Prediction of resting cardiovascular functioning in youth with family histories of essential hypertension: A 5-year follow-up

Two hundred forty-six children (96 Whites, of whom 51 were mates; 150 African- Americans, of whom 69 were males) with a familial history of essential hypertension (EH) were re-evaluated 5 years after an initial evaluation. During the initial visit, anthropometric, demographic, and resting cardiovascular (CV) parameters (designated initial baseline levels) were assessed. These CV parameters (systolic and diastolic blood pressure [BP], heart rate, cardiac output index [CI], and total peripheral resistance index [TPRI]) were also measured during postural challenge, a video game challenge, and a cold pressor task. At follow-up, resting CV parameters were again evaluated, and designated as follow-up resting levels. Moderate temporal stability (r range = .43-.56) was observed for all resting CV parameters. Mean stress responses for each CV parameter for all 3 stressors during the initial visit were positively related to the respective CV follow-up resting level. BP stress responses to postural change and video game challenge were found to be significant independent predictors of future resting BP after controlling for standard EH risk factors. Follow-up resting CI was not predicted by any stress responses, whereas follow-up resting TPRI was predicted by TPRI responses to the video game after controlling for standard EH risk Factors. These results contrast with those from an earlier 1-year follow-up. where stress responses for neither CI nor TPRI predicted follow-up resting levels. It appears that, as children get older. TPRI stress responses play a stronger role in vasoconstrictive function. This research was supported by National Institutes of Health Grant HL41781.     

Reporting of life events, family history of hypertension, and cardiovascular activity at rest and during psychological stress

This study investigated whether relations between stressful life events and cardiovascular activity obtained during periods of rest and stress varied as a function of family history of hypertension. Within the family history of hypertension group, males exhibited a positive association between the number of negative avoidable events and resting systolic blood pressure, whereas an inverse association between these two variables was obtained for females. Among females with a family history of hypertension, inverse associations between resting diastolic blood pressure and the subjective effects of life event and number of avoidable events were obtained. Analyses revealed that diastolic blood pressure reactivity to stress was associated with those persons with a family history of hypertension who reported fewer negative life events and less subjective effects for these events.     

The investigation of prooxidant-antioxidant balance in serum of children with family histories of essential hypertension

It has been accepted that essential hypertension is associated with a loss of the balance between prooxidation and antioxidation. Thus, excessive oxygen free radical production may be an early event in the pathogenesis of hypertension. To compare lipid peroxidation and antioxidant system in serum of children of essential hypertensive and normotensive parents. Serum malondialdehyde (MDA) levels were measured spectrofluorometrically. Antioxidant activity, glutathione peroxidase, selenium levels in serum were measured as indices of antioxidant power. The peroxidation of apo B containing lipoproteins (VLDL+LDL) was measured as the susceptibility to oxidation in vitro. Serum MDA levels increased, but no marked differences in total antioxidant activity, glutathione peroxidase activity, selenium levels and VLDL+LDL oxidation were found in serum of children with family histories of essential hypertension as compared to children of normotensive parents.     

Environmental tobacco smoke: Association with cardiovascular function at rest and during stress

Chronic exposure to environ mental tobacco smoke (ETS) contributes to cardiovascular disease morbidity and mortality, and ETS alters cardiovascular performance during exercise stress. However, no study has examined whether those with ETS exposure have altered cardiovascular functioning during psychological stress, relative to those with no substantial ETS exposure. Seventy-eight healthy, nonsmoking adult men with either high levels of current ETS exposure at home and work or no current or significant lifetime ETS exposure were tested in a stress reactivity protocol. Blood pressure and heart rate were monitored during rest and during two psychological stressors. Those with high ETS exposure had significantly elevated heart rate and blood pressure at baseline, relative to those with no exposure. The groups did not differ on their cardiovascular stress responses. These data suggest that chronic ETS exposure is associated with altered cardiovascular functioning at rest, but not during stress. Results are discussed with regard to the role of ETS on the development of heart disease among nonsmokers.     

