Biomedical subjects

D M Murray

Publications and source records attributed to D M Murray.

At least 73 records · Page 4Linked to original sources

PubMed1996

Sources of alcohol for underage drinkers.

OBJECTIVE: We assessed the extent to which various sources of alcoholic beverages are used by early, middle and older teenagers, the extent to which teenagers perceive alcohol to be available from different sources and factors related to use of alternative sources. METHOD: Ninth graders (n = 2,269), twelfth graders (n = 2,377) and youth aged 18-20 (n = 1,738) were surveyed in 15 upper-midwestern communities using a nested cross-sectional design. Analyses were based on mixed-model regressions, with both the individual and community treated as random effects, taking into account the intraclass correlation for each dependent variable. Analyses focused on current (last 30 day) drinkers to avoid recall bias for drinking events in the distant past. RESULTS: A person aged 21 or over was the most common source of alcohol for current drinkers in all three age groups; 46% of 9th graders, 60% of 12th graders and 68% of those aged 18-20 obtained alcohol from a person age 21 or older for their last drinking occasion. A person under age 21 was the second most prevalent source for 9th and 12th graders (29% of each group obtained alcohol from someone under age 21 for their last drinking occasion). A commercial outlet was the second most prevalent source for those aged 18-20 (14% obtained alcohol directly from an outlet for their last drinking occasion). CONCLUSIONS: Perceived availability, binge drinking and several demographic characteristics were independently related to source of alcohol used, and age interacted with several factors in predicting source of alcohol. We conclude that increased attention to sources of alcohol used by youths would facilitate efforts to reduce underage drinking.

Adolescent↗

PubMed1996

Intraclass correlation among measures related to alcohol use by school aged adolescents: estimates, correlates and applications in intervention studies.

School-based alcohol use prevention studies frequently employ designs in which schools are assigned to treatment conditions while observations are made on individuals. The nesting of schools within treatment conditions requires that the treatment effect be assessed against the between-school variance; unfortunately, that variance is usually larger than for randomly constituted groups and its precision is usually less than that for the within-school variance. These factors often combine to reduce power substantially. To address these problems, investigators need good estimates for the intraclass correlation which together with the number of observations per school determines the magnitude of the extra variation in the nested design. This article presents estimates of school-level intraclass correlation for measures related to alcohol use among ninth and twelfth grade students and discusses their use in planning new studies and analyzing previous or current studies.

Adolescent↗

PubMed1995

Enzyme/prodrug gene therapy: comparison of cytosine deaminase/5-fluorocytosine versus thymidine kinase/ganciclovir enzyme/prodrug systems in a human colorectal carcinoma cell line.

We have been developing an enzyme/prodrug gene therapy approach for the treatment of primary and metastatic tumors in the liver. This system uses the cytosine deaminase/5-fluorocytosine (CD/5-FCyt) enzyme/prodrug combination. Another system that has received considerable attention is the herpes simplex virus thymidine kinase/ganciclovir (HSV-TK/GCV) enzyme/prodrug combination. The purpose of the present study was to compare these two enzyme/prodrug systems. The human colorectal tumor cell line, WiDr, was genetically modified to express either the CD gene (WiDr/CD) or the HSV-TK gene (WiDr/TK). The IC50 (concentration of drug producing 50% inhibition of cell growth) for GCV was approximately 3.4 microM in WiDr/TK cells, while the IC50 for 5-FCyt was approximately 27 microM in WiDr/CD cells. In vivo antitumor studies were conducted using high but nontoxic levels of GCV (50 mg/kg/day) or 5-FCyt (500 mg/kg/day). When tumor xenografts were composed of 100% of cells expressing either HSV-TK or CD, 100% tumor-free animals were observed after GCV or 5-FCyt treatment, respectively. However, when only 10% of the tumor cells expressed HSV-TK, no antitumor effect by GCV treatment could be observed. In contrast, when tumors were composed of 4% of the cells expressing CD, 60% of the animals were tumor-free after 5-FCyt treatment. Transmission electron microscopy of the WiDr solid tumors revealed the presence of desmosomes but no gap junctions.

Animals↗

PubMed1995

Design and analysis of community trials: lessons from the Minnesota Heart Health Program.

