Antimicrobial potential of natural deep eutectic solvents.

Natural deep eutectic solvents (NADES) are a new class of green solvents, which can solubilize natural and synthetic chemicals of low water solubility. NADES are mixtures of two or three compounds of hydrogen bond acceptors and hydrogen bond donors. Many NADES' components are of natural origin and therefore, NADES are presumed to be nontoxic and often exhibit antimicrobial activity. This work aimed to investigate the potential antimicrobial effect of menthol, capric acid and Solutol™, and their associated eutectic system on two Gram-positive bacteria (Staphylococcus aureus ATCC 6538 and Bacillus subtilis ATCC 6633), two Gram-negative bacteria (Escherichia coli ATCC 8739 and Pseudomonas aeruginosa ATCC 9027) and one fungus (the yeast Candida albicans ATCC 10231). The results obtained showed a stronger antimicrobial effect for the NADES when compared to their individual components and that they exhibit a promising antimicrobial activity against S. aureus and C. albicans and good activity against P. aeruginosa. NADES exhibited no observable antimicrobial activity against spore-forming B. subtilis.

A review of the antimicrobial activity of thermodynamically stable microemulsions.

Microemulsions are thermodynamically stable, transparent, isotropic mixtures of oil, water and surfactant (and sometimes a co-surfactant), which have shown potential for widespread application in disinfection and self-preservation. This is thought to be due to an innate antimicrobial effect. It is suggested that the antimicrobial nature of microemulsions is the result of a combination of their inherent kinetic energy and their containing surfactants, which are known to aid the disruption of bacterial membranes. This review examines the contemporary evidence in support of this theory.

Investigating possible association between multidrug resistance and isolate origin with some virulence factors of Escherichia coli strains isolated from infant faeces and fresh green vegetables.

AIMS: In this study, the association between multidrug resistance (MDR) and the expression of some virulence factors were evaluated in Escherichia coli strains isolated from infant faeces and fresh green vegetables. The effect of isolate origin on associated virulence factors was evaluated. In addition, genetic fingerprinting of a sample of these isolates (10 isolates from each group) was studied in order to detect any genetic relatedness among these isolates. METHODS AND RESULTS: Escherichia coli isolates were divided into four groups based on their origin (human faeces or plant) and their antibiotic resistance (multiresistance or susceptible). PCR was used to investigate heat-labile and heat-stable enterotoxin genes, and four siderophore genes (aerobactin, enterobactin, salmochelin and yersiniabactin). Genetic fingerprinting of the isolates was performed using enterobacterial repetitive intergenic consensus PCR. Siderophore production was measured by a colorimetric method. Biofilm formation was evaluated by a crystal violet assay. The results of the study showed that the expression of MDR is not significantly associated with an increase in these virulence factors or with biofilm formation. However, the origin of isolates had a significant association with siderophore gene availability and consequently on the concentrations of siderophores released. Genetic fingerprinting indicated that human and plant isolates have the same clonal origin, suggesting their circulation among humans and plants. CONCLUSION: Antibiotic-susceptible strains of E. coli may be as virulent as MDR strains. Results also suggest that the environment can play a potential role in selection of strains with specific virulence factors. SIGNIFICANCE AND IMPACT OF THE STUDY: Antibiotic-susceptible isolates of Escherichia coli from plant or human origin can be as virulent as the multidrug resistance (MDR) ones. Genetic relatedness was detected among the isolates of plant and human origin, indicating the circulation of these bacteria among human and plants. This could imply a potential role for environmental antimicrobial resistant bacteria in human infection.

Ammonia mobility in chabazite: insight into the diffusion component of the NH3-SCR process.

The diffusion of ammonia in commercial NH3-SCR catalyst Cu-CHA was measured and compared with H-CHA using quasielastic neutron scattering (QENS) and molecular dynamics (MD) simulations to assess the effect of counterion presence on NH3 mobility in automotive emission control relevant zeolite catalysts. QENS experiments observed jump diffusion with a jump distance of 3 Å, giving similar self-diffusion coefficient measurements for both Cu- and H-CHA samples, in the range of ca. 5-10 × 10(-10) m(2) s(-1) over the measured temperature range. Self-diffusivities calculated by MD were within a factor of 6 of those measured experimentally at each temperature. The activation energies of diffusion were also similar for both studied systems: 3.7 and 4.4 kJ mol(-1) for the H- and Cu-chabazite respectively, suggesting that counterion presence has little impact on ammonia diffusivity on the timescale of the QENS experiment. An explanation is given by the MD simulations, which showed the strong coordination of NH3 with Cu(2+) counterions in the centre of the chabazite cage, shielding other molecules from interaction with the ion, and allowing for intercage diffusion through the 8-ring windows (consistent with the experimentally observed jump length) to carry on unhindered.

