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Biomedical subjects

J Wilson

Publications and source records attributed to J Wilson.

At least 37 records · Page 2Linked to original sources
PubMed2005

Comparison of two peri-wound skin protectants in venous leg ulcers: a randomised controlled trial.

OBJECTIVE: A randomised controlled trial was designed to determine whether or not early intervention with a suitable skin barrier preparation could prevent skin breakdown. This study was conducted to compare the efficacy and cost-effectivenss of two skin protectants, Cavilon No Sting Barrier Film (NSBF) (3M Health Care) and zinc paste compound, in the management of maceration and irritation of the peri-wound area of venous leg ulcers. METHOD: Thirty-five patients with venous leg ulcers and surrounding skin problems were randomised to receive either NSBF or zinc paste compound. The preparation was then applied at each dressing change for 12 weeks. All patients had been receiving compression bandaging before entering the study and continued wearing it throughout the 12-week study period. RESULTS: The decrease in wound area was 5.11+/-8.39cm2 in the NSBF group and 4.59+/-5.83cm2 in the zinc paste group. The healing rate was 0.046cm per week with NSBF and 0.039cm per week with zinc paste. There was a significant difference in the time required to remove and re-apply the skin protectants: an average of 0.19 (+/-0.17) minutes in the NSBF group and 5.53 (+/-2.10) minutes in the zinc paste group (p<0.0001). CONCLUSION: Both products were effective barrier preparations. However, NSBF was easy to apply and transparent. The zinc paste was messy to apply and difficult to remove, and thus took up considerably more nursing time than NSBF. DECLARATION OF INTEREST: This study was supported by 3M Health Care.

Aged↗
PubMed2005

Infection of the surgical site after arthroplasty of the hip.

We wished to estimate the incidence of surgical-site infection (SSI) after total hip replacement (THR) and hemiarthroplasty and its strength of association with major risk factors. The SSI surveillance service prospectively gathered clinical, operative and infection data on inpatients from 102 hospitals in England during a four-year period. The overall incidence of SSI was 2.23% for 16,291 THRs, 4.97% for 5769 hemiarthroplasty procedures, 3.68% for 2550 revision THRs and 7.6% for 198 revision hemiarthroplasties. Staphylococcus aureus was identified in 50% of SSIs; 59% of these isolates were methicillin-resistant (MRSA). In the single variable analysis of THRs, age, female gender, American Society of Anesthesiologists (ASA) score, body mass index, trauma, duration of operation and pre-operative stay were significantly associated with the risk of SSI (p < 0.05). For hemiarthroplasty, the ASA score and age were significant factors. In revision THRs male gender, ASA score, trauma, wound class, duration of operation and pre-operative stay were significant risk factors. The median time to detection of SSI was eight days for superficial incisional, 11 days for deep incisional and 11 days for joint/bone infections. For each procedure the mean length of stay doubled for patients with SSI. The multivariate analysis identified age group, trauma, duration of operation and ASA score as significant, independent risk factors for SSI. There was significant interhospital variation in the rates of SSI. MRSA was the most common pathogen to cause SSI in hip arthroplasty, especially in patients undergoing hemiarthroplasty, but coagulase-negative Staph. aureus may be more important in deep infections involving the joint.

Age Factors↗
PubMed2005

Imatinib for the treatment of patients with unresectable and/or metastatic gastrointestinal stromal tumours: systematic review and economic evaluation.

