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Purpose: The effects of carnitine depletion upon exercise performance and skeletal muscle mitochondrial function remain largely unexplored. We therefore investigated the effect of N-trimethyl-hydrazine-3-propionate (THP), a carnitine analog inhibiting carnitine biosynthesis and renal carnitine reabsorption, on physical performance and skeletal muscle mitochondrial function in rats. Methods: Male Sprague Dawley rats were treated daily with water (control rats; n = 12) or with 20 mg/100 g body weight THP (n = 12) via oral gavage for 3 weeks. Following treatment, half of the animals of each group performed an exercise test until exhaustion. Results: Distance covered and exercise performance were lower in THP-treated compared to control rats. In the oxidative soleus muscle, carnitine depletion caused atrophy (–24%) and impaired function of complex II and IV of the mitochondrial electron transport chain. The free radical leak (ROS production relative to oxygen consumption) was increased and the cellular glutathione pool decreased. Moreover, mRNA expression of markers of mitochondrial biogenesis and mitochondrial DNA were decreased in THP-treated compared to control rats. In comparison, in the glycolytic gastrocnemius muscle, carnitine depletion was associated with impaired function of complex IV and increased free radical leak, whilst muscle weight and cellular glutathione pool were maintained. Markers of mitochondrial proliferation and mitochondrial DNA were unaffected. Conclusions: Carnitine deficiency is associated with impaired exercise capacity in rats treated with THP. THP-induced carnitine deficiency is associated with impaired function of the electron transport chain in oxidative and glycolytic muscle as well as with atrophy and decreased mitochondrial DNA in oxidative muscle. [ABSTRACT FROM AUTHOR]

Besides their use as contrast agents for ultrasound imaging, microbubbles are increasingly studied for a wide range of therapeutic applications. In particular, their ability to enhance the uptake of drugs through the permeabilization of tissues and cell membranes shows great promise. In order to fully understand the numerous paths by which bubbles can interact with cells and the even larger number of possible biological responses from the cells, thorough and extensive work is necessary. In this review, we consider the range of experimental techniques implemented in in vitro studies with the aim of elucidating these microbubble-cell interactions. First of all, the variety of cell types and cell models available are discussed, emphasizing the need for more and more complex models replicating in vivo conditions together with experimental challenges associated with this increased complexity. Second, the different types of stabilized microbubbles and more recently developed droplets and particles are presented, followed by their acoustic or optical excitation methods. Finally, the techniques exploited to study the microbubble-cell interactions are reviewed. These techniques operate over a wide range of timescales, or even off-line, revealing particular aspects or subsequent effects of these interactions. Therefore, knowledge obtained from several techniques must be combined to elucidate the underlying processes. [ABSTRACT FROM AUTHOR]

Catheter-associated urinary tract infections (CAUTIs) are one of the most commonly occurring hospital-acquired infections. Current coating strategies to prevent catheter-associated biofilm formation are limited by their poor long-term efficiency and limited applicability to diverse materials. Here, the authors report a highly effective non-fouling coating with long-term biofilm prevention activity and is applicable to diverse catheters. The thin coating is lubricous, stable, highly uniform, and shows broad spectrum prevention of biofilm formation of nine different bacterial strains and prevents the migration of bacteria on catheter surface. The coating method is adapted to human-sized catheters (both intraluminal and extraluminal) and demonstrates long-term biofilm prevention activity over 30 days in challenging conditions. The coated catheters are tested in a mouse CAUTI model and demonstrate high efficiency in preventing bacterial colonization of both Gram-positive and Gram-negative bacteria. Furthermore, the coated human-sized Foley catheters are evaluated in a porcine CAUTI model and show consistent efficiency in reducing biofilm formation by Escherichia coli (E. coli) over 95%. The simplicity of the coating method, the ability to apply this coating on diverse materials, and the high efficiency in preventing bacterial adhesion increase the potential of this method for the development of next generation infection resistant medical devices., (© 2021 Wiley-VCH GmbH.)