Downmodulation of key inflammatory cell markers with a topical Janus kinase 1/2 inhibitor.

BACKGROUND: INCB018424 is a novel, potent Janus kinase (JAK)1/JAK2 inhibitor that blocks signal transduction of multiple proinflammatory cytokines. OBJECTIVES: To evaluate the safety, tolerability, pharmacokinetics, pharmacodynamics and preliminary efficacy of topical INCB018424 phosphate cream in patients with plaque psoriasis. METHODS: Topical INCB018424 phosphate 1·0% or 1·5% cream was applied once daily (QD) or twice daily (BID) for 4 weeks to 2-20% body surface area in five sequential cohorts of five patients aged 18-65 years. Target lesions were scored on a scale of 0-4 for erythema, scaling and thickness. Additionally, the overall disease activity in each patient was measured using Physician's Global Assessment. INCB018424 concentrations were measured in plasma, and cytokine stimulated phosphorylated signal transducer and activator of transcription 3 phosphorylation (pSTAT3) levels in peripheral blood cells were evaluated. Pretreatment and post-treatment skin biopsies were compared with healthy skin, including evaluation of histopathology, immunohistochemistry and mRNA expression. RESULTS: Treatment with INCB018424 phosphate cream either 1·0% QD or 1·5% BID resulted in improvements in lesion scores. No significant inhibition of pSTAT3 in peripheral blood cells was observed following topical application, consistent with the generally low steady-state plasma concentrations of INCB018424 measured. Transcriptional markers of immune cell lineage/activation in lesional skin were reduced by topical INCB018424, with correlations observed between clinical improvement and decreases in markers of T helper 17 lymphocyte activation, dendritic-cell activation and epidermal hyperplasia. INCB018424 treatment reduced epidermal hyperplasia and dermal inflammation in most patient samples, with reductions in CD3, CD11c, Ki67 and keratin 16 observed by immunohistochemical analysis. CONCLUSIONS: Topical INCB018424 dosed for 28 days QD or BID is pharmacologically active in patients with active psoriasis and modulates proinflammatory cytokines in the pathogenesis of psoriatic lesions.

Rationalization of interactions in precious metal/ceria catalysts using the d-band center model.

A correlation between ceria reducibility and the precious-metal d-band center is reported for ceria-supported precious-metal catalysts. The results could provide the missing link to fully explain the occurrence of strong metal-support interaction (SMSI) and hydrogen spillover in catalysts that consist of dispersed metals in contact with reducible metal oxides.

Enhanced proprioceptive acuity at the knee in the competitive athlete.

STUDY DESIGN: Controlled laboratory study: cross-sectional. OBJECTIVE: To determine if proprioception, measured by the threshold to detection of passive motion (TDPM), differed in individuals who regularly participate in moderate-intensity exercise for fitness as compared to individuals involved in high-intensity skilled exercise. BACKGROUND: Previous research has been equivocal as to whether exercise training is associated with superior proprioceptive acuity, in particular, exercise that includes dynamic postural challenges such as cutting and pivoting. METHODS: Two groups of 25 healthy individuals (18-32 years old) were recruited. One group consisted of individuals who performed moderate-activity level exercises for 5 to 10 hours per week. Participants in the other group performed high-activity level exercises, including high-speed cutting and pivoting activities, at least 10 hours per week. Proprioception was determined using TDPM, in which the knee was slowly extended or flexed at an angular velocity of 0.5°/s or less from a starting position of 40° of knee flexion. RESULTS: Individuals participating in competitive, high-intensity skilled exercise demonstrated better acuity (average of both limbs) of TDPM (mean ± SD, 0.81° ± 0.38°; P<.001) than those participating in moderate-intensity exercise for fitness (1.53° ± 0.58°). A low but statistically significant association (r = -0.38, P = .006) was found between weekly duration of exercise and proprioceptive threshold as measured by TDPM. CONCLUSION: These results suggest that perceptual thresholds of passive movement may be enhanced, depending on activity level and associated postural challenge, and that higher level and increased amount of exercise may promote enhanced neurosensory processing in these individuals. Consequently, high-intensity skilled training may deserve further emphasis in orthopaedic rehabilitation.

A simple bioanalytical method for the quantification of antiepileptic drugs in dried blood spots.

