Search PubMed⌕ Search

Biomedical subjects

T N Robinson

Publications and source records attributed to T N Robinson.

At least 37 records · Page 2Linked to original sources
PubMed2000

Selective mitochondrial adenosine triphosphate-sensitive potassium channel activation is sufficient to precondition human myocardium.

OBJECTIVES: Recently, the mitochondrial adenosine triphosphate-sensitive potassium channel has been suggested to be the final common effector of myocardial preconditioning. The purpose of this study is to determine whether selective mitochondrial adenosine triphosphate-sensitive potassium channel activation alone can precondition human myocardium from an ischemia/reperfusion insult. METHODS: Isolated human right atrial trabeculae were placed in tissue baths, paced, and subjected to 30 minutes of normothermic hypoxia (ischemia) followed by 45 minutes of reoxygenation (reperfusion). Trabeculae were preconditioned with a selective mitochondrial adenosine triphosphate-sensitive potassium channel opener (diazoxide 30 micromol/L) or a nonselective purinergic agonist, adenosine (125 micromol/L), for 5 minutes (adenosine) followed by a 10-minute washout period. Developed force at end reperfusion (mean +/- standard error) was compared with baseline, and tissue creatine kinase and adenosine triphosphate levels were measured after ischemia/reperfusion. RESULTS: Trabeculae subjected to ischemia/reperfusion exhibited 30% +/- 2% of baseline developed force, whereas trabeculae subjected to selective adenosine triphosphate-sensitive potassium channel opening (diazoxide) and nonselective purinergic agonist (adenosine) recovered to 55% +/- 7% and 46% +/- 3% of baseline developed force, respectively. Tissue creatine kinase activity was preserved in both the diazoxide- and adenosine-treated trabeculae (5.4 +/- 12 and 5.4 +/- 14 micromol/L per gram wet tissue) compared with ischemia/reperfusion (1.8 +/- 0.2 U/mg wet tissue). Adenosine triphosphate levels at end reperfusion were also increased in the trabeculae treated with selective (diazoxide) and nonselective (adenosine) adenosine triphosphate-sensitive potassium channel opener (4.1 +/- 0.01 and 4. 4 +/- 0.2 micromol/L per gram wet tissue) compared with trabeculae subjected to ischemia/reperfusion (1.5 +/- 0.1 micromol/L per gram wet tissue). CONCLUSIONS: These results suggest that selective mitochondrial adenosine triphosphate-sensitive potassium channel activation preconditions human myocardium and the protection conferred is equal to that of adenosine preconditioning. Targeted openers of mitochondrial adenosine triphosphate- sensitive potassium channels promote constructive protection of myocellular energy levels, contractile function, and cellular viability in human myocardium after ischemia/reperfusion.

Adenosine↗
PubMed1999

Reducing children's television viewing to prevent obesity: a randomized controlled trial.

