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Biomedical subjects

R Evans

Publications and source records attributed to R Evans.

At least 37 records · Page 2Linked to original sources
PubMed2006

Testing by Sysmex UF-100 flow cytometer and with bacterial culture in a diagnostic laboratory: a comparison.

A large proportion of the samples tested in routine diagnostic microbiology laboratory are urine samples. The gold standard is bacterial culture, but a high proportion of samples cultured are negative. Unnecessary testing can be reduced and an improved service provided by an effective screening test. The Sysmex UF-100 flow cytometer has been developed to count cells and casts accurately in urine samples. Its performance in a screening test was compared with bacterial culture by using 1005 consecutive urine samples, and cut-off criteria were established. Cut-off values of 3000 bacteria/microl and 111 WBC/microl provided the best discrimination. Of 1005 samples, 606 (60%) would be cultured. Sixteen samples that were not selected according to these criteria were culture positive. This was considered acceptable for our routine use. The use of a testing algorithm incorporating the Sysmex UF-100 flow cytometer has improved the quality and efficiency of urine testing within the routine microbiology laboratory.

Bacterial Infections↗
PubMed2006

The potential of Aedes triseriatus (Diptera: Culicidae) as an enzootic vector of West Nile virus.

The susceptibility of Aedes triseriatus (Say) (Diptera: Culicidae) to low levels of West Nile virus (family Flaviviridae, genus Flavivirus, WNV) was determined and compared with that of Culex pipiens L. to assess the likelihood of its participation in an enzootic cycle involving mammals. Ae. triseriatus and Cx. pipiens were exposed to WNV by feeding on baby chickens with WNV serum titers ranging from 10(4.1 +/- 0.1) to 10(8.6 +/- 0.1) plaque-forming units (PFU)/ml and from 10(4.1 +/- 0.1) to 10(7.0) PFU/ml, respectively. Infection rates and 95% confidence intervals (CIs) of 8% (4, 14) and 25% (15, 38) occurred in Ae. triseriatus and Cx. pipiens after feeding on chickens with WNV titers of 10(4.1 +/- 0.1) PFU/ml and increased to 65% (49, 79) and 100% (72, 100) in Ae. triseriatus and Cx. pipiens after feeding on chickens with titers of 10(7.1 +/- 0.1) PFU/ml. The mean infection rate of Ae. triseriatus ranged from 97% (84, 100) to 100% (79, 100) after feeding on chickens with WNV titers of > or = 10(8.2) PFU/ml. The infectious dose (ID)50 values for Ae. triseriatus and Cx. pipiens were 10(6.5) (6.4, 6.7) and 10(4.9) (4.6, 5.1) PFU/ml, respectively. The combined estimated transmission rate of Ae. triseriatus at 14 and 18 d after feeding on chickens with a mean WNV titer of 10(8.6 +/- 0.1) PFU/ml was 55%. Although Ae. triseriatus is significantly less susceptible to WNV than Cx. pipiens, the susceptibility of Ae. triseriatus to WNV titers < 10(5.0) PFU/ml and its ability to transmit WNV suggest that Ae. triseriatus has the potential to be an enzootic vector among mammalian populations.

Aedes↗
PubMed2006

An investigation of misoprostol in the promotion of wound healing.

Misoprostol is a synthetic analogue of prostaglandin E1 that is known to attenuate the inflammatory process and promote collagen formation by inhibiting IL-1 and TNF. The objective of this study was to determine if the application of misoprostol wound powder to open wounds in dogs would modulate inflammation and decrease wound healing time. This prospective randomized study included 20 dogs with 281 surgically created 8 mm open wounds over the dorsum. The wounds were assigned to one of three treatments: control (no treatment), treatment (misoprostol powder with 'avicel'), or vehicle ('avicel' alone). Open wounds were digitally photographed on days zero, one, three, seven, 10, and 15 to measure wound size. All wounds were harvested at day 15 and evaluated histologically for evidence of edema, inflammation, necrosis, and collagen characteristics. Amount of epithelialization of open wounds was not significantly different among the groups at days three, seven, 10, and 15. The vehicle treated wounds were found to have a significantly higher degree of necrosis in comparison to control and treatment wounds. The control wounds had significantly lower scores for deep inflammation. All of the other parameters evaluated including location of wound, oedema, and characteristics of collagen fibres in the wound showed no significance among groups. However, the total wound score for the misoprostol was statistically higher than that for the control wounds. Therefore the value of using misoprostol wound powder with 'avicel' as the vehicle to enhance wound healing cannot be substantiated by the results of this study.

