PubMed Health⌕ Search

Biomedical subjects

J W Bush

Publications and source records attributed to J W Bush.

17 recordsLinked to original sources
PubMed1988

Internal Consistency Analysis: a method for studying the accuracy of function assessment for health outcome and quality of life evaluation.

Social, mental and physical function are major components of health outcomes and health related life quality, but the accuracy of function measurement is difficult to study rigorously. Internal Consistency Analysis (ICA) uses multiple sources of evidence from a survey interview to study the accuracy of a classification. It was developed to study function classifications for a general health outcome measure, the Quality of Well-being (QWB) scale. ICA is described and evidence of its utility in improving the classifications needed for the QWB is presented.

Aged↗
PubMed1986

Classifying function for health outcome and quality-of-life evaluation. Self- versus interviewer modes.

Validity assessment and the underreporting of dysfunction have been major problems in health-related quality-of-life measurement, including collecting data for analysis by the General Health Policy Model, using the Quality of Well-being scale (QWB). This analysis compares the results of self- versus interviewer modes of measurement and short, direct-answer questions versus probing algorithms in the QWB. The comparisons are made in terms of 1) correlations; 2) aggregate frequencies; 3) individual subject classifications; and 4) the actual state, established using evidence from multiple sources. Despite extremely high correlations between QWB scores from the two modes (greater than 0.98), the lowest interviewer mode sensitivity (0.86) and predictive value dysfunctional (0.91) were substantially superior to the highest self-classification characteristics (0.66 and 0.73). In the populations studied, specificities and predictive values functional were equivalent (greater than 0.94) for the two modes. The probe pattern of the interviewer mode was also less susceptible to false reports of dysfunction. These results are consistent with the underreporting of dysfunction noted by several major investigations of health status measurement. The authors conclude that interviewer-administered instruments using question algorithms are necessary if health-related quality of life is to be measured with sufficient reliability and validity to evaluate major clinical trials and follow-up studies.

Adult↗
PubMed1985

Enzymatic lysis of the pseudomurein-containing methanogen Methanobacterium formicicum.

A streptomycete isolated from cow manure produces an extracellular enzyme capable of lysing the pseudomurein-containing methanogen Methanobacterium formicicum. The lytic activity has been partially purified from culture fluid and appears to be a serine protease. Similar lytic activity has been fractionated from pronase. Optimal conditions have been developed for lysis of M. formicicum by commercial preparations of proteinase K. The three lytic enzymes have been partially characterized. The results with the three enzyme preparations tend to confirm that proteolytic enzymes are capable of lysing methanogen cells.

Cell Fractionation↗
PubMed1982

"Counterintuitive" preferences in health-related quality-of-life measurement.

The published preferences for scale steps in a health-related quality-of-life scale have been noted to be contrary to some prior assumptions about their rank ordering. The differences noted are actually statistically nonsignificant, and the observed ordering has a clear intuitive explanation. Several alternative explanations, including vagueness in the case descriptions, inaccuracy in the scaling method, the presence of interactions in the subjects' cognitive integration rules and chance inversions in the presence of the flat response surface characteristic of linear models, are all shown to be impossible or unlikely contributors to the empirical results. The implications of the "negative preferences" for other measurement approaches are discussed, as well as the role of separate attribute coefficients in health policy analyses.

Abstracting and Indexing↗
PubMed1979

Utilization of promoter and terminator sites on bacteriophage T7 DNA by RNA polymerases from a variety of bacterial orders.

The transcriptional properties of bacterial RNA polymerases purified from seven different species and representing a variety of bacterial orders have been studied using the well characterized DNA from phage T7 as template. The subunit composition of the different preparations suggests that each RNA polymerase holoenzyme has a promoter structure (betabeta'alpha2sigma) similar to that of the well studied E. coli and B. subtilis enzymes. Each enzyme utilizes DNA from bacteriophage T7 as an effective template for RNA synthesis, although all preparations contain a substantial fraction of inactive enzyme. Electrophoretic analysis of the RNA products made with the different RNA polymerases in vitro using T7 DNA (deletion mutant deltaD111) as template reveals that with minor exceptions, all of the heterologous RNA polymerases utilize the same collection of promoter sites on T7 used by the E. coli host enzyme, and only those promoter sites. The T7 early terminator is also efficiently utilized by each enzyme. Since the different bacterial species from which the RNA polymerases were derived are genetically quite distant, it appears that there is a structural element in the promoter which governs its recognition and which is universally recognized among RNA polymerases of different bacterial species. While the different bacterial RNA polymerases generally utilize the same set of T7 promoter sites, the efficiency of utilization of the different promoters varies considerably for different RNA polymerases and for different reaction conditions with the same RNA polymerase. Hence although the several T7 promoter sites share the ability to be recognized by bacterial RNA polymerases, each shows a unique pattern of utilization and therefore must possess a unique element of promoter structure as well. It has previously been shown (Stahl and Chamberlin, 1977) that T7 promoters A1, C, D and E interact differently with E. coli RNA polymerase as judged by the properties of complexes formed between each promoter and the latter enzyme. Since competition takes place among different promoter sites on a template and since these sites can differ functionally, small changes in reaction conditions or in the structure of the RNA polymerase can lead to significant changes in the rate of utilization of different promoter sites even when these promoter sites share common elements. Because the T7 promoters and terminator are utilized efficiently by such a wide range of RNA polymerases and because each of the several T7 promoters possesses unique properties which govern its utilization by RNA polymerase, analysis of the transcripts formed on a T7 DNA template provides a simple and rapid procedure for detecting and analyzing alterations in bacterial RNA polymerases which affect promoter or terminator recognition or utilization.