Caffeine effects on several indices of cardiovascular activity at rest and during stress

The effects of caffeine on cardiovascular responses to a mental arithmetic task were assessed using a between-subjects, double-blind design. Thirty-six male undergraduates were randomly assigned to either a placebo group or a group which received 250mg of caffeine. Repeated measurements of systolic and diastolic blood pressure (SBP, DBP), heart rate (HR), digital blood volume pulse (DBVP), and finger pulse transit time (FPTT) were obtained during a predrug baseline, a postdrug resting period, and a mental arithmetic task. Significant Period (i.e., stress) effects were observed on all measures, except DBVP which revealed a marginally significant Period effect. Significant main effects of Drug were observed on DBP and DBVP. There were no significant Drug X Period interactions. These results indicate that the increases in DBP and the decreases in DBVP produced by caffeine were additive with effects produced by stress.This research was supported by a Medical Research Council of Canada Studentship awarded to the first author and by Grant (MA-9224) from the Medical Research Council of Canada awarded to the second.     

A comparison of catecholamine concentrations and dopamine-β-hydroxylase activities in plasma from normotensive subjects and from patients with essential hypertension at rest and during exercise

Summary In 8 normotensive subjects and in 8 patients with essential hypertension total catecholamine content and dopamine--hydroxylase (DBH) activity in plasma were measured at rest and during physical exercise. Catecholamine levels at rest were significantly higher in the hypertensive than in the normotensive persons whereas the 2 groups of subjects did not differ in DBH activity at rest. At a work load of 150 watts there was a more pronounced increase of the catecholamine concentrations and of the DBH activity in the hypertensive patients than in the normotensives. One may conclude from the data that there is an increased sympathetic nerve activity in patients with essential hypertension.Part of the results has been presented at the 81. Meeting of the Deutsche Gesellschaft für Innere Medizin in Wiesbaden 1975     

Hemodynamics during rest and behavioral stress in normotensive men at high risk for hypertension

Persons at risk for hypertension may show elevated blood pressure (BP) at rest and during mental stress; however, the hemodynamics underlying the BP of those persons at high risk are not well characterized. We chose 21 high risk and 21 low risk men using their parental hypertension history and resting systolic blood pressures on two screenings. Then, on a day of extended rest versus a day with prolonged mental arithmetic and reaction time tasks, we examined whether high risk BP elevations reflected greater vascular resistance or cardiac output. High risk men had raised systolic/diastolic pressures ( F s = 74/15, p s < .0001/.0001) and higher vascular resistance ( F = 6.6, p < .02) with minimal differences in heart rate and cardiac output. This finding implicates vascular resistance as the altered element in BP control in these high risk men tested in a familiar environment with minimal task-related threat.     

Role of sex hormones in cardiovascular resistance to atropine in rats at rest and during stress

Castration of males and females reduces the sensitivity of cardiac chronotropic function to atropine and potentiates the vascular component in the reaction to atropine in females (during stress) and males (at rest and during stress). Our results show that estrogens and androgens increase the sensitivity of the cardiovascular system to cholinergic influences at rest and during stress. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 141, No. 3, pp. 270–272, March, 2006     

Nociceptive flexion reflex thresholds and pain during rest and computer game play in patients with hypertension and individuals at risk for hypertension

Supraspinal pain modulation may explain hypertensive hypoalgesia. We compared nociceptive flexion reflex (NFR) thresholds and pain during rest and computer game play in hypertensives and normotensives (Experiment 1) and normotensives with and without hypertensive parents (Experiment 2). The game was selected to modulate activity in pain pathways. NFR thresholds did not differ between groups during rest or game play. Pain ratings never differed between hypertensives and normotensives, whereas individuals with hypertensive parents reported less pain during the first two NFR assessments, compared to those without. NFR thresholds and pain were reduced by game play compared to rest. The failure of game play to differentially modulate NFR thresholds or associated pain reports between groups argues against enhanced supraspinal modulation of nociception and pain in hypertensives and those at increased risk for hypertension.     

Cardiovascular (CV) responsivity and recovery to acute stress and future CV functioning in youth with family histories of CV disease: a 4-year longitudinal study.