CONTEXT: Some observational studies have found an association between television viewing and child and adolescent adiposity. OBJECTIVE: To assess the effects of reducing television, videotape, and video game use on changes in adiposity, physical activity, and dietary intake. DESIGN: Randomized controlled school-based trial conducted from September 1996 to April 1997. SETTING: Two sociodemographically and scholastically matched public elementary schools in San Jose, Calif. PARTICIPANTS: Of 198 third- and fourth-grade students, who were given parental consent to participate, 192 students (mean age, 8.9 years) completed the study. INTERVENTION: Children in 1 elementary school received an 18-lesson, 6-month classroom curriculum to reduce television, videotape, and video game use. MAIN OUTCOME MEASURES: Changes in measures of height, weight, triceps skinfold thickness, waist and hip circumferences, and cardiorespiratory fitness; self-reported media use, physical activity, and dietary behaviors; and parental report of child and family behaviors. The primary outcome measure was body mass index, calculated as weight in kilograms divided by the square of height in meters. RESULTS: Compared with controls, children in the intervention group had statistically significant relative decreases in body mass index (intervention vs control change: 18.38 to 18.67 kg/m2 vs 18.10 to 18.81 kg/m2, respectively; adjusted difference -0.45 kg/m2 [95% confidence interval [CI], -0.73 to -0.17]; P = .002), triceps skinfold thickness (intervention vs control change: 14.55 to 15.47 mm vs 13.97 to 16.46 mm, respectively; adjusted difference, -1.47 mm [95% CI, -2.41 to -0.54]; P=.002), waist circumference (intervention vs control change: 60.48 to 63.57 cm vs 59.51 to 64.73 cm, respectively; adjusted difference, -2.30 cm [95% CI, -3.27 to -1.33]; P<.001), and waist-to-hip ratio (intervention vs control change: 0.83 to 0.83 vs 0.82 to 0.84, respectively; adjusted difference, -0.02 [95% CI, -0.03 to -0.01]; P<.001). Relative to controls, intervention group changes were accompanied by statistically significant decreases in children's reported television viewing and meals eaten in front of the television. There were no statistically significant differences between groups for changes in high-fat food intake, moderate-to-vigorous physical activity, and cardiorespiratory fitness. CONCLUSIONS: Reducing television, videotape, and video game use may be a promising, population-based approach to prevent childhood obesity.

Body Mass Index↗
PubMed1999

Ethnic variation in cardiovascular disease risk factors among children and young adults: findings from the Third National Health and Nutrition Examination Survey, 1988-1994.

CONTEXT: Knowledge about ethnic differences in cardiovascular disease (CVD) risk factors among children and young adults from national samples is limited. OBJECTIVE: To evaluate ethnic differences in CVD risk factors, the age at which differences were first apparent, and whether differences remained after accounting for socioeconomic status (SES). DESIGN: Third National Health and Nutrition Examination Survey, 1988-1994. SETTING: Eighty-nine mobile examination centers. PARTICIPANTS: A total of 2769 black, 2854 Mexican American, and 2063 white (non-Hispanic) children and young adults aged 6 to 24 years. MAIN OUTCOME MEASURES: Ethnicity and household level of education (SES) in relation to body mass index (BMI), percentage of energy from dietary fat, cigarette smoking, systolic blood pressure, glycosylated hemoglobin (HbA1c), and non-high-density lipoprotein cholesterol (non-HDL-C [the difference between total cholesterol and HDL-C]). RESULTS: The BMI levels were significantly higher for black and Mexican American girls than for white girls, with ethnic differences evident by the age of 6 to 9 years (a difference of approximately 0.5 BMI units) and widening thereafter (a difference of >2 BMI units among 18- to 24-year-olds). Percentages of energy from dietary fat paralleled these findings and were also significantly higher for black than for white boys. Blood pressure levels were higher for black girls than for white girls in every age group, and glycosylated hemoglobin levels were highest for black and Mexican American girls and boys in every age group. In contrast, smoking prevalence was highest for white girls and boys, especially for those from low-SES homes (77% of young men and 61% of young women, aged 18-24 years, from low-SES homes were current smokers). All ethnic differences remained significant after accounting for SES and age. CONCLUSION: These findings show strong ethnic differences in CVD risk factors among youths of comparable age and SES from a large national sample. The differences highlight the need for heart disease prevention programs to begin early in childhood and continue throughout young adulthood to reduce the risk of atherosclerosis.

Adolescent↗
PubMed1999

Behavioural treatment of childhood and adolescent obesity.

Current state-of-the-art behavioural treatments for childhood and adolescent obesity, produce long-term weight control in up to one-third of participants. A review of the most effective treatments suggests structural and organizational components and treatment content that are most likely to be successful. These include a group format with individualized behavioural counseling; parent participation; frequent sessions; a long treatment duration; a simple and explicit diet that produces a calorie deficit; a physical activity program emphasizing choice and reinforcing reduced sedentary behaviours; making changes in the home and family environment to help reduce cues and opportunities associated with calorie intake and inactivity, and to increase cues and opportunities for physical activity; self-monitoring; goal setting and contracting; parenting skills training; skills for managing high-risk situations; and skills for maintenance and relapse prevention. Still, there are many unanswered questions about the implementation of all the components of treatment. Further research, to identify treatment approaches that promote long-term maintenance of weight control, is greatly needed.

