Accuracy of skin cancer incidence data in the United Kingdom.
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Humans↗
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Results for “Data Accuracy”
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Direct determination of Helicobacter pylori vacA genotypes and cagA gene in gastric biopsies and relationship to gastrointestinal diseases.
OBJECTIVE: Our aim was to detect Helicobacter pylori (H. pylori) from gastric biopsies of 248 patients using a novel, polymerase chain reaction (PCR)-based methodology, which simultaneously facilitates the determination of H. pylori vacA genotypes and cagA gene. METHODS: A simple methodology for sample preparation was established and PCR was performed with primer systems for the 16S rRNA, vacA, and cagA genes, thus circumventing the need to culture H. pylori and to extract DNA from biopsy samples. RESULTS: Infection with H. pylori was detected in 147 (59.3%) of 248 patients. The vacA signal sequence genotype s1 was present in 104 (81.3%) of 128 H. pylori-positive patients, and 24 (18.8%) patients had the genotype s2. The vacA middle region types m1 and m2 were detected in 46 (35.9%) and 79 (61.7%) patients, respectively. The combinations s1/m2 (43%) and s1/m1 (35.9%) were found more frequently than s2/m2 (18.8%). The cagA gene was detected in 75 (72.1%) of 104 H. pylori-positive biopsies with the vacA genotype s1. All 24 biopsies with the type s2 were cagA negative. Strains of the type vacA s1 were found in 97% of H. pylori-positive patients with peptic ulcer disease and were associated with the presence of the cagA gene, whereas 96% of the strains of the type vacA s2 were detected in patients who only had nonulcer dyspepsia. CONCLUSIONS: Using a novel PCR-based methodology, H. pylori 16S rRNA gene, vacA genotypes, and cagA gene can now be rapidly detected directly in gastric biopsies with high accuracy. These data demonstrate that infection with H. pylori strains of the vacA s1 genotype and the cagA gene are more likely to result in peptic ulcer disease. Determination of vacA genotypes and cagA gene may contribute to the potential clinical identification of patients at different levels of risk.
Adult↗
Oral lesions in elderly population: a biopsy survey using 2250 histopathological records.
OBJECTIVE: To perform an oral biopsy survey focused on the incidence of oral lesions in Brazilian elderly patients. METHODS: A total of 17 329 oral biopsy records were analysed and divided into two age groups: elderly patients, > or =60 years old; and non-elderly patients, <60 years old. Information about sex, race, age and histopathological diagnosis (categorised in non-neoplastic and neoplastic lesions) was collected. Differences of diagnosis incidence were tested by comparison between two proportions (binomial test). RESULTS: The incidence of epithelial malignant neoplasms and pre-malignant lesions in the elderly group was higher than non-elderly group, as well as autoimmune diseases and salivary gland tumours. The three most prevalent lesions in the elderly group were inflammatory fibrous hyperplasia, squamous cell carcinoma, and fibroma. CONCLUSION: The distribution of oral diseases using biopsies allows greater accuracy in data about oral health of elderly patients, especially when considering malignant and pre-malignant lesions.
Age Distribution↗
On predicting improvement and relapse in generalized anxiety disorder following psychotherapy.
This paper concerns an investigation of outcome predictors in a clinical trial of psychological therapies for generalized anxiety disorder. A variety of information of potential predictive value was obtained at three stages of patient contact: the initial referral, a screening interview and early sessions of therapy. Three measures of the clinical significance of change over a 12-month follow-up period were used to construct a composite measure which categorized outcome in terms of sustained improvement, relapse and no consistent change. Logistic regression was used to examine the validity of predictors identified in previous research and the relative importance of data obtained from the three different stages. Seventy-one per cent of patients were correctly classified as improved or not from initial data with a significant increase in accuracy with information from the screening interview (77 per cent) and early sessions (82 per cent). Patients who relapsed or not were predicted with considerable accuracy from initial data (90 per cent) and there was no significant increase in predictive power with additional information. The most powerful and robust predictors were: type of treatment received, marital status, marital tension and complexity of clinical presentation in terms of axis 1 co-morbidity. A conceptual framework for prediction is outlined.
Adolescent↗
3D interfractional patient position verification using 2D-3D registration of orthogonal images.