An increasing number of publications on the dried blood spot (DBS) sampling approach for the quantification of drugs and metabolites have been spurred on by the inherent advantages of this sampling technique. In the present research, a selective and sensitive high-performance liquid chromatography method for the concurrent determination of multiple antiepileptic drugs (AEDs) [levetiracetam (LVT), lamotrigine (LTG), phenobarbital (PHB)], carbamazepine (CBZ) and its active metabolite carbamazepine-10,11 epoxide (CBZE)] in a single DBS has been developed and validated. Whole blood was spotted onto Guthrie cards and dried. Using a standard punch (6mm diameter), a circular disc was punched from the card and extracted with methanol: acetonitrile (3:1, v/v) containing hexobarbital (Internal Standard) and sonicated prior to evaporation. The extract was then dissolved in water and vortex mixed before undergoing solid phase extraction using HLB cartridges. Chromatographic separation of the AEDs was achieved using Waters XBridge™ C18 column with a gradient system. The developed method was linear over the concentration ranges studied with r≥0.995 for all compounds. The lower limits of quantification (LLOQs) were 2, 1, 2, 0.5 and 1 µg/mL for LVT, LTG, PHB, CBZE and CBZ, respectively. Accuracy (%RE) and precision (%CV) values for within and between day were <20% at the LLOQs and <15% at all other concentrations tested. This method was successfully applied to the analysis of the AEDs in DBS samples taken from children with epilepsy for the assessment of their adherence to prescribed treatments.

The impact and mode of action of phenolic compounds extracted from brown seaweed on mixed anaerobic microbial cultures.

AIMS: This study discusses the effect of phenolic compounds extracted from brown seaweed (phlorotannins) on mixed microbial cultures found in anaerobic systems. METHODS AND RESULTS: Assays were conducted with phloroglucinol as the nonpolymerized form of phlorotannin and with phlorotannins extracted from the brown seaweed Laminaria digitata. Electron micrographs revealed that phlorotannins induce significant extra- and intracellular effects upon cells, with the disruption of cell membranes observed with most micro-organisms. Microscopy results were further confirmed by cell membrane leakage assays demonstrating that phloroglucinol strongly affects cell membrane permeability. However, cell membrane leakage could not be observed with phlorotannins as the cell suspension immediately started to coagulate and impaired spectrophotometric measurements. CONCLUSIONS: Results suggest that the bactericidal activity of phlorotannins is a function of the level of polymerization of the compounds. By monitoring intermediary compounds during the anaerobic digestion of phlorotannins, it was also found that higher energy consumption is required by micro-organisms for survival under stress induced by phlorotannins. SIGNIFICANCE AND IMPACT OF THE STUDY: The successful anaerobic degradation of brown seaweed is thus likely to be dependant on the concentration of phenolic compounds present and their bactericidal effect on micro-organisms. This is the first article to posit a probable mode of action for the antimicrobial effect of phlorotannins.

Diagnostics and therapeutic interventions in myocardial interstitial disease, a previously neglected pathology.

The emergence of cardiac fibrosis (the prototypal myocardial interstitial disease) as an important adverse predictor of risk in heart disease is not surprising given that it is largely responsible for cardiac stiffness, provides a substrate for rhythm disturbances and promotes tissue hypoxia and development of heart failure. Yet, this diagnosis remains difficult, treatment options remain limited and underlying mechanisms remain elusive. More recently, however, many notable advances in imaging techniques and biomarker discovery have been made to improve our understanding of remodelling changes that occur within the myocardial interstitium. Ground-breaking new evidence now suggests that fibrosis within the heart may not only be reversible but that it also may be amenable to pharmacological intervention. In this review, we discuss these recent advances and highlight the pressing urgency to better detect myocardial interstitial disease and to understand the underlying molecular biology that may enable discovery of more specific anti-remodelling therapies.

Getting to the heart of cardiac remodeling; how collagen subtypes may contribute to phenotype.