OBJECTIVES: To assess the clinical and cost-effectiveness of imatinib in the treatment of unresectable and/or metastatic, KIT-positive, gastrointestinal stromal tumours (GISTs), relative to current standard treatments. DATA SOURCES: Electronic databases. REVIEW METHODS: As there were no randomised trials that have directly compared imatinib with the current standard treatment in patients with advanced GIST, this review included non-randomised controlled studies, cohort studies, and case series that reported effectiveness results of treatment with imatinib and/or other interventions in patients with advanced GIST. The effectiveness assessment was based on the comparison of results from imatinib trials and results from studies of historical control patients. Economic evaluation was mainly based on an assessment and modification (when judged necessary) of a model submitted by Novartis. RESULTS: Evidence from published uncontrolled trials involving 187 patients, and from abstracts reporting similar uncontrolled trials involving 1700 patients, indicates that approximately 50% of imatinib-treated individuals with advanced GIST experience a dramatic clinical response in terms of at least a 50% reduction in tumour mass. At present, although useful data are accumulating, it is not possible to predict which patients may respond in this way. Fifteen studies where possible GIST patients had been treated with therapies other than imatinib or best supportive care were also identified. All imatinib-treated patients experienced adverse effects, although they were relatively mild. Overall, imatinib was reported to be well tolerated. The most common serious events included unspecified haemorrhage and neutropenia. Skin rash, oedema and periorbital oedema were the common adverse events observed. Patients on the highest dose regimen (1000 mg per day in one trial) may experience dose-limiting drug toxicity. A structured assessment was carried out of the Novartis economic evaluation of imatinib for unresectable and/or metastatic GIST. The model was clearly presented and well written, its structure and input data were transparent, and the level of simplification was reasonable in terms of the objectives and data availability. However, the original Novartis model overestimated the cost-effectiveness of imatinib because of disproportion of survival and time-to-treatment failure in the imatinib arm, and the use of a possibly biased survival curve for patients in the control arm. The original Novartis model was modified to correct these two important shortcomings, which made it less sensitive to the choice of the survival curve for the control patients. According to the modified Novartis model, the estimated cost per quality-adjusted life-year (QALY) was 85,224 UK pounds (range 51,515--98,889 UK pounds) after 2 years, 41,219 UK pounds (27,331--44,236 UK pounds) after 5 years and 29,789 UK pounds (21,404--33,976 UK pounds) after 10 years. The results from a new Birmingham model were also within the range of estimates from the modified Novartis model. CONCLUSIONS: Evidence from uncontrolled studies indicates that the treatment with imatinib brings about clinically significant shrinkage of tumour mass in about half of patients with unresectable and/or metastatic, KIT-positive GIST. Results of modelling based on data from uncontrolled studies suggest that imatinib treatment improves survival in patients with unresectable and/or metastatic GIST. The economic evaluation modelling suggests that the cost per QALY gained ranges from 51,515 to 98,889 UK pounds after 2 years, from 27,331 to 44,236 UK pounds after 5 years, and from 21,404 to 33,976 UK pounds after 10 years. Further research is needed into quality of life within trials involving patients with advanced malignancy, and long-term follow-up of adverse events is needed. Subgroup analysis of which, if any, patient types have a better or worse response to imatinib is also required. Analysis of individual patient data may be a good way of exploring these issues. There are many uncertainties surrounding imatinib prescription, such as the length of time patients should be on imatinib, the dose, drug resistance and the optimum time-point in the disease course at which to give the drug. Secondary research such as an update of this systematic review and a reassessment of the model is highly recommended when ongoing trials reach completion.

Adult↗
PubMed2004

Localization and physical property experiments conducted by Opportunity at Meridiani Planum.

The location of the Opportunity landing site was determined to better than 10-m absolute accuracy from analyses of radio tracking data. We determined Rover locations during traverses with an error as small as several centimeters using engineering telemetry and overlapping images. Topographic profiles generated from rover data show that the plains are very smooth from meter- to centimeter-length scales, consistent with analyses of orbital observations. Solar cell output decreased because of the deposition of airborne dust on the panels. The lack of dust-covered surfaces on Meridiani Planum indicates that high velocity winds must remove this material on a continuing basis. The low mechanical strength of the evaporitic rocks as determined from grinding experiments, and the abundance of coarse-grained surface particles argue for differential erosion of Meridiani Planum.

Extraterrestrial Environment↗
PubMed2004

Functional properties and pharmacological inhibition of ASIC channels in the human SJ-RH30 skeletal muscle cell line.