Adolescent↗
PubMed1999

Policy issues relevant to evaluation of interactive health communication applications. The Science Panel on Interactive Communication and Health.

This article provides an analysis of policy-related issues associated with the evaluation of interactive health communication (IHC) applications. These include an assessment of the current health and technology policy environment pertinent to public (government, education, public health) and private (medical care providers, purchasers, consumers, IHC developers) IHC stakeholders and discussion of issues likely to merit additional consideration by these stakeholders in the future.

Community Participation↗
PubMed1998

An evidence-based approach to interactive health communication: a challenge to medicine in the information age. Science Panel on Interactive Communication and Health.

OBJECTIVE: To examine the current status of interactive health communication (IHC) and propose evidence-based approaches to improve the quality of such applications. PARTICIPANTS: The Science Panel on Interactive Communication and Health, a 14-member, nonfederal panel with expertise in clinical medicine and nursing, public health, media and instructional design, health systems engineering, decision sciences, computer and communication technologies, and health communication, convened by the Office of Disease Prevention and Health Promotion, US Department of Health and Human Services. EVIDENCE: Published studies, online resources, expert panel opinions, and opinions from outside experts in fields related to IHC. CONSENSUS PROCESS: The panel met 9 times during more than 2 years. Government agencies and private-sector experts provided review and feedback on the panel's work. CONCLUSIONS: Interactive health communication applications have great potential to improve health, but they may also cause harm. To date, few applications have been adequately evaluated. Physicians and other health professionals should promote and participate in an evidence-based approach to the development and diffusion of IHC applications and endorse efforts to rigorously evaluate the safety, quality, and utility of these resources. A standardized reporting template is proposed to help developers and evaluators of IHC applications conduct evaluations and disclose their results and to help clinicians, purchasers, and consumers judge the quality of IHC applications.

Evidence-Based Medicine↗
PubMed1998

Nicotine dependence among adolescent smokers.

OBJECTIVE: To assess nicotine dependence among adolescents to determine whether quitting smoking is associated with the emergence of nicotine withdrawal symptoms and craving, and to identify the factors associated with these symptoms. DESIGN: Cross-sectional survey. PARTICIPANTS: We studied 2197 10th-grade students in 6 San Jose, Calif, high schools. MAIN OUTCOME MEASURES: Smoking status; history of quitting smoking; Modified Fagerstrom Tolerance Questionnaire (mFTQ) scores; subjective nicotine withdrawal symptoms from the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition; Center for Epidemiologic Studies Depression Scale (CES-D); and saliva cotinine levels. RESULTS: Of the 485 participants who reported having smoked during the past 30 days, 249 reported previous attempts to quit smoking. Among the participants who had attempted to quit, the self-reported frequencies of subjective withdrawal symptoms were a strong need to smoke (45.4%), nervous and tense (31.8%), restless (29.4%), irritable (28.7%), hungry (25.3%), unable to concentrate (21.7%), miserable and sad (15.3%), and trouble sleeping (12.8%). The total number of withdrawal symptoms was correlated with the mFTQ score (Spearman r = 0.51; P < .001). In a stepwise linear regression analysis, the mFTQ score and the CES-D score accounted for approximately 35% of the variance in total number of withdrawal symptoms (R2 = 0.35; P < .001). Males smoked significantly more and had significantly higher mFTQ scores than did females, while female smokers had significantly higher CES-D scores than did their male counterparts. CONCLUSIONS: Considerable levels of nicotine dependence were present among adolescent smokers. Use of mFTQ scores; withdrawal symptoms including nicotine craving; CES-D scores; and saliva cotinine levels may be helpful in designing cessation programs targeted to nicotine-dependent adolescents.

Adolescent↗
PubMed1998

Psychosocial factors associated with youth involvement in community activities promoting heart health.

