Biomedical subjects

A L Shroyer

Publications and source records attributed to A L Shroyer.

58 records · Page 4Linked to original sources

PubMed1995

Analysis of clonality by polymerase chain reaction for phosphoglycerate kinase-1. Heteroduplex generator.

Polymerase chain reaction (PCR) amplification has been used to determine the clonal composition of tissues based on analysis of the pattern of X-chromosome inactivation, but its use has been limited by technical difficulties. This report presents an expedited method to use PCR in the analysis of clonality. The method uses gel electrophoresis of heteroduplexes formed with an artificial heteroduplex generator (HG) and PCR products from the phosphoglycerate kinase-1 (PGK-1) gene from the tissue sections. Amplification was successful in 36 of 37 cases originally diagnosed as endometrial adenocarcinoma. HG analysis of 36 cases confirmed heterozygosity in 12 cases (33.3%). PGK-1 PCR amplification product was obtained from both control and lesional tissue in 10 of the 12 heterozygous cases. Of these 10 cases, seven were shown to consist of clonal cell populations by HG analysis. Two of three cases diagnosed as well-differentiated endometrioid adenocarcinoma were found to be comprised of polyclonal populations of cells. One case produced an anomalous pattern with HG analysis and was shown to be aneuploid by fluorescence in situ hybridization (FISH) with a chromosome X alpha-satellite probe. It is concluded that HG is a useful alternative to restriction fragment length polymorphism (RFLP) analysis of X-chromosome inactivation as a marker of tissue clonality in cases in women.

Adult↗

PubMed1994

Bayesian-logit model for risk assessment in coronary artery bypass grafting.

Predictive models for the assessment of operative risk using patient risk factors have gained popularity in the medical community as an important tool for the adjustment of surgical outcome. The Bayes' theorem model is among the various models used to predict mortality among patients undergoing coronary artery bypass grafting procedures. Comparative studies of the various classic statistical techniques, such as logistic regression, cluster of variables followed by a logistic regression, a subjectively created sickness score, classification trees model, and the Bayes' theorem model, have shown that the Bayes' model is among those with the highest predictive power. In this study, the Bayes' theorem model is reformulated as a logistic equation and extended to include qualitative and quantitative risk factors. We show that the resulting model, the Bayesian-logit model, is a mixture of logistic regression and linear discriminant analysis. This new model can be created easily without complex computer programs. Using 12,712 patients undergoing coronary artery bypass grafting procedures at the Department of Veterans Affairs Continuous Improvement in Cardiac Surgery Study between April 1987 and March 1990, the predictive power of the Bayesian-logit model is compared with the Bayes' theorem model, logistic regression, and discriminant analysis. The ability of the Bayesian-logit model to discriminate between operative deaths and operative survivors is comparable with that of logistic regression and discriminant analysis.

Age Factors↗

PubMed1994

The Veterans Affairs Continuous Improvement in Cardiac Surgery Study.

The Department of Veterans Affairs Cardiac Surgery Consultants Committee is responsible for reviewing the quality of cardiac surgical treatment at the 43 Veterans Affairs cardiac surgical centers where these procedures are performed. It does so by reviewing both the unadjusted and risk-adjusted operative mortality data and the incidence of perioperative complications. These data are reviewed by the committee semiannually, and the overall summary and hospital-specific data are shared with the individual cardiac surgical program directors. Paper audits and site visits are performed when indicated by increased unadjusted and risk-adjusted operative mortality. Constructive criticism is shared with the program director and medical center administration. The relative risk of death for numerous patient risk factors has been estimated, and is now used in prospective clinical decision making. During the 7-year period that risk-adjusted outcomes have been utilized, there has been an overall significant reduction in the observed-to-expected operative mortality ratio. Although many factors could have contributed to this, including continually improving surgical techniques, it is also likely that part of this improvement has occurred because of the continuous feedback of these quality improvement data to our cardiothoracic surgeons and cardiologists.

Cardiac Surgical Procedures↗

PubMed1994

Provider perceptions in using outcomes data to improve clinical practice.

In this article we report on the perceptions of health care providers concerning the use of health care outcomes. These perceptions were identified during two afternoon workshops at the symposium on outcomes data held in Keystone, Colorado, in June 1994. The overall goal of these workshops was to explore the potential use of outcomes data within the clinical practice setting. The attitudes and concerns of several key providers formed the framework for the workshop discussions. The strengths and weaknesses associated with using risk-adjusted outcomes data, both to assess and to improve quality of patient care, were debated within the workshop groups. Overall, conference participants agreed that the risk-adjusted outcomes of cardiac care could be used both to assess and to improve the quality of patient care. The research to date, however, represents only a first step toward this goal. The meeting participants challenged the research community to improve on the measures currently available, with the goal of providing clinicians better information to improve the "art" of medicine.

Attitude of Health Personnel↗