Blood pressure (BP) and heart rate (HR) data obtained during supine rest, in response to and recovery from four laboratory stressors in a baseline year were used to predict supine resting BP and HR values obtained during each of four consecutive annual follow-up evaluations. Subjects were 385 normotensive youth [95 African American (AA) males, 106 AA females, 92 European American (EA) males, 92 EA females] (mean age 12.7+/-2.6 at baseline year) with a positive family history of cardiovascular disease (CVD). During the baseline evaluation subjects were presented with four laboratory stressors (namely, postural change, video game challenge, social competence interview, and parent--child conflict discussion). The BP and HR values taken during each of the laboratory stressors and during the post stressor recovery periods were converted to z-scores which were averaged to yield aggregate measures for systolic and diastolic BP and HR responsivity and recovery. The data obtained during the baseline evaluation were subsequently used to predict the follow-up values of supine resting BP and HR. The prediction models were fairly consistent across each of the 4 follow-up years. Responsivity or recovery accounted for up to 6% of the total variance after accounting for baseline values. Within the prediction models responsivity or recovery accounted for 4--56% of the variance. The predictive value of the derived models did not decline from one annual evaluation to the next over the length of the study. CV recovery may supplement resting and responsivity in the prediction of future development of CVD     

Hydration status and cardiovascular function: effects of hydration enhancement on cardiovascular function at rest and during psychological stress.

This study examined the effects of a 3-day enhanced hydration regimen on resting cardiac function and reactivity to acute stress. Healthy volunteers (14 male, 14 female) were assigned to one of two groups: Enhanced Hydration and Normal Hydration Group. Participants in the Enhanced Group were given six 1-l bottles of water and instructed to drink two bottles a day in addition to normal fluid intake for 3 days preceding their laboratory session; no extra water was given to the Normal Group. Heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), cardiac output (CO), stroke volume (SV), and total peripheral resistance (TPR) were recorded during a 10-min baseline, 6-min Paced Auditory Serial Addition Test (PASAT), 5-min recovery, 5-min intermediate baseline, and 3-min Cold Pressor Test. Repeated-measures ANOVA revealed a significant Hydration GroupxTask interaction for DBP during the cold pressor (p<0.01) with the Enhanced Group exhibiting greater DBP reactivity to cold stress relative to the Normal Group. Analysis revealed significant Hydration GroupxGender interactions for SV and TPR (p<0.05) at rest and during both the PASAT and Cold Pressor Test. Females in the Enhanced Group displayed higher SV and lower TPR relative to Enhanced Group males, whereas females in the Normal Group displayed lower SV and greater TPR relative to Normal Group males. These results suggest that 3-day hydration enhancement influences blood pressure reactivity in both men and women, and that long-term hydration enhancement is related to resting gender differences in cardiac function.     

Gender differences and the relationships of perceived background stress and psychological distress with cardiovascular responses to laboratory stressors

The primary aim of this study was to evaluate the relationships of perceived background stress and self-reported psychological distress on cardiovascular reactivity during acute laboratory stressors. The Perceived Stress Scale (PSS) was used as the measure of perceived background stress, and the General Health Questionnaire (GHQ) was used as the measure of psychological distress. A secondary aim was to examine whether background stress and psychological distress affected the susceptibility to induction of a negative mood using music. Heart rate (HR) and blood pressure (BP) were measured in 149 female and male college students at rest and during a stressful mental arithmetic (MA) task and a mood induction procedure. Higher scores on the GHQ were associated with lower systolic BP reactivity during the MA task by all participants. Higher scores on the PSS and GHQ were also associated with lower diastolic BP and HR reactivity, but only in females. Thus, higher self-reports of background stress and psychological distress tended to result in blunted reactivity to an acute laboratory challenge. Higher levels of background stress and psychological distress were not associated with greater susceptibility to a negative mood induction. This study adds to the growing literature indicating that potentially negative health outcomes may be associated with diminished cardiovascular reactivity under certain conditions.     

