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Biomedical subjects

S Hughes

Publications and source records attributed to S Hughes.

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

The value of testing urine in non-gonococcal urethritis.

This audit was conducted to look into the necessity of testing urine threads, in the diagnosis of non-gonococcal urethritis (NGU). In a sample of 280 NGU cases, it was found that in 8.8% of cases there was a risk of the diagnosis being missed, should Gram-stained urethral smears be totally relied on. The study showed that examining urine threads is beneficial in diagnosing NGU, especially, in symptomatic men with negative Gram-stained urethral smears. It should be noted, however, that in the group of patients studied for this audit, urine threads testing did not detect any chlamydia-positive NGU cases.

Gentian Violet↗
PubMed2004

Enhanced single-photon emission from quantum dots in photonic crystal waveguides and nanocavities.

A theoretical formalism is presented to investigate enhanced radiative decay of excited dipoles in photonic crystal waveguides and nanocavities with a view to achieving efficient single-photon emission from embedded quantum dots. Surprisingly, large enhancement effects are achievable in both waveguides and nanocavities, and enhanced emission in the waveguide is shown to scale proportionally (inversely) with the photon group index (velocity). Further, a way to include radiative coupling of the quantum dot is shown, and the importance of its inclusion is subsequently demonstrated.

Journal Article↗
PubMed2004

Export of dissolved organic carbon from peatlands under elevated carbon dioxide levels.

Peatlands represent a vast store of global carbon. Observations of rapidly rising dissolved organic carbon concentrations in rivers draining peatlands have created concerns that those stores are beginning to destabilize. Three main factors have been put forward as potential causal mechanisms, but it appears that two alternatives--warming and increased river discharge--cannot offer satisfactory explanations. Here we show that the third proposed mechanism, namely shifting trends in the proportion of annual rainfall arriving in summer, is similarly unable to account for the trend. Instead we infer that a previously unrecognized mechanism--carbon dioxide mediated stimulation of primary productivity--is responsible. Under elevated carbon dioxide levels, the proportion of dissolved organic carbon derived from recently assimilated carbon dioxide was ten times higher than that of the control cases. Concentrations of dissolved organic carbon appear far more sensitive to environmental drivers that affect net primary productivity than those affecting decomposition alone.

Atmosphere↗
PubMed2004

Cloning and sequencing of badger (Meles meles) interferon gamma and its detection in badger lymphocytes.

The European badger (Meles meles) has been identified as a reservoir for Mycobacterium bovis and is implicated in the maintenance and transmission of tuberculosis in cattle. There is a need for a sensitive test of M. bovis infection in badgers and the current serodiagnostic test used for this purpose has low sensitivity. As observed for other species, assay of interferon-gamma (IFNgamma) produced in response to M. bovis antigens is a more sensitive test of tuberculosis. With this objective in sight, we report the first step in the development of an ELISA for badger IFNgamma. The badger IFNgamma gene was cloned and sequenced and used to generate a specific polyclonal antibody to the cytokine. The gene sequence demonstrated regions that were conserved within the IFNgamma genes of other mammals. The badger sequence was most similar to the canine, showing similar structural organisation of the gene and 88% amino acid identity. Rabbits were immunised with DNA encoding badger IFNgamma and the resulting polyclonal antiserum demonstrated specificity for canine IFNgamma by immunoblot of a commercial recombinant canine IFNgamma. The antiserum was used to detect intracellular badger IFNgamma by flow cytometry analysis of badger lymphocytes stimulated with mitogen.

Amino Acid Sequence↗
PubMed2004

Anastomotic technique and survival after right hemicolectomy for colorectal cancer.

AIM: To compare the long-term outcome of patients after right hemicolectomy for colorectal cancer undergoing ileocolonic reconstruction either by a sutured technique or by side-to-side stapled anastomosis. METHODS: Single surgeon series from 1992 to 2001 comprising 100 consecutive patients, 59 with hand sutured reconstruction and 41 undergoing TLC 55mm stapled side-to-side anastomosis. Details of gender, patient age, and elective versus emergency presentation, Dukes stage, and curative versus palliative resection were recorded prospectively. In addition, post-operative hospital stay and subsequent survival were determined by prospective protocol follow-up. RESULTS: Overall 24% of the patients studied presented as emergencies and underwent a palliative procedure. There were no anastomotic leaks in either the stapled or sutured groups. Hospital mortality was also not significantly different--stapled reconstruction, 7%, sutured reconstruction, 10% (p value 0.624). Overall long-term cancer outcome was the same for both anastomotic techniques, both stapled and sutured groups having a median survival of 2.9 years. CONCLUSIONS: Stapled ileocolonic reconstruction after right hemicolectomy for colonic carcinoma is a safe and reliable surgical technique associated with long-term cancer outcomes comparable with those obtained by the sutured anastomotic technique.

