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Biomedical subjects

W B Strong

Publications and source records attributed to W B Strong.

At least 37 records · Page 2Linked to original sources
PubMed1995

Temporal stability of children's cardiovascular (CV) reactivity: role of ethnicity, gender and family history of myocardial infarction.

Cardiovascular responses to three laboratory stressors (i.e., postural change, treadmill exercise, forehead cold) were evaluated in 106 children (72 Whites, 34 Blacks) who varied in family history (FH) of early myocardial infarction (53 positive FH, 53 negative FH). Subjects were evaluated on two occasions separated by one year. In general, regardless of ethnicity, gender or FH, stability of resting blood pressures (BP) and heart rates were comparable to existing data. Resting cardiac output (CO) and total peripheral resistance (TPR) stability estimates were comparable or higher than the BP estimates across groups except for the +FH subjects and males who showed poor stability to one or both parameters. Moderate stability was observed for all parameters in response to forehead cold and low to moderate stability was observed in HR, CO, and TPR postural change reactivity. The only consistent pattern of significant differences in stability estimates involved ethnicity. African-Americans exhibited significantly higher coefficients compared to Whites in TPR at rest and during postural change and forehead cold. Reasons for the low to moderate resting and reactivity stability estimates are discussed.

Black People↗
PubMed1995

Evaluation and recommendations for participation in athletics for children with heart disease.

Physical fitness is becoming increasingly emphasized in our society. Everyone is encouraged to participate in routine exercise, and many desire to compete in organized athletics. Patients with heart disease are living longer, healthier lives and may also desire sports participation. Because selected patients may be at risk for sudden death, a thorough evaluation should be performed. The purpose of this article is to familiarize the reader with basic principles of exercise physiology and preparticipation evaluation and to provide a guideline to recommending athletic involvement in patients with heart disease.

Arrhythmias, Cardiac↗
PubMed1994

Two structural domains of initiation factor eIF-4B are involved in binding to RNA.

Translation initiation factor eIF-4B promotes the binding of mRNA to 40 S preinitiation complexes and together with eIF-4A possesses RNA helicase activity. To elucidate structural features involved in its function, a series of internal and C-terminal deletions, as well as point mutations, were constructed in the eIF-4B cDNA. The mutated cDNAs were expressed in transiently transfected COS-1 cells, and mutant forms of the factor were overproduced up to about 25-fold over endogenous eIF-4B levels. Inhibition of dihydrofolate reductase (DHFR) synthesis by high levels of eIF-4B variants was determined in vivo, and the binding of the eIF-4B forms to biotinylated RNA was measured in vitro. The results indicate that the N-terminal region containing the RNA binding motif with its RNP1 and RNP2 consensus elements is sufficient for inhibition of DHFR synthesis. Deletion of the RNP1 sequence abrogates RNA binding, but amino acid substitutions at conserved residues do not always inhibit RNA binding. Deletion of the DRYG domain near the middle of eIF-4B results in inhibition of RNA binding, but not of DHFR synthesis. Up to 164 residues of the C terminus are not required for RNA binding, but removal of 226 or more residues completely inhibits RNA binding, perhaps by the loss of two arginine-rich regions. The results suggest that both the RNA recognition motif and the arginine-rich region are required for stable RNA binding but that both are not necessary for in vivo inhibition of protein synthesis.

Amino Acid Sequence↗
PubMed1994

Systolic blood pressure response to exercise in black and white preadolescent and early adolescent boys.

OBJECTIVE: To investigate differences in the response of systolic blood pressure (SBP) to exercise in black and white boys while controlling for the possible confounding effects of relative body weight, body surface area, physical work capacity index, preexercise SBP, and average power output. DESIGN: Comparative and correlational. PARTICIPANTS: Eighty-seven black and 52 white boys between the ages of 5 and 16 years. Participants were recruited from day camps, community centers, and summer recreation programs in and near Augusta, Ga. INTERVENTIONS: None. MEASUREMENTS/MAIN OUTCOMES: The slope of the SBP response to exercise was not significantly different between groups. Analysis of covariance revealed race, age, relative body weight, body surface area, preexercise SBP, and average power output to be significant univariate predictors of SBP at each power output. With multiple regression analyses, the effect of race was removed, and only preexercise SBP and average power output were found to be significant predictors of exercise SBP. CONCLUSION: There were no significant differences between black and white boys in the SBP response to exercise after controlling for the effects of preexercise SBP and average power output.

