Search PubMed⌕ Search

Biomedical subjects

R M Kaplan

Publications and source records attributed to R M Kaplan.

At least 145 records · Page 8Linked to original sources
PubMed1989

Exercise suppresses heritability estimates for obesity in Mexican-American families.

In multivariate analysis, suppressor variables attenuate the true relationship between predictor and outcome variables. Although suppressor variables relationships were described more than 45 years ago, few examples have been reported in the health care literature. We studied the correspondence between body mass in 111 Mexican-American families. Estimates of exercise suppressed the correlation between body mass for some dyads within these families. We concluded that the suppressor variable relationship may cause underestimates of heritability in multivariate studies.

Adolescent↗
PubMed1989

Health policy.

Explore the source record for details and available documents.

Health Policy↗
PubMed1989

Role of milk secretion in transport of prolactin from blood into milk.

In a first experiment prolactin was shown to be uniformly distributed in the milk of dairy cows. Accumulation of prolactin in milk increased with milking interval although milk prolactin content was proportionally greater after 2 h than accumulation of milk. Concentration of milk prolactin and total transfer of prolactin into milk was greater in mammary glands of cows milked just prior to initiation of intravenous infusion of exogenous prolactin. Similarly, inhibition of milk secretion as induced by intramammary infusion of colchicine, markedly reduced milk prolactin concentration and total transfer of prolactin into milk 5h following start of intravenous infusion of exogenous prolactin. Data indicate that transfer of prolactin from blood into milk during established lactation occurs primarily in conjunction with milk secretion.

Animals↗
PubMed1989

Familial similarities of changes in cognitive, behavioral, and physiological variables in a cardiovascular health promotion program.

A number of studies have demonstrated that physiological and behavioral cardiovascular disease (CVD) risk factors aggregate within families. This fact, and the potential mediating role that the family plays in behavior change, have led to the development of family-based CVD risk reduction programs, including the San Diego Family Health Project. The aggregation of behavioral, physiological, and cognitive changes within families was assessed during a 1-year intervention. We found evidence of modest but significant aggregation of change. There was more aggregation of change in behavioral variables than in physiological or cognitive variables. More significant correlations were found among 3-day food record measures than among 24-hour recall dietary measures, suggesting an influence of assessment method. Aggregation of change within families was stronger within generations than across generations. These data point to the importance of involving all age groups in health promotion programs.

Adult↗
PubMed1989

The Quality of Well-being Scale. Applications in AIDS, cystic fibrosis, and arthritis.

The Quality of Well-being (QWB) Scale combines preference-weighted measures of symptoms and functioning to provide a numerical point in-time expression of well-being that ranges from zero (0) for death to 1.0 for asymptomatic optimum functioning. The QWB includes three scales of function: mobility, physical activity, and social activity. Each step of these scales is associated with preference weights. Preference adjustments for symptoms are also included. This paper describes how this general system was used to evaluate outcomes in three different clinical conditions: acquired immune deficiency syndrome (AIDS), cystic fibrosis, and arthritis. In one study, the QWB was administered to 31 patients participating in evaluation of azidothymidine (AZT) treatment for AIDS. The QWB system demonstrated substantial benefits of AZT treatment in comparison to placebo. In a second study, the QWB and a series of pulmonary function measures were administered to 44 patients with cystic fibrosis. The QWB was demonstrated to be significantly correlated with measures of pulmonary function, including FEV1 and maximal midexpiratory flow rate (MMEFR). In addition, there were significant associations between the QWB and measures of exercise tolerance. In the third study, the QWB and an arthritis-specific measure were administered to 83 arthritis patients before and after their treatment. The QWB was at least as capable of detecting clinical change in this population as was the disease-specific measure. For all three conditions, the QWB considered side effects and benefits of treatment in a common unit. Clinical trial data are cited to suggest that the QWB is a valuable outcome measure in arthritis treatment evaluation. We conclude that the QWB has substantial validity as a general health outcome measure and that the system can be used with different populations.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Using composite health status measures to assess the nation's health.

Research in progress at the National Center for Health Statistics for evaluating the usefulness of composite measures of health status for assessing the nation's health is described. Three measures suitable for use in the general population, the Health Insurance Experiment-Functional Limitations (HIE-FL), the Health Utility Index (HUI), and the Quality of Well-being (QWB) scale, have been mapped to data collected in the 1980 National Health Interview Survey (NHIS). Analysis using current algorithms for making composite function status measures according to the QWB methods suggests that traditional single indicators of health tend to overestimate the level of health by about 10%. When symptoms and problems are added to the composite function score, the overestimate as measured by the single indicator is at least 50%. The authors are continuing to validate these algorithms, to develop similar ones for the HIE-FL and HUI, and to extend the analysis to data collected in 1977, 1979, and 1984. Current results indicate that to realize fully the benefits of composite measures, well-established, valid, and reliable measures of health-related quality of life should be included as part of the regular NHIS data collection procedures.