Adenocarcinoma↗
PubMed2004

Educational psychology in medical learning: a randomised controlled trial of two aide memoires for the recall of causes of electromechanical dissociation.

OBJECTIVES: Although mnemonics are commonly used in medical education there are few data on their effectiveness. A RCT was undertaken to test the hypothesis that a new aide memoire, "EMD-aide", would be superior to the conventional "4Hs+4Ts" mnemonic in facilitating recall of causes of electromechanical dissociation (EMD) among house officers. METHOD: "EMD-aide", organises causes of EMD by frequency of occurrence and ease of reversibility: four groups organised by shape, colour, position, numbering, clockwise sequence, and use of arrows. Eight hospitals were randomised in a controlled trial and 149 house officers were then recruited by telephone. Baseline ability to recall causes of EMD was recorded at one minute and overall. House officers were then sent a copy of either "4Hs+4Ts" or "EMD-aide" according to randomisation group. Recall ability was retested at one month. RESULTS: 68 of 80 and 51 of 69 house officers completed the study in the "4Hs+4Ts" and "EMD-aide" groups respectively (NS) with similar baseline recall. After intervention median number of recalled causes was greater in the "EMD-aide" group, eight compared with seven at one minute (p = 0.034) and eight compared with seven overall, p = 0.067. Recall of all eight causes was more common in "EMD-aide" group, 54% compared with 35%, p = 0.054, and these house officers spent longer examining their aide memoire, p<0.001. CONCLUSIONS: "EMD-aide" may be superior to "4Hs+4Ts" in facilitating the recall of the causes of electromechanical dissociation. Educational psychology of medical learning and the use of aide memoires in general are worthy of further study.

Abbreviations as Topic↗
PubMed2004

Use of whole genome amplification and comparative genomic hybridisation to detect chromosomal copy number alterations in cell line material and tumour tissue.

We have established that whole genome amplification (WGA), in conjunction with genomic DNA array comparative genomic hybridisation (gaCGH) allows for the identification of genome-wide copy number abnormalities (CNAs) in DNA extracted from both cell line and patient material. To determine the fidelity and reproducibility of WGA to detect copy number imbalances using gaCGH, well characterized cell line genomic DNA was analysed. The gaCGH data obtained from non-amplified DNA and amplified DNA for the neuroblastoma cell line NUB7 and a paediatric medulloblastoma patient was almost identical. In addition, laser capture microdissection (LCM) of prostate tumour cells and subsequent WGA allowed for the detection of a number of CNAs that may not have been identified if DNA had been extracted in bulk from heterogeneous tissue. The results presented here demonstrate the use of WGA for generating sufficient DNA for gaCGH analysis without the introduction of significant sequence representation bias. The combination of amplification and gaCGH using DNA extracted from archival patient material has the potential for permitting the studying of DNA from small cancerous or pre-cancerous foci, which may help to identify potential genomic markers for early diagnosis.

Cell Line↗
PubMed2004

CT-guided fine-needle aspiration of lung nodules: effect on outcome of using coaxial technique and immediate cytological evaluation.