The objective of this study was to investigate the nature and biomechanical properties of collagen fibers within the human myocardium. Targeting cardiac interstitial abnormalities will likely become a major focus of future preventative strategies with regard to the management of cardiac dysfunction. Current knowledge regarding the component structures of myocardial collagen networks is limited, further delineation of which will require application of more innovative technologies. We applied a novel methodology involving combined confocal laser scanning and atomic force microscopy to investigate myocardial collagen within ex-vivo right atrial tissue from 10 patients undergoing elective coronary bypass surgery. Immuno-fluorescent co-staining revealed discrete collagen I and III fibers. During single fiber deformation, overall median values of stiffness recorded in collagen III were 37±16% lower than in collagen I [p<0.001]. On fiber retraction, collagen I exhibited greater degrees of elastic recoil [p<0.001; relative percentage increase in elastic recoil 7±3%] and less energy dissipation than collagen III [p<0.001; relative percentage increase in work recovered 7±2%]. In atrial biopsies taken from patients in permanent atrial fibrillation (n=5) versus sinus rhythm (n=5), stiffness of both collagen fiber subtypes was augmented (p<0.008). Myocardial fibrillar collagen fibers organize in a discrete manner and possess distinct biomechanical differences; specifically, collagen I fibers exhibit relatively higher stiffness, contrasting with higher susceptibility to plastic deformation and less energy efficiency on deformation with collagen III fibers. Augmented stiffness of both collagen fiber subtypes in tissue samples from patients with atrial fibrillation compared to those in sinus rhythm are consistent with recent published findings of increased collagen cross-linking in this setting.

Triclosan - an update.

The discovery in 1998 that triclosan has a site-specific action in the bacterial cell as an inhibitor of NADH- or NADPH-dependent enoyl-acyl carrier protein reductase led to a lively debate in the scientific press. The thesis of this debate was that such a mode of action may allow triclosan to induce resistance and cross-resistance in bacterial cells. The debate last saw review in 2004, and this paper aims at updating our knowledge in this area, given recent research on the topic.

The effect of subminimal inhibitory concentrations of antibiotics on virulence factors expressed by Staphylococcus aureus biofilms.

AIMS: The effect of subminimal inhibitory concentrations (sub-MICs) of cefalexin, ciprofloxacin and roxithromycin was investigated on some virulence factors [e.g. coagulase, Toxic Shock Syndrome Toxin 1 (TSST-1) and biofilm formation] expressed by Staphylococcus aureus biofilms. METHODS AND RESULTS: Biofilms were grown with and without the presence of 1/16 MIC of antibiotics on Sorbarod filters. Eluate supernatants were collected, and coagulase and TSST-1 production were evaluated. Coagulase production was reduced in eluates exposed to roxithromycin when compared to control, while TSST-1 production was reduced in biofilms exposed to cefalexin and to a lesser extent, ciprofloxacin. In addition, the ability of Staph. aureus to produce biofilm in microtitre plates in the presence of sub-MIC antibiotics indicated that cefalexin induced biofilm formation at a wide range of sub-MICs. TSST-1 produced from the challenged and control biofilms was purified, and its proliferative activity was studied on single cell suspension of mouse splenocytes using MTS/PMS assay. No significant difference in the activity between the treated toxin and the control has been observed. CONCLUSIONS: Antibiotics at sub-MIC levels interfere with bacterial biofilm virulence expression depending on the type and concentration of antibiotic used. SIGNIFICANCE AND IMPACT OF THE STUDY: The establishment of sub-MICs of antibiotics in clinical situations may result in altered virulence states in pathogenic bacteria.

Public awareness and views on unlicensed use of medicines in children.

AIMS: To explore awareness and views of the general public on unlicensed use of medicines in children and on the participation of children in clinical trials. METHODS: Members of the public completed a questionnaire survey administered by face-to-face interview in public areas in N. Ireland. The main outcome measures were the views on unlicensed use of medicines in children and on clinical trials in children. RESULTS: One thousand participants (59.2% female) took part; 610 were parents. Most participants (86%) had no previous knowledge about unlicensed use of medicines in children. Being a parent did not influence this nor did being a parent of a child who suffered from a health problem (P > 0.05). Most participants (92%) felt that parents should be told about unlicensed use of medicines, with the doctor most frequently selected as the person who should inform parents. At the outset, only 1.8% of participants felt that the use of medicines in children was unsafe. However, having been informed about unlicensed use of medicines, this proportion increased dramatically (62.4%; P < 0.001). Views on whether participants would enter a child of their own into a clinical trial varied according to the health status of the child (P < 0.05) i.e. a child in good health (3.9%) vs a child with a life-threatening condition (41.9%). CONCLUSIONS: There is limited public knowledge of unlicensed use of medicines in children and a general reluctance to involve children in clinical trials unless the child to be involved has a life-threatening condition.

Structural analysis of anaerobic granules in a phase separated reactor by electron microscopy.