The rhabdomyosarcoma cell line (SJ-RH30) exhibits both ultrastructural and electrophysiological hallmarks of mammalian skeletal muscle. We have used patch-clamp electrophysiology to study acid-gated currents in these cells. At a holding potential of -60 mV, rapid application of extracellular solutions of pH 6.5 produced inward current responses in approximately 85% of cells. The amplitude of these responses exhibited a marked pH dependence. In addition, the kinetics of both activation and desensitization were faster at more acidic pH, whereas the deactivation rate was pH independent. Repeated applications of a pH 6.0 solution produced a tachyphalaxis that could be substantially attenuated by reducing the duration of the acid challenge and increasing the interstimulus interval. The current-voltage relationship of the acid-induced currents was linear at positive potentials but an area of negative slope conductance was observed in the negative potential range. This was not eliminated by removal of extracellular Ca(2+), a manoeuvre which did, however, substantially increase current amplitude. Changing the transmembrane Na(+) gradient altered the current-voltage relationship in a fashion commensurate with an underlying conductance predominantly permeable to Na(+). Pharmacologically, acid-induced currents were blocked 84.4 +/- 1.2% by 30 microm amiloride and 91.8 +/- 3.0% by a 1 : 1000 dilution of Psalmopoeus cambridgei venom. Inhibition by both agents could be reversed by a short period of compound washout. By contrast, APETx2 had no significant effect on acid-evoked currents. These observations strongly suggest the acid-induced current is mediated by ASIC1 channels. In agreement with this, current responses of SJ-RH30 cells to a pH 6.0 challenge were greatly enhanced by extracellular lactate. These data demonstrate the presence of ASIC1 channels in a cell line with skeletal muscle characteristics. In addition, significant levels of ASIC1 and ASIC3 mRNA were found in skeletal muscle tissue samples. These findings are discussed with regard to the role such a conductance might play if present in skeletal muscle in vivo.

Acid Sensing Ion Channels↗
PubMed2004

Time-frequency and coherence analysis of fMEG signals.

Fetal magnetoencephalographic (fMEG) measurements are performed with interference from the fetal and maternal magnetocardiogram (MCG). Fetal movement, fetal breathing, fetal eye blinks or eye rollings and maternal muscle-contraction may generate detectable signals. These factors can be called "interventions," which can be manifested in space and/or time. They make the fMEG signals nonstationary. By examining temporal relationship of the multi-channel records, we are able to find the spatial signature of these "interventions." The aim of this study is to examine nonstationarity in single channel and nonhomogeniety in multiple channels of the fMEG data. Preliminary results are reported here, and may be used in further studies, leading toward intervention identification, and ultimately fetal state determination.

Fetal Monitoring↗
PubMed2004

Spatial-temporal analysis of non-stationary fMEG data.

Magnetoencephalography (MEG) is a technique used to non-invasively record neuromagnetic fields generated by the human brain. Our new SARA (SQUID Array for Reproductive Assessment) is a unique MEG device designed specifically for the study of the fetal neurophysiology. During the acquistion of fetal magnetoencephalography (fMEG), many other interfering bio-magnetic signals are collected as well. Examples include the movement of fetus or muscle contraction of the mother. As a result, the recorded signals may show unexpected patterns, other than the target signal of interest. These interventions makes it difficult for a physician to assess the exact fetal condition, including its response to various stimuli. We propose using intervention analysis and spatial-temporal autoregressive moving average (STARMA) modeling to address the problem. STARMA is a statistical method that examines the relationship between the current observations as a linear combination of past observations, as well as observations at neighboring sites. Through intervention analysis, the change in pattern due to interfering signals can be well accounted for. When these interferences are removed, the end product is a template time series, or a typical signal from the target of interest thus providing a more reliable means to monitor the actual signals generated by the fetal brain and other organs of interest.

Female↗
PubMed2004

Absence of long-term modulation of ventilation by dead-space loading during moderate exercise in humans.