PURPOSE: To evaluate the risk of pneumothorax during CT-guided fine-needle aspiration (FNA) of lung nodules with single needle and coaxial needle techniques and to assess the effect on diagnostic accuracy of immediate cytological examination of lung FNA samples. MATERIALS AND METHODS: This prospective study analysed 53 patients undergoing transthoracic FNA biopsy of lung. 36 cases were performed by a radiologist using a coaxial technique, with 17 cases performed by a radiologist using a direct single-needle method. Effect of technique on occurrence of pneumothorax was recorded. FNA samples from all the patients in the study were examined immediately on-site by a cytologist or MLSO to determine whether sufficient aspirate had been obtained. Provisional diagnosis at immediate examination was compared to final diagnosis following full pathological evaluation. RESULTS: Coaxial and non-coaxial groups were comparable for age and gender. Number of pleural passes was significantly lower in coaxial group (P < 0.01). Pneumothorax occurred in six (17%) of the 36 patients biopsied by coaxial technique, compared to four (24%) of the 17 patients by non-coaxial method (P = 0.55). Chest tube placement was required in four patients (11%) in the coaxial group, and two patients (12%) in the non-coaxial group (P = 0.85). A provisional cytological diagnosis was recorded for 74% of the patients in the study. 83% of the provisional reports were accurate on comparison with full pathology report. Specimen size was sufficient in 81% of cases. CONCLUSIONS: The use of coaxial technique for CT-guided lung FNA biopsy reduced the number of pleural passes but did not significantly reduce the occurrence of pneumothorax. Immediate cytological examination of FNA specimens provided an accurate provisional diagnosis in the majority of cases, and should be routinely employed.

Aged↗
PubMed2003

Predicting the release of metals from ombrotrophic peat due to drought-induced acidification.

Ombrotrophic peats in northern England and Scotland, close to industrial areas, have substantial contents of potentially toxic metals (Al, Ni, Cu, Zn, Cd and Pb) and of pollutant sulphur, all derived from atmospheric deposition. The peat sulphur, ordinarily in reduced form, may be converted to sulphuric acid under drought conditions, due to the entry of oxygen into the peats. The consequent lowering of soil solution pH is predicted to cause the release of metals held on ligand sites of the peat organic matter. The purpose of the present study was to explore, by simulation modelling, the extent of the metal response. Chemical variables (elemental composition, pH, metal contents) were measured for samples of ombrotrophic peats from three locations. Water extracts of the peats, and samples of local surface water, were also analysed, for pH, dissolved organic carbon (DOC) and metals. Metal release from peats due to acidification was demonstrated experimentally, and could be accounted for reasonably well using a speciation code (WHAM/Model VI). These data, together with information on metal and S deposition, and meteorology, were used to construct a simple description of peat hydrochemistry, based on WHAM/Model VI, that takes into account ion-binding by humic substances (assumed to be the "active" constituents of the peat with respect to ion-binding). The model was used to simulate steady state situations that approximated the observed soil pH, metal pools and dissolved metal concentrations. Then, drought conditions were imposed, to generate increased concentrations of H2SO4, in line with those observed during the drought of 1995. The model calculations suggest that the pH will decrease from the initial steady state value of 4.3 to 3.3-3.6 during rewetting periods following droughts, depending upon assumptions about the amount of potentially mobile soil S. The pH decreases will be accompanied by increases in concentrations of dissolved metals (Mg, Al, Ca, Ni, Cu, Zn, Cd, Pb) of an order of magnitude or more, depending upon assumptions about the replenishment of soil metal pools by deposition. In the most realistic scenario for present conditions, the severity of pH depressions will gradually decline due to the relatively slow depletion of the soil S pool by droughts. However, the magnitudes of heavy metal pulses will decline quite rapidly (over two or three droughts) because current and future metal deposition is unable to compensate for leaching losses from the soil pools.

Disasters↗
PubMed2003

Measurements of linear dimensions on fundus photographs: comparison between photographic film and digital systems.

PURPOSE: The aim of this study is to compare linear fundal landmarks measurements of standard photographic film with colour digital fundal images. METHODS: Pairs of fundus fluorescein images were acquired with a digital system and photographic film on 10 patients. Each pair of images was assessed independently by two observers who calculated the distance between two selected points on each image using easily identifiable landmarks. Measurements made using film images were compared to measurements made using the corresponding digital images. Agreement between the two methods of measurements was assessed using a linear correlation and graphical method. RESULTS: The patients were divided into two groups based on the field setting on the digital software. In Group 1, the correlation coefficient was 0.99 and in Group 2 it was 0.98, indicating a high level of agreement between measurements with the computer measuring tool for digital images compared to photographic films using a standard reticule. CONCLUSION: On the basis of the strong correlation between linear fundal landmark measurements between standard photographic film and colour digital fundal images, we conclude that the measurements from the digital images are acceptable for diagnostic and therapeutic purposes. Although there was a tendency for the measurements to be less accurate with increasing distances measured.

