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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Repeated measurements of resting blood pressure and heart rate were obtained at the worksite for a sample of 441 male municipal employees ranging widely in age (M = 41 yr.), job level, and education. As a result of unusually high diastolic values (M = 91), over-all uncontrolled hypertension rates were very high (33% of the men exceeding 160 systolic or 95 diastolic including those on medication). Higher rates were obtained for blue collar as opposed to white collar employees and for those plant workers in the Division of Water as opposed to Sewerage and Drainage. Net of age, weight, smoking, education, and anti-hypertensive medication use, higher systolic and diastolic mean values were obtained for supervisors who were primarily employed as foremen and clerical personnel. Inter-plant differences in blood pressure were also found for primarily blue collar Sewers and Drains employees, though whites' and blacks' values were nearly identical. Comparisons with national blood pressure data indicate significant effects for level of job and education which again disfavored supervisors and clerical employees and in addition men who had more education. Whites' and blacks' blood pressures deviated significantly from expected values, the differences favoring blacks. Social psychological mechanisms which may mediate these effects are discussed.
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PMID:Blood pressure of male municipal employees: effects of job status and worksite. 715 54

We have recently shown that mental stress increases local net release of tissue-type plasminogen activator (t-PA) across the forearm vascular bed. However, the mechanisms responsible for the t-PA release in man during stress are undefined. To study the effects of endothelial cell receptor stimulation and fluid shear stress we used the perfused forearm model to characterize the in vivo tissue plasminogen activator (t-PA) response in man to methacholine (Mch) and sodium nitroprusside (SNP), at doses calculated to cause similar degrees of vasodilation. The study was performed in 7 healthy young men (age 22-24 yrs) without hypertension, diabetes mellitus, or hypercholesterolemia. Each subject received double-blind step-wise i. a. infusions of Mch (0.1-0.8-4.0 micrograms/min) and SNP (0.5-2.5-10 micrograms/min) in randomized order. Each dose step was infused for 5 min. Forearm blood flow was assessed by plethysmography. Net release/uptake was expressed as the product of arterio-venous concentration gradient and forearm plasma flow. At pre-infusion baseline, there was a significant net release of t-PA antigen of approximately 0.9 ng x min-1 x 100 ml-1 and t-PA activity of 3.5 fmol x min-1 x 100 ml-1 across the forearm. I.a. infusion of Mch and SNP increased forearm blood flow from 1.9 to 14.9 and from 1.8 to 12.1 ml x min-1 x 100 ml-1, respectively (Mch vs SBP N.S.).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Release of tissue-type plasminogen activator in response to muscarinic receptor stimulation in human forearm. 787 38

Noncompliance with antihypertensive medication remains an obstacle to the management of hypertension, and despite research efforts over the past decade, the predictors of noncompliance remain unclear. According to values expectancy theory, individuals rationally choose noncompliance when the barriers or costs of treatment outweigh the expected benefits. Noncompliance, therefore, is likely to occur when net costs of treatment are high. Using a cross-sectional study design among subjects (n = 197) attending a specialized clinic for hypertension, we measured "net barriers" (costs), self-reported compliance, and possible determinants of noncompliance, including socio-demographics, the medical regimen, and locus of control. The effect of each quartile of the net barriers score (none, low, moderate, and high) on compliance, controlling for potential effect modifiers, was assessed using logistic regression modeling. Noncompliance (47%) was associated with younger age, higher salt use, longer duration of treatment, and higher levels of net barriers, but duration of treatment modified the effect of net barriers. Among subjects in short-term treatment, noncompliance increased with severity of net barriers suggesting a dose-response effect. In contrast, patients in long-term treatment showed no dose-response effect but a consistent association between noncompliance and levels of net barriers. Subjects at greater risk for noncompliance, however, were those who reported high net barriers, regardless of duration of treatment. Net barriers accounted for 50% of the noncompliance and appeared most important for patients who were younger or in the early stages of treatment. Implications for health care providers are discussed.
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PMID:Effect of perceived barriers on compliance with antihypertensive medication. 830 68