This study examined factors that influence youth participation in heart disease prevention activities among 2,609 ninth graders in six inner-city public high schools. Constructs derived from social cognitive, empowerment, and community development theories informed the conceptual framework employed. Study participants were diverse with respect to gender, ethnicity, parent education, acculturation, and academic achievement. Perceived incentive value, self-efficacy, outcome expectancies, sense of community, and perceived policy control were all significantly associated with participation in community activities promoting heart health. In multivariate analyses, perceived incentive value, defined as the extent to which participants valued a heart-healthy environment, was most strongly associated with community participation, accounting for 11.9% of the total variance. These findings have implications for designing school curricula and after-school and community programs targeting adolescents' involvement in health advocacy activities.

Adolescent↗
PubMed1998

Television and music video exposure and risk of adolescent alcohol use.

OBJECTIVE: Alcohol use is frequently portrayed in television programming and advertising. Exposure to media portrayals of alcohol use may lead to increased drinking. To address this issue, we examined prospectively the associations between media exposure and alcohol use in adolescents. DESIGN: Prospective cohort study. Setting. Six public high schools in San Jose, California. Participants. Ninth-grade students (N = 1533; mean age = 14.6 years). OUTCOME MEASURES: Students reported hours of television, music video, and videotape viewing; computer and video game use; and lifetime and past 30 days' alcohol use at baseline and 18 months later. Associations between baseline media exposure and subsequent alcohol use were examined with multiple logistic regression. RESULTS: During the 18-month follow-up, 36.2% of baseline nondrinkers began drinking and 50.7% of baseline drinkers continued to drink. Onset of drinking was significantly associated with baseline hours of television viewing (odds ratio [OR] = 1.09; 95% confidence interval [95% CI] = 1.01-1.18), music video viewing (OR = 1.31; 95% CI = 1. 17-1.47), and videotape viewing (OR = 0.89; 95% CI = 0.79-0.99), controlling for age, sex, ethnicity, and other media use. Computer and video game use was not significantly associated with the subsequent onset of drinking. Among baseline drinkers, there were no significant associations between baseline media use and maintenance of drinking. CONCLUSIONS: Increased television and music video viewing are risk factors for the onset of alcohol use in adolescents. Attempts to prevent adolescent alcohol use should address the adverse influences of alcohol use in the media.

Adolescent↗
PubMed1997

Do cigarette warning labels reduce smoking? Paradoxical effects among adolescents.

OBJECTIVE: To examine the association between adolescents knowledge of cigarette warning labels and actual smoking behavior. DESIGN: Cohort analytic study. SETTING: Four public high schools in northern California. SUBJECTS: Seventeen hundred forty-seven ninth graders (mean age, 14.9 years). Students from 2 of the schools (n = 803) were observed for approximately 3 months. MAIN OUTCOME MEASURES: Self-reported knowledge of warning labels was assessed at baseline. Self-reports of smoking behavior were completed at baseline and at follow-up. RESULTS: Greater knowledge of cigarette package warning labels was significantly associated with higher levels of smoking. Knowledge of warning labels on magazine and billboard advertisements did not differ significantly by level of smoking. In the longitudinal sample, greater knowledge of cigarette package warning labels was significantly associated with a subsequent increase in smoking, controlling for the baseline level of smoking, sex, ethnicity, and knowledge of warning labels on cigarette advertisements (odds ratio [OR], 1.22; 95% confidence interval [CI], 1.02-1.46). Knowledge of warning labels on cigarette advertisements was not associated with a significant change in smoking behavior (OR, 1.06; 95% CI, 0.82-1.35). CONCLUSIONS: Sizable proportions of adolescent smokers are not seeing, reading, or remembering cigarette warning labels. In addition, knowledge of warning labels on cigarette packages and advertisements is not associated with reduced smoking. The current warning labels are ineffective among adolescents.

Adolescent↗
PubMed1997

Prospective study of risk factors for the initiation of cigarette smoking.