Fluorescein Angiography↗
PubMed2003

Fluticasone propionate in asthma: a long term dose comparison study.

BACKGROUND: Few dose ranging studies have investigated optimal dosing with inhaled corticosteroids in children with asthma. AIMS: To compare the efficacy and tolerability of fluticasone propionate 100 or 200 microg twice daily in children with moderate to severe asthma for one year. METHODS: One year, randomised, double blind, parallel group, multicentre study. Children aged 4-11 years (n = 528) with moderate to severe asthma who had previously received high dose inhaled corticosteroids were given fluticasone propionate 100 or 200 microg twice daily for the 52 week treatment period. Efficacy (exacerbations, lung function, and symptoms) and tolerability (adverse events and cortisol levels) were measured. RESULTS: There was a non-significant decreased risk of experiencing an exacerbation at any time with fluticasone propionate 200 microg twice daily compared with fluticasone propionate 100 microg twice daily. This difference reached significance among patients with more severe asthma (defined by previous inhaled corticosteroid dose >800 microg/day). Daily record card morning peak expiratory flow (PEF) in the total population improved significantly more with the higher dose of fluticasone propionate (between group difference, weeks 1-52: 11.4 l/min). Clinic visit mean PEF improved from baseline with both doses, but the response was significantly greater with the higher dose (between group difference, week 52: 17.8 l/min). Both doses were equally well tolerated and overnight urinary cortisol concentrations were unchanged or slightly increased during treatment with either dose. CONCLUSION: This long term dose comparison study shows that treatment with fluticasone propionate 200 micro g twice daily may offer benefits over a lower dose, particularly in children with more severe asthma.

Androstadienes↗
PubMed2002

Phosphorus in soils and field drainage water in the Thame catchment, UK.

Field drains were sampled at five farms in a catchment in south-central England. The farms were selected to include the main soil types present in the catchment, stagnogleys and pelosols. The phosphorus content of field drainage water was measured on several occasions from 1999 to 2000, under varying flow conditions. The components measured were soluble reactive phosphorus (SRP), total dissolved phosphorus (TDP) and total phosphorus (TP). SRP concentrations in drainage water were lower than in streams in the catchment which had no apparent point source. This indicated that many streams were receiving unidentified point sources of SRP. Measurements of P in field drainage water samples under high flow conditions showed concentrations of particulate phosphorus and SRP up to 1300 and 300 microg l(-1), respectively, these being associated with high suspended sediment concentrations. Comparison of field drain and soil phosphorus contents at the locations sampled did not provide evidence of an inter-relationship. The equilibrium phosphorus content (EPC0) of surface soil was generally higher than the SRP content of drainage water, at one farm by 1 order of magnitude. The variability in measurements suggested a larger-scale and more focussed survey would be required to characterise catchment-scale phosphorus losses from commercial farms by land use and soil type.

Journal Article↗
PubMed2002

The phosphorus budget of the Thame catchment, Oxfordshire: 2. Modelling.

The phosphorus budget of the River Thame was modelled at a daily time scale, using estimates of diffuse and point source contributions of discharge. The model simulated suspended sediment (SS), soluble unreactive phosphorus (SUP), soluble reactive phosphorus (SRP) and particulate phosphorus (PP) concentrations within the main river and major tributaries. Diffuse source estimates of phosphorus loads were based on characteristic losses from identified main landscape classes, with hydrology described by a simple conceptual storage model. In-stream flow was modelled using a kinematic wave equation. Transfer of suspended sediment and phosphorus components was approximated by advection. In-stream sources and sinks included uptake and release of soluble reactive phosphorus by bed sediment, instant equilibration between SRP and the PP concentration on suspended sediment, and flow-related entrainment and deposition of suspended sediment. Simulations at sites within the catchment were compared with measurements made in 1998-1999. Results showed the P budget is dominated by mixing of diffuse and point source water, but some within-river processes have been shown to be capable of significantly influencing SRP concentrations. The development of a sediment entrainment and deposition component of the model has proved particularly valuable in emulating the hysteretic relationship between discharge and suspended sediment concentration in the river. It also provides a measure of available bed sediment.