Administration, Cutaneous↗
PubMed2005

Adenine nucleotide loss in the skeletal muscles during exercise in chronic obstructive pulmonary disease.

BACKGROUND: Skeletal muscle adenine nucleotide loss has been associated with fatigue during high intensity exercise in healthy subjects but has not been studied in patients with chronic obstructive pulmonary disease (COPD). Changes in adenine nucleotides and other metabolites in the skeletal muscles were measured in patients with COPD and age matched healthy volunteers by obtaining biopsy samples from the quadriceps muscle at rest and following a standardised exercise challenge. METHODS: Eighteen patients with COPD (mean (SD) forced expiratory volume in 1 second 38.1 (16.8)%) and eight age matched healthy controls were studied. Biopsy samples were taken from the vastus lateralis muscle at rest and immediately after a 5 minute constant workload cycle test performed at 80% peak work achieved during a maximal incremental cycle test performed previously. RESULTS: The absolute workload at which exercise was performed was substantially lower in the COPD group than in the controls (56.7 (15.9) W v 143.2 (26.3) W, p<0.01). Despite this, there was a significant loss of adenosine triphosphate (mean change 4.3 (95% CI -7.0 to -1.6), p<0.01) and accumulation of inosine monophosphate (2.03 (95% CI 0.64 to 3.42), p<0.01) during exercise in the COPD group that was similar to the control group (-4.8 (95% CI -9.7 to 0.08), p = 0.053 and 1.6 (95% CI 0.42 to 2.79), p<0.01, respectively). CONCLUSIONS: These findings indicate that the ATP demands of exercise were not met by resynthesis from oxidative and non-oxidative sources. This suggests that significant metabolic stress occurs in the skeletal muscles of COPD patients during whole body exercise at low absolute workloads similar to those required for activities of daily living.

Adenine Nucleotides↗
PubMed2005

Dynamics of urinary levels of hCG during early pregnancy and accuracy of the home pregnancy test.

The paper ‘Dynamics of urinary levels of hCG during early pregnancy and accuracy of the home pregnancy test’ has been retracted at the request of the authors. Since initiating the work 3 years ago improvements have been made to home pregnancy tests, and the device used in the study is no longer commercially available. The authors are conducting a similar study with a new pregnancy test device which suggests that some of the conclusions drawn in the retracted paper could now be misleading to health professionals and consumers.

Retraction of Publication as Topic↗
PubMed2005

Asymptotic decay of pair correlations in a Yukawa fluid.

We analyze the r-->infinity asymptotic decay of the total correlation function h (r) for a fluid composed of particles interacting via a (point) Yukawa pair potential. Such a potential provides a simple model for dusty plasmas. The asymptotic decay is determined by the poles of the liquid structure factor in the complex plane. We use the hypernetted-chain closure to the Ornstein-Zernike equation to determine the line in the phase diagram, well removed from the freezing transition line, where crossover occurs in the ultimate decay of h (r) , from monotonic to damped oscillatory. We show that (i) crossover takes place via the same mechanism (coalescence of imaginary poles) as in the classical one-component plasma and in other models of Coulomb fluids and (ii) leading-order pole contributions provide an accurate description of h (r) at intermediate distances r as well as at long range.

Journal Article↗
PubMed2005

Solvent mediated interactions close to fluid-fluid phase separation: microscopic treatment of bridging in a soft-core fluid.

