Most bowel cancer symptoms do not indicate colorectal cancer and polyps: a systematic review

<p>Abstract</p> <p>Background</p> <p>Bowel symptoms are often considered an indication to perform colonoscopy to identify or rule out colorectal cancer or precancerous polyps. Investigation of bowel symptoms for this purpose is recommended by numerous clinical guidelines. However, the evidence for this practice is unclear. The objective of this study is to systematically review the evidence about the association between bowel symptoms and colorectal cancer or polyps.</p> <p>Methods</p> <p>We searched the literature extensively up to December 2008, using MEDLINE and EMBASE and following references. For inclusion in the review, papers from cross sectional, case control and cohort studies had to provide a 2×2 table of symptoms by diagnosis (colorectal cancer or polyps) or sufficient data from which that table could be constructed. The search procedure, quality appraisal, and data extraction was done twice, with disagreements resolved with another reviewer. Summary ROC analysis was used to assess the diagnostic performance of symptoms to detect colorectal cancer and polyps.</p> <p>Results</p> <p>Colorectal cancer was associated with rectal bleeding (AUC 0.66; LR+ 1.9; LR- 0.7) and weight loss (AUC 0.67, LR+ 2.5, LR- 0.9). Neither of these symptoms was associated with the presence of polyps. There was no significant association of colorectal cancer or polyps with change in bowel habit, constipation, diarrhoea or abdominal pain. Neither the clinical setting (primary or specialist care) nor study type was associated with accuracy.</p> <p>Most studies had methodological flaws. There was no consistency in the way symptoms were elicited or interpreted in the studies.</p> <p>Conclusions</p> <p>Current evidence suggests that the common practice of performing colonoscopies to identify cancers in people with bowel symptoms is warranted only for rectal bleeding and the general symptom of weight loss. Bodies preparing guidelines for clinicians and consumers to improve early detection of colorectal cancer need to take into account the limited value of symptoms.</p

Numerical investigation of the leakage current and blocking capabilities of high-power diodes with doped dlc passivation layers

Diamond-like carbon (DLC) is a very attractive material for Microelectronics, as it can be used to create robust passivation layers in semiconductor devices. In this work, the modelling of DLC in a TCAD framework is addressed, with special attention to the role played as the bevel coating of large-Area high-voltage diodes. The TCAD simulations are nicely compared with experiments, giving rise to a detailed explanation of the role played by the DLC conductivity on the diode performance

Coincidence gamma-gamma spectroscopy system for instrumental neutron activation analysis

A flexible facility for ¿–¿ coincidence spectroscopy with two HPGe detectors based on NIM spectrometric modules in connection with VME or CAMAC data acquisition systems is described. First results of its application for Coincidence Instrumental Neutron Activation Analysis (CINAA) are presented

Coincidence gamma-gamma spectroscopy system for instrumental neutron activation analysis

A flexible facility for ¿–¿ coincidence spectroscopy with two HPGe detectors based on NIM spectrometric modules in connection with VME or CAMAC data acquisition systems is described. First results of its application for Coincidence Instrumental Neutron Activation Analysis (CINAA) are presented

Gold volatile compound generation: optimization, efficiency and characterization of the generated form

The generation of an analytically useful volatile form of Au has been studied. The flow injection generation was performed in a dedicated generator consisting of a special mixing apparatus and gas-liquid separator design in the presence of surfactants (Triton X-100, Antifoam B) and diethyldithiocarbamate. The on-line atomization in the quartz tube multiatomizer for atomic absorption (AAS) detection has been employed as the convenient atomization/detection means. The optimization of generation and atomization conditions resulted in an analytical procedure yielding the detection limit of 17 ng ml(-1) and a very good long range reproducibility of the analytical signal. A 198,199 Au radioactive indicator of high specific activity together with AAS measurements was used to track quantitatively the transfer of analyte in the course of generation and transport to the atomizer and to determine the generation efficiency of 11.9 +/- 0.1% at the Ar carrier flow rate optimized for the multiatomizer of 240 ml min(-1). The efficiency was twice as high at the Ar carrier flow rate of 600 ml min(-1). In situ trapping in GF for AAS was explored as an alternative to the on-line atomization. The detection limit of 3.0 ng ml(-1) was achieved even though the Ar flow rate optimum for trapping (115 ml min(-1)) was too low for efficient generation: the overall efficiency of generation and trapping was 1.11 perpendicular to 0.03%. Transmission electron microscopy measurements proved the presence of Au nanoparticles of diameter of approximately 10 nm and smaller transported from the generator by the flow of carrier Ar