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A Wijesinha

Publications and source records attributed to A Wijesinha.

4 recordsLinked to original sources

Clinical efficacy of dental radiography in the detection of dental caries and periodontal diseases.

This article reports the ability of dental radiographs to correctly detect evidence of dental caries and periodontal disease (sensitivity) and to correctly establish the absence of these diseases (specificity). The analysis used a unique data set that was collected as part of the Veterans Administration Dental Longitudinal Study in Boston. Periapical, panoramic, and posterior bitewing radiographs were independently compared with a consensus radiographic standard of all three radiographs read simultaneously. Findings showed that the sensitivities of all three radiographs to detect dental caries were lower than expected, at approximately 60%, whereas the sensitivities to detect evidence of periodontal disease averaged approximately 85%. Panoramic radiographs were substantially less sensitive for detecting dental caries than periapical and posterior bitewing radiographs, but no difference between these modalities was observed in the analysis of sensitivity to periodontal disease. The proportion of false-negative and false-positive readings from dental radiographs was substantial and requires further investigation.

Adult↗

Selection criteria for upper gastrointestinal examinations: attempts at improvement.

An attempt was made to improve upon selection criteria for the performance of upper gastrointestinal (UGI) series in three settings: a teaching hospital, a community hospital, and a health maintenance organization. Two statistical techniques, the polychotomous logistic model (to develop predictive algorithms for the identification of specific diseases) and the maximum attainable discrimination technique, were used to show the relationship between the percentage of patients with any disease detected and the percentage of UGI examinations performed. Results showed that neither technique improved significantly upon selection criteria for identifying patients with abnormal UGI series.

Decision Theory↗

Methodology for the differential diagnosis of a complex data set. A case study using data from routine CT scan examinations.

Data from routine CT scan examinations are employed to illustrate the use of the polychotomous logistic regression model as a statistical diagnostic tool. The assumptions of the model, the interpretation of its parameters, and its capabilities are described in detail. In carrying out the analysis on the CT data, a large, relatively sparse data set, many technical difficulties were encountered. Modifications to the methodology that were necessary to permit its implementation are described, and it is demonstrated that an unbiased analysis of T + 1 diagnostic categories can be implemented by separately performing T individual simple logistic analyses. The limitations of the methodology are discussed. It is hoped that this paper may serve as a basis for the practical implementation of the polychotomous logistic model in similar diagnostic settings.

Adult↗

Decreased motility of bull spermatozoa caused by Mycoplasma bovigenitalium.

Mycoplasma bovigenitalium mixed with bull semen in egg yolk-citrate buffer and held at 5 C caused a highly significant time- and dose-dependent depression in sperm motility. Mycoplasma adhered to a majority of spermatozoa, principally to the acrosome, but also the the midpiece and tail. This may reflect the basis for a naturally observed condition in young bulls in which genital mycoplasmosis is associated with low sperm motility.

Animals↗