Bacteria↗
PubMed1979

Health status index: category rating versus magnitude estimation for measuring levels of well-being.

Levels of Well-Being are social preferences, or weights that members of society associate with time-specific states of function. A Weighted Life Expectancy, which can be used to measure program outputs, is created by summing the levels across diverse cases and multiplying them by probable transitions (prognoses) among the states and levels. This operation requires however, that the Levels of Well-Being be measured on underlying metric scale. The present analysis compares preference measurements from a simple category rating procedure with those obtained using the more complex and difficult magnitude estimation method which has been claimed to yield ratio level measures. In a randomly counterbalanced design, 65 college students rated 30 case descriptions representing the range of the Well-Being continuum. The results exhibit the classical logarithmic relation observed for a prothetic continua. When transformed to a meaningful 0-1 unit scale, however, the magnitude responses are compressed at the lower end of the scale near death. Such results are inconsistent not only with category rating, but also with intuitive notions of the relative importance of the function states, with the results of rating procedures that simulate social choice, and with evidence that confirms the interval properties of the category ratings themselves. Furthermore, the ease of administration of category rating means that multiple attributes of cases can be considered jointly, avoiding the need to aggregate scale values for different attributes by arbitrary rules. In sum, magnitude estimation is inappropriate as a measurement method for a Health Status Index and is probably also inappropriate for other measures of utility and social choice.

Activities of Daily Living↗
PubMed1976

Health status: types of validity and the index of well-being.

The concept of validity as it applies to measures of health and health status is examined in the context of a set of standard, widely accepted definitions of validity. Criterion validity is shown to be irrelevant to health status measures because of the lack of a single specific, directly observable measure of health for use as a criterion. To overcome this problem, the Index of Well-being has been constructed to fulfill the definition of content validity by including all levels of function and symptom/problem complexes, a clearly defined relation to the death state, and consumer ratings of the relative desirability of the function levels. Data from a two-wave household interview survey provide convergent evidence of construct validity by demonstrating an expected positive correlation of the Index of Well-being with self-rated well-being and expected negative correlations with age, number of chronic medical conditions, number of reported symptoms or problems, number of physician contacts, and dysfunctional status. Discriminant evidence of construct validity is demonstrated by predicted differences in correlation between concurrent Index of Well-being scores and self-assessed overall health status, and between the Index of Well-being scores and self-rated well-being on different days. A simple method of estimating a currently usable comprehensive population index of health status, the Weighted Life Expectancy, is described.

Activities of Daily Living↗
PubMed1976

Maximizing health system output with political and administrative constraints using mathematical programming.

Decisions about delivery programs to improve health status are characterized by indivisibilities or "lumpiness," interdependencies between case types with varying health output, high fixed costs, administrative constraints, and qualitative quity and political considerations. The nature of the constraints and the goal of health services strongly suggest a mathematical programming model to maximize a comprehensive measure of health status. In a previously unreported development, binary integer programming can be extended to consider shared fixed costs, a widespread problem in optimizing effectiveness measures such as health status. The model proposed here applies conceptually across all target populations and health programs and could be used to optimize the output of a total health system. The effects of such optimization would be appropriately reflected in the weighted life expectancy computed as a social indicator.

Cost-Benefit Analysis↗
PubMed1975

No-fault malparactice insurance. Proximate cause and the quality of medical care.

No-fault medical malpractice insurance has been proposed as an alternative to the present tort liability approach. Statistical examination of the concept of proximate cause reveals not only that the question of acceptable care, and therefore of fault, is unavoidable in identifying patients deserving compensation, but also that specifying fault in an individual case is scientifically untenable. A simple formula for a Coefficient of Causality clarifies the question of proximate cause in existing trial practices and suggests that many of the threats associated with malpractice suits arise from the structure of the tort-insurance system rather than from professional responsibility for medical injury. The concepts could provide the basis for a revised claims and compensation procedure.

Expert Testimony↗
PubMed1975

Successive intervals analysis of preference measures in a health status index.

The method of successive intervals, a procedure for obtaining equal intervals from category data, is applied to social preference data for a health status index. Several innovations are employed, including an approximate analysis of variance test for determining whether the intervals are of equal width, a regression model for estimating the width of the end intervals in finite scales, and a transformation to equalize interval widths and estimate item locations on the new scale. A computer program has been developed to process large data sets with a larger number of categories than previous programs.

Computers↗