Activities of Daily Living↗
PubMed1989

Are large differences in "lifesaving" costs justified? A psychometric study of the relative value placed on preventing deaths.

Government actions to reduce risks to health have varied greatly in their cost per death prevented, frequently by 10-fold or even 100-fold. This research asks whether disparities of this magnitude are justified by citizens' preferences abut the relative value of reducing deaths from different hazards. Four samples were asked to rank the relative priority of preventing deaths through 8 realistic programs, each addressed to a different hazard, and then to rate how large the differences in spending should be. Subjects were not asked to give absolute values on preventing deaths and were asked only for their relative valuation of the benefits of preventing a death, not to weigh the benefits and costs or to determine an optimal spending level. We found that in all samples the median respondent valued his top-rated program 5 to 6 times more than his bottom-rated program. However, because individuals disagreed upon the relative priority for different programs, the aggregated rankings barely showed more than a 2-fold difference in the amounts that should be spent. Thus, for the important programs considered by these samples, a large variation in spending does not appear to be justified on the basis of differentials in the values placed on preventing different types of deaths. A more deliberative methodology like the one used here appears fruitful for providing insights to policymakers about preferences in this sensitive area.

California↗
PubMed1989

The quality of well-being in cystic fibrosis.

Traditional outcome measures in CF include PFTs, exercise tests, and several scoring systems that depend on pulmonary status and are largely subjective. The Quality of Well-being scale (QWB) is a widely used tool for measuring quality of life by three subscales: mobility, physical activity, and social activity, with points assigned within each subscale. The QWB has been shown to be valid in patients with COPD. We administered the QWB scale to 44 patients with CF, aged 7 to 36 years, and examined the relationship between QWB and PFTs, and in 15 patients the QWB vs exercise performance (peak VO2) on a progressive cycle ergometer test. QWB was significantly correlated with each variable examined: QWB vs FEV1, r = 0.5518 (p less than .0001); QWB vs FEF25-75%, r = 0.4793 (p less than .001); QWB vs PEFR, r = 0.4018 (p less than .01); QWB vs peak VO2, r = 0.5778 (p less than .01). The QWB scale is an objective measure that is significantly correlated with measures of performance and pulmonary function in CF. The relationship is not one of identity; further, the QWB is broad based and takes into account general well-being, not just pulmonary health, adding an important dimension to the care of patients with CF.

Activities of Daily Living↗
PubMed1989

An analysis of clinical toxicology urine specimens using the KDI Quik test.

The KDI Quik test is a rapid qualitative method for detecting narcotics, cocaine, PCP, and amphetamines in urine. The accuracy of this test was evaluated by testing 106 clinical toxicology urine specimens. Three investigators independently reviewed the test results and compared them to results of standard toxicological analyses. Of 83 samples found positive by the reference technique, only 70 were correctly identified as positive on the Quik test; only nine of 23 truly negative controls were correctly identified as negative by the Quik test. The overall sensitivity of the test was 84.7% while the specificity was 39.1%. As inaccuracies of this degree could result in frequent clinical error, use of the Quik test is not recommended.

Amphetamines↗
PubMed1989

Health outcome models for policy analysis.

The increasing therapeutic options in health care have created new dilemmas because resources to pay for the new technologies are limited. Cost/effectiveness and cost/utility models are required in order to evaluate the return on the invested dollar for various health care technologies. The problem is that different technologies are often evaluated using very different outcome units. The alternatives may range from liver transplantation to rehabilitation to preventive care. This article presents an overview of a general health policy model that expresses the benefits of all programs in a common unit known as the well-year--defined as the equivalent of 1 completely well year of life. The model uses two data sources: life expectancy and health-related quality of life during years prior to death. The quality-of-life component considers behavioral scales for mobility, physical activity, social activity, and symptoms. These dimensions are weighted by utility or preference to create a single scale that ranges from 0 (for death) for 1.0 (for optimum health). The model also considers duration of stay in each health state. Because all providers in health care attempt to extend life expectancy and improve quality of life, very different approaches in health care can be evaluated against one another. Preliminary analyses suggest that some behavioral interventions compete favorably with traditional medical and surgical treatments in terms of cost/well-year of life production. Various applications of the model are discussed.

Behavior Therapy↗
PubMed1988

Oxygen enrichment of bag-valve-mask units during positive-pressure ventilation: a comparison of various techniques.

Bag-mask devices are used frequently to provide patients with positive-pressure-assisted ventilation. To increase the percentage of oxygen delivered (FDO2) from the bag, supplemental oxygen must be provided by way of an oxygen inlet nipple attached to the unit. Using ten medical volunteers and a test lung with oxygen analyzer, we studied the effect of several variables on the FDO2 and determined the most effective reservoir that would provide the highest consistent FDO2 from the ventilating port of the bag. An FDO2 of 1.00 was consistently provided by the 2.5-L bag reservoir and a demand-valve set-up attached to the reservoir port of the ventilating bag. Bag refill time significantly affected the FDO2 when no reservoir or corrugated tube reservoirs were used. Corrugated tube reservoirs were found to be more sensitive to all variations in ventilatory technique and to oxygen flow rates. From our findings we recommend that corrugated tube reservoirs not be used for oxygen supplementation, as they are sensitive to variations in ventilatory technique and cannot alert clinicians to problems with oxygen flow. While both the 2.5-L bag reservoir and demand-valve provide a consistent FDO2 of 1.00, the demand valve has the advantage of audible filling of the ventilating bag as well as being compact and independent of ventilatory technique.

