process of stone formation is decreased urinary level of crystallizing inhibitors. The aim of our study was to investigate whether the existing stone or applied therapeutic procedure - extracorporeal shock waves lithotripsy (ESWL) - has effect to urinary levels of Mg, citrate and pyrophosphate. Study included 128 patients with the upper urinary tract stones. ESWL using the Lithostar (Siemens) device was used as a mode of treatment. Out of all patients, 76 (59%) were free of stone particles before 1 month, while 52 (41%) had residual stone fragments even 3 months after ESWL. Mg, citrate and pyrophosphate were measured in 24hurine specimens: before, between days 2 and 3, as well as 1 and 3 months after ESWL. The analysis of the results revealed that stone itself had no effect on urinary crystallizing inhibitors. Detected increased urinary levels of Mg, citrate and pyrophosphate after ESWL, compared with pre-treatment values, could be attributed to applied therapeutic procedure.

Wall Shear Stress Determination in a Small-Scale Parallel Plate Flow Chamber Using Laser Doppler Velocimetry Under Laminar, Pulsatile and Low-Reynolds Number Turbulent Flows

2018 ◽  
Vol 140 (6) ◽  
Author(s):  
Hamed Avari ◽  
Kem A. Rogers ◽  
Eric Savory
Keyword(s):  
Shear Stress ◽  
Wall Shear Stress ◽  
Laser Doppler Velocimetry ◽  
Parallel Plate ◽  
Flow Chamber ◽  
Laser Doppler ◽  
Small Scale ◽  
Doppler Velocimetry ◽  
Flow Conditions ◽  
Parallel Plate Flow Chamber

The parallel plate flow chamber (PPFC) has gained popularity due to its applications in fields such as biological tissue engineering. However, most of the studies using PPFC refer to theoretical relations for estimating the wall shear stress (WSS) and, hence, the accuracy of such quantifications remains elusive for anything other than steady laminar flow. In the current study, a laser Doppler velocimetry (LDV) method was used to quantify the flow in a PPFC (H = 1.8 mm × W = 17.5 mm, Dh = 3.26 mm, aspect ratio = 9.72) under steady Re = 990, laminar pulsatile (carotid Re0-mean = 282 as well as a non-zero-mean sinusoidal Re0-mean = 45 pulse) and low-Re turbulent Re = 2750 flow conditions. A mini-LDV probe was applied, and the absolute location of the LDV measuring volume with the respect to the wall was determined using a signal monitoring technique with uncertainties being around ±27 μm. The uniformity of the flow across the span of the channel, as well as the WSS assessment for all the flow conditions, was measured with the uncertainties all being less than 16%. At least two points within the viscous sublayer of the low-Re turbulent flow were measured (with the y+ for the first point < 3) and the WSS was determined using two methods with the differences between the two methods being within 5%. This paper for the first time presents the experimental determination of WSS using LDV in a small-scale PPFC under various flow conditions, the challenges associated with each condition, and a comparison between the cases. The present data will be useful for those conducting biological or numerical modeling studies using such devices.

scholarly journals Plasma Activation as a Powerful Tool for Selective Modification of Cellulose Fibers towards Biomedical Applications

Plasma ◽  
2020 ◽  
Vol 3 (4) ◽  
pp. 196-203
Author(s):  
Olivia Mauger ◽  
Sophia Westphal ◽  
Stefanie Klöpzig ◽  
Anne Krüger-Genge ◽  
Werner Müller ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Bacterial Adhesion ◽  
Biomedical Applications ◽  
Cellulose Fibers ◽  
Plasma Technology ◽  
X Ray ◽  
Cellulose Modification ◽  
Plasma Activation ◽  
Low Pressure Plasma ◽  
Pre Treatment

Cellulosic substrates are known for their biocompatibility, non-cytotoxicity, hypoallergenicity and sterilizability. It is therefore desirable to have a bundle of methods to equip them with tailored properties such as affinity profiles for various applications. In the case of highly swelling materials such as cellulose sponges, “dry” functionalization using plasma activation is the method of choice. The purpose of the study was to adapt low-pressure plasma technology for targeted cellulose modification. Using plasma (pre-) treatment combined with gaseous reactants like O2, ethylene oxide or silane, three different cellulose modifications were obtained and characterized by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). Swelling measurements and bacterial adhesion tests revealed distinctive material properties compared to educt. The development of these non-aqueous methods demonstrated an effective procedural route towards modified cellulosic materials for usage in wound dressing, micro patterned assays or bacterial filtration.

scholarly journals A Retrospective Study of Immunotherapy Treatment with Uro-Vaxom (OM-89®) for Prophylaxis of Recurrent Urinary Tract Infections

2020 ◽  
Vol 14 (3) ◽  
pp. 130-134
Author(s):  
Andrew Brodie ◽  
Omar El-Taji ◽  
Ibrahim Jour ◽  
Charlotte Foley ◽  
Damian Hanbury
Keyword(s):  
Urinary Tract ◽  
Urinary Tract Infections ◽  
Primary Outcome Measure ◽  
Effective Treatment Option ◽  
Recurrent Utis ◽  
Recurrent Uti ◽  
Recurrent Urinary Tract Infections ◽  
Pre Treatment ◽  
The Uk ◽  
Tract Infections

<b><i>Objectives</i></b>: To present our experience with the long-term preventive effect of immunotherapy with Uro-Vaxom® on recurrent urinary tract infections (UTI) in adult patients. <b><i>Materials and Methods</i></b>: Retrospective analysis of 79 patients with recurrent UTI treated with Uro-Vaxom. Recurrent UTIs were defined as ≥ 2 infections in 6 months or ≥ 3 in 12 months. Patients received a 6 mg Uro-Vaxom capsule daily for 90 days followed by discontinuation for 3 months and then administration for the first 10 days of subsequent months 7, 8 and 9 as a ‘booster' regime. The primary outcome measure was the number of UTIs encountered in the 12 months pre-treatment compared to 12 months post-treatment. <b><i>Results</i></b>: There was a significant decrease in the mean number of UTIs in the year following initiation of Uro-Vaxom® compared to the year preceding administration 3.14 versus 1.53 (p < 0.05) respectively. <b><i>Conclusion</i></b>: Uro-Vaxom represents a safe and effective treatment option for prophylaxis of recurrent UTIs. In the UK, Uro-Vaxom is currently unlicensed. This study adds to a growing body of evidence in favor of non-antibiotic immune-prophylaxis for recurrent UTI.

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