Biomedical subjects

I R Kramer

Publications and source records attributed to I R Kramer.

49 records · Page 3Linked to original sources

PubMed1970

A computer-aided study on the tissue changes in oral keratoses and lichen planus, and an analysis of case groupings by subjective and objective criteria.

In a retrospective survey of 235 cases in which the diagnosis on biopsy was lichen planus, keratosis or leukoplakia, the histological features were re-assessed in as objective a manner as possible. For each case, the tissue changes were recorded under 37 headings, without any attempt at interpretation. The information was then transferred to punched cards, and used for various types of computer-aided analysis. Firstly, the frequency with which each tissue change occurred was assessed for each diagnostic group, and the data presented also show how often each change occurred in those cases that subsequently developed a carcinoma.Re-analysis of the cases on the basis of short lists of tissue changes that were thought to characterize each diagnostic category showed, as expected, that many other factors must have played a part in the original diagnosis.Analysis of the histological findings on an objective basis, using a cluster analysis programme, provided an encouraging degree of separation into the diagnostic groups. When a number of known carcinoma cases were included in the cluster analysis as "markers", a small number of leukoplakia and keratosis cases were placed by the computer into the same cluster as these "markers". Of the original 187 cases originally diagnosed as leukoplakia or keratosis, 4.8% are known to have developed a carcinoma, but of the 11 cases the computer placed in the same cluster as the "marker" cases of carcinoma, 36% have subsequently developed carcinoma. Thus, in the cluster analyses, the computer is tending to "recognize" those cases that later developed carcinoma, and to separate them from the bulk of the cases in which malignant change has not occurred.

Basement Membrane↗

PubMed1970

The use of discriminant analysis for examining the histological feathers of oral keratoses and lichen planus.

In a retrospective survey of 235 cases in which the diagnosis on biopsy was lichen planus, keratosis or leukoplakia, the histological features were re-assessed as objectively as possible and without reference to the original diagnosis.The tissue changes were recorded under 39 headings, and many were assessed on a roughly quantitative basis. In addition, two clinical features were included; whether the biopsy was from the buccal mucosa (as opposed to some other intraoral site) and whether the lesions involved multiple intraoral sites. For each possible pair of diagnostic categories (keratosis and leukoplakia, lichen planus and keratosis, lichen planus and leukoplakia) the recorded findings were subjected to discriminant analysis in order to provide a quantitative assessment of the value of each individual feature for discriminating between the two diagnostic groups. The computer programme also provided for the application of these calculated values to yield a "score" for each case, and for an assessment of the significance of the separation of the diagnostic groups thus achieved. In general, the values calculated by the computer for the discriminatory value of each tissue change accorded with our subjective impressions, but a number of features that were given a relatively high value had not previously been recognized as important in differential diagnosisA discriminant analysis was also performed on those cases of leukoplakia known to have later developed a carcinoma, in comparison with the leukoplakia cases that did not develop carcinoma. High values were accorded mainly to the well-known features of epithelial atypia, but a similar high value was indicated for the presence of Russell bodies. we had not previously realized that the presence of Russell bodies was of prognostic significance in this context.When the total scores for the groups of cases were analysed, it was found that the separation of each pair of diagnostic groups was significant at the 1% level. The separation of leukoplakia cases that subsequently developed carcinoma, from those that did not develop carcinoma, was significant at the 5% level. In this latter analysis, a better separation might be achieved with larger numbers of cases, but there will always be the complicating factor that an unknown number of leukoplakia cases would develop carcinoma if the patient had received no treatment.

Biopsy↗

PubMed1969