The surface modifications of natural rubber latex films by argon plasma pretreatment, followed by UV-induced graft copolymerization of hydroxyethyl methacrylate, were carried out to improve the latex hydrophilicity. The effect of plasma pretreatment time, monomer concentration and UV irradiation time on the graft densities was studied. ATR-FTIR analyses indicates the efficient grafting of poly(hydroxyethyl methacrylate) onto the surface of latex film. The surface roughness of natural rubber latex films increases to 360 nm from 9 nm, leading to a decrease of water contact angle value of NR latex film surface to about 60° from 100°, and thus confirmed improvement of the hydrophilicity of latex film. Biocompatibility of the film was evaluated with vitro cytotoxicity test; the results proved a good biocompatibility of modified latex. [ABSTRACT FROM AUTHOR]

The crystallization of magnesium ammonium phosphate hexahydrate (struvite) often occurs under conditions of fluid flow, yet the dynamics of struvite growth under these relevant environments has not been previously reported. In this study, we use a microfluidic device to evaluate the anisotropic growth of struvite crystals at variable flow rates and solution supersaturation. We show that bulk crystallization under quiescent conditions yields irreproducible data owing to the propensity of struvite to adopt defects in its crystal lattice, as well as fluctuations in pH that markedly impact crystal growth rates. Studies in microfluidic channels allow for time-resolved analysis of seeded growth along all three principle crystallographic directions and under highly controlled environments. After having first identified flow rates that differentiate diffusion and reaction limited growth regimes, we operated solely in the latter regime to extract the kinetic rates of struvite growth along the [100], [010], and [001] directions. In situ atomic force microscopy was used to obtain molecular level details of surface growth mechanisms. Our findings reveal a classical pathway of crystallization by monomer addition with the expected transition from growth by screw dislocations at low supersaturation to that of two-dimensional layer generation and spreading at high supersaturation. Collectively, these studies present a platform for assessing struvite crystallization under flow conditions and demonstrate how this approach is superior to measurements under quiescent conditions., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

There is an urgent need for antimicrobial functionalization of urinary catheters to prevent microbial colonization and biofilm formation on them. Here, the antimicrobial hydrogen peroxide (H2O2) producing enzyme cellobiose dehydrogenase (CDH) was for the first time grafted onto polydimethylsiloxanes (PDMS) using an ultrasound assisted coating method. This resulted in the development of an effective in situ continous H2O2 producing system able to continuously prevent microbial colonization and biofilm formation on catheters. This enzyme has an added advantage that it uses various oligosaccharides including expolysaccharides (an important part of the bioflim produced by the microbes while colonizing biomaterials) as electron donors to produce H2O2. Successful immobilization of active CDH nanoparticles on PDMS was confirmed by ESEM and AFM analysis as well as quantification of H2O2. Depending on the initial enzyme concentration, CDH-nanoparticles of varying sizes from 65 ± 17 nm to 93 ± 17 nm were created by the ultrasonic waves and subsequently deposited on the PDMS surface. PDMS sheets treated for 3 min produced 18 μM of H2O2 within 2 hours which was sufficient to significantly reduce the amount of viable S. aureus cells as well as the total amount of biomass deposited on the surface. The ultrasound assisted coating of antimicrobial enzymes therefore provides an easy approach to immobilize enzymes and create a surface with antimicrobial properties. [ABSTRACT FROM AUTHOR]

Biosensors are being developed to provide rapid, quantitative, diagnostic information to clinicians in order to help guide patient treatment, without the need for centralised laboratory assays. The success of glucose monitoring is a key example of where technology innovation has met a clinical need at multiple levels – from the pathology laboratory all the way to the patient's home. However, few other biosensor devices are currently in routine use. Here we review the challenges and opportunities regarding the integration of biosensor techniques into body fluid sampling approaches, with emphasis on the point-of-care setting. [ABSTRACT FROM AUTHOR]

In situ light initiated synthesis of silver nanoparticles (AgNP) was employed for AgNP incorporation within the polymeric matrices of medical grade polyurethane. The resulting materials showed improved antibacterial and antibiofilm activity against Pseudomonas aeruginosa with negligible toxicity for human primary skin cells and erythrocytes. [ABSTRACT FROM AUTHOR]

The table of contents for the August 2014 issue of the "Journal of Internal Medicine" is presented.