Adolescent↗
PubMed1994

Consistency of children's hemodynamic responses to laboratory stressors.

Hemodynamic responses to three standard laboratory stressors (i.e., postural change, video game, forehead cold) were evaluated in 341 children (170 males) who had a mean age of 11.2 +/- 2.6 years. Inter-task consistency was evaluated for five physiological parameters for all stressor pairings. Evidence of consistency in systolic and diastolic blood pressure, heart rate, cardiac output, and total peripheral resistance responses to all three stressors was observed. The highest and most consistent correlations across stressors were observed for cardiac output and total peripheral resistance responses. The need for clarification in the categorization of laboratory stressors used to measure reactivity is discussed.

Blood Pressure↗
PubMed1994

Pressor reactivity, ethnicity, and 24-hour ambulatory monitoring in children from hypertensive families.

We assessed blood pressure responses of a multiethnic (Black and White) sample of 120 children of hypertensive families to orthostasis, video game, forehead cold, and dynamic exercise, and monitored the children's ambulatory pressure 24 hours later. Thirteen children were studied twice (1-year stability). The Black children exhibited higher 24-hour ambulatory systolic and diastolic pressures than the White children. Regardless of ethnicity, peak and mean systolic pressures during each task were generally positively correlated with mean systolic pressure while the children were awake and asleep. Associations between diastolic pressor responses and ambulatory measurements were somewhat dependent upon ethnicity and task. Relatively few reactivity-ambulatory correlations were significant, using pressor reactivity change scores. The children who participated twice exhibited significant 1-year stability for most ambulatory and pressor measurements. Children's pressor responses to laboratory tasks may generalize to the natural environment.

Adolescent↗
PubMed1994

Ethnic differences in the myocardial and vascular reactivity to stress in normotensive girls.

Cardiovascular reactivity to stress has been proposed as a mechanism partially responsible for the increased prevalence of essential hypertension in African-Americans compared with whites. However, few studies have examined ethnic differences in cardiovascular reactivity among women. The present study evaluated potential ethnic differences in the cardiovascular reactivity to three laboratory stressors (postural change, video game challenge, forehead cold stimulation). The sample consisted of 171 normotensive girls (74 whites, 97 African-Americans) with a mean age of 11.1 +/- 2.7 years, all with positive family histories of essential hypertension. African-American girls showed higher resting diastolic blood pressures and higher resting total peripheral resistance compared with white girls. African-American girls also exhibited higher peak responses in systolic and diastolic blood pressure and total peripheral resistance and lower cardiac index responses during video game challenge and forehead cold stressor. The findings extend previous observations of ethnic differences in blood pressure reactivity to stress and indicate that concomitant increases in total peripheral resistance appear to account for the greater blood pressure reactivity in African-American girls.

Adolescent↗
PubMed1994

1-year stability and prediction of cardiovascular functioning at rest and during laboratory stressors in youth with family histories of essential hypertension.

Blood pressure (BP). heart rate, cardiac index, and total peripheral resistance index were measured at rest and in response to postural change, forehead cold stimulation, and a video game challenge in a sample of 128 White and 155 African-American normotensive youth with family histories of essential hypertension (EH). These measurements were readministered 1 year later (12.5 +/- 3.2 months). Moderate temporal stability was observed for all resting and absolute stress responses. Reliability estimates for reactivity change scores were lower, although some were within acceptable ranges. African-American youth exhibited greater BP and peripheral resistance index reactivity to forehead cold on both evaluations. After controlling for various anthropometric and demographic parameters and the pertinent previous year's resting cardiovascular (CV) parameter, mean video game systolic blood pressure (SBP) responses were predictive of resting SBP whereas absolute forehead cold and video game diastolic responses predicted resting diastolic blood pressure (DBP) 1 year later. Mean video game DBP responses were also predictive of resting peripheral resistance index after controlling for significant demographic and anthropometric measures. CV reactivity is discussed with regard to possible value in prediction of changes in resting BP and cardiac structure prior lo establishment of EH.

Journal Article↗
PubMed1994

Cardiac arrhythmias.

Explore the source record for details and available documents.

