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Biomedical subjects

R J Beckman

Publications and source records attributed to R J Beckman.

7 recordsLinked to original sources
PubMed1995

Classification and regression trees for bone marrow immunophenotyping.

Methods are needed to assist with automating three-color flow cytometric immunophenotyping of bone marrow from leukemia patients. Described is a method in which a normal bone marrow data set is used as a template against which to compare leukemic bone marrow data sets. This template is obtained using techniques of cluster analysis and cluster editing. Leukemic cells often inappropriately express antigens and appear in a different part of the multivariate data space than normal cells. To recognize the cells exhibiting inappropriate antigen expression, an artificial cluster of "cells" is added to the normal template. The "cells" in this cluster fill the space not occupied by normal cells. Classification and regression tree (CART) analysis is used to train a classifier that can then be used to isolate the major cell types and the inappropriate expression cells in a leukemic bone marrow specimen.

Automation↗
PubMed1988

Practice patterns of teaching testicular self-examination to adolescent patients.

Testicular self-examination has been proposed as a screening technique for the early detection of testicular neoplasms. Previous work suggests that few adolescent males have received instruction in the technique. We report the results of a physician survey to assess the frequency with which self-examination is taught and to identify the reasons why some physicians do not teach testicular self-examination. Only 17.5% of the physicians surveyed taught testicular self-examination to adolescent male patients on a routine basis. Eighty-two percent stated that they were unfamiliar with the technique or had not thought about it.

Adolescent↗
PubMed1988

Using immersion test data to screen chemical protective clothing.

A test to screen chemical protective materials in order to select potential candidates for further testing has been examined. The method involved determining the weight and volume changes in materials caused by immersion in the challenge chemical. Simple regression analysis showed that relatively short breakthrough times based on weight change and final thickness could be predicted with 90% confidence. Better results were obtained when discriminant analysis was used to classify breakthrough times greater than either 4 or 8 hr as a function of the weight change and final thickness. In 6% or less of the cases, actual breakthrough times were less than 4 or 8 hr when the predicted times were greater than these values. Discriminant analysis also was used to classify permeation rates as less than either 90 or 400 mg/m2-min based on weight change and initial thickness. In this case, actual permeation rates less than these were predicted to be greater in 4% and 7% of the cases, respectively.

Immersion↗
PubMed1982

Hierarchical analysis of influenza A hemagglutinin gene sequences.

Five recently sequenced hemagglutinin genes from Influenza A virus strains are studied for similarities in a hierarchical fashion. The sequences are compared for similarity, first on the level of sequence homology, and then on several progressively more general levels. Though the HA1 subsequences contain regions where homology drops to that of a Monte Carlo generated reference value, subsequent tests reveal great similarity due to constraints on the level of amino acid sequence. Other tests detect statistically significant differences between subtypes due to constraints acting below the level of amino acid sequence, such as the 2 degrees structure of the viral RNA, or involving translation of the mRNA. The general applicability of the hierarchical approach to sequence analysis is discussed.

Base Sequence↗