England↗
PubMed2002

Double contrast barium enema sensitivity: a comparison of studies by radiographers and radiologists.

PURPOSE: A retrospective study of histologically proven cases of colorectal cancer (CRC) was performed to assess whether the sensitivity of the radiographer-performed double contrast barium enema (DCBE) differed from that of the radiologist-performed study. MATERIALS AND METHODS: Histologically proven cases of CRC were reviewed over a 3-year period to ascertain whether: the diagnosis had been made by DCBE in the 3 years before histological diagnosis; the lesion had been correctly diagnosed; the examination had been performed by a radiologist or radiographer. RESULTS: In the 3-year period there were 478 cases with histologically proven CRC. Of these, 239 (50%) had undergone DCBE as the initial radiological investigation of the colon. Sixty-four examinations had been performed by radiographers. A correct diagnosis was made in 58 cases (90.6%), the report was equivocal in one case (1.6%), there were four false-negatives (6.25%), and one case was abandoned (1.6%). One hundred and seventy-five examinations were performed by radiologists. A correct diagnosis was made in 157 cases (89.7%), the report was equivocal in one case (0.6%), there were 16 false-negatives (9.1%), and one case was abandoned (0.6%). CONCLUSION: A sensitivity of 90.6% for radiographer-performed studies compared favourably with 89.7% for radiologist-performed studies and supports the practice of radiographers undertaking barium enemas.

Barium Sulfate↗
PubMed2002

Eosinophilic gastroenteritis mimicking pancreatic cancer.

Eosinophilic gastroenteritis is a condition characterised by eosinophilic infiltration of the gastrointestinal tract. Biliary obstruction is an unusual presentation. A case where the initial investigations were consistent with carcinoma of the head of pancreas but the resection specimen showed no malignancy is presented. The diagnosis was suspected from a review of the patient's past history and confirmed by re-examination of the histology.

Cholestasis, Extrahepatic↗
PubMed2002

Evaluating the effects of asthma therapy on childhood growth: principles of study design.

Inhaled corticosteroids have been established as the most effective treatment for childhood asthma. However, concerns persist regarding their potential effects on growth and, most importantly, final height. To assess their effects on growth, inhaled corticosteroids can be compared with placebo (type 1 study), nonsteroidal anti-asthma therapy (type 2 study), another inhaled corticosteroid (type 3 study) or "real-life" anti-asthma therapy (type 4 study). Owing to the difficulties in obtaining final height data, several different surrogate measures have often been used: short-term lower leg growth, longer-term statural height growth velocity, childhood height and predicted final height. This paper discusses the choice of end point, key trial design issues (including selection and number of subjects in the active and control populations) duration of assessments and methods for measuring height and data analysis, in the context of the different study types. Specific study design recommendations have been developed after consideration of these factors, and these principles will be used to guide the interpretation of previously published growth studies.

Anti-Asthmatic Agents↗
PubMed2002

Evaluating the effects of asthma therapy on childhood growth: what can be learnt from the published literature?

The difficulties of assessing the effects of asthma therapy on childhood growth were explored in the first part of this review. In this part of the review growth studies with inhaled corticosteroids were selected that included a control group, measured height by stadiometry and were of > or = 1 yr duration. The studies were classified as type 1 (placebo control), type 2 (nonsteroidal therapy control), type 3 (comparator inhaled corticosteroid control) or type 4 ("real-life" studies with dose adjustment). The design attributes of these studies were then compared with the recommendations described in the first part of this review. Of the 18 studies identified, 17 were susceptible to one or more important confounding factors. Nevertheless, the outcomes of all 18 studies were mostly consistent. At recommended doses, beclomethasone dipropionate and budesonide demonstrated a small degree of growth suppression over 1-2 yrs (study types 1 and 2), but there was little evidence of such an effect with fluticasone propionate. Studies comparing different inhaled corticosteroids at recommended doses indicated more rapid growth with fluticasone propionate than with beclomethasone dipropionate or budesonide. However, none of the inhaled corticosteroids appeared to affect final height. In conclusion, the results from the majority of published growth studies with inhaled corticosteroids must be interpreted with a degree of caution owing to their potential susceptibility to important confounding factors. Further well-designed studies are needed to establish whether different inhaled corticosteroids have different effects on growth in the long term.

Anti-Asthmatic Agents↗