beta-Adrenoceptor blocking agents impair endurance exercise performance in healthy subjects and in patients with hypertension. A possible explanation for the reduced exercise tolerance is a diminished availability of plasma non-esterified fatty acids (NEFA) for energy production during exercise. This study investigated the effect of beta-adrenoceptor blockade on NEFA uptake of exercising skeletal muscle at elevated blood NEFA concentrations. In 11 healthy volunteers a triacylglycerol emulsion was infused at increasing rate for 1 hour before and 1 hour during one-armed cranking exercise at 60% Wpeak with and without prior administration of the beta 1+2-adrenoceptor blocking agent propranolol (80 mg per os). Arteriovenous concentration differences of NEFA across the active forearm were measured and forearm blood flow was estimated using venous occlusion plethysmography. Heart rate and blood flow were significantly lower after propranolol (p < 0.05). Propranolol did not affect arterial NEFA concentration, arteriovenous NEFA difference or NEFA flux significantly. Net NEFA uptake increased with increasing arterial NEFA concentration or inflow in a similar manner with and without prior propranolol administration. Therefore, the results do not support the hypothesis that beta-adrenergic activity plays a role in the regulation of active skeletal muscle NEFA uptake under the conditions studied.
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PMID:The effect of beta-adrenergic blockade on non-esterified fatty acid uptake of exercising skeletal muscle during arm cranking. 855 Feb 51

We explored how in parallel-group trials interindividual variability, correction for placebo effects, and smoothing of blood pressure profiles can be handled in measuring the trough-to-peak ratio in 244 individuals with isolated systolic hypertension (> or = 60 years) enrolled in the placebo-controlled Systolic Hypertension in europe Trial. Net treatment effects were computed by subtracting the mean changes from baseline during placebo (n = 133) from those during active treatment (n = 111). At entry, systolic/diastolic pressures averaged 176/86 mm Hg in the clinic and 149/80 mm Hg on 24-hour ambulatory monitoring. With corrections applied for baseline and placebo, nitrendipine (10 to 40 mg/d), with the possible addition of enalapril (5 to 20 mg/d) and/or hydrochlorothiazide (12.5 to 25 mg/d), reduced (P < .001) these blood pressure values by 16.6/7.3 and 9.8/4.7 mm Hg, respectively. The net trough-to-peak ratios were first determined from blood pressure profiles (12 hours) with 1-hour precision, synchronized by the morning and evening doses of the double-blind medication. According to the usual approach, disregarding interindividual variability, the systolic/diastolic net trough-to-peak ratios were 0.46/0.40 in the morning and 0.77/0.99 in the evening. In individual subjects, the baseline-adjusted trough-to-peak ratios were nonnormally distributed. We therefore used a nonparametric technique to calculate the net trough-to-peak ratios from the results in individual subjects. In the morning, these ratios averaged 0.25 systolic (95% confidence interval, 0.09 to 0.41) and 0.15 diastolic (95% confidence interval, 0.00 to 0.31) and in the evening, 0.19 and 0.36 (95% confidence intervals, 0.00 to 0.38 and 0.14 to 0.56), respectively. When the blood pressure profiles were smoothed by substituting the 1-hour averages by moving or fixed 2-hour averages or by Fourier modeling, the trough-to-peak ratios remained unchanged after the morning dose (0.20/0.13, 0.20/0.14, and 0.16/0.21, respectively) but tended to increase in the evening (0.32/0.38, 0.28/0.40, and 0.48/0.49). In conclusion, the parallel-group analysis proposed makes it possible for one to correct the trough-to-peak ratio for baseline as well as placebo, to account for interindividual variability, and to calculate a confidence interval for the net trough-to-peak ratio. Accounting for interindividual variability reduces the trough-to-peak ratio. Smoothing affects the individualized net trough-to-peak ratios in an unpredictable way and should therefore be avoided.
Hypertension 1997 Feb
PMID:Determining the trough-to-peak ratio in parallel-group trials. Systolic Hypertension in Europe (SYST-EUR) Trial Investigators. 904 Apr 53

