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Effective Test (effective + test)
Selected AbstractsEffectiveness of screening and monitoring tests for diabetic retinopathy , a systematic reviewDIABETIC MEDICINE, Issue 7 2000A. Hutchinson SUMMARY Aims To determine which screening and monitoring tests for diabetic retinopathy are most effective and under what circumstances. Methods A systematic review of the English language literature, published from 1983 to April 1999. Results Available studies are generally limited in their ability to answer the important questions on the effectiveness of tests for early detection of diabetic retinopathy. No randomized controlled trials were identified although primary studies exist for two screening tests: ophthalmoscopy, either direct or indirect, and retinal photography, using either mydriasis or non-mydriasis. Retinal photography under mydriasis appears to be the most effective test, with the majority reporting levels of sensitivity in excess of 80%. However effectiveness is compromised when photographs are ungradable. Ophthalmoscopy can also reach acceptable standards of sensitivity and specificity. Conclusion Based on an assessment of available cohort studies, the most effective strategy for testing is the use of mydriatic retinal photography with the additional use of ophthalmoscopy for cases where photographs are ungradable. This does not exclude the use of ophthalmoscopy alone for opportunistic case finding but there is evidence of considerable variation in effectiveness of this test. [source] Active MMP-2 effectively identifies the presence of colorectal cancerINTERNATIONAL JOURNAL OF CANCER, Issue 12 2009Mary Jo Murnane Abstract Fully active MMP-2 is expressed at such low levels in human tissues that studies often fail to confirm its value as a cancer marker despite strong associations with malignancy. Our study utilized careful extraction, accurate activity measurements, standardization to purified controls and a new statistical metric to determine whether active MMP-2 is an effective indicator of colorectal cancer compared to pro-MMP-2 or pro-MMP-9. MMP-2 and MMP-9 activities were analyzed in matched normal and cancer samples from 269 patients by gelatin zymography, computer-assisted image analysis, serial dilutions of strong samples and standardization to controls. An index of effect size was designed for comparative evaluation of active MMP-2, pro-MMP-2 and pro-MMP-9 activities. For each gelatinase, mean activity and protein levels/mg soluble protein in normal mucosa and colorectal cancer were calculated for the first time with respect to commercial standards. Active MMP-2 activity, detected in 99% of colorectal cancers, was higher in 95% of cancers (on average 10-fold) than in normal mucosa. Levels of pro-MMP-2 and pro-MMP-9, but not active MMP-9, activities were also significantly higher in cancers versus normal. However, active MMP-2 activity provided the most effective test for the presence of cancer (p < 0.0.0001) with an effect size statistically significantly larger than for either pro-MMP-2 or pro-MMP-9. Receiver operating characteristic (ROC) curves demonstrated that a cut-off for active MMP-2 of >44 SDU activity/mg soluble protein (>180 pg/mg), which is three times mean normal levels, would permit detection of colorectal cancer with an estimated sensitivity of 84% and estimated specificity of 93%. © 2009 UICC [source] Testing against smooth stochastic trendsJOURNAL OF APPLIED ECONOMETRICS, Issue 3 2001Jukka Nyblom A trend estimated from an unobserved components model tends to be smoother when it is modelled as an integrated random walk rather than a random walk with drift. This article derives a test of the null hypothesis that the trend is deterministic against the alternative that it is an integrated random walk. It is assumed that the other component in the model is normally distributed white noise. Critical values are tabulated, the asymptotic distribution is derived and the performance of the test is compared with the test against a trend specified as a random walk with drift. The test is extended to allow for serially correlated and evolving seasonal components. When there is a stationary process containing a single autoregressive unit root close to one, a bounds test can be applied. In the case of a first-order autoregressive disturbance, it is shown that a consistent test can still be obtained by carrying out estimation of the nuisance parameters under the null hypothesis. The overall conclusion is that the most effective test against an integrated random walk is a parametric one based on the random walk plus drift test statistic, constructed from innovations, with the nuisance parameters estimated in the unrestricted model. Copyright © 2001 John Wiley & Sons, Ltd. [source] Evaluation of a new, fully automated immunoassay for detection of HTLV-I and HTLV-II antibodiesJOURNAL OF MEDICAL VIROLOGY, Issue 3 2008Xiaoxing Qiu Abstract Screening blood donations for human T-lymphotropic virus types I and II (HTLV-I/II) continues to be important in protecting the safety of blood products and controlling the global spread of these retroviruses. We have developed a fully automated, third generation chemiluminescent immunoassay, ARCHITECT rHTLV-I/II, for detection of antibodies to HTLV-I/II. The assay utilizes recombinant proteins and synthetic peptides and is configured in a double antigen sandwich assay format. Specificity of the assay was 99.98% (9,254/9,256, 95% CI,=,99.92,100%) with the negative specimens from the general population including blood donors, hospital patients and pregnant women from the US, Japan and Nicaragua. The assay demonstrated 100% sensitivity by detecting 498 specimens from individuals infected with HTLV-I (n,=,385) and HTLV-II (n,=,113). ARCHITECT rHTLV-I/II results were in complete agreement with the Murex HTLV-I/II reference assay and 99.7% agreement with the Genelabs HTLV Blot 2.4 confirmatory assay. Analytical sensitivity of the assay was equivalent to Murex HTLV-I/II assay based on end point dilutions. Furthermore, using a panel of 397 specimens from Japan, the ARCHITECT rHTLV-I/II assay exhibited distinct discrimination between the antibody negative (Delta Value,=,,7.6) and positive (Delta Value,=,7.6) populations. Based on the excellent specificity and sensitivity, the new ARCHITECT rHTLV-I/II assay should be an effective test for the diagnosis of HTLV-I/II infection and also for blood donor screening. J. Med. Virol. 80:484,493, 2008. © 2008 Wiley-Liss, Inc. [source] Genetic variation in the bovine myostatin gene in UK beef cattle: Allele frequencies and haplotype analysis in the South DevonANIMAL GENETICS, Issue 5 2000J A Smith Work on Belgian Blue cattle revealed that an 11 base pair (bp) deletion within the bovine myostatin gene (GDF8) is associated with the double-muscled phenotype seen in this breed. Investigations focusing on other European breeds known to show double-muscling identified several mutations within the coding region of the gene associated with the double-muscled phenotype in different breeds. The number of mutations found suggest that myostatin is highly variable within beef cattle. Variations that alter the structure of the gene product such that the protein is inactivated are associated with the most pronounced form of double-muscling as seen in the Belgian Blue. However, other mutations may have a less extreme affect on muscle development. While overt double-muscling gives rise to a high incidence of dystocia (calving difficulty), it is possible that some variants may give enhanced muscling, but with limited calving problems. We describe sequence analysis of the myostatin gene in ten beef breeds commonly used in the UK and show that the 11-bp deletion responsible for double-muscling in the Belgian Blue is also present in the South Devon cattle population. Allele frequencies and haplotypes in the South Devon and a polymerase chain reaction (PCR) based test for the deletion are described. PCR amplification across the deleted region provides a quick and effective test with clear identification of heterozygous individuals. We discuss our results with regard to the effect of genotype on phenotype and differences observed between the Belgian Blue and the South Devon. [source] | |||||||||||||