The stability of arterial PCO(2) (P(a)CO(2)) during moderate exercise in humans suggests a CO(2)-linked control that matches ventilation (V(E)) to pulmonary CO(2) clearance (VCO(2)). An alternative view is that V(E) is subject to long-term modulation (LTM) induced by "hyperpnoeic history". LTM has been reported with associative conditioning via dead-space (V(D)) loading in exercising goats (Martin and Mitchell 1993). Whether this prevails in humans is less clear, which may reflect differences in study design (e.g. subject familiarisation; V(D) load; whether or not V(E) is expressed relative to VCO(2); choice of P(a)CO(2) estimator). After familiarisation, nine healthy males performed moderate constant-load cycle-ergometry (20 W-80 W-20 W; <lactate threshold, theta;(L)): day 1, pre-conditioning, n=3; day 2, conditioning (V(D)=1.59 l, doubling V(E) at 20 W and 80 W), n=8 with 10 min rest between tests; and, after 1 h rest, post-conditioning, n=3. Gas exchange was determined breath-by-breath. Post-conditioning, neither the transient [phase 1, phase 2 (capital EF, Cyrillic1, capital EF, Cyrillic2)] nor steady-state V(E) exercise responses, nor their proportionality to VCO(2), differed from pre-conditioning. For post-conditioning trial 1, steady-state V(E) was 28.1 (4.7) l min(-1) versus 29.1 (3.8) l min(-1) pre-conditioning, and mean-alveolar PCO(2) (a validated P(a)CO(2) estimator) was 5.53 (0.48) kPa [41.5 (3.6) mmHg] versus 5.59 (0.49) kPa [41.9 (3.7) mmHg]; the capital EF, Cyrillic1 V(E) increment was 4.2 (2.9) l min(-1) versus 5.2 (1.9) l min(-1); the capital EF, Cyrillic2 V(E) time-constant (tau) was 64.4 (24.1) s versus 64.1 (25.3) s; tauV(E)/tauVCO(2) was 1.12 (0.04) versus 1.10 (0.04); and the V(E)-VCO(2) slope was 21.7 (3.4) versus 21.2 (3.2). In conclusion, we could find no evidence to support ventilatory control during moderate exercise being influenced by hyperpnoeic history associated with dead-space loading in humans.

Adaptation, Physiological↗
PubMed2004

Surgical wound infection as a performance indicator: agreement of common definitions of wound infection in 4773 patients.

OBJECTIVE: To assess the level of agreement between common definitions of wound infection that might be used as performance indicators. DESIGN: Prospective observational study. SETTING: London teaching hospital group receiving emergency cases as well as tertiary referrals. PARTICIPANTS: 4773 surgical patients staying in hospital at least two nights. MAIN OUTCOME MEASURES: Numbers of wound infections based on purulent discharge alone, on the Centers for Disease Control (CDC) definition of wound infection, on the nosocomial infection national surveillance scheme (NINSS) version of the CDC definition, and on the ASEPSIS scoring method. RESULTS: 5804 surgical wounds were assessed during 5028 separate hospital admissions. The mean percentage of wounds classified as infected differed substantially with different definitions: 19.2% with the CDC definition (95% confidence interval 18.1% to 20.4%), 14.6% (13.6% to 15.6%) with the NINSS version, 12.3% (11.4% to 13.2%) with pus alone, and 6.8% (6.1% to 7.5%) with an ASEPSIS score > 20. The agreement between definitions with respect to individual wounds was poor. Wounds with pus were automatically defined as infected with the CDC, NINSS, and pus alone definitions, but only 39% (283/714) of these had ASEPSIS scores > 20. CONCLUSIONS: Small changes made to the CDC definition or even in its interpretation, as with the NINSS version, caused major variation in estimated percentage of wound infection. Substantial numbers of wounds were differently classified across the grades of infection. A single definition used consistently can show changes in percentage wound infection over time at a single centre, but differences in interpretation prevent comparison between different centres.

Adult↗
PubMed2004

Localization and physical properties experiments conducted by Spirit at Gusev Crater.

The precise location and relative elevation of Spirit during its traverses from the Columbia Memorial station to Bonneville crater were determined with bundle-adjusted retrievals from rover wheel turns, suspension and tilt angles, and overlapping images. Physical properties experiments show a decrease of 0.2% per Mars solar day in solar cell output resulting from deposition of airborne dust, cohesive soil-like deposits in plains and hollows, bright and dark rock coatings, and relatively weak volcanic rocks of basaltic composition. Volcanic, impact, aeolian, and water-related processes produced the encountered landforms and materials.

Extraterrestrial Environment↗
PubMed2004

Compound and rotational damping in warm deformed rare-earth nuclei.

The gamma decay in the quasicontinuum from selected configurations of the rotational nucleus 163Er has been measured with the EUROBALL array. A new analysis technique has allowed for the first time to directly measure the compound and rotational damping widths Gamma (micro) and Gamma (rot). Values of Gamma (micro) approximately 20 keV and Gamma (rot) approximately 200 keV are obtained in the spin region I approximately 30-40 variant Planck's over 2pi, in good agreement with microscopic cranked shell model calculations. A dependence of Gamma (micro) and Gamma (rot) on the K-quantum number of the nuclear states is also presented.

