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High False Positive Rates (high + false_positive_rate)
Selected AbstractsAtypical papillary proliferation in gynecologic patients: A study of 32 pelvic washes,DIAGNOSTIC CYTOPATHOLOGY, Issue 2 2005Karyna C. Ventura M.D. Abstract Papillary clusters in gynecologic pelvic washes frequently cause diagnostic challenges because they can be associated with borderline or malignant ovarian tumors, as well as benign pelvic diseases. The objective of our study was to review all pelvic washes with atypical papillary proliferation (APP) and investigate whether cytomorphology and/or immunohistochemistry on cell block could determine their origin. Thirty-two pelvic washes from 31 patients containing APP were reviewed and correlated with their corresponding gynecologic or pelvic disease. Previously obtained cell blocks with immunohistochemical (IHC) stains were reviewed also. Nine of 32 washes (28%) were overcalled as malignant and were from patients with 5 borderline serous ovarian tumors (BSTO), 1 ovarian follicular cyst, 1 serous cystadenofibroma, and 1 endometrial carcinoma with ovarian seromucinous cystadenoma. BSTO and endometriosis were the most common sources of APP. Cell blocks could not discriminate further the etiology of APP. Immunohistochemistry was performed rarely and not fully contributory. Caution in interpreting papillary groups and cytohistological correlation is recommended to prevent a high false positive rate. Diagn. Cytopathol. 2005;32:76,81. © 2005 Wiley-Liss, Inc. [source] Protein C and protein S levels can be accurately determined within 24 hours of diagnosis of acute venous thromboembolismINTERNATIONAL JOURNAL OF LABORATORY HEMATOLOGY, Issue 1 2006M. J. KOVACS Summary In the 50% of cases of acute idiopathic venous thromboembolism, laboratory testing for inherited causes is often performed. Most physicians are under the impression that assays for protein C and protein S should not be measured at the time of diagnosis because of a high false positive rate. We performed a prospective cohort study from two outpatient thromboembolism clinics on consecutive patients with an objectively confirmed diagnosis of first acute idiopathic venous thromboembolism. Assays for protein C and protein S were performed prior to the initiation of oral anticoagulation therapy and within 24 h of diagnosis of venous thromboembolism. Abnormal results were repeated when patients discontinued oral anticoagulant therapy. Of 253 patients tested for both protein C and protein S, 229 (91%; 95% confidence interval 87,94%) were negative and 484 of 508 (95%) tests were normal. Of the 24 initial abnormal results, 21 were repeated and 10 (48%; 95% confidence interval 26,70%) were still abnormal. Overall, 97.8% of initial protein C and protein S results were accurate. If protein C and protein S are measured at the time of diagnosis of acute venous thromboembolism, the majority of the results will be normal and false positives are uncommon. [source] Mild cognitive impairment in the older population: Who is missed and does it matter?INTERNATIONAL JOURNAL OF GERIATRIC PSYCHIATRY, Issue 8 2008Blossom C. M. Stephan Abstract Objectives Classifications of mild cognitive impairment (MCI) vary in the precision of the defining criteria. Their value in clinical settings is different from population settings. This difference depending on setting is to be expected, but must be well understood if population screening for dementia and pre-dementia states is to be considered. Of importance is the impact of missed diagnosis. The magnitude of missed ,at-risk' cases in the application of different MCI criteria in the population is unknown. Methods Data were from the Medical Research Council Cognitive Function and Ageing Study, a large population based study of older aged individuals in the UK. Prevalence and two-year progression to dementia in individuals whose impairment failed to fulfil published criteria for MCI was evaluated. Results Prevalence estimates of individuals not classified from current MCI definitions were extremely variable (range 2.5,41.0%). Rates of progression to dementia in these non-classified groups were also very variable (3.7,30.0%), reflecting heterogeneity in MCI classification requirements. Conclusions Narrow definitions of MCI developed for clinical settings when applied in the population result in a large proportion of individuals who progress to dementia being excluded from MCI classifications. More broadly defined criteria would be better for selection of individuals at risk of dementia in population settings, but at the possibility of high false positive rates. While exclusion may be a good thing in the population since most people are presumably ,normal', over-inclusion is more likely to be harmful. Further work needs to investigate the