Reproducible positioning of the patient during fractionated external beam radiation therapy is imperative to ensure that the delivered dose distribution matches the planned one. In this paper, we expand on a 2D-3D image registration method to verify a patient's setup in three dimensions (rotations and translations) using orthogonal portal images and megavoltage digitally reconstructed radiographs (MDRRs) derived from CT data. The accuracy of 2D-3D registration was improved by employing additional image preprocessing steps and a parabolic fit to interpolate the parameter space of the cost function utilized for registration. Using a humanoid phantom, precision for registration of three-dimensional translations was found to be better than 0.5 mm (1 s.d.) for any axis when no rotations were present. Three-dimensional rotations about any axis were registered with a precision of better than 0.2 degrees (1 s.d.) when no translations were present. Combined rotations and translations of up to 4 degrees and 15 mm were registered with 0.4 degrees and 0.7 mm accuracy for each axis. The influence of setup translations on registration of rotations and vice versa was also investigated and mostly agrees with a simple geometric model. Additionally, the dependence of registration accuracy on three cost functions, angular spacing between MDRRs, pixel size, and field-of-view, was examined. Best results were achieved by mutual information using 0.5 degrees angular spacing and a 10 x 10 cm2 field-of-view with 140 x 140 pixels. Approximating patient motion as rigid transformation, the registration method is applied to two treatment plans and the patients' setup errors are determined. Their magnitude was found to be < or = 6.1 mm and < or = 2.7 degrees for any axis in all of the six fractions measured for each treatment plan.
Algorithms↗
Matrix-assisted laser desorption ionization-time of flight mass spectrometry for the discrimination of food-borne microorganisms.
A methodology based on matrix-assisted laser desorption ionization-time of flight mass spectrometry of intact bacterial cells was used for rapid discrimination of 24 bacterial species, and detailed analyses to identify Escherichia coli O157:H7 were carried out. Highly specific mass spectrometric profiles of pathogenic and nonpathogenic bacteria that are well-known major food contaminants were obtained, uploaded in a specific database, and made available on the Web. In order to standardize the analytical protocol, several experimental, sample preparation, and mass spectrometry parameters that can affect the reproducibility and accuracy of data were evaluated. Our results confirm the conclusion that this strategy is a powerful tool for rapid and accurate identification of bacterial species and that mass spectrometric methodologies could play an essential role in polyphasic approaches to the identification of pathogenic bacteria.
Bacteria↗
Use of radioactive antibodies for characterizing antigens and application to the study of flagella synthesis.
A simple rapid immunochemical procedure has been developed which provides information about the qualitative and quantitative nature of antigens. It involves the use of purified radioactive ((125)I-labeled) antibodies. The amount of antibody bound to the antigen is determined by filtering the mixture through diethylaminoethyl (DEAE)-cellulose paper. All of the antigen, as well as the antibody complexed with it, is trapped on the paper, whereas free antibody is removed by repeated washing. This technique has been applied to the study of three immune systems, bovine serum albumin, Escherichia coli tryptophan synthetase B protein, and Bacillus subtilis flagella. The results obtained by the DEAE-antibody binding technique were comparable, in terms of sensitivity, specificity, and accuracy, to data obtained by microcomplement fixation and precipitin methods. The assay was used to measure the kinetics of flagella regeneration in B. subtilis.
Antibodies↗
Detection of early antibodies in human immunodeficiency virus infection by enzyme-linked immunosorbent assay, Western blot, and radioimmunoprecipitation.
A current concept of the serological response to human immunodeficiency virus (HIV) infection in humans is that antibodies to core antigens (p55, p24, and p15) are detectable earlier during initial stages of antibody production than antibodies against envelope antigens (gp160, gp120, and gp41). Comparative studies of Western blot (immunoblot), radioimmunoprecipitation assay (RIPA), and enzyme-linked immunosorbent assay (ELISA) during initial antibody production are limited to case reports and have not resolved the issue. Thirty of the 37 participants who are part of a prospective study had at least one specimen that was negative for anti-gp41 but had one or more other bands on Western blot. Twenty-seven of these 30 specimens were reactive for anti-gp120/160 in the RIPA. Of the same 30 specimens, kits from Bionetics identified 2 (7%), ElectroNucleonics 4 (13%), Abbott 13 (43%), Du Pont 25 (83%), and Genetic Systems 25 (83%). All participants had evidence of serological progression by Western blot, including a gp41 band, on subsequent visits; the ELISA kits of all manufacturers identified these later specimens with greater accuracy. These data show that the RIPA detects anti-envelope antibodies that may be not detectable by Western blot and that the production of anti-envelope antibodies approximately parallels the production of anti-core antibodies. The false-negative results by ELISA would permit transmission of HIV by blood transfusion from donors in early stages of infection. The sensitivity of licensed ELISA kits should be improved to identify antibody as soon as possible after infection.
