Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.11.18 (MAP)
 7,412 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The purpose of this study was to examine whether 14 days of head-down tilt bed rest (HDBR) alters autonomic regulation during Valsalva's manoeuvre (VM) and if this would predict blood pressure control during a 60 degrees head-up tilt (HUT) test. To examine autonomic control of blood pressure, we measured the changes in systolic (delta SBP) and diastolic (delta DBP) blood pressure between baseline and the early straining (Phase IIE) period of VM (20 sec straining to 40 mmHg; N = 7) in conjunction with changes in muscle sympathetic nerve activity (MSNA; microneurography) burst frequency (B/min) and total activity (% delta) from baseline over the 20-sec straining period. MSNA data were successfully recorded from 6 of the 7 individuals. The averaged responses from three repeated VMs performed in the supine position were compared between the pre- and post-HDBR tests. Compared with the pre-HDBR test, a greater reduction in SBP, DBP, and MAP was observed during Phase IIE following HDBR, p < 0.05. The increase in MSNA burst frequency during straining was augmented in the post- compared with the pre-HDBR test, p < 0.0001, as was the Phase IV blood pressure overshoot, p < 0.05. Although all subjects completed the 20-min pre-HDBR tilt test without evidence of hypotension or orthostatic intolerance, the post-HDBR test was stopped early in 5 of the 7 subjects due to systolic hypotension. The responses during the VM suggest that acute autonomic adjustments to rapid blood pressure changes are preserved after bed rest. Furthermore, MSNA and blood pressure responses during VM did not predict blood pressure control during orthostasis following HDBR.
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PMID:Sympathetic responses to Valsalva's manoeuvre following bed rest. 1295 63

The purpose of this study was to examine the difference between hemodynamic pressures and parameters obtained pre- compared to post-thermodilution CO measurements. A repeated measures within subject design was conducted with a cardiac surgical cohort. Three measures of hemodynamic pressures and parameters were determined pre- and post-CO measurements (Set 1) and repeated in 30 minutes (Set 2). The sequence was duplicated in four hours (Sets 3 and 4). Hemodynamic pressures lower pre-CO were PAS at Sets 1 and 3, and SBP, DBP, and MAP at Set 3. Hemodynamic parameters lower pre-CO were PVRI at Set 1 and SVRI at Set 3. These pre-post CO differences did not vary by greater than 10%. As the CO injectate volume had minimal effect, hemodynamic pressures may be obtained pre- or post-CO to derive hemodynamic parameters.
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PMID:Timing of hemodynamic pressure measurements on derived hemodynamic parameters. 1472 42

The aim of the present study was to determine the effects on blood pressure response of 50 g carbohydrate drinks with differing glycaemic effects in ten healthy elderly subjects (age > 65 years; randomized crossover design). Systolic (SBP), diastolic (DBP) and mean arterial (MAP) blood pressure, heart rate and plasma glucose levels were determined following ingestion of equal volumes (379 ml) of water and 50 g carbohydrate drinks with differing reported glycaemic indices (GI) (surrogate marker for glycaemic effect): (1) low-GI: Apple & Cherry Juice; (2) intermediate-GI: Fanta Orange; (3) high-glucose. Glucose (SBP and DBP P < 0.001; MAP P = 0.005) and Fanta Orange (SBP P = 0.005; DBP and MAP P < 0.001) ingestion caused a significant decrease in BP whilst blood pressure increased (SBP P = 0.008; MAP P = 0.005) from baseline following Apple & Cherry Juice ingestion. Water had no significant effect on postprandial blood pressure. Fanta Orange and Apple & Cherry Juice caused similar (P = 0.679) glycaemic effects, which were significantly greater than water, but lower than glucose (P < 0.001). There was no significant correlation between the glycaemic effect of the carbohydrate drinks and there was no change in blood pressure from baseline (SBP r - 0.123, P = 0.509; DBP r - 0.051, P = 0.784; MAP r - 0.069, P = 0.712). Apple & Cherry Juice and Fanta Orange had similar glycaemic effects, but differing effects on blood pressure. Therefore, it is unlikely that the glycaemic effect of a drink can be used to predict the subsequent cardiovascular response.
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PMID:Blood pressure responses in healthy older people to 50 g carbohydrate drinks with differing glycaemic effects. 1533 65