Community trials remain the only design appropriate for the evaluation of lifestyle interventions that cannot be allocated to individuals. The Minnesota Heart Health Program, conducted in Minnesota and the Dakotas between 1980 and 1993, is one of the largest community trials ever conducted in the United States. That study suggests several lessons that should guide future community trials. Planners should 1) carefully assess the secular trends for their outcomes and be confident that they can demonstrate an intervention effect against those trends; 2) be confident that they have effective programs than can be delivered to a sufficiently large fraction of their target population; 3) avoid differences between study conditions in levels and trends for their outcomes through random allocation of a sufficient number of communities to each condition; 4) develop good estimates of community-level standard errors prior to launching future trials; and 5) take steps to ensure that power will be sufficient to test the hypotheses of interest.

Adult↗

PubMed1995

Commercial availability of alcohol to young people: results of alcohol purchase attempts.

OBJECTIVES: Commercial availability is an important contributor to alcohol use by young people. The purpose of this study was to test the purchasability of alcohol by youth who appeared to be under the legal age of sale in all types of businesses licensed to sell alcohol in upper Midwest communities. METHODS: Female buyers who were age 21 but whose apparent age as rated by a panel averaged 19 years attempted to purchase beer without age identification at all off-sale outlets (n = 395) and a random sample of on-sale outlets (n = 492) in 24 communities in Minnesota and Wisconsin. Two purchase attempts were made at each outlet, with the buyer randomly assigned to outlet and community. Characteristics of the outlets, clientele, signs, interaction with the sellers or servers, and purchase success were recorded. RESULTS: The buyers were successful in purchasing beer without age identification in 50% of attempts in on-sale outlets and 52% of off-sale attempts. Almost 75% of the outlets sold beer to the buyers at least once in two attempts. In off-sale businesses buyers were more successful if the salespersons were male and if the businesses were located in residential areas or malls. On-sale purchase attempts were more likely to be successful if the server appeared to be younger than 30 years, if the business was a restaurant as opposed to a bar alone, and if signs warning against sales to minors were located at the checkouts. CONCLUSIONS: The results of this study confirm and extend previous reports of the ability of youth to purchase alcohol and support the conclusion that commercial availability of alcohol to youth is widespread.

Adolescent↗

PubMed1995

Statistical design of the Child and Adolescent Trial for Cardiovascular Health (CATCH): implications of cluster randomization.

This paper describes some statistical considerations for the Child and Adolescent Trial for Cardiovascular Health (CATCH), a large-scale community health trial sponsored by the National Heart, Lung, and Blood Institute. The trial involves randomization of entire schools rather than individual students to the experimental arms. The paper discussed the implications of this form of randomization for the design and analysis of the trial. The power calculations and analysis plan for the trial are presented in detail. The handling of outmigrating and immigrating students is also discussed.

Adolescent↗

PubMed1995

Physician knowledge and attitudes about cancer pain management: a survey from the Minnesota cancer pain project.

The purposes of the study were to determine the knowledge and attitudes about cancer pain management (CPM) among practicing physicians in six Minnesota communities and to determine the physician-related barriers to optimal CPM. Eligible community physicians were surveyed by telephone. The study analyzed responses of 145 physicians (response rate, 87%). The majority of the physicians were primary care specialists (73%). Significant knowledge deficits were identified in nine of 14 CPM principles, but inappropriate attitudes were found in only two of nine CPM concepts. Medical specialty had the strongest influence on knowledge and attitudes, with primary care physicians having significantly better outcomes than surgeons or medical subspecialists. Effective education strategies must address knowledge deficits, attitudes, and motivations of the relevant peer group influencing physicians, as well as those of individual physicians. The Minnesota Cancer Pain Project is testing strategies to enhance CPM by physicians and improve patient outcomes.

Clinical Competence↗

PubMed1995

The Minnesota Cancer Pain Project: design, methods, and education strategies.

The Minnesota Cancer Pain Project (MCPP) is a community-based research project to test various innovative education strategies for improving cancer pain management (CPM) in Minnesota. The main hypothesis is that community-based, multidisciplinary and integrated education programs can improve CPM and change knowledge, attitudes, and behaviors regarding CPM in cancer patients, their families, and community physicians and nurses. The specific aim of the MCPP is to demonstrate effective methods to improve CPM in communities. The MCPP design is a randomized trial with before- and after-intervention assessments of cancer pain and CPM knowledge, attitudes, and behaviors among cancer patients and their families, physicians, and nurses. The unit of randomization and study is the community, with six Minnesota communities participating in the MCPP. This paper describes the hypotheses, design, methods, and education strategies of the MCPP. Baseline data from the participating communities and the cancer patient sample are reported.