This paper discusses the microbial community structure of anaerobic granules and the effect of phase separation in anaerobic reactor on the characteristics of granules. Electron micrographs revealed that the core of anaerobic granular sludge consists predominantly of Methanosaeta-like cells, a key microorganism in granulation process. Granules in the methanogenic dominant zone of the reactor were stable and densely packed with smooth regular surface. On the other hand, granules subjected to acidogenic activities were less stable structures with broken parts and an irregular fissured surface. Anaerobic granules consisted of a vast diversity of species from the outer surface to the core of the granule and possessed a multi-layered structure. Viruses in the granules suggests the presence of bacteriophage in the granular biomass. These could be responsible for destroying cells and weakening the internal structure of granules, and thus possibly causing the breaking of granules. The observation of protozoa-like microorganism on the exterior zone of granular structure is believed to play an important role as bacterial predator and control the growth of bacterial cells. The images observed in this study shows that anaerobic granule harbour diverse number of microbial species, and act differently in acidogenic and methanogenic microbial zones.

The performance of a phase separated granular bed bioreactor treating brewery wastewater.

This study presents the performance characteristics of a plug flow phase separated anaerobic granular bed baffled reactor (GRABBR) fed with brewery wastewater at various operating conditions. The reactor achieved chemical oxygen demand (COD) removal of 93-96% with high methane production when operated at organic loading rates (OLRs) of 2.16-13.38kg COD m(-3)d(-1). The reactor configuration and microbial environment encouraged the acidogenic dominant zone to produce intermediate products suitable for degradation in the predominantly methanogenic zone. Noticeable phase separation between acidogenesis and methanogenesis mainly occurred at high OLR, involving a greater number of compartments to contribute to wastewater treatment. The highly active nature and good settling characteristics of methanogenic granular sludge offered high biomass retention and enhanced methanogenic activities within the system. The granular structure in the acidogenic dominant zone of the GRABBR was susceptible to disintegration and flotation. Methanogenic granular sludge was a multi-layered structure with Methanosaeta-like organisms dominant in the core.

The impact of psoriasis guidelines on appropriateness of referral from primary to secondary care: a randomized controlled trial.

BACKGROUND: Most patients with psoriasis have limited disease which can be managed effectively in primary care. There is a marked variation in the frequency of referrals between practices reflecting, in part, inadequate training of general practitioners (GPs) in the management of psoriasis. OBJECTIVES: To assess the effectiveness of guidelines and training sessions on the management of psoriasis in reducing inappropriate referrals from primary care. METHODS: Patients aged 18 years or over with psoriasis were eligible for the cluster-randomized, randomized controlled trial if they were referred by their GP between 9 September 2002 and 31 December 2003 to one of four hospital dermatology departments in Greater Manchester, North-West England. All GPs from 165 health centres were invited to a lecture by a local dermatologist on the diagnosis and management of psoriasis. Health centres in the intervention arm received guidelines on the management of psoriasis in primary care, developed by local dermatologists, supplemented by the offer of a practice-based nurse-led training session; those in the control arm received neither guidelines nor training sessions. RESULTS: Eighty-two health centres were randomized to the intervention arm and 83 to the control arm. Outcome data were available for 188 of the 196 eligible patients referred during the study period. Patients in the intervention arm were significantly more likely to be appropriately referred in comparison with patients in the control arm [difference = 19.1%; odds ratio (OR) 2.47; 95% confidence interval (CI) 1.31-4.68; intracluster correlation coefficient (ICC) = 0]. Only 25 (30%) health centres in the intervention arm took up the offer of training sessions. There was no significant difference in outcome between health centres in the intervention arm that received a training session and those that did not (OR 1.28, 95% CI 0.50-3.29, ICC = 0). CONCLUSIONS: Dissemination of guidelines on the management of psoriasis in primary care can significantly enhance the appropriateness of referral of patients to secondary care.

Assessment of morphology for anaerobic-granular particles.

This study shows that a proper assessment of granule morphology is fundamental before applying any mathematical derivation or empirical formula based on the shape factor of anaerobic-granular particles to determine granular characteristics. The granular images and size distribution of samples observed in this study revealed two different dimensions along two axes, which characterize these particles as ellipsoids. In the literature, theoretical-settling velocities and particle-size distribution of anaerobic granules have been calculated by assuming granules as spherical-shaped and using the numerical correlation between the size and settling velocity. This resulted in large deviations in results reported for settling velocities and size distribution calculated by using empirical equations when compared with experimentally measured values. It is believed that, because of the nonspherical nature of these particles, errors have been made in the earlier studies (which considered these particles as spherical), while evaluating granular-physical properties.