The purpose of the study was to examine the stability of variables associated with the metabolic syndrome from adolescence to adulthood. The sample included 48 subjects from the Aerobics Center Longitudinal Study who had one clinical visit during adolescence (mean age = 15.8 years) and a follow-up visit during adulthood (mean age = 26.6 years). The following variables were considered: treadmill time to exhaustion (TM), body mass index (BMI), waist circumference (WC), percent body fat (%BF), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), TC:HDL-C, triglycerides (TG), glucose (GLU), and systolic (SBP), diastolic (DBP), and mean (MAP) blood pressure. A composite risk factor score using variables consistent with the WHO and ATP III definition of the metabolic syndrome (WC, HDL-C, TG, MAP, and GLU) was calculated. Tracking coefficients were computed as partial correlations, controlling for length of follow-up (mean = 11 years). Tracking coefficients (r values) were moderate for all variables (TM, 0.53; BMI, 0.64; WC; 0.79;%BF, 0.44; TC, 0.62; HDL-C, 0.60; TG, 0.54; TC:HDL-C, 0.78; SBP, 0.45; and MAP, 0.41), except GLU (0.26) and DBP (0.21). The composite risk factor score also tracked moderately well (0.56) from adolescence into adulthood. The results support previous findings that variables associated with the metabolic syndrome track moderately well from adolescence to adulthood. The findings support the prevention and treatment of obesity, atherosclerosis, type 2 diabetes, and the metabolic syndrome during childhood and adolescence.
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PMID:Stability of variables associated with the metabolic syndrome from adolescence to adulthood: the Aerobics Center Longitudinal Study. 1549 27

Although cardiovascular disease (CVD) remains the leading cause of mortality in women, few studies have examined the role of psychosocial factors in its development. This study examined the moderating effects of sociotropic cognition (SC), a need for social acceptance and approval, on psychosocial stress-induced cardiovascular responsiveness (CVR) and affect reactivity in women. Sixty-eight normotensive, college-aged females were randomly assigned to a low or high social threat condition. Measures of systolic, diastolic and mean arterial blood pressures (SBP, DBP and MAP, respectively), heart rate (HR), cardiac output (CO), total peripheral resistance (TPR) and negative affect were collected during rest, and under conditions of high vs. low interpersonal threat. A two-step hierarchical regression analysis was performed to predict all response variables (BPs, HR, CO, TPR and affect). Increases in SBP, DBP, MAP, TPR and negative affect were greater in the high threat than low threat condition. Changes in SBP, MAP and TPR positively covaried with SC under conditions of high interpersonal threat, but showed no significant covariation in the low threat condition. The data suggest that an excessive need for social acceptance may contribute to rises in BP through an increase in TPR, but not CO under conditions of high social threat.
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PMID:Sociotropic cognition moderates stress-induced cardiovascular responsiveness in women through effects on total peripheral resistance, but not cardiac output. 1572 90

The purpose of this study was to investigate the short-, medium- and long-term reproducibility of cardiovascular responses during 90 degrees head-up tilt (HUT) in healthy older men. Twenty-eight healthy male subjects aged 69 (95% confidence intervals, 68-70) years participated in the study. Eight subjects underwent duplicate 90 degrees HUT tests on consecutive days, while 20 subjects underwent four 90 degrees HUT tests performed at baseline, and after 1 week, 1 month and 1 year. Following a 20-min supine resting period, each subject was rapidly tilted to the upright vertical position (90 degrees HUT) and remained in that position for 15 min. Beat-by-beat recordings of mean (MAP), systolic (SBP) and diastolic (DBP) pressures were made via Finapres, while heart rate (HR) was monitored continuously from an electrocardiogram. No significant test-retest differences (P > 0.05) were observed for the changes in HR, MAP, SBP or DBP during 90 degrees HUT. These measurements demonstrated high reproducibility (intraclass correlation coefficient, r = 0.91-0.99, P < 0.05). The supine resting and tilted HR, MAP, SBP and DBP over the 1-week, 1-month and 1-year period were not significantly different (P > 0.05) from baseline, and demonstrated high reproducibility (intraclass correlation coefficient, r = 0.82-0.98, P < 0.05). The results of this study demonstrate that in healthy older men, cardiovascular responses during orthostasis are highly reproducible, and this reproducibility is maintained over a 12-month period. These findings demonstrate that the 90 degrees HUT test offers a reproducible method of monitoring longitudinal orthostatic responses in healthy older men.
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PMID:Reliability of orthostatic responses in healthy men aged between 65 and 75 years. 1583 51

Childhood obesity and its consequences have been the subject of intense interest in recent years. In this study we examined the influence of overweight on circadian variations of ambulatory blood pressure (ABP) in Chinese adolescents. First, 24-hr ABP monitoring was performed in 252 adolescents divided into two groups with equivalent sex, age, and body height (49 girls and 77 boys in each group): controls (normal weight) were aged 13.68 +/- 1.21 years, height 165.37 +/- 9.45 cm, body mass index (BMI) 18.82 +/- 2.3; overweights (BMI > or = 24) were aged 13.71 +/- 1.23 years, height 165.75 +/- 9.47 cm, BMI 27.70 +/- 3.1. ABP recordings were treated by ABP database system and analyzed by cosinor method and conventional statistics methods. The circadian variations of ABP in adolescent patterned as "dipper" and circadian rhythmicity of ABP variations were confirmed by cosinor analysis in most adolescents of both groups. Significant statistical differences were found for rhythm parameters: the MESOR (midline estimate statistic of rhythm), peak, trough (the maximum and minimum values derived from the composed curves, respectively), and amplitude values between control and overweight groups. Significant higher values also were seen in the overweight group for most of ABP parameters (p < .01), such as, BP means (SBP, DBP, MAP: mean arterial pressure, or PP: pulse pressure), BP variability, BP loads and rate-pressure product (HR x SBP). Our results have shown that overweight influenced significantly on ABP and parameters derived from ABP recordings in Chinese adolescents, which suggests an increasing risk of cardiovascular diseases in overweight adolescents.
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PMID:Overweight influence on circadian variations of ambulatory blood pressure in Chinese adolescents. 1583 82

