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Biomedical subjects

F A Treiber

Publications and source records attributed to F A Treiber.

64 records · Page 4Linked to original sources

Temperament differences between infants who do and do not complete laboratory testing.

Temperament differences were examined in a group of 24 Caucasian infants classified as completers (n = 16) and noncompleters (n = 8) on the basis of their performance in a visual habituation study. Maternal ratings of infant temperament based upon the Infant Temperament Questionnaire Revised revealed that noncompleters, in comparison with completers, were found to be more: arrhythmic, withdrawing, and intense, and less distractible. A composite measure of difficultness found the completers more likely to be classified as "easy" while the noncompleters were often classified as "difficult" babies. The findings suggest that to increase the external validity of infant research it may be beneficial to include more exact descriptions both of Ss who complete and those who fail to complete experiments.

Cognition↗

Racial differences in hemodynamic responses to the cold face stimulus in children and adults.

The prevalence of essential hypertension is higher among blacks than whites. One reason for this difference may be that blacks are more reactive to stressors that produce vasoconstrictive responses. Two studies were conducted to test this hypothesis, one with 10- to 14-year-old males (20 whites, 20 blacks) and one with young adult males (10 whites, 10 blacks). Subjects had blood pressure, heart rate, cardiac output, and total peripheral resistance measured before, during, and after exposure to forehead cold stimulation. In both studies, blacks exhibited greater increases in diastolic blood pressure and total peripheral resistance to the stressor than whites. The findings are discussed in relation to blacks' greater pressor reactivity to stress, which appears to be mediated by changes in total peripheral resistance.

Adolescent↗

Ethnicity, family history of hypertension and patterns of hemodynamic reactivity in boys.

This study compared blood pressure, heart rate, stroke volume, vascular resistance, and cardiac output responses to a video game challenge and forehead cold stressor in 6- to 15-year-old males who varied in ethnicity and family history of essential hypertension. Controlling for age, significant baseline differences were obtained with black boys exhibiting higher systolic and diastolic pressures than their white cohorts. Positive family history children were found to have higher cardiac outputs and stroke volumes indexed by body surface area during baseline. Controlling for baseline hemodynamic responses and age, positive family history children exhibited greater increases in systemic vascular resistance and systolic and diastolic pressure and greater decreases in heart rate to the cold stressor. The positive family history children exhibited greater decreases in cardiac index during both the video game and cold stressor phases. Implications of the findings and directions for future research are discussed.

Arousal↗

Acute effects of transcendental meditation on hemodynamic functioning in middle-aged adults.

OBJECTIVE: Increased peripheral vasoconstriction (ie, total peripheral resistance, or TPR) has been implicated as playing an important role in the early development of essential hypertension. Some studies have demonstrated that Transcendental Meditation (TM) reduces high blood pressure, but the hemodynamic adjustments behind these blood pressure reductions have not been elucidated. The aim of this study was to provide a preliminary investigation of the acute effects of TM on TPR. METHODS: Subjects were 32 healthy adults (16 women and 16 men; 30 white and two African American; mean age, 46.4 +/- 3.9 years). Subjects were divided into a TM group of long-term TM practitioners (eight white women, nine white men, and one African American man; mean years of twice-daily TM practice, 22.4 +/- 6.7) and a control group (eight white women, five white men, and one African American man). Hemodynamic functioning was assessed immediately before and during three conditions: 20 minutes of rest with eyes open (all subjects), 20 minutes of TM (TM group), and 20 minutes of eyes-closed relaxation (control group). RESULTS: During eyes-open rest, the TM group had decreases in systolic blood pressure (SBP) and TPR, compared with increases in the control group (SBP: -2.5 vs. +2.4 mm Hg, p < .01; TPR: -0.7 vs. +0.5 mm Hg/liter per minute, p < .004). During TM, there was a greater decrease in SBP due to a concomitantly greater decrease in TPR compared with the control group during eyes-closed relaxation (SBP: -3.0 vs. +2.1 mm Hg, p < .04; TPR: -1.0 vs. +0.3 mm Hg/liter per minute, p < .03). CONCLUSIONS: TPR decreased significantly during TM. Decreases in vasoconstrictive tone during TM may be the hemodynamic mechanism responsible for reduction of high blood pressure over time. The results of this study provide a preliminary contribution to the understanding of the underlying hemodynamic mechanisms responsible for the beneficial influence of TM on cardiovascular risk factors.