Risk factors for the initiation of cigarette smoking were examined in 2 consecutive cohorts of teenagers (N = 1,901). Students in Cohort 1 were followed over 4 years from 9th to 12th grade; those in Cohort 2 were followed over 3 years from 9th to 11th grade. Among girls with no history of smoking at baseline, those with more friends who smoked at baseline (p < .001) and those with higher sociability scores (p < .05) were significantly more likely to have tried smoking over the study interval. Among boys with no history of smoking at baseline, those with more friends who smoked at baseline (p < .05) and those with higher depression symptoms scores (p < .01) were significantly more likely to have tried smoking over the study interval. The data suggest that future research is needed to examine potential gender differences that may have implications for the next generation of smoking-prevention programs.

Adolescent↗
PubMed1996

Effects of structured encounter forms on pediatric house staff knowledge, parent satisfaction, and quality of care. A randomized, controlled trial.

OBJECTIVE: To evaluate the effects of health supervision structured encounter forms on pediatric house staff knowledge, parent satisfaction, and quality of care. DESIGN: Randomized, controlled trial. SETTING: Pediatric house staff continuity clinic in a university-based children's hospital. PARTICIPANTS: 53 pediatric house officers and 153 parents. INTERVENTIONS: House staff were randomized to use structured encounter forms focused on developmental milestones (group 1) or anticipatory guidance/preventive care (group 2) during health supervision visits. OUTCOME MEASURES: Changes in house staff knowledge were assessed with pretests and posttests. Parent satisfaction was assessed with surveys. Quality of care, defined as compliance with recommended guidelines for age-specific health supervision, was assessed by audiotaping visits. RESULTS: Group 1 demonstrated greater but not significantly different improvement in knowledge of developmental milestones than group 2, while group 2 improved more than group 1 in knowledge of anticipatory guidance/ preventive care. Parent satisfaction with developmental screening was significantly greater for group 1 visits than for group 2 visits (P < .001). Group 1 demonstrated significantly greater compliance than group 2 with recommended standards of developmental screening (P = .001). CONCLUSIONS: The use of structured encounter forms for health supervision in pediatric house staff continuity clinics may increase house staff knowledge of developmental milestones and anticipatory guidance/preventive care, increases parent satisfaction with developmental assessment during health supervision, and improves compliance with recommended guidelines for developmental assessment.

Adolescent↗
PubMed1996

Effects of the serotonin receptor agonists 8-OH-DPAT and TFMPP on learning as assessed using a novel water maze.

We evaluated the effects of two drugs active at serotonin receptors, 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT, a 5-HT1A agonist) and N-3-trifluoromethylphenyl)piperazine hydrochloride (TFMPP, a 5-HT2C agonist) on learning using a novel water maze previously characterized in our laboratory. The water maze utilized is a traditional type of maze with alleyways and doors through which the rats learn to swim to reach a platform, unlike the open pool Morris water maze task. Performance is assessed by swim time required to reach the platform and errors committed. Following initial training on maze configuration A, rats were assigned to saline, TFMPP and 8-OH-DPAT treatment groups and tested for performance once per dose, 30 min after administration of drug (0.25, 0.5, and 1.0 mg/kg IP). Swim times were significantly increased as compared to saline for all doses for both drugs. The error rate was increased for 8-OH-DPAT at all doses, while TFMPP had no effect on error rate at any dose. Next, rats were challenged to learn new mazes following daily administration of 0.25 or 0.5 mg/kg of each drug 30 min prior to each daily swim trial. Rats given 0.25 mg/kg of 8-OH-DPAT learned new maze C more slowly than saline-treated rats, while TFMPP had no effect at this dose. At the higher dose of 0.5 mg/kg, tested on new maze B, TFMPP administration significantly increased swim times but not errors, while this dose of 8-OH-DPAT markedly increased both swim time and errors. Finally, rats from all groups were tested on maze E after drug administration was discontinued, and there were no performance differences among groups. These data suggest that serotonin1A receptors may inhibit learning.

8-Hydroxy-2-(di-n-propylamino)tetralin↗