best classification system for application in the population. Copyright © 2008 John Wiley & Sons, Ltd. [source] Lectin precipitation using phytohemagglutinin-L4 coupled to avidin,agarose for serological biomarker discovery in colorectal cancerPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 16 2008Yong-Sam Kim Abstract N -acetylglucosaminyltransferase V (GnT-V) has been reported to be upregulated in malignant cancer cells, and its targets have been sought after with regard to biomarker identification. The low capacity and high false positive rates of 2-DE gel-based lectin blots using phytohemagglutinin-L4 (L-PHA) prompted us to develop a novel protocol for identifying GnT-V targets, in which serum proteins were subjected to immunodepletion, alkylation, and lectin precipitation using L-PHA coupled to avidin,agarose bead complexes, and tryptic digestion. Proteins captured by L-PHA conjugates were analyzed by a nano-LC-FT-ICR/LTQ MS. Here, we report 26 candidate biomarkers for colorectal cancer (CRC) that show 100% specificity and sensitivities of greater than 50%. Not only can these candidate proteins be used as analytes for validation, but the novel protocol described herein can be applied to biomarker discovery in nonCRCs. [source] Development of a parathyroid database in Melbourne and review of the last 50 casesANZ JOURNAL OF SURGERY, Issue 9 2004Meei J. Yeung Background: Minimally invasive parathyroidectomy (MIP) is only possible if preoperative localization studies accurately identify the abnormal parathyroid tissue. The aim of the present paper was to evaluate the accuracy of these studies in our geographical region and the consequences on MIP. Methods: A Filemaker Pro database was designed and a retrospective analysis was carried out on the last 50 parathyroidectomies. Results: There were a total of 49 patients who underwent parathyroidectomy; with one patient having two operations. Forty-nine preoperative ultrasound localization studies were performed. Ultrasound sensitivity of correct localization of abnormal parathyroids was 41% with a false positive rate of 25%. Twenty-two sestamibi scans identified 14 abnormal parathyroids. Sestamibi scanning had a sensitivity of 32% for correct localization and a false positive rate of 32%. There were 16 different radiologists or nuclear medicine physicians involved with the nuclear medicine scans, and 22 different radiologists involved in the preoperative ultrasound scans. Forty-seven patients were cured of hyperparathyroidism after a primary operation, with a total of 48 patients in all being cured following re-exploration. One patient was lost to follow up. The success of primary exploration was therefore 96% and following re-exploration this increased to 98%. Conclusion: We found preoperative localization studies to have low sensitivities and high false positive rates. To move successfully towards MIP, we need to identify a radiologist with a special interest in localization studies to achieve greater accuracy. [source] Affinity Ligand Selection from a Library of Small Molecules: Assay Development, Screening, and ApplicationBIOTECHNOLOGY PROGRESS, Issue 1 2005Lakshmi D. Saraswat A facile and cost-effective process for screening synthetic libraries for an affinity ligand is described. A high throughput 96-well plate filtration method was designed to screen both discrete compounds and mixtures of compounds attached to a solid support. Human serum albumin (HSA) was used as a target protein to demonstrate the proof of concept. Detection and quantitation by fluorescence was accomplished with the use of fluorescamine to conjugate the protein in the filtrate. It is found that mixtures demonstrating low average binding reflect an overall lower hit rate of the components, whereas deconvolution of mixtures with high protein binding consistently provides a high hit rate. This differs from many of the previous experiences screening solid-phase mixtures in which high false positive rates are noted to occur. A total of 100K compounds were tested: 25K as discrete samples and 75K as mixtures. An overall hit rate of 8% was observed. Secondary screening of compounds measured specificity, recovery, and dynamic binding capacity. The effectiveness of the method is illustrated using an affinity column made with a representative lead compound. A similar purity was achieved in a single-step purification of HSA from serum as compared to that obtained by two steps of ion-exchange chromatography. The process for primary screening of a large number of compounds is simple, inexpensive, and applicable to any soluble target protein of known or unknown function from crude mixtures and may have additional utility as a generic chemical affinity tool for the functional characterization of novel proteins emerging from proteomics work. [source] | ||||||||||