Covalently attached lysozyme-ZnO nanoparticle (L-ZNP) conjugates were synthesized by a low temperature solution route. Tailored L-ZNP conjugates exhibit pronounced antibacterial features against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). [ABSTRACT FROM AUTHOR]

This review is largely based on a previous paper published in the journal Spinal Cord. The care of many patients undergoing long-term bladder catheterization is complicated by encrustation and blockage of their Foley catheters. This problem stems from infection by urease-producing bacteria, particularly Proteus mirabilis. These organisms colonize the catheter forming an extensive biofilm; they also generate ammonia from urea, thus elevating the pH of urine. As the pH rises, crystals of calcium and magnesium phosphates precipitate in the urine and in the catheter biofilm. The continued development of this crystalline biofilm blocks the flow of urine through the catheter. Urine then either leaks along the outside of the catheter and the patient becomes incontinent or is retained causing painful distension of the bladder and reflux of urine to the kidneys. The process of crystal deposition can also initiate stone formation. Most patients suffering from recurrent catheter encrustation develop bladder stones. P. mirabilis establishes stable residence in these stones and is extremely difficult to eliminate from the catheterized urinary tract by antibiotic therapy. If blocked catheters are not identified and changed, serious symptomatic episodes of pyelonephritis, septicaemia and endotoxic shock can result. All types of Foley catheters including silver- or nitrofurazone-coated devices are vulnerable to this problem. In this review, the ways in which biofilm formation on Foley catheters is initiated by P. mirabilis will be described. The implications of understanding these mechanisms for the development of an encrustation-resistant catheter will be discussed. Finally, the way forward for the prevention and control of this problem will be considered. [ABSTRACT FROM AUTHOR]

In peritoneal dialysis (PD), the catheter, usually made of silicone, has been considered the 'lifeline' of the patient. However, the PD catheter also serves as a nidus for bacterial infection. Furthermore, complications can result from fibrin deposition and omental wrapping of the catheter, which obstructs the dialysate flow. In this work, a crosslinked agarose (AG) polymer layer is covalently grafted as a microscale coating on the silicone surface. This coating reduces Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa biofilm formation by more than two orders of magnitude. In addition, cell and platelet adhesion and protein adsorption is also reduced by ≥90%. Without compromising the antibacterial and antifouling property, further improvement in hemocompatibility, as shown by the inhibition of platelet adhesion and activation, prolonged plasma recalcification time and lower hemolysis degree, is achieved by co-immobilization of 2.6 μg cm−2 of heparin (HEP) in the agarose coating. The AG-HEP coatings are not cytotoxic to mammalian cells, and are stable for extended periods in lysozyme aqueous solution and under autoclaving at 121 °C for 20 min. [ABSTRACT FROM AUTHOR]

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The introduction of effective antibacterial therapies for infectious diseases in the mid-20th century completely revolutionized clinical practices and helped to facilitate the development of modern medicine. Many potentially life-threatening conditions became easily curable, greatly reducing the incidence of death or disability resulting from bacterial infections. This overwhelming historical success makes it very difficult to imagine life without effective antibacterials; however, the inexorable rise of antibiotic resistance has made this a very real and disturbing possibility for some infections. The ruthless selection for resistant bacteria, coupled with insufficient investment in antibacterial research, has led to a steady decline in the efficacy of existing therapies and a paucity of novel structural classes with which to replace them, or complement their use. This situation has resulted in a very pressing need for the discovery of novel antibiotics and treatment strategies, the development of which is likely to be a key challenge to 21st century medicinal chemistry. [ABSTRACT FROM AUTHOR]

In this paper, we propose a consistent method of estimation for the parameters of the three-parameter inverse Gaussian distribution. We then discuss some properties of these estimators and show by means of a Monte Carlo simulation study that the proposed estimators perform better than some other prominent estimators in terms of bias and root mean squared error. Finally, we present two real-life examples to illustrate the method of inference developed here. [ABSTRACT FROM AUTHOR]