We recently showed that muscarinic receptor stimulation causes a marked increase in the net release of tissue-type plasminogen activator (TPA) antigen and activity across the human forearm in vivo, in conjunction with endothelium-dependent vasodilation. Because hypertension has been associated with endothelial dysfunction, the aim of the study was to compare forearm TPA release and vasodilation in response to muscarinic stimulation in normotensive (NC) and borderline hypertensive (BH) subjects. The study was performed in 10 apparently healthy young men with BH and 10 male NC subjects. Methacholine (MCh: 0.1, 0.8, and 4.0 micrograms/min) and sodium mitroprusside (SNP: 0.5, 2.5, and 10 micrograms/min) were administered in randomized order as double-blind, stepwise, intrabrachial artery infusions. Forearm blood flow was assessed by plethysmography. Net release/uptake was calculated as the product of the arteriovenous concentration gradient and forearm plasma flow. Vasodilator responses to MCh were similar in both groups (P = NS), whereas the decrease in forearm vascular resistance in response to SNP was somewhat less in BH subjects (P = .005). At rest, both groups showed a significant arteriovenous gradient and net release of TPA antigen across the forearm (P < .05 throughout). However, in contrast to the significant net increment in TPA activity across the forearm in the NC group (P < .018), BH subjects had no basal forearm increment in TPA activity (NC vs BH, P = .006). Arterial and venous plasma levels of plasminogen activator inhibitor 1 (PAI-1) antigen and activity were higher in BH subjects (P < or = .05 throughout), who in contrast to NC subjects, also had a significant forearm net release of PAI-1 antigen (P = .006). Across the whole group, there was a significant inverse relation between arterial PAI-1 antigen levels and increment in TPA activity across the forearm (r = -.57, P = .008) but no relation to TPA antigen release. In response to MCh infusion, both the net release of TPA antigen and increment in TPA activity increased markedly and to similar extents in both groups (P < .01 throughout). SNP infusion had no effect on either TPA antigen release or increment in TPA activity in the NC group but elicited a significant net release of TPA antigen and increase in TPA activity in the BH group (P < .05). Both circulating levels and local release of PAI-1 antigen were significantly correlated to fasting plasma insulin. Endothelium-dependent vasodilation and endothelial TPA release in response to muscarinic receptor stimulation were preserved in BH subjects. At rest, BH subjects had higher circulating PAI-1 antigen levels and a corresponding decrease in circulating levels and local increment of TPA activity. In contrast to NC subjects, BH subjects responded with a TPA release also in response to increased flow, which may indicate an enhanced endothelial cell responsiveness to fluid shear stress.
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PMID:Endothelium-dependent vasodilation and tissue-type plasminogen activator release in borderline hypertension. 943 82

Many patients treated with peritoneal dialysis (PD) are overhydrated. We investigated whether hypertension in PD patients is related to ultrafiltration-failure-induced fluid retention. Twenty-four-hour blood pressure measurements were performed in 10 normotensive and 9 hypertensive PD patients, aged 20 to 77 years, and treated with PD for 2 to 125 months. Antihypertensive medication had been discontinued for 3 weeks. Twenty-four-hour blood pressure was monitored with a Spacelabs 90207. Mean 24-hour systolic, mean, and diastolic pressure were calculated, together with the nighttime (23:00-07:00)/daytime (07:00-23:00) ratio. Ultrafiltration was determined separately during a standardized 4-hour peritoneal permeability analysis (SPA) with 1.36% glucose. Based on the SPA, patients were divided into a group with negative net ultrafiltration (NUF) and a group with positive net ultrafiltration (PUF). In 8 patients with NUF, systolic, mean, and diastolic pressures were 142 +/- 16 mmHg, 110 +/- 14 mmHg, and 95 +/- 13 mmHg, compared to 135 +/- 22 (ns), 99 +/- 14 (ns), and 81 +/- 11 (P < 0.05) in 11 patients with PUF. Net ultrafiltration during the test dwell correlated negatively with diastolic blood pressure (r = -0.53, P < 0.05). Diurnal blood pressure variations were not related to ultrafiltration capacity. In conclusion, hypertension in PD patients may in part be explained by fluid retention caused by impaired ultrafiltration.
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PMID:Elevated 24-hour blood pressure in peritoneal dialysis patients with ultrafiltration failure. 1064 5

