143 research outputs found
Factors associated with the efficacy of polyp detection during routine flexible sigmoidoscopy
Objective: Flexible sigmoidoscopy reduces the incidence of colonic cancer through the detection and removal of premalignant adenomas. However, the efficacy of the procedure is variable. The aim of the present study was to examine factors associated with the efficacy of detecting polyps during flexible sigmoidoscopy.
Design and patients: Retrospective observational cohort study of all individuals undergoing routine flexible sigmoidoscopy in NHS Greater Glasgow and Clyde from January 2013 to January 2016.
Results: A total of 7713 patients were included. Median age was 52 years and 50% were male. Polyps were detected in 1172 (13%) patients. On multivariate analysis, increasing age (OR 1.020 (1.016–1.023) p<0.001), male sex (OR 1.23 (1.10–1.38) p<0.001) and the use of any bowel preparation (OR 3.55 (1.47–8.57) p<0.001) were associated with increasing numbers of polyps being detected. There was no significant difference in the number of polyps found in patients who had received an oral laxative preparation compared with an enema (OR 3.81 (1.57–9.22) vs 3.45 (1.43–8.34)), or in those who received sedation versus those who had not (OR 1.00 vs 1.04 (0.91–1.17) p=0.591). Furthermore, the highest number of polyps was found when the sigmoidoscope was inserted to the descending colon (OR 1.30 (1.04–1.63)).
Conclusions: Increasing age, male sex and the utilisation of any bowel preparation were associated with an increased polyp detection rate. However, the use of sedation or oral laxative preparation appears to confer no additional benefit. In addition, the results indicate that insertion to the descending colon optimises the efficacy of flexible sigmoidoscopy polyp detection
Measuring deformation performance of geogrid reinforced structures using a terrestrial laser scanner
Geogrid Reinforced Structures (GRS) are inherently flexible and although the design for ul-timate limit state is relatively mature, GRS are often defined by their deformation performance, in the serviceability limit state (Koerner and Koerner, 2013). Currently, serviceability design protocol does not determine or prescribe deformation limits for the built wall or slope, but rather imposes limits on the theo-retical mobilised strain of geogrid reinforcement.
Current understanding of the principle mechanisms for GRS deformation is weak and often the only way to assess the serviceability of structures is by the observational method. Typically this has been done with external surveying instruments such as total stations or internally using strain gauges, extensometers and inclinometers. Laser scanning has previously been used to measure the serviceability performance of conventional geotechnical structures and slopes and provided useful information (Mechelke et al., 2007) but has not yet been used on GRS. This paper assesses the potential of a Terrestrial Laser Scanner (TLS) to rapidly survey GRS. This assessment covers a range of structures including a 6.5 m high steel mesh faced retaining wall and a 3.6 m wrap faced structure. The measured behaviour obtained from this range of structures demonstrates the importance of facing stiffness on controlling deformations. Terrestrial laser scanning has potential because it is unobtrusive, only requiring lines of sight to the face and does not use targets located on the GRS. The system can be used to measure the position of the GRS face to within a noise range of ±5 mm (Kersten et al., 2008), across a large surface area from a single observation point in minutes. This paper assesses the application of using TLS to measure deformations during construction and in-service and proposes a standard scanning procedure. It also details experience gained surveying GRS constructed with a range of face systems and discusses accuracy and repeatability issues. It con-cludes with possible implications of using the TLS method for routine monitoring of GRS
Increased accumulation of sulfur in lake sediments of the high Arctic
Author Posting. © The Author(s), 2010. This is the author's version of the work. It is posted here by permission of American Chemical Society for personal use, not for redistribution. The definitive version was published in Environmental Science & Technology 44 (2010): 8415-8421, doi:10.1021/es101991p.We report a synchronous increase in accumulation of reduced inorganic sulfur since c. 1980 in sediment cores from eight of nine lakes studied in the Canadian Arctic and Svalbard (Norway). Sediment incubations and detailed analyses of sediment profiles from two of the lakes indicate that increases in sulfur accumulation may be due ultimately to a changing climate. Warming-induced lengthening of the ice-free season is resulting in well-documented increases in algal production and sedimentation of the resulting detrital matter. Algal detritus is a rich source of labile carbon, which in these sediments stimulates dissimilatory sulfate reduction. The sulfide produced is stored in sediment (as acid volatile sulfide), converted to other forms of sulfur, or reoxidized to sulfate and lost to the water column. An acceleration of the sulfur cycle in Arctic lakes could have profound effects on important biogeochemical processes, such as carbon burial and mercury methylation.Funding was provided by the WHOI Ocean and Climate Change Institute, the USGS WHOI
Postdoctoral Scholar Program, Environment Canada, the Danmarks Grundforskningsfond, and
the Norges forskningsråd (grant number 107745/730)
Effects of residue management on decomposition in irrigated rice fields are not related to changes in the decomposer community
Copyright: © 2015 Schmidt et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Decomposers provide an essential ecosystem service that contributes to sustainable production in rice ecosystems by driving the release of nutrients from organic crop residues. During a single rice crop cycle we examined the effects of four different crop residue management practices (rice straw or ash of burned straw scattered on the soil surface or incorporated into the soil) on rice straw decomposition and on the abundance of aquatic and soildwelling invertebrates. Mass loss of rice straw in litterbags of two different mesh sizes that either prevented or allowed access of meso- and macro-invertebrates was used as a proxy for decomposition rates. Invertebrates significantly increased total loss of litter mass by up to 30%. Initially, the contribution of invertebrates to decomposition was significantly smaller in plots with rice straw scattered on the soil surface; however, this effect disappeared later in the season. We found no significant responses in microbial decomposition rates to management practices. The abundance of aquatic fauna was higher in fields with rice straw amendment, whereas the abundance of soil fauna fluctuated considerably. There was a clear separation between the overall invertebrate community structure in response to the ash and straw treatments. However, we found no correlation between litter mass loss and abundances of various lineages of invertebrates. Our results indicate that invertebrates can contribute to soil fertility in irrigated paddy fields by decomposing rice straw, and that their abundance as well as efficiency in decomposition may be promoted by crop residue management practices
Relationship between emergency presentation, systemic inflammatory response, and cancer-specific survival in patients undergoing potentially curative surgery for colon cancer
Background
Emergency presentation is recognized to be associated with poorer cancer-specific survival following curative resection for colorectal cancer. The present study examined the hypothesis that an enhanced systemic inflammatory response, prior to surgery, might explain the impact of emergency presentation on survival.