Adult↗

The effects of life events on cardiovascular reactivity to behavioral stressors as a function of socioeconomic status, ethnicity, and sex.

OBJECTIVE: The purposes of this study were 1) to examine the effects of stressful life events on cardiovascular reactivity to acute laboratory stressors in youth and 2) to determine whether these effects varied as a function of socioeconomic status, ethnicity, and/or sex. METHODS: Four hundred eighty-three youths (mean age = 16.7 years; 249 Caucasian Americans [126 males, 123 females] and 234 African Americans [109 males, 125 females]) completed the Adolescent Resources Challenge Scale (ARCS), a measure of stressful life events, and underwent two laboratory stressors (a car-driving simulation and the Social Competence Interview) during which blood pressure, heart rate, cardiac output, and total peripheral resistance were assessed. RESULTS: Youths who reported high levels of stressful life events showed smaller increases in blood pressure (both systolic and diastolic) and heart rate to the car-driving simulation but larger increases in cardiac output in response to the Social Competence Interview than did youths who reported low levels of stressful life events. The effect of stressful life events on cardiovascular reactivity was not moderated by sex, ethnicity, or socioeconomic status. Higher family socioeconomic status was associated with greater blood pressure, heart rate, and cardiac output increases in response to the Social Competence Interview. CONCLUSIONS: The attenuating effects of stressful life events on cardiovascular reactivity in response to car-driving simulation in youths are consistent with an inoculation effect, whereas the potentiating impact of stressful life events on reactivity observed during the social stressor interview is compatible with a possible cost of coping effect.

Adaptation, Psychological↗

Effects of Theraband and lightweight dumbbell training on shoulder rotation torque and serve performance in college tennis players.

The purpose of this study was to determine whether a 4-week isotonic resistance training program using Theraband elastic tubing and lightweight dumbbells would significantly increase concentric shoulder rotator strength or velocity of serve or both in a group of elite-level tennis players. Twenty-two male and female varsity college tennis players were randomly assigned to control or 4-week training groups. Subjects were pre- and posttested in concentric internal and external rotation torque using an isokinetic dynamometer. Functional performance was assessed before and after training by recording the peak and average velocities of eight maximal serves. The experimental group exhibited significant gains in internal rotation torque at both slow (120 deg/sec) and fast speeds (300 deg/sec) for total work and in peak torque to body weight ratio and torque acceleration energy at the fast speed. This group also exhibited significant gains in external rotation torque for the same parameters at fast speed. Regarding speed to serve, the experimental group exhibited significantly greater increase in peak speed (+6.0% compared with -1.8%) and average speed (+7.9% compared with -2.3%) compared with the control group. Men exhibited greater internal and external rotation torque on all parameters and in peak and mean speed of serve on both evaluations. Men also exhibited greater imbalance in external to internal rotation torque ratios. In conclusion, resistance training using Theraband tubing and lightweight dumbbells may have beneficial effects on strength and functional performance in college-level tennis players.

Acceleration↗

Racial differences in ambulatory blood pressure monitoring-derived 24 h patterns of blood pressure in adolescents.

BACKGROUND: Many pathologic conditions are characterized by a blunted nocturnal decline in blood pressure. OBJECTIVE: To review the evidence that African Americans display a similar pattern and examine factors associated with the pattern. METHOD: We reviewed published racial comparisons of patterns of ambulatory blood pressure in adults and youths. RESULTS: Authors of 15 studies reported finding blunted nocturnal declines in African Americans and authors of two studies did not. Authors of studies of Africans in Africa and of blacks from other countries reported normal nocturnal declines. Both intake of sodium and indexes of body size have been related to nocturnal blood pressure in African-American youths. This pattern is related to greater than normal target-organ changes. CONCLUSION: ; We conclude that the race of a patient should be considered when evaluating a 24h pattern of blood pressure in an adolescent; and the blunted nocturnal decline displayed by many African-American adolescents is the result of a gene-environment interaction and therefore is susceptible to modification through changes in diet, level of activity, and other environmental factors.

Adolescent↗