Acquired Immunodeficiency Syndrome↗
The interaction of vpr with uracil DNA glycosylase modulates the human immunodeficiency virus type 1 In vivo mutation rate.
The Vpr protein of human immunodeficiency virus type 1 (HIV-1) influences the in vivo mutation rate of the virus. Since Vpr interacts with a cellular protein implicated in the DNA repair process, uracil DNA glycosylase (UNG), we have explored the contribution of this interaction to the mutation rate of HIV-1. Single-amino-acid variants of Vpr were characterized for their differential UNG-binding properties and used to trans complement vpr null mutant HIV-1. A striking correlation was established between the abilities of Vpr to interact with UNG and to influence the HIV-1 mutation rate. We demonstrate that Vpr incorporation into virus particles is required to influence the in vivo mutation rate and to mediate virion packaging of the nuclear form of UNG. The recruitment of UNG into virions indicates a mechanism for how Vpr can influence reverse transcription accuracy. Our data suggest that distinct mechanisms evolved in primate and nonprimate lentiviruses to reconcile uracil misincorporation into lentiviral DNA.
Animals↗
Accuracy of hospital activity analysis data in estimating the incidence of proximal femoral fracture.
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Aged↗
Blood flow patterns in the human aorta studied by magnetic resonance.
Magnetic resonance velocity mapping by the field even echo rephasing sequence was used to provide two dimensional velocity profiles in the ascending and the descending aorta. Flow patterns were studied in ten healthy volunteers by a display method that gave clear details of the profiles. Velocity profiles in the ascending aorta were skewed in systole with an axis of skew roughly symmetrical about the plane of the aortic arch. During diastole flow was reversed along the posterior left wall of the ascending aorta while it continued forwards at the anterior right wall. In the descending aorta plug flow occurred but with minimal skew. Flow along the right wall was reversed during diastole. Turbulent flow did not occur in the ascending or descending aorta of any healthy subject. Magnetic resonance velocity mapping is a very powerful tool for the study of cardiovascular physiology. Its non-invasiveness, its quantitative two-dimensional data, its accuracy, and its high spatial resolution make it suitable for clinical use.
Aorta↗
Accuracy of Scottish hospital morbidity data.
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Hospital Administration↗
Comparison of fluorescent antibody, bacitracin susceptibility, latex agglutination, coagglutination, and API 20S for identifying group A streptococci.
A total of 200 beta-hemolytic streptococci, isolated from clinical specimens submitted to our laboratory, were identified as group A versus non-A using the fluorescent antibody technique (FA), bacitracin susceptibility (BBL, Difco, and Raven disks), SeroSTAT, Streptex, Phadebact, and the API 20S system. Of the 122 group A isolates, all methods except SeroSTAT and Phadebact yielded 92-99% agreement when compared with the Lancefield precipitin test. Phadebact yielded an 84% agreement and SeroSTAT changed from 83 to 98% after trypsinization. Numerous false positives were obtained and only FA (91%) and API 20S (96%) yielded better than 90% agreement on non-A identification when compared with the Lancefield test. The most false positives were obtained (45%) using the SeroSTAT reagents. Considering accuracy, our data suggests the FA technique to be the method of choice for identifying group A streptococci.
Agglutination Tests↗
Ultrasound in the staging of lymphoma.
Ultrasonography of the abdomen and pelvis was performed in 16 patients with lymphoma who underwent clinical and pathologic staging. The results of the ultrasound examinations were correlated with the pathological findings as were the results of gallium-67 scans, inferior vena cavagrams and lymphangiograms obtained in the same group. Analysis of the data indicated accuracies in the 80-90% range and specificities of greater than 90% for ultrasound. The sensitivity of ultrasound was somewhat lower, in the 60-70% range. These findings compare favorably with those of the other diagnostic procedures evaluated and indicate the usefulness of ultrasound in the staging of lymphoma.
Gallium Radioisotopes↗
Accuracy of subspace mapping of spatiotemporal frequency domain visual receptive fields.