Family↗

PubMed1995

Intraclass correlation among measures related to alcohol use by young adults: estimates, correlates and applications in intervention studies.

OBJECTIVE: Alcohol intervention studies that allocate intact social groups to study conditions require adjustment to the usual analytic methods to account for the positive intraclass correlation that exists in such groups. This article presents intraclass correlations for measures related to alcohol use among young adults and discusses the use of those estimates to plan new studies. METHOD: Young adults aged 18-20 were selected at random from driver's license lists in each of the 15 communities participating in the Communities Mobilizing for Change on Alcohol project. Respondents were surveyed by telephone to assess their drinking habits and other factors related to alcohol use. Community-level intraclass correlations were computed for those measures, both prior to and after adjustment for person- and community-level covariates. RESULTS: The community-level intraclass correlations tend to be small, with larger values for belief and attitude items than for self-reported behaviors. Even so, correlations of this magnitude can have important deleterious effects on the power to detect important treatment effects in an otherwise well-designed and well-executed study. Adjustment for person-level covariates often reduced those correlations, and adjustment for community-level covariates often reduced them substantially. CONCLUSIONS: There is measurable variation in measures related to alcohol use among young adults that is attributable to their community of residence. With adjustment for selected person- and community-level covariates, the magnitude of these correlations can be sharply reduced allowing the investigator to plan a more efficient community trial.

Adolescent↗

PubMed1995

Changes in adult cigarette smoking in the Minnesota Heart Health Program.

OBJECTIVES: The Minnesota Heart Health Program was a research and demonstration project designed to reduce risk factors for heart disease in whole communities. This paper describes smoking-specific interventions and outcomes. METHODS: Three pairs of matched communities were included in the study. After baseline surveys, one community in each pair received a 5-year education program, while both cross-sectional and cohort surveys continued in all sites. Adult education programs for smoking cessation included Quit and Win contests, classes, self-help materials, telephone support, and home correspondence programs. RESULTS: Encouraging short-term results were obtained for several adult education programs. Overall long-term outcomes were mixed, with evidence of an intervention effect only for women in cross-sectional survey data. Unexpectedly strong secular declines in smoking prevalence were observed in comparison communities. CONCLUSIONS: The findings suggest that community education may be unlikely to exceed dramatic secular reductions in smoking prevalence. The success of several key interventions and the incorporation of Minnesota Heart Health Program interventions by education communities are encouraging, however.

Adult↗

PubMed1994

Intraclass correlation among common measures of adolescent smoking: estimates, correlates, and applications in smoking prevention studies.

Most adolescent smoking prevention studies employ designs in which classrooms, schools, school districts, or sometimes whole communities are assigned to treatment conditions while observations are made on individual students. The critical design feature in such community trials is the nesting of intact social groups within treatment conditions. This combination requires that the treatment effect be assessed against the between-group variance; unfortunately, that variance is usually larger than for randomly constituted groups and its precision is usually less than that for the within-group variance. These factors often combine to reduce power so that it is almost impossible to detect important treatment effects in an otherwise well designed and properly executed study. To address these problems, investigators need good estimates of the intraclass correlation for the variables of interest, which together with the number of observations per unit determine the magnitude of the extra variation in the nested design. The purpose of this paper is to describe the methods and results from a study designed to generate estimates of intraclass correlation for common outcomes in adolescent smoking prevention studies and to discuss the use of these estimates in the planning of new studies.

Adolescent↗

PubMed1994

Assessing intervention effects in the Minnesota Heart Health Program.

The Minnesota Heart Health Program is a 13-year research and demonstration project to reduce morbidity and mortality from coronary heart disease in whole communities in the upper Midwest. Six communities were selected for the study: three intervention and three comparison sites, matched to increase baseline comparability. After 2-4 years of baseline observations, a 5- to 6-year program of intensive intervention was introduced in the three intervention communities. Periodic cross-sectional and cohort surveys provided data on risk factors and related behaviors. Regression adjustments within and between communities reduced the confounding influences of important covariates and the variance inflation associated with the nesting of individuals within communities and surveys. Post hoc stratification allowed exploration of the main and strata-specific effects of the intervention program. Finally, the intervention effect was modeled as a departure from the trend line fit to the nonintervention city-year means. Together, these procedures explicitly acknowledged the component of variance associated with communities, and so avoided a major source of bias created in the usual analysis when that variation is ignored. They also increased the interpretability of the analyses and reduced the mean square errors used to assess the treatment effects.