Methods
In all, 188 patients undergoing potentially curative resection for colorectal cancer were studied. Of these, 55 (29%) presented as emergencies. The systemic inflammatory response was assessed using the Glasgow Prognostic Score (mGPS), which is the combination of an elevated C-reactive protein (>10 mg/L) and hypoalbuminemia (<35 g/L).
Results
In the emergency group, tumor stage was greater (P < 0.01), more patients received adjuvant therapy (P < 0.01) more patients had an elevated mGPS (P < 0.01), and more patients died of their disease (P < 0.05). The minimum follow-up was 12 months; the median follow-up of the survivors was 48 months. Emergency presentation was associated with poorer 3-year cancer-specific survival in those patients aged 65 to 74 years (P < 0.01), in both males and females (P < 0.05), in the deprived (P < 0.01), in patients with tumor-node-metastasis (TNM) stage II disease (P < 0.01), in those who received no adjuvant therapy (P < 0.01), and in the mGPS 0 and 1 groups (P < 0.05) groups. On multivariate survival analysis of patients undergoing potentially curative surgery for TNM stage II colon cancer, emergency presentation (P < 0.05) and mGPS (P < 0.05) were independently associated with cancer-specific survival.
Conclusions
These results suggest that emergency presentation and the presence of systemic inflammatory response prior to surgery are linked and account for poorer cancer-specific survival in patients undergoing potentially curative surgery for colon cancer. Both emergency presentation and an elevated mGPS should be taken into account when assessing the likely outcome of these patients
Vascular calcification and response to neoadjuvant therapy in locally advanced rectal cancer: an exploratory study
Purpose:
Patients with locally advanced rectal cancer (LARC) may experience a clinical complete response (cCR) to neoadjuvant chemoradiotherapy (NACRT) and opt for non-operative management. Pathological factors that relate to NACRT response have been well described. Host factors associated with response, however, are poorly defined. Calcification of the aortoiliac (AC) vessels supplying the rectum may influence treatment response.
Methods:
Patients with LARC having NACRT prior to curative surgery at Glasgow Royal Infirmary (GRI) and St Mark’s hospital (SMH) between 2008 and 2016 were identified. AC was scored on pre-treatment CT imaging. NACRT response was assessed using pathologic complete response (pCR) rates, tumour regression grades (TRGs), the NeoAdjuvant Rectal score and T-/N-downstaging. Associations were assessed using Chi-squared, Mantel–Haenszel and Fisher’s exact tests.
Results:
Of 231 patients from GRI, 79 (34%) underwent NACRT for LARC. Most were male (58%), aged over 65 (51%) with mid- to upper rectal tumours (56%) and clinical T3/4 (95%), node-positive (77%) disease. pCR occurred in 10 patients (13%). Trends were noted between higher clinical T stage and poor response by Royal College of Pathologist’s TRG (p = 0.021) and tumour height > 5 cm and poor response by Mandard TRG (0.068). In the SMH cohort, 49 of 333 (15%) patients underwent NACRT; 8 (16%) developed a pCR. AC was not associated with NACRT response in either cohort.