Journal Article↗
PubMed2004

Double-blind, randomized, placebo-controlled trial comparing rofecoxib with dexketoprofen trometamol in surgical dentistry.

BACKGROUND: Rofecoxib, a selective cyclooxygenase-2 inhibitor, and dexketoprofen trometamol, a single isomer non-steroidal anti-inflammatory drug (NSAID), are available for the treatment of acute pain. Both are claimed to have fewer adverse effects than traditional NSAIDs. We have compared them in a clinical setting. METHODS: We performed a double-blind randomized controlled trial involving 120 patients undergoing surgical removal of a single mandibular third molar at the Edinburgh Dental Institute. Those who developed moderate pain within 4 h of the procedure were allocated to one of three groups: rofecoxib 50 mg (Group RO, n=37); dexketoprofen trometamol 25 mg (Group DE, n=42); or placebo (Group PL, n=41). Participants monitored pain intensity and pain relief for 24 h using visual analogue scales (VAS) and verbal rating scales (VRS). The summed, time-weighted pain relief score to 8 h derived from the VRS (TOTPAR 8) was used as the primary outcome variable. RESULTS: No significant difference was demonstrated between Groups RO and DE using TOTPAR 8 as the primary outcome variable. Both drugs were significantly different compared with placebo. Rescue analgesia during the trial period was required by only 15 out of 37 subjects in Group RO, but 35 out of 42 subjects in Group DE. The median times to use of rescue medication were 150 (Group PL), 398 (Group DE) and 1440 min (Group RO). Both drugs were well tolerated and adverse events reported were mild to moderate in severity. CONCLUSIONS: Rofecoxib and dexketoprofen trometamol are effective treatments for acute pain using a dental pain model and are well tolerated. Rofecoxib has a longer duration of action as a single dose and gave adequate analgesia for over half of that study group; patients in the dexketoprofen trometamol group needed more rescue analgesia.

Adult↗
PubMed2004

Initial healing rates of venous ulcers: are they useful as predictors of healing?

Clinical trials that follow venous ulcers to complete healing can be costly because of the prolonged healing time involved. Initial healing rates in venous ulcers are calculated by 2 methods, which are based on a metric using wound area and perimeter. It has been proposed that these rates allow the prediction of complete healing and that they may be useful as surrogate end points for clinical trials. The objective of this study was to compare the 2 proposed methods for calculating initial healing rates and determine their usefulness in predicting the healing of venous ulcers. Venous leg ulcers from patients enrolled in a randomized, double-blind, placebo-controlled study were measured weekly for up to 12 weeks. Their healing status was determined for up to 24 weeks. Initial healing rates were calculated using the 2 proposed methods. The ability of these rates to predict time to complete healing was assessed. Information from 17 patients was available. The initial healing rates, calculated by either method, were quite similar; both methods produced the same median value of 0.046 cm/week in our patients. Five of the patients had negative initial healing rates, which do not allow any prediction of a healing time. Three of 7 patients predicted to heal within 24 weeks failed to do so. One of the 5 patients was predicted to heal at some time after 24 weeks but actually healed within 24 weeks. None of the 5 patients with negative initial healing rates healed within 24 weeks. Initial healing rates, as calculated by either method, have limited utility in describing healing curves and predicting a healing time. This poor predictive ability argues against using these initial healing rates as surrogate end points for clinical trials. The great variability observed in venous ulcer healing curves may limit the development of useful predictive models in this patient population.

Aged↗
PubMed2004

Determinants of the geographical distribution of endemic giardiasis in Ontario, Canada: a spatial modelling approach.