Using density functional theory we calculate the density profiles of a binary solvent adsorbed around a pair of big solute particles. All species interact via repulsive Gaussian potentials. The solvent exhibits fluid-fluid phase separation, and for thermodynamic states near to coexistence the big particles can be surrounded by a thick adsorbed "wetting" film of the coexisting solvent phase. On reducing the separation between the two big particles we find there can be a "bridging" transition as the wetting films join to form a fluid bridge. The effective (solvent mediated) potential between the two big particles becomes long ranged and strongly attractive in the bridged configuration. Within our mean-field treatment the bridging transition results in a discontinuity in the solvent mediated force. We demonstrate that accounting for the phenomenon of bridging requires the presence of a nonzero bridge function in the correlations between the solute particles when our model fluid is described within a full mixture theory based upon the Ornstein-Zernike equations.

Journal Article↗
PubMed2005

Wetting and drying at a curved substrate: long-ranged forces.

We examine the interfacial properties of a hard spherical cavity, radius R , immersed in a solvent in which the fluid-fluid interaction potential contains both a hard-sphere repulsive part and an attractive - r(-6) component. Near to liquid-gas coexistence where the chemical potential deviation deltamu identical withmu- mu(co) (T) --> 0(+) complete wetting by the gas (drying) occurs and a coarse-grained effective Hamiltonian approach shows that the wall/liquid surface tension has a term in R(-2/3) , i.e., a leading-order power-law nonanalyticity in the curvature ( R-1 ) in the large cavity limit. For states sufficiently well removed from coexistence the surface tension can be expanded in integer powers of the curvature R-1 , provided R> R(c) with the length scale given by R(c) =2 gamma(gl) (infinity) / (Deltarhodeltamu) , where gamma(gl) (infinity) is the planar liquid/gas surface tension and Deltarho is the difference between the coexisting densities. However, even in these circumstances there are additional R-2 ln R contributions to the surface tension arising from the dispersion forces. An exact statistical mechanical sum rule is used to relate the density of the fluid at the point of contact with the cavity, rho ( R+ ,mu) , to the pressure of the reservoir and the surface tension. This predicts that rho ( R+ ,mu) acquires a term in R(-5/3) in the regime R< R(c) . Numerical results obtained by applying classical density functional theory to this model confirm all the predictions from the coarse-grained approach for both the surface tension and the contact density. We argue that our results for leading-order nonanalytic contributions are exact, i.e., they should remain valid in the presence of interface fluctuations, and we discuss briefly the repercussions for solvation phenomena and for other wetting situations.

Journal Article↗
PubMed2005

Coagulation necrosis in malignant mediastinal nodes on endoscopic ultrasound: a new endosonographic sign.

AIMS: Endoscopic ultrasound (EUS) can be used to assess mediastinal lymph nodes, and EUS-guided transoesophageal fine needle aspiration (EUS-FNA) can provide a tissue diagnosis. Previous studies suggest that a uniformly hypoechoic echotexture is a feature of malignant nodes, and echogenic structures within nodes are due to the normal hilum. Ill-defined, non-shadowing echogenic areas within malignant lymph nodes have been termed coagulation necrosis (CN) on neck ultrasound. The purpose of this study is to determine whether CN can be detected on EUS and be used as a predictive sign for malignancy in mediastinal lymph nodes. METHODS: A total of 36 individuals who underwent EUS-FNA of mediastinal lymph nodes were initially included. A radiologist experienced in neck ultrasound, and blinded to the final diagnosis, reviewed hard-copy films for CN. Comparison was made with the EUS-FNA result and the final diagnosis. RESULTS: Four patients were excluded because their films were deemed inadequate for retrospective diagnosis. The remaining 32 patients were all included, and 11 showed CN. Of the 11 cases, 10 had malignant cytology on EUS-FNA; and in the remaining case follow-up indicated a false-negative EUS-FNA. Of the 21 subjects with no CN, the final diagnosis was malignant in 12 and non-malignant in 9 cases. No participant with a final benign diagnosis had CN. CONCLUSION: Echogenic structures within mediastinal lymph nodes on EUS are not necessarily due to the normal hilum. Careful analysis of the intranodal echo pattern may reveal CN. CN can be used as a predictive sign of malignancy and EUS-FNA should be targeted towards these nodes.

Adult↗
PubMed2005

Skin symptoms in the seafood-processing industry in north Norway.