Orientation and spatial frequency selectivities are fundamental properties of cells in the early visual cortex. Although they are customarily tested with drifting sinusoidal gratings, a recently developed subspace reverse correlation method may be a better replacement for obtaining a selectivity map in a joint orientation and spatial frequency domain at higher resolution efficiently. These two methods are examined for their accuracy and data compatibility for cells in areas 17 and 18 of anesthetized and paralyzed cats. Peaks and bandwidths of tuning curves from these two methods are highly correlated. However, spatial frequency bandwidths obtained by reverse correlation tend to be slightly narrower for the subspace reverse correlation than those from the drifting grating tests. Consistency between the two methods is improved if the entire duration of data containing signal are taken into account for the subspace reverse correlation rather than using the map only at the optimal correlation delay. Examination of convergence of the subspace mapping process shows that reliable 2-day profiles can be obtained within 5-10 min. for the majority of cells. Temporal dynamics of tuning properties are also examined more directly with the subspace mapping than with the drifting gratings. For many cells, the optimal spatial frequency shifts substantially, measured as a fraction of tuning bandwidth, over the time course of response. In comparison, the optimal orientation remains highly stable throughout the duration of response. Overall, these results suggest that the subspace reverse correlation is a better substitute for the conventional method.
Action Potentials↗
Three-dimensional models of the tracheostoma using stereolithography.
The availability of an accurate three-dimensional (3-D) model of the tracheostoma and trachea of the laryngectomy patient would be of great help in prototyping of endotracheal prostheses. Stereolithography has been described for skull and jaw models but never for soft-tissue reconstructions of the trachea. CT was performed on tracheostomas of 8 patients. The CT data were used to make 3-D models by means of stereolithography. Inverted CT data were used to create air contour models of the same tracheostomas. Eight soft-tissue and 8 air contour models were reconstructed from CT data, showing accuracy and great detail. In this paper we present a previously unreported application of the stereolithography technique. Measurements and prosthesis prototyping, which are impossible to perform on tracheostomas in patients, can now be executed safely. We are using the 3-D tracheostoma models in our research project to develop an endotracheal fixation method for tracheostomal valves.
Humans↗
Use of the speed accuracy trade-off to characterize information processing in schizophrenics and normals.
Subjects performed a signal discrimination task under four conditions: normal pace, accuracy, speed, and SATO (equal effort to speed and accuracy). Characteristically, schizophrenics demonstrated decreased accuracy, poorer compliance, increased total response time, and increased simple reaction time. Surprisingly, central processing time (decision time) was equivalent. Analysis of processing resource allocation identified significant group differences only under the SATO condition. Here, controls balanced attentional resources but patients worked almost exclusively for speed. Under conjoint performance conditions, patients apparently minimize categorical processing time at the expense of accuracy. These data are interesting as they identify specific circumstances under which schizophrenics manifest an attentional deficit.
Adult↗
Prediction of outcome after mitral valve replacement in patients with symptomatic chronic mitral regurgitation. The importance of left atrial size.
BACKGROUND: The ability to predict outcome after mitral valve replacement remains limited in patients with symptomatic chronic mitral regurgitation. The aims of this study were to determine the preoperative predictors of postoperative cardiac-related mortality and to assess the additive prognostic value of tests performed in such patients. METHODS AND RESULTS: Accordingly, 176 patients (mean age, 57 +/- 14 years) who underwent mitral valve replacement were followed up for 3.8 +/- 0.5 years. Four categories of variables were analyzed to predict postoperative cardiac-related mortality: clinical, laboratory, two-dimensional echocardiographic (2DE), and cardiac catheterization. There were 39 cardiac-related deaths (29 due to congestive heart failure and 10 sudden). When the four categories were analyzed separately, two clinical, one laboratory, two 2DE, and one catheterization variable best predicted postoperative death. When these six variables were examined simultaneously, only three (one clinical and two 2DE) remained significant predictors of cardiac-related mortality: presence of pulmonary rales, left atrial size, and the ratio of left ventricular wall thickness to left ventricular cavity dimension in end systole. A model based on these three variables may predict cardiac-related death with considerable accuracy. Laboratory data did not add to clinical information for predicting death. 2DE variables provided significant additional information in this regard (p less than 0.001). Further addition of catheterization variables was not useful. Prognostic value did not change significantly when 50 patients with prior mitral valve surgery or 49 patients undergoing concomitant aortic valve replacement or coronary artery bypass surgery were excluded from analysis. CONCLUSIONS: We conclude that 1) measures of both left ventricular systolic function and left atrial size are equally important in predicting postoperative cardiac-related mortality in patients with symptomatic chronic mitral regurgitation undergoing mitral valve replacement; 2) left atrial size may be important because it reflects the "history" (severity and duration) of mitral regurgitation; 3) 2DE assessment of left atrial size and left ventricular function provides prognostic information that is significantly greater than that obtained from clinical and laboratory parameters alone; the addition of catheterization variables does not increase the prognostic value of the clinical and 2DE data.
Atrial Function, Left↗