Most noninvasive blood pressure (NIBP) devices use the oscillometric method. Published studies of oscillometric methodology introduced varied algorithmic approaches for determination of systolic (SBP), diastolic (DBP), and mean arterial (MAP) blood pressures. While there is a general agreement about MAP determination, controversy exists about the determination of SBP and DBP Accuracy of oscillometric devices has been questioned and validation studies have revealed problems. Several validation protocols have been developed but they are expensive and time consuming to conduct and they have their own limitations. Instruments for bench testing of NIBP devices are useful for some device functions, but they cannot perform dynamic accuracy tests. The issue of accuracy is becoming very important as health care professionals increasingly rely on electronic NIBP devices. The authors developed a compact system for acquisition of NIBP waveforms. Some representative oscillometric waveforms are introduced here to demonstrate the oscillometric method and its shortcomings. A finger photoplethysmograph (PPG) was used to demonstrate a potential improvement of SBP determination. The concept and significance of an oscillometric blood pressure waveform database is introduced and its applications are discussed.
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PMID:Oscillometric blood pressure measurement: the methodology, some observations, and suggestions. 1591 8

A cross-sectional study of 150 adult Bengalee Hindu male jute mill workers of Belur, a suburb of Kolkata, West Bengal, India, was undertaken to study the relationship of age, body mass index (BMI) and waist circumference (WC) with systolic (SBP), diastolic (DBP) and mean arterial (MAP) blood pressure. The mean age and the BMI of the subjects were 40.7 years (S.D. = 15.2) and 23.2 kg/m2 (S.D. = 3.2), respectively. The mean SBP, DBP and MAP were 124.7 mmHg (S.D. = 7.8), 81.5 mmHg (S.D. = 5.7) and 95.9 mmHg (S.D. = 6.1), respectively. Age had similar significant (p < 0.001) correlations with BMI and WC. Age and WC were significantly correlated (p < 0.001) with all the three blood pressure variables. In general, the correlations of BMI with SBP (r = 0.24, p < 0.01), DBP (r = 0.15, n.s.) and MAP (r = 0.19, p < 0.05) were weaker. Age controlled multiple regression analyses demonstrated that BMI did not have a significant effect of any blood pressure variable. However, WC had a significant impact (p < 0.0001) on SBP (t = 7.068), DBP (t = 5.190) and MAP (t = 6.387), even after adjusting for the effect of age. Moreover, even after age adjustment, percent variations in SBP (20.7%), DBP (12.5%) and MAP (17.2%) explained by WC were high. This significant impact (p < 0.0001) of WC on SBP (t = 9.426), DBP (t = 8.349) and MAP (t = 9.642) remained even after controlling for the combined effects of age and BMI.
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PMID:The relationship of age, body mass index and waist circumference with blood pressure in Bengalee Hindu male jute mill workers of Belur, West Bengal, India. 1596 71

Increased oxidative stress and reduced nitric oxide (NO) bioactivity are key features of diabetes mellitus that eventually result in cardiovascular abnormalities. We assessed whether N-acetylcysteine (NAC), an antioxidant and glutathione precursor, could prevent the hyperglycaemia induced increase in oxidative stress, restore NO availability and prevent depression of arterial blood pressure and heart rate in vivo in experimental diabetes. Control (C) and streptozotocin-induced diabetic (D) rats were treated or not treated with NAC in drinking water for 8 weeks, initiated 1 week after induction of diabetes. At termination, plasma levels of free 15-F2t-isoprostane, a specific marker of oxygen free radical induced lipid peroxidation, was increased while the plasma total antioxidant concentration was decreased in untreated diabetic rats as compared to control rats (P<0.05). This was accompanied by a significant reduction of plasma levels of nitrate and nitrite, stable metabolites of NO, (P<0.05, D vs. C) and a reduced endothelial NO synthase protein expression in the heart and in aortic and mesenteric artery tissues. Systolic, diastolic and mean arterial blood pressures (SBP, DBP and MAP) and heart rate (HR) were reduced in diabetic rats (P<0.05 vs. C) and NAC normalised the changes that occurred in the diabetic rats. The protective effects may be attributable to restoration of NO bioavailability in the circulation.
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PMID:Antioxidant N-acetylcysteine restores systemic nitric oxide availability and corrects depressions in arterial blood pressure and heart rate in diabetic rats. 1639 Aug 27


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