Arrhythmias, Cardiac↗
PubMed1994

The effect of adiposity on children's left ventricular mass and geometry and haemodynamic responses to stress.

This study evaluated the relationship between adiposity, left ventricular mass and geometry, and haemodynamic parameters at rest and during laboratory stressors in a sample of 69 normotensive children with positive family histories of essential hypertension. Children were classified as overweight if they were above the 85th percentile of weight-for-height for their age and gender compared to national normative data. Nineteen children (7 whites, 12 blacks) were classified as overweight and the remaining 50 (26 whites, 24 blacks) were not overweight. Overweight children were found to have higher resting systolic and diastolic blood pressures, heart rates (HR), cardiac output (CO) and stroke volumes (SV), and lower resting total peripheral resistance than the non-overweight children. No differences were noted in haemodynamic reactivity to the stressors. Echocardiographic findings indicated that the overweight children had greater left ventricular mass indexed by height2.7, interventricular septal thickness and left ventricular end diastolic diameter (LVEDD) compared to non-overweight children. These findings are the first to indicate that the higher resting pressures of overweight normotensive children are a reflection of increased normotensive children are a reflection of increased preload (i.e. greater HR, SV, CO, LVEDD). These findings point out the early deleterious effects of obesity on the cardiovascular system in the young and highlight the need for effective obesity prevention and intervention programmes.

Adipose Tissue↗
PubMed1993

Ethnicity, gender, family history of myocardial infarction, and hemodynamic responses to laboratory stressors in children.

Relationship among ethnicity, gender, grandparents' histories of early myocardial infarction, and hemodynamic responses to forehead cold and treadmill exercise were examined in 87 6-to-8-year-olds (57 White, 30 Black). Boys had greater increases in systemic vascular resistance and decreases in cardiac index to forehead cold. Girls had greater increases and quicker recovery in heart rate to dynamic exercise. Blacks had greater increases and slower recovery in diastolic pressure to exercise and forehead cold. Blacks showed greater increases and slower recovery in systemic vascular resistance to forehead cold. Positive-family-history children had greater increases in diastolic pressure and systemic vascular resistance to forehead cold and greater diastolic pressure increases to exercise. Positive-family-history Blacks had greater increases in systolic pressure to exercise and slower recovery than all other groups.

Black or African American↗
PubMed1993

Defining the year 2000 fruit and vegetable goal.

Various nutrition guidelines recommend increased consumption of fruits and vegetables (F+V); a Year 2000 goal targets five or more daily servings of F+V. Decisions are needed regarding how to define F+V to facilitate measurement of goal achievement. Four alternative definitions (narrow and broad, each with and without legumes) were developed and applied to food frequencies from 133 children and 211 parents. Results varied by definition. Mean intake met the goal of five or more daily servings regardless of definition and exceeded it for both broad definitions by children and both broad definitions and the narrow definition with legumes for adults. Median intakes met the goal for all definitions except for children with the narrow definition without legumes, and exceeded it for children with both broad definitions and for adults with the broad definition with legumes. These differences by definition indicate that a clear definition of F+V is needed.

Adult↗
PubMed1993

Relationship between family environment and children's hemodynamic responses to stress: a longitudinal evaluation.

Because interpersonal relationships may have an impact on the risk of developing cardiovascular disease, the authors examined the prospective relationship of family functioning upon hemodynamic stress responses in 87 6- to 8-year-old children. The parents completed the cohesion, conflict, expressiveness, and control subscales of the Family Environment Scale; 2 years later, the authors assessed the children's hemodynamic responses to postural change, forehead cold stimulation, and treadmill exercise. Maternal reports of greater cohesion and expressiveness were related to less increases in systolic pressure and systemic vascular resistance in response to the forehead cold. Mothers' reports of expressiveness were related to lower systolic pressure and cardiac index reactivity to postural change. Fathers' reports of greater control were associated with greater diastolic pressure and vascular resistance increases to forehead cold and to greater vascular resistance responses to exercise. Paternal reports of greater conflict were associated with greater systemic vascular resistance increases and with lower cardiac index increases to exercise. Results suggest family functioning may predict later hemodynamic reactivity to stress. The findings are discussed in terms of previous research on parent-child interaction patterns and children's cardiovascular health.

Arousal↗