Equipment Design↗
PubMed1988

Myths and pitfalls in emergency translaryngeal ventilation: correcting misimpressions.

Translaryngeal jet ventilation has been proven an effective emergency airway alternative. However, confusion exists as to the proper cannulae and oxygen sources for this technique. Our study was designed to determine the delivered volumes of gas using cannulae and oxygen sources recommended in previous reports on translaryngeal jet ventilation. From this, we hope to clarify the proper technique of translaryngeal jet ventilation. Using a variety of oxygen sources and cannulae, peak flow rates were measured using a digital flowmeter. Delivered volumes of gases generated with each combination were then calculated. All of the cannulae tested (standard 16-gauge IV cannulae and larger) provided peak flow rates high enough so that predicted tidal volumes would be adequate to maintain adequate ventilation in apneic adults when a 50-psi source was used. Only a 4-mm tracheal cannula provided comparable values when a bag-valve device was used. No cannulae provided sufficient flow rates to ensure adequate ventilation in apneic adults when a demand-valve mechanism of 60 cm H2O driving pressure served as the source. Our observations were consistent with previous clinical studies and suggest that standard translaryngeal jet ventilation cannulae (12 to 16 gauge) must be connected to an oxygen source of 50 psi in apneic adults. Demand-valve devices do not provide sufficient driving pressures for these cannulae. A cannula of 4 mm ID should be placed if only a bag-valve device is available for ventilation.

Apnea↗
PubMed1988

Assessment of methods for measuring social support.

A rapidly expanding literature documents the effects of social support on physical and psychological well-being. Although definitions vary, most include both tangible components (e.g., financial assistance and physical aid) and intangible components (e.g., encouragement and guidance). Social support has been implicated in the mediation of stressful life events, recovery from illness, and increased program adherence. There are many inconsistent findings in the literature, however, and it is difficult to resolve discrepancies because measures of social support vary widely from study to study. To guide in the selection of measurement methods for research and applied work, 23 techniques for assessing social support are reviewed and evaluated. Criteria for favorable evaluation included reliability coefficients greater than .8 and documentation of validity. Correlations between various social support and criterion measures are simulated in order to demonstrate the consequences of choosing a measure with low reliability. Scale developers reported reliability data for 19 of the reviewed measures. Internal consistency coefficients ranged from .31 to .98. Test-retest coefficients ranged from .22 to .96. At least some validity documentation was available for 13 of the scales. Discriminant validity evidence, however, is almost universally absent. Despite psychometric weaknesses and variability among the scales, researchers have several instruments available to them.

Adaptation, Psychological↗
PubMed1988

A general health policy model: update and applications.

This article describes the development of a General Health Policy Model that can be used for program evaluation, population monitoring, clinical research, and policy analysis. An important component of the model, the Quality of Well-being scale (QWB) combines preference-weighted measures of symptoms and functioning to provide a numerical point-in-time expression of well-being, ranging from 0 for death to 1.0 for asymptomatic optimum functioning. The level of wellness at particular points in time is governed by the prognosis (transition rates or probabilities) generated by the underlying disease or injury under different treatment (control) variables. Well-years result from integrating the level of wellness, or health-related quality of life, over the life expectancy. Several issues relevant to the application of the model are discussed. It is suggested that a quality of life measure need not have separate components for social and mental health. Social health has been difficult to define; social support may be a poor criterion for resource allocation; and some evidence suggests that aspects of mental health are captured by the general measure. Although it has been suggested that measures of child health should differ from those used for adults, we argue that a separate conceptualization of child health creates new problems for policy analysis. After offering several applications of the model for the evaluation of prevention programs, we conclude that many of the advantages of general measures have been overlooked and should be given serious consideration in future studies.

Aged↗
PubMed1987

Sex differences in weight loss among adults with type II diabetes mellitus.

The treatment of choice for Type II or non-insulin-dependent diabetes mellitus is a behavioral program for the management of weight. However, compliance with this lifelong dietary regimen is often poor. In the current investigation male and female adults with diagnosed Type II diabetes were randomly assigned to either a behavior modification, a cognitive modification, a cognitive-behavior modification, or a control group. Patients were evaluated in terms of weight, percentage of body fat, and glycosylated hemoglobin measures. Men lost significantly more weight than women and subjects in the behavior modification group lost more weight and demonstrated greater decreases in diabetes control than subjects in the cognitive-behavior modification, cognitive, and control groups. A significant interaction indicated that diabetic men may benefit more from behavioral weight reduction programs than diabetic women. Several explanations for these findings are considered.

Adult↗