A survey of occupational skin problems, based on a questionnaire, was carried out among 883 workers in different types of seafood-processing industries in northern Norway. The prevalence of dry skin, itching, rash/eczema, chapped skin and chronic sores was significantly higher among production workers (55.6%) in the white fish-, shrimp- and salmon-processing industries, compared to administrative workers in the same industries (27.5%). Among production workers, there was a significantly higher prevalence of skin symptoms among females (60.2%) compared to males (50.1%). A strong sex division of work tasks rather than sex itself may explain this. There was no sex difference among administrative workers. Several risk factors for skin symptoms to occur are indicated. The workers are exposed to raw materials and a mixture of water and juice from the fish or shrimp, salt, detergents and disinfectants. Gloves may also cause skin problems. Major risk factors believed to cause skin symptoms were contact with raw materials, fish juice, water and gloves. The results also indicate that skin symptoms are of moderate severity and seldom interfere with working capacity.

Adult↗
PubMed2005

Infliximab treatment results in significant improvement in the quality of life of patients with severe psoriasis: a double-blind placebo-controlled trial.

BACKGROUND: Psoriasis is a chronic disease that significantly diminishes the health-related quality of life (HRQOL). Infliximab is a chimeric, tumour necrosis factor alpha monoclonal antibody that has been shown to improve the signs and symptoms of plaque psoriasis. OBJECTIVES: The objective of this study was to evaluate the effect of infliximab induction therapy on the HRQOL of patients with severe plaque psoriasis. METHODS: In this double-blind, placebo-controlled trial, 249 patients were randomly assigned to receive intravenous infusions of 3 or 5 mg kg(-1) of infliximab or placebo and were treated at weeks 0, 2 and 6. Patients completed the Dermatology Life Quality Index (DLQI) at baseline and week 10. RESULTS: Infliximab induction therapy resulted in a substantial improvement in HRQOL. At week 10, patients in the infliximab 3- and 5-mg kg(-1) groups showed a median percentage improvement in DLQI scores of 84.0% and 91.0%, respectively, compared with 0% in the placebo group (P < 0.001). The median decrease from baseline in DLQI score at week 10 was 8.0 and 10.0 for the 3 and 5 mg kg(-1) infliximab groups, respectively, compared with 0 in the placebo group (P < 0.001). Thirty-three per cent and 40% of patients in the 3 and 5 mg kg(-1) infliximab groups, respectively, had a DLQI score of 0 at week 10, compared with 2% in the placebo group (P < 0.001). There was a strong correlation between the percentage change from baseline at week 10 in Psoriasis Area and Severity Index (PASI) scores and the percentage change in DLQI scores during the same period (Spearman's correlation, 0.61, P < 0.001). When the infliximab and placebo treatment groups were combined, patients with at least 75% improvement in PASI scores between baseline and week 10 had a greater mean improvement in DLQI scores (81%) than those with 50-75% improvement in PASI during the same period (60%). CONCLUSIONS: Infliximab induction therapy resulted in significant improvement in HRQOL in patients with severe psoriasis.

Adult↗
PubMed2005

Interchanging lexical information for a multilingual dictionary.

OBJECTIVE: To facilitate the interchange of lexical information for multiple languages in the medical domain. To pave the way for the emergence of a generally available truly multilingual electronic dictionary in the medical domain. METHODS: An interchange format has to be neutral relative to the target languages. It has to be consistent with current needs of lexicon authors, present and future. An active interaction between six potential authors aimed to determine a common denominator striking the right balance between richness of content and ease of use for lexicon providers. RESULTS: A simple list of relevant attributes has been established and published. The format has the potential for collecting relevant parts of a future multilingual dictionary. An XML version is available. CONCLUSION: This effort makes feasible the exchange of lexical information between research groups. Interchange files are made available in a public repository. This procedure opens the door to a true multilingual dictionary, in the awareness that the exchange of lexical information is (only) a necessary first step, before structuring the corresponding entries in different languages.

Dictionaries, Medical as Topic↗
PubMed2004

Nonanalytic curvature contributions to solvation free energies: influence of drying.