The Indian government's plan to introduce the new long-acting contraceptive Norplant in the National Family Planning Program under pressure from the US government is opposed because Norplant has not been adequately tested. The government has reduced the funding for the national program for eradication of malaria and tuberculosis, but it is proposing to finance a Norplant based population project for the State of Uttar Pradesh. The powers that can turn a deaf ear to the possible hazards of Norplant. Implanted in the arm of a woman, the chemical is released into the bloodstream providing contraception for 5 years. Severe adverse reactions include depression, heart disease thromboembolism, high blood pressure, and ovarian cysts. Many such long-acting contraceptives are being developed including injectables, vaccines, nasal sprays, and vaginal rings with potential permanent impairment to fertility. One of the major objectives of the Family Planning Program is the improvement of the health status of women, but the introduction of Norplant would harm healthy young women. Therefore, the group Saheli and others in the campaign demand: 1) that plans for introduction of Norplant in the Family Planning Program be halted immediately; 2) that the introduction of any other long acting invasive contraceptive such as Net-En, vaginal ring, nasal spray, and anti-fertility vaccine be banned, both on the grounds of inadequacy of the health services and loss of user controls; 3) that information on the safety aspects of Norplant and the basis on which the Drugs Controller has granted his approval be made public; 4) that each and every one of the hundreds of women who still have the implant should be located, and the implant removed; and 5) that all hormonal contraceptive preparations be banned in the social marketing program as their use involves extensive monitoring.
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PMID:Norplant campaign in India. 1228 26

The PREMIER trial assessed the aggregate effect on blood pressure (BP) of nationally recommended lifestyle modifications in free-living adults with high-normal (stage 1) hypertension. Participants (N=810) were randomized to the advice-only group; the established group (consisting of weight loss, increased physical activity, and reduced sodium and alcohol intake); or the established plus Dietary Approaches to Stop Hypertension (DASH) diet group (consisting of the established interventions in addition to the DASH dietary pattern). The primary outcome was change in systolic BP at 6 months. Net of advice only, mean systolic BP declined by 3.7 mm Hg for members of the established group (p<0.001) and 4.3 mm Hg for the established plus DASH group (p<0.001). The prevalence of hypertension decreased from a baseline of 38% to 17% in the established group (p=0.01) and to 12% in the established plus DASH group (p<0.001) compared with a decrease to 26% in the advice-only group. The PREMIER trial demonstrated that persons with above-optimal BP and stage 1 hypertension can make multiple lifestyle changes leading to better control of BP.
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PMID:Comprehensive lifestyle modification and blood pressure control: a review of the PREMIER trial. 1524 94

Sodium reduction is efficacious for primary prevention of hypertension, but the feasibility of achieving this effect is unclear. The objective of the paper is detailed analyses of adherence to and effects of the sodium reduction intervention among overweight adults in the Trials of Hypertension Prevention, Phase II. Sodium reduction (comprehensive education and counselling about how to reduce sodium intake) was tested vs no dietary intervention (usual care) for 36-48 months. A total of 956 white and 203 black adults, ages 30-54 years, with diastolic blood pressure 83-89 mmHg, systolic blood pressure (SBP) <140 mmHg, and body weight 110-165% of gender-specific standard weight were included in the study. At 36 months, urinary sodium excretion was 40.4 mmol/24 h (24.4%) lower in sodium reduction compared to usual care participants (P<0.0001), but only 21% of sodium reduction participants achieved the targeted level of sodium excretion below 80 mmol/24 h. Adherence was positively related to attendance at face-to-face contacts. Net decreases in SBP at 6, 18, and 36 months of 2.9 (P<0.001), 2.0 (P<0.001), and 1.3 (P=0.02) mmHg in sodium reduction vs usual care were associated with an overall 18% lower incidence of hypertension (P=0.048); were relatively unchanged by adjustment for ethnicity, gender, age, and baseline blood pressure, BMI, and sodium excretion; and were observed in both black and white men and women. From these beneficial but modest results with highly motivated and extensively counselled individuals, sodium reduction sufficient to favourably influence the population blood pressure distribution will be difficult to achieve without food supply changes.
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PMID:Sodium reduction for hypertension prevention in overweight adults: further results from the Trials of Hypertension Prevention Phase II. 1537 64


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