Giardiasis surveillance data as well as drinking water, socioeconomic and land-use data were used in spatial regression models to investigate determinants of the geographic distribution of endemic giardiasis in southern Ontario. Higher giardiasis rates were observed in areas using surface water [rate ratio (RR) 2.36, 95 % CI 1.38-4.05] and in rural areas (RR 1.79, 95 % CI 1.32-2.37). Lower rates were observed in areas using filtered water (RR 0.55, 95 % CI 0.42-0.94) and in those with high median income (RR 0.62, 95 % CI 0.42-0.92). Chlorination of drinking water, cattle density and intensity of manure application on farmland were not significant determinants. The study shows that waterborne transmission plays an important role in giardiasis distribution in southern Ontario and that well-collected routine surveillance data could be useful for investigation of disease determinants and identification of high-risk communities. This information is useful in guiding decisions on control strategies.

Animals↗
PubMed2004

Paneth cell granule depletion in the human small intestine under infective and nutritional stress.

Paneth cells are important contributors to the intestinal antimicrobial barrier through synthesis and release of antimicrobial peptides and proteins. Animal studies indicate that Paneth cell numbers, location and granule morphology are altered by infection and zinc status. We examined human tissue to determine whether Paneth cell numbers, distribution or granule morphology are altered in infective, inflammatory and nutritional disorders. Archival sections from infective disorders (giardiasis, cryptosporidiosis, HIV, helminth infection) were compared with active inflammatory conditions (coeliac, Crohn's and graft-versus-host diseases) and histologically normal tissues. A subset of tissues was studied by electron microscopy and TUNEL staining for apoptosis. Human defensin-5 (HD5) peptide and mRNA was analysed by immunohistochemistry, in situ hybridization and quantitative reverse transcription polymerase chain reaction. Sections from a tropical population cohort study were then analysed to determine the relationship of granule depletion to infection, nutritional status and plasma zinc concentration. In HIV-related cryptosporidiosis, but not other disorders, Paneth cells were reduced in number and markedly depleted of granules. Paneth cell granule depletion was associated with reduced HD5 immunoreactivity, but this was not due to apoptosis and there was no reduction in mRNA transcripts. In the tropical population studied, depletion of granules was associated with reduced body mass index, reduced plasma zinc levels and HIV infection. Paneth cell granules in human small intestine may be depleted in response to infective and nutritional stress. We postulate that this is one mechanism through which zinc status influences host susceptibility to intestinal infection.

AIDS-Related Opportunistic Infections↗
PubMed2004

Managing recurrent bacterial vaginosis.

Bacterial vaginosis (BV) is the most frequently found condition of the female genital tract. It increases a woman's risk of acquiring HIV, is associated with increased complications in pregnancy, and may be involved in the pathogenesis of pelvic inflammatory disease. Yet there are many unanswered questions about its aetiology, making management of recurrent infection difficult and often idiosyncratic. This paper discusses the current knowledge and possible management of recurrent BV.

Administration, Intravaginal↗
PubMed2004

Comparison of techniques for measurement of rumen pH in lactating dairy cows.

Subacute rumen acidosis is thought to be a common condition in early lactating dairy cattle; however, diagnosis is difficult. There are currently only two techniques available for measuring rumen pH under field conditions: rumenocentesis and oral stomach tube. Sixteen rumen-fistulated cows were sampled in four sites of the rumen (cranial-ventral, caudal-ventral, central, and cranial-dorsal) with a rumen cannula. Rumen pH results were compared to those obtained at the same time with rumenocentesis and with an oro-ruminal (Geishauser) probe. Rumen fluid was obtained between 6 and 12 wk of lactation. Samples were analyzed for pH, lactate, bicarbonate, sodium, potassium, and chloride. Rumen pH results were also compared to those obtained from 24-h continuous rumen pH measurement using indwelling rumen pH probes. Oro-ruminal probe samples had the highest pH values and the highest bicarbonate concentrations. Rumenocentesis samples had the lowest pH values and the lowest bicarbonate concentrations. Small differences in electrolyte concentrations were noted among rumen fluid collection techniques in the different rumen sites. The highest correlations of rumen pH were obtained between rumenocentesis and rumen cannulation (cranial-ventral), and between rumen cannulation (cranial-ventral) and the 24-h indwelling pH meter. Compared with samples obtained from the cranial-ventral rumen, rumenocentesis was more sensitive than the oro-ruminal probe in the measurement of low rumen pH; both techniques were moderately specific. The most accurate field technique was rumenocentesis. Improved field techniques are required for better on-farm diagnosis of subacute rumen acidosis.

Acidosis↗