We investigate the solvation of a hard spherical cavity, of radius R, immersed in a fluid for which the interparticle forces are short ranged. For thermodynamic states lying close to the liquid binodal, where the chemical potential deviation deltamu is identical with mu-muco(T) is very small and positive, complete wetting by gas (drying) occurs and two regimes of interfacial behavior can be identified. These are characterized by the length scale Rc=2gamma(gl)infinity/(Deltarhodeltamu), where gamma(gl)infinity is the planar gas-liquid surface tension and Deltarho is the difference in coexisting densities at temperature T. For R>Rc, the interfacial free energy and the density profile of the fluid near the hard wall can be expanded in powers of the curvature R(-1), in keeping with the analysis of Stillinger and Cotter [J. Chem. Phys. 55, 3449 (1971)]. In the other regime, R 0, of the work of formation of a hard spherical cavity and of the Gibbs adsorption and the fluid density at contact with the wall. Our analysis, which is based on an effective interfacial Hamiltonian combined with exact statistical mechanical sum rules, is confirmed fully by the results of microscopic density functional calculations for a square-well fluid. We discuss the repercussions of our results for solvation phenomena, emphasizing that nonanalytic behavior equivalent to that we find for complete drying in solvophobic systems will also arise in the case of complete wetting, i.e. when liquid films are adsorbed on the surface of large (colloidal) particles or at curved substrates. We reassess various results in the important but neglected Stillinger-Cotter paper, where drying was not considered explicitly, in the light of our present analysis.

Journal Article↗
PubMed2004

Decay of correlation functions in hard-sphere mixtures: structural crossover.

We investigate the decay of pair correlation functions in a homogeneous (bulk) binary mixture of hard spheres. At a given state point the asymptotic decay r-->infinity of all three correlation functions is governed by a common exponential decay length and a common wavelength of oscillations. Provided the mixture is sufficiently asymmetric, size ratios q less than or approximately 0.7, we find that the common wavelength reflects either the size of the small or that of the big spheres. By analyzing the (complex) poles of the partial structure factors we find a sharp structural crossover line in the phase diagram. On one side of this line the common wavelength is approximately the diameter of the smaller sized spheres whereas on the other side it is approximately the diameter of the bigger ones; the wavelength of the longest ranged oscillations changes discontinuously at the structural crossover line. Using density functional theory and Monte Carlo simulations we show that structural crossover also manifests itself in the intermediate range behavior of the pair correlation functions and we comment on the relevance of this observation for real (colloidal) mixtures. In highly asymmetric mixtures, q< or =0.1, where there is metastable fluid-fluid transition, we find a Fisher-Widom line with two branches. This line separates a region of the phase diagram where the decay of pair correlations is oscillatory from one in which it is monotonic.

Journal Article↗
PubMed2004

Dynamical density functional theory and its application to spinodal decomposition.

We present an alternative derivation of the dynamical density functional theory for the one-body density profile of a classical fluid developed by Marconi and Tarazona [J. Chem. Phys. 110, 8032 (1999)]. Our derivation elucidates further some of the physical assumptions inherent in the theory and shows that it is not restricted to fluids composed of particles interacting solely via pair potentials; rather it applies to general, multibody interactions. The starting point for our derivation is the Smoluchowski equation and the theory is therefore one for Brownian particles and as such is applicable to colloidal fluids. In the second part of this paper we use the dynamical density functional theory to derive a theory for spinodal decomposition that is applicable at both early and intermediate times. For early stages of spinodal decomposition our nonlinear theory is equivalent to the (generalized) linear Cahn-Hilliard theory, but for later times it incorporates coupling between different Fourier components of the density fluctuations (modes) and therefore goes beyond Cahn-Hilliard theory. We describe the results of calculations for a model (Yukawa) fluid which show that the coupling leads to the growth of a second maximum in the density fluctuations, at a wave number larger than that of the main peak.

Journal Article↗
PubMed2004

Non-invasive physical treatments for chronic/recurrent headache.