Association analysis of polymorphisms at the interleukin-1 locus in essential hypertension

Infection with microorganisms such as Helicobacter pylori and Chlamydia pneumoniae has been associated with coronary heart disease (CAD) and hypertension (HT). Infection increases the release of pro-inflammatory cytokines, thus facilitating interactions that lead to vascular damage and other effects. We hypothesized that genetically determined differences in activity or responsiveness of cytokine(s) might contribute to HT. The interleukin-1 gene (IL1) cluster on chromosome 2q14 contains three related genes (IL1A, IL1B, and IL1RN) located within a 430-kb region. These encode IL-1alpha and IL-1beta, as well as their endogenous receptor antagonist, IL-1ra. The IL1RN gene has a penta-allelic 86-bp tandem repeat in intron 2. Allele IL1RN* 2 is associated with a wide range of chronic inflammatory and autoimmune conditions, and its combination with the -31T variant of an IL1B C(-31)T polymorphism constitutes a pro-inflammatory haplotype that leads to vigorous IL-1beta production. We therefore tested each of these polymorphisms for association with HT. Subjects were white Anglo-Celtic residents of Sydney, Australia. Frequencies of IL1B C(-31)T genotypes CC, CT, and TT were 0.50, 0.40, and 0.10 in normotensive (NT) and 0.46, 0.46, and 0.08 in HT, respectively (chi(2) = 1.2, P = 0.55). T allele frequency in NT (0.30) was similar to that in HT (0.31). For the IL1RN variant, frequencies of alleles IL1RN* 1 and * 2 and combined minor alleles * 3, * 4, and * 5 were 0.61, 0.36, and 0.03 in NT and 0.54, 0.36, and 0.10 in HT, respectively (chi(2) = 11, P = 0.004). In conclusion, no association of the IL1B C(- 31)T with HT was found, whereas combined frequency of the minor alleles of the IL1RN polymorphism was increased in the HT cohort studied.     

Effects of rhythmic muscle compression on cardiovascular responses and muscle oxygenation at rest and during dynamic exercise

We examined the way in which the duration of rhythmic muscle compressions affects cardiovascular responses and muscle oxygenation at rest and during dynamic exercise. We measured the mean arterial pressure (MAP), heart rate (HR) and oxygenation of the vastus lateralis muscle (by near-infrared spectroscopy) in eight healthy male subjects at rest and during supine bicycle exercise (50 and 100 W at 60 r.p.m.) while applying pulsed muscle compressions at 1000 ms intervals. Compression pressure and durations were 150 mmHg and 300, 600, 900 and 1000 ms (1000 ms being static continuous compression), respectively. During exercise, the pulsed leg compression was synchronized to each thigh extensor muscle contraction. The observed changes in muscle oxygenation were dependent on compression duration (increased at 300 ms, no change at 600 ms and decreased at 900 or 1000 ms) and were different from those seen at rest (increases at < 1000 ms and decrease at 1000 ms). This suggests that the effects of external pulsed muscle compression may have a duration threshold below which muscle pumping counteracts the obstruction to flow caused by the compression, and that the threshold is set at a shorter compression duration during exercise than at rest. Although HR and MAP did not change during pulsed compression at rest, during exercise they both increased progressively as compression duration increased. Thus, while exercising, the increased MAP and HR seen during the compression could be due to the combination and interaction of mechanical effects and the muscle mechanoreflex and/or metaboreflex.     

Observational assessment of family functioning at mealtime in preschool children with cystic fibrosis

OBJECTIVE: To examine functioning during a dinner meal in families of a child with a chronic illness that requires dietary treatment recommendations, as compared to families of a child without a chronic illness. METHODS: Ratings of seven dimensions of family functioning on the McMaster Mealtime Family Interaction Coding System (MICS) were obtained on 29 families of children with CF and 29 families of children with no chronic illness, ages 2 to 6 years, during a videotaped dinner meal at home. RESULTS: Ratings of families with a child with CF were significantly lower than those for families of children without a chronic illness on Overall Family Functioning and five of the six MICS dimensions: Communication, Interpersonal Involvement, Affect Management, Behavior Control, and Role Allocation and approached significance on the Task Accomplishment dimension. The ratings of families of a child with CF were in the "clinically significant" range on all subcales, including Task ACCOMPLISHMENT. CONCLUSIONS: This study suggests that family functioning at mealtimes may be different in families of children with CF in which explicit dietary guidelines exist than in families of children with no illness or dietary guidelines. These results are discussed in terms of global family functioning and treatment approaches to dietary treatment recommendations.