Cohort Studies↗

PubMed1994

An organizational strategy to improve adolescent measles-mumps-rubella vaccination in a low socioeconomic population. A method to reduce missed opportunities.

OBJECTIVE: To determine whether a clinical organization strategy can improve measles-mumps-rubella vaccination rates in adolescents by reducing missed opportunities. DESIGN: Nonequivalent control group design with a treatment clinic and a comparison clinic. Measurements were made for 8 months before intervention and for 9 months after intervention. SETTING: Two urban family practice clinics serving a low socioeconomic population. POPULATION: All clinic visits by adolescents aged 11 to 18 years. INTERVENTION: A clinic organizational strategy that systematically identified and vaccinated adolescents seen in the clinic for any reason. MAIN OUTCOME MEASURES: Two vaccination indexes were measured monthly at each clinic: the percentage of eligible visits at which measles-mumps-rubella vaccination was given and the percentage of visits that were up to date, with adolescents having received the measles-mumps-rubella vaccine at that visit or at a previous visit. RESULTS: The intervention resulted in a significant increase at the treatment clinic in the mean percentage of vaccinations given (from 7.8% to 17.4%) (Student's t = 3.02; P = .0087) and the mean percentage of up-to-date visits (from 17.2% to 38.6%) (t = 8.33; P < .0001). During the same period, there was no significant change in the mean vaccination rates in the comparison clinic. CONCLUSIONS: An organizational strategy appears to be a useful method to reduce missed opportunities and improve measles-mumps-rubella vaccination rates in adolescents from a low socioeconomic population.

Adolescent↗

PubMed1994

Effects of a statewide antismoking campaign on mass media messages and smoking beliefs.

BACKGROUND. In 1985, The Minnesota Legislature initiated a long-term and broad-based program to deter adolescent tobacco use. The initiative was funded by higher taxes on tobacco products and combined school-based programming, mass-media campaigns, and local community grants. The Minnesota-Wisconsin Adolescent Tobacco-Use Research Project was designed to evaluate this effort by monitoring adolescent tobacco use and related factors in Minnesota and Wisconsin from 1986 to 1990. The results presented in this paper indicate that the Minnesota initiative dramatically increased Minnesota schoolchildren's reported exposure to the anti-smoking messages in the mass media but had little effect on smoking-related beliefs or smoking behaviors. CONCLUSIONS. These results, together with the findings from other recent studies, suggest that even dramatic increases in exposure to anti-tobacco messages in the mass-media, in the absence of a substantial and sustained school-based tobacco prevention measures, may be insufficient to generate reductions in adolescent tobacco use.

Adolescent↗

PubMed1994

Parameters to aid in the design and analysis of community trials: intraclass correlations from the Minnesota Heart Health Program.

Community trials involve the assignment of intact social groups to study conditions and are becoming increasingly common in epidemiologic research. In both the design and analysis of these studies, whether cross-sectional or cohort, allowance must be made for the dependence of elements within intact groups if variances are to be properly estimated. In the design phase, the statistician needs estimates of the level of dependence likely to be encountered. In the analysis phase, external estimates of the level of dependence may be useful in preventing the erosion of power associated with small numbers of intact groups assigned to each condition. We report the intraclass correlation coefficients of the city-year component of variance as estimated in the Minnesota Heart Health Program for a variety of community survey variables and illustrate their use in both design and analysis. Of 23 variables assessed, all but two showed positive estimates of city-year intraclass correlations. In these data, estimates of intraclass correlation coefficients generally were in the range 0.002-0.012.

Analysis of Variance↗

PubMed1994

Community education for cardiovascular disease prevention: risk factor changes in the Minnesota Heart Health Program.