BACKGROUND: Non-invasive physical treatments are often used to treat common types of chronic/recurrent headache. OBJECTIVES: To quantify and compare the magnitude of short- and long-term effects of non-invasive physical treatments for chronic/recurrent headaches. SEARCH STRATEGY: We searched the following databases from their inception to November 2002: MEDLINE, EMBASE, BIOSIS, CINAHL, Science Citation Index, Dissertation Abstracts, CENTRAL, and the Specialised Register of the Cochrane Pain, Palliative Care and Supportive Care review group. Selected complementary medicine reference systems were searched as well. We also performed citation tracking and hand searching of potentially relevant journals. SELECTION CRITERIA: We included randomized and quasi-randomized controlled trials comparing non-invasive physical treatments for chronic/recurrent headaches to any type of control. DATA COLLECTION AND ANALYSIS: Two independent reviewers abstracted trial information and scored trials for methodological quality. Outcomes data were standardized into percentage point and effect size scores wherever possible. The strength of the evidence of effectiveness was assessed using pre-specified rules. MAIN RESULTS: Twenty-two studies with a total of 2628 patients (age 12 to 78 years) met the inclusion criteria. Five types of headache were studied: migraine, tension-type, cervicogenic, a mix of migraine and tension-type, and post-traumatic headache. Ten studies had methodological quality scores of 50 or more (out of a possible 100 points), but many limitations were identified. We were unable to pool data because of study heterogeneity. For the prophylactic treatment of migraine headache, there is evidence that spinal manipulation may be an effective treatment option with a short-term effect similar to that of a commonly used, effective drug (amitriptyline). Other possible treatment options with weaker evidence of effectiveness are pulsating electromagnetic fields and a combination of transcutaneous electrical nerve stimulation [TENS] and electrical neurotransmitter modulation. For the prophylactic treatment of chronic tension-type headache, amitriptyline is more effective than spinal manipulation during treatment. However, spinal manipulation is superior in the short term after cessation of both treatments. Other possible treatment options with weaker evidence of effectiveness are therapeutic touch; cranial electrotherapy; a combination of TENS and electrical neurotransmitter modulation; and a regimen of auto-massage, TENS, and stretching. For episodic tension-type headache, there is evidence that adding spinal manipulation to massage is not effective. For the prophylactic treatment of cervicogenic headache, there is evidence that both neck exercise (low-intensity endurance training) and spinal manipulation are effective in the short and long term when compared to no treatment. There is also evidence that spinal manipulation is effective in the short term when compared to massage or placebo spinal manipulation, and weaker evidence when compared to spinal mobilization. There is weaker evidence that spinal mobilization is more effective in the short term than cold packs in the treatment of post-traumatic headache. REVIEWERS' CONCLUSIONS: A few non-invasive physical treatments may be effective as prophylactic treatments for chronic/recurrent headaches. Based on trial results, these treatments appear to be associated with little risk of serious adverse effects. The clinical effectiveness and cost-effectiveness of non-invasive physical treatments require further research using scientifically rigorous methods. The heterogeneity of the studies included in this review means that the results of a few additional high-quality trials in the future could easily change the conclusions of our review.

Chronic Disease↗
PubMed2004

Fixed or mobile bearing unicompartmental knee replacement? A comparative cohort study.

Unicompartmental knee replacement (UKR) for anteromedial osteoarthritis is a well-established technique. Numerous clinical outcome studies demonstrate good medium and long-term results. The aim of this prospective study was to compare the complications and short-term clinical outcome of the St. Georg Sled, a fixed bearing UKR, with the Oxford mobile bearing UKR. Outcome at 2 years was assessed using the Bristol knee score and the Oxford knee score; in addition, complications occurring since formal scoring at 2-year follow-up were recorded. A total of 47 Oxford UKRs and 57 St. Georg Sled UKRs were performed in 91 patients, none of whom were lost to follow-up. At 2 years, both outcome measures were better for the St. Georg Sled Group. The pain component of the Bristol knee score was significantly better for this group (p-value = 0.013). Three patients in the Oxford group had bearing dislocations and a further four patients required revision (mean time to revision 3.0 years). In the St. Georg Sled group, three patients required revisions (mean time to revision 3.4 years). These results demonstrate that in the short-term, the Oxford mobile bearing prosthesis has a higher re-operation rate and that the St. Georg Sled achieves better pain relief. The functional scores of the two groups were similar.

Aged↗