Conclusions:
AC was not associated with NACRT response in this cohort. Larger contemporary cohorts are required to better assess host determinants of NACRT response and develop predictive models to improve patient selection
The relationship between 18F-FDG-PETCT-derived tumour metabolic activity, nutritional risk, body composition, systemic inflammation and survival in patients with lung cancer
The aim of this study was to examine the relationship between PET-CT derived tumour glucose uptake as measured by maximum standard glucose uptake (SUVmax) and total lesion glycolysis (TLG), nutritional risk as measured by the malnutrition universal screening tool (MUST), CT derived body composition as measured by skeletal muscle index (SMI) and skeletal muscle radiodensity (SMD), the systemic inflammatory response as measured by the modified Glasgow prognostic score (mGPS) and the neutrophil to lymphocyte ratio (NLR) and survival in patients with lung cancer, treated with radiotherapy. In a retrospective cohort study, 119 patients were included in final analyses. The majority of patients were over 65 (86%), female (52%), had a performance status (ECOG-PS) of 0 or 1 (57%), were at nutritional risk (57%), were overweight (53%), had visceral obesity (62%), had a normal SMI (51%), had a low SMD (62%) and were systemically inflammed (mGPS 1/2, 51%). An elevated TLG was associated with sex (p < 0.05), TNM stage (p < 0.001), MUST (p < 0.01) and mGPS (p < 0.01). An elevated mGPS was associated with age (p < 0.05), NLR (p < 0.01), MUST (p < 0.01), and TLG (p < 0.01). On univariate survival analysis, TNM stage (p < 0.01), mGPS (p < 0.05), NLR (p < 0.01), MUST (p ≤ 0.001), Low SMD (p < 0.05), SUVmax (p ≤ 0.001) and TLG (p < 0.001) were associated with overall survival. On multivariate survival analysis MUST (HR: 1.49 95%CI 1.12–01.98 p < 0.01) and TLG (HR: 2.02 95%CI 1.34–3.04 p = 0.001) remained independently associated with survival. In conclusion, elevated tumour metabolic activity was associated with more advanced stage, greater nutritional risk, the systemic inflammatory response and poorer survival but not body composition analysis in patients with lung cancer. These results suggest that detrimental body composition is not directly determined by tumour metabolic activity but rather an ongoing systemic inflammatory response
A Randomized Trial of Rofecoxib for the Chemoprevention of Colorectal Adenomas
BACKGROUND & AIMS: In human and animal studies, nonsteroidal anti-inflammatory drugs have been associated with a reduced risk of colorectal neoplasia. Although the underlying mechanisms are unknown, inhibition of cyclooxygenase (COX), particularly COX-2, is thought to play a role. We conducted a randomized, placebo-controlled, double-blind trial to assess whether use of the selective COX-2 inhibitor rofecoxib would reduce the risk of colorectal adenomas.
METHODS: We randomized 2587 subjects with a recent history of histologically confirmed adenomas to receive daily placebo or 25 mg rofecoxib. Randomization was stratified by baseline use of cardioprotective aspirin. Colonoscopic follow-up evaluation was planned for 1 and 3 years after randomization. The primary end point was all adenomas diagnosed during 3 years' treatment. In a modified intent-to-treat analysis, we computed the relative risk of any adenoma after randomization, using Mantel-Haenszel statistics stratified by low-dose aspirin use at baseline.
RESULTS: Adenoma recurrence was less frequent for rofecoxib subjects than for those randomized to placebo (41% vs 55%; P < .0001; relative risk [RR], 0.76; 95% confidence interval [CI], 0.69-0.83). Rofecoxib also conferred a reduction in risk of advanced adenomas (P < .01). The chemopreventive effect was more pronounced in the first year (RR, 0.65; 95% CI, 0.57-0.73) than in the subsequent 2 years (RR, 0.81; 95% CI, 0.71-0.93). As reported previously, rofecoxib was associated with increased risks of significant upper gastrointestinal events and serious thrombotic cardiovascular events.
CONCLUSIONS: In this randomized trial, rofecoxib significantly reduced the risk of colorectal adenomas, but also had serious toxicity
Macroeconomic policy change: Ireland in comparative perspective
This paper sets out to develop an improved framework for examining critical junctures. This a priori framework is a significant improvement over existing critical juncture frameworks that lack any predictive element. It is an advance for historical institutionalism in particular, and political science in general. After the new framework is set out in detail here, it is tested. The framework is used to examine a number of potential critical junctures in macroeconomic policy, drawn from Ireland, Sweden, Britain, and America in the latter half of the twentieth century
Altering gait by way of stimulation of the plantar surface of the foot: the immediate effect of wearing textured insoles in older fallers
Background: Evidence suggests that textured insoles can alter gait and standing balance by way of enhanced plantar tactile stimulation. However, to date, this has not been explored in older people at risk of falling. This study investigated the immediate effect of wearing textured insoles on gait and double-limb standing balance in older fallers.Methods: Thirty older adults >65 years (21 women, mean [SD] age 79.0 [7.1]), with self-reported history of ≥2 falls in the previous year, conducted tests of level-ground walking over 10 m (GAITRite system), and double-limb standing with eyes open and eyes closed over 30 seconds (Kistler force platform) under two conditions: wearing textured insoles (intervention) and smooth (control) insoles in their usual footwear.Results: Wearing textured insoles caused significantly lower gait velocity (P = 0.02), step length (P = 0.04) and stride length (P = 0.03) compared with wearing smooth insoles. No significant differences were found in any of the balance parameters (P > 0.05).Conclusions: A textured insole worn by older adults with a history of falls significantly lowers gait velocity, step length and stride length, suggesting that this population may not have an immediate benefit from this type of intervention. The effects of prolonged wear remain to be investigated
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