OBJECTIVES: The Minnesota Heart Health Program is a 13-year research and demonstration project to reduce morbidity and mortality from coronary heart disease in whole communities. METHODS: Three pairs of communities were matched on size and type; each pair had one education site and one comparison site. After baseline surveys, a 5- to 6-year program of mass media, community organization, and direct education for risk reduction was begun in the education communities, whereas surveys continued in all sites. RESULTS: Many intervention components proved effective in targeted groups. However, against a background of strong secular trends of increasing health promotion and declining risk factors, the overall program effects were modest in size and duration and generally within chance levels. CONCLUSIONS: These findings suggest that even such an intense program may not be able to generate enough additional exposure to risk reduction messages and activities in a large enough fraction of the population to accelerate the remarkably favorable secular trends in health promotion activities and in most coronary heart disease risk factors present in the study communities.

Adult↗

PubMed1994

The effect of live weight gain and live weight loss on body composition of Merino wethers: chemical composition of the noncarcass organs and the empty body.

Chemical composition of the noncarcass organs, combined noncarcass organs, and fleece-free empty body (FFEB) was measured during live weight gain (LWG) and live weight loss (LWL) to determine the effect of different periods of normal and retarded growth on chemical composition of noncarcass organs and FFEB. Thirty-five Merino wethers had ad libitum access to the experimental diet (17.23% CP and 12.09 MJ/kg of DE) to grow from 23.0 to 33.0 kg live weight and then were fed to lose a total of 10 kg in three periods of 25 d each at the rate of 133 g/d. Groups of five wethers were slaughtered at live weights of 23.0, 26.3, 29.6, and 33.0 kg during LWG and 29.6 (first period), 26.3 (second period), and 23.0 kg (third period) during LWL. The lower combined noncarcass weight in LWL wethers than in LWG wethers at 23.0 and 26.3 kg of live weights was due to the significantly lower protein weight at 23.0 and 26.3 kg (P < .01) and water weight at all common slaughter weights (P < .01). Chemical fat in the combined noncarcass organs was significantly greater in LWL wethers than in LWG wethers at 23.0, 26.3 (P < .01), and 29.6 kg (P < .05). The general increase of chemical fat in the combined noncarcass organs of the LWL wethers was mainly due to the significant increase in the chemical fat in the head and feet at 23.0 (P < .01), 26.3, and 29.6 kg (P < .05), liver at 23.0 kg (P < .01), and total alimentary tract fat at 23.0 (P < .01) and 29.6 kg (P < .05). Although fleece-free empty body weight (FFEBW) was similar in LWG and LWL wethers at all common slaughter weights, FFEB water weight was lower significantly in LWL wethers at 23.0, 26.3 (P < .01), and 29.6 kg (P < .05) and that of chemical fat was greater significantly in LWL wethers at 23.0 (P < .01), 26.3, and 29.6 kg (P < .05) than in LWG wethers. Wethers after weight loss had more chemical fat and less water in their FFEB than normal growing wethers at the same FFEBW.

Animals↗

PubMed1994

Cerebral aneurysms and arteriovenous malformations: implications for rehabilitation.

Arteriovenous malformations (AVM) and intracranial aneurysms often have devastating impact when they present as subarachnoid hemorrhage (SAH). With an overall incidence of 10 to 16 per 100,000, subarachnoid hemorrhage is relatively rare; however, these patients often comprise a significant component of a rehabilitation specialist's practice. There exists a host of risk factors and premorbid characteristics that correlate with long-term outcome after aneurysmal and AVM-related subarachnoid hemorrhage. Physical, cognitive, behavioral, and social deficits are relatively common after SAH, and can have a significant impact on effective home, community, and work reentry. Seizure risk after SAH or craniotomy and the use of prophylactic anticonvulsant medications is often a confusing and troublesome issue for the rehabilitation specialist. This situation often is handled by weighing the potential risk of serious medication side effects against the potential seizure risk. Cognitive, behavioral, and social sequelae are most frequent in patients with anterior cerebral and communicating artery lesions; however, delayed ischemic dysfunction often accounts for these deficits in patients with lesions in other distributions. An understanding of the classification, incidence, presentation, complications and treatment of arteriovenous malformations and intracranial aneurysms is especially important for the rehabilitation specialist. Knowledge about these areas assists the rehabilitation specialist in developing an individual rehabilitation plan that sets realistic goals for predicted outcomes. In addition, such knowledge enhances appropriate monitoring of patient progress, so that early interventions can be established when there is an alteration in clinical status.

Adolescent↗