This article presents a non-complex method of producing biodegradable polylactide (PLA) fiber mats containing AlO-Ag nanopowder which display strong antimicrobial activities against E.coli and S. lutea. The method of preparing fiber mats was electrospinning. This article also gathers the results of the analysis of morphology and mechanical properties of both the AlO nanopowder and the PLA-AlO/Ag fiber mats. The examination of the AlO nanopowder was conducted with the use of a scanning electron microscope (SEM) and surface area measurements (BET). The morphology of the PLAAlO/Ag fiber mats was examined using SEM and TEM. The results of the study confirm the great potential of the electrospun PLA-AlO/Ag fiber mats for antibacterial application. [ABSTRACT FROM AUTHOR]

n-Heptyl α- D-mannoside (HM) has previously been identified as a nanomolar FimH antagonist able to prevent Escherichia coli adhesion. We have designed mono- and heptavalent glycoconjugates in which HM is tethered to β-cyclodextrin (β-CD) through short and long spacers. One-pot click or co-clicking procedures were developed to directly obtain the glycoconjugates from unprotected HM and β-CD precursors. These FimH antagonists were examined biophysically and in vivo. Reverse titrations by isothermal calorimetry led to trapping of the short-tethered heptavalent β-CD in a complex with three FimH lectins. Combined dynamic light scattering and small-angle X-ray solution scattering data allowed the construction of a model of the FimH trimer. The heptavalent β-CDs were shown to capture and aggregate living bacteria in solution and are therefore also able to aggregate FimH when attached to different bacteria pili. The first in vivo evaluation of multivalent FimH inhibitors has been performed. The heptavalent β-CDs proved to be much more effective anti-adhesive agents than monovalent references with doses of around 2 μg instilled in the mouse bladder leading to a significantly decreased E. coli load. Intravenously injected radiolabeled glycoconjugates can rapidly reach the mouse bladder and >2 μg concentrations can easily be retained over 24 h to prevent fluxing bacteria from rebinding. [ABSTRACT FROM AUTHOR]

Nanoscale surface roughness is an important factor in determining the properties of surfaces and can affect the performance of a range of devices prepared by lithographic methods. Here, a method is reported, which enables modulation of the nanoscale roughness of surfaces through the directed self assembly (DSA) of positively charged polymersomes, composed of specifically designed block copolymers, onto negatively charged surfaces. Assembly of the polymersomes on surfaces can result in an increase in the nanoscale surface roughness; however, through a controlled annealing step we can also significantly reduce the nanoscale roughness of the original surface. The ability to decrease the roughness of lithographic patterns is expected to have a significant impact on the manufacture of integrated circuits. [ABSTRACT FROM AUTHOR]

In addition to extensive studies of conventional linear poly(ionic liquids) (PILs), exploration of the effects of PIL topology, especially cyclic architecture, on bactericidal properties will expand the design possibilities for the development of excellent antibacterial surfaces. Herein, the preparation of antibacterial surfaces based on cyclic PIL brushes is reported for the first time and how the cyclic PIL architecture affects bactericidal activity is investigated. It is shown that the cyclic architecture imparted PIL brushes with enhanced bactericidal activity, achieving only 1.7% of bacterial viable percentage against gram-negative Escherichia coli using Live/Dead staining methods, compared to 6.6% for the corresponding linear PIL brushes. The enhanced bactericidal activity is also validated by the direct observation of scanning electron microscopy and a colony counting assay. Further mechanism studies reveal that the substantially different morphologies of cyclic aggregates and altered surface charge density induced by the cyclic PIL architecture can account for the enhanced bactericidal activity., (© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The appearance of highly resistant bacterial biofilms in both community and hospitals environments is a major challenge in modern clinical medicine. The biofilm structural morphology, believed to be an important factor affecting the behavioral properties of these 'super bugs', is strongly influenced by the local hydrodynamics over the microcolonies. Despite the common use of agitated well plates in the biology community, they have been used rather blindly without knowing the flow characteristics and influence of the rotational speed and fluid volume in these containers. The main purpose of this study is to characterize the flow in these high-throughput devices to link local hydrodynamics to observed behavior in cell cultures. In this work, the flow and wall shear stress distribution in six-well culture plates under planar orbital translation is simulated using Computational Fluid Dynamics (CFD). Free surface, flow pattern and wall shear stress for two shaker speeds (100 and 200 rpm) and two volumes of fluid (2 and 4 mL) were investigated. Measurements with a non-intrusive optical shear stress sensor and High Frame-rate Particle Imaging Velocimetry (HFPIV) are used to validate CFD predictions. An analytical model to predict the free surface shape is proposed. Results show a complex three-dimensional flow pattern, varying in both time and space. The distribution of wall shear stress in these culture plates has been related to the topology of flow. This understanding helps explain observed endothelial cell orientation and bacterial biofilm distributions observed in culture dishes. The results suggest that the mean surface stress field is insufficient to capture the underlying dynamics mitigating biological processes. [ABSTRACT FROM AUTHOR]

Congenital anomalies such as meningomyelocele and diseases/damage of the central, peripheral, or autonomic nervous systems may produce neurogenic bladder dysfunction, which untreated can result in progressive renal damage, adverse physical effects including decubiti and urinary tract infections, and psychological and social sequelae related to urinary incontinence. A comprehensive bladder-retraining program that incorporates appropriate education, training, medication, and surgical interventions can mitigate the adverse consequences of neurogenic bladder dysfunction and improve both quantity and quality of life. The goals of bladder retraining for neurogenic bladder dysfunction are prevention of urinary incontinence, urinary tract infections, detrusor overdistension, and progressive upper urinary tract damage due to chronic, excessive detrusor pressures. Understanding the physiology and pathophysiology of micturition is essential to select appropriate pharmacologic and surgical interventions to achieve these goals. Future perspectives on potential pharmacological, surgical, and regenerative medicine options for treating neurogenic bladder dysfunction are also presented. [ABSTRACT FROM AUTHOR]

This paper summarizes some applications of ultrasonic vibrations regarding heat transfer enhancement techniques. Research literature is reviewed, with special attention to examples for which ultrasonic technology was used alongside a conventional heat transfer process in order to enhance it. In several industrial applications, the use of ultrasound is often a way to increase productivity in the process itself, but also to take advantage of various subsequent phenomena. The relevant example brought forward here concerns heat exchangers, where it was found that ultrasound not only increases heat transfer rates, but might also be a solution to fouling reduction. [ABSTRACT FROM AUTHOR]

Antibacterial efficacy of silver nanoparticles (Ag NPs) deposited alternatively layer by layer (LBL) on chitosan polymer in the form of a thin film over a quartz plate and stainless steel strip has been studied. An eight-bilayer chitosan/silver (Cs/Ag)8 hybrid was prepared having a known concentration of silver. Techniques such as UV-visible spectroscopy, inductively coupled plasma optical emission spectroscopy (ICP-OES), and atomic force microscopy (AFM) were carried out to understand and elucidate the physical nature of the film. Gram-negative bacteria, Escherichia coli (E. coli), were used as a test sample in saline solution for antibacterial studies. The growth inhibition at different intervals of contact time and, more importantly, the antibacterial properties of the hybrid film on repeated cycling in saline solution have been demonstrated. AFM studies are carried out for the first time on the microbe to know the morphological changes affected by the hybrid film. The hybrid films on aging (3 months) are found to be as bioactive as before. Cytotoxicity experiments indicated good biocompatibility. The hybrid can be a promising bioactive material for the prevention of biofilms specific to E. coli and in purification of water for safe drinking. [ABSTRACT FROM AUTHOR]

Cell adhesion is a multi-process phenomenon involving physical, physico-chemical and biological mechanisms. The complexity of interfaces is the reason why progress in the theory of cell adhesion has been slow. Greater understanding of interaction mechanisms has been enhanced by complete knowledge of supports and of biological components, in particular the extracellular matrix, membrane walls, cell multiplication processes and apoptosis. The construction of novel surfaces with strongly hydrophilic or ultrahydrophobic properties has allowed new theoretical advances, while at the same time offering numerous and varied technological applications. These include: • Bioadhesion with mechanical anchoring using ubiquitous surface roughness and deformability of certain micro-organisms. • Physico-chemical bioadhesion or repellence resulting mainly from the energy characteristics of support surfaces. • Processes of sorting and guidance by biomolecules present at the support-biofilm interface, generating biochemical responses that can induce cell multiplication or degeneration (as in cancer), or cell death. [ABSTRACT FROM AUTHOR]