Effectiveness of angiotensin-converting enzyme inhibitor or angiotensin II receptor blocker on atrial natriuretic peptide.

Sata N, Tanaka Y, Suzuki S, Kamimura R, Mifune H, Nakamura K, Miyahara K, Arima T.

Second Department of Internal Medicine, Kagoshima University, Kagoshima, Japan.

The aim of this study was to evaluate the effectiveness of an angiotensin-converting enzyne inhibitor (ACEI, quinapril) or angiotensin II receptor blocker (ARB, candesartan) on atrial natriuretic peptide (ANP) activity in rats with hypertension induced by nitric oxide (NO) inhibition. ACEI and ARB have a number of pharmacologic effects, including blood pressure reduction, myocardial preservation, and an unknown effect in the circulation. The changes in ANP in NO inhibitor-induced hypertensive rats were evaluated in order to elucidate the interaction between ANP and NO in the regulation of blood pressure. Thirty-six rats were divided into 4 groups and administered the experimental agents for 8 weeks: group Control was given regular food (n=9), group N(G)-nitro-L-arginine (L-NNA) was administered L-NNA (25 mg. kg(-1). day(-1), n=9), group ACEI was administered L-NNA and quinapril (10 mg. kg(-1). day(-1), n=9), and group ARB was administered L-NNA and candesartan (10 mg. kg(-1). day(-1), n=9). Blood pressure, plasma ANP, atrial ANP, ANP mRNA, and ANP granules were measured. A significant elevation in blood pressure was observed in group L-NNA. However, there were no increases in plasma ANP (L-NNA: 138.8+/-64.4, Control: 86.7+/-36.4), ANP mRNA (L-NNA: 2.2+/-1.0, Control: 1.7+/-0.5) or ANP granules (L-NNA: 61.1+/-10.2, Control: 64.5+/-8.5). No increase in blood pressure was seen in groups ACEI and ARB. However, plasma ANP (ACEI: 1,392.3+/-1,034.4, ARB: 1,142.8+/-667.3), ANP mRNA (ACEI: 52.8+/-29.1, ARB: 42.9+/-21.2), and ANP granules (ACEI: 122.5+/-23.4, ARB: 136.3+/-33.2) increased significantly. NO inhibitor-induced hypertension caused no changes in ANP concentrations. However, the ACEI and ARB had a direct effect on the induction of ANP secretion. The findings suggest that ANP secretion is directly effected by ACEI and ARB, which seems to play a key role in lowering blood pressure, relieving heart failure symptoms, and preserving the myocardium.

Online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=14639023&dopt=Abstract blood pressure, high blood pressure




Effect of dietary calcium supplements and amlodipine on growth, arterial blood pressure, and cardiac hypertrophy of spontaneously hypertensive rats.

Civantos B, Aleixandre A.

Departamento de Farmacologia, Facultad de Medicina, Universidad Complutense, Madrid, Spain.

It has been shown that calcium-enriched diets cause a decrease in arterial blood pressure in hypertensive patients and animals. Moreover, it has been suggested that the combination of dietary calcium and calcium antagonists could paradoxically have a synergistic effect in order to decrease arterial blood pressure. The combination of these treatments may also have potential therapeutic benefit in the attenuation of cardiac hypertrophy. In this study, after being weaned at three weeks, male spontaneously hypertensive rats (SHR) were randomized in four groups of animals. Two of these groups were fed on a normal calcium diet (Ca 1%) and another two groups were fed on a calcium-enriched diet (Ca 2.5%). One of the groups fed on each diet also received amlodipine (1 mg/kg/day) in the drinking water after being weaned. Body weight was measured weekly in all the groups, and arterial blood pressure was also measured in all the 10-, 15-, 20-, and 25-week-old SHR by the tail cuff method. We established the ratio heart weight/body weight x 1000 (R), and we weighed the left ventricle in the 25-week-old animals at the end of the different treatments. The Ca 2.5% diet caused a delay in the development of hypertension in SHR. This effect could not be correlated with alterations in body weight since this diet improved growth in these rats. Amlodipine did not alter growth in SHR. This pharmacological treatment caused a decrease in the arterial blood pressure of the SHR and it intensified the antihypertensive effect of the Ca 2.5% diet. Nevertheless, this drug attenuated the effect of dietary calcium on body weight and when the treatment was prolonged, almodipine also antagonized the effect of dietary calcium on arterial blood pressure. At the end of the different treatments the ratio R and the left ventricular weight were similar in all the groups of animals. Therefore, the use of dietary calcium with a calcium antagonist to control arterial blood pressure seems not to be advisable, and the present data do not prove the usefulness of the mentioned antihypertensive treatments in preventing cardiac hypertrophy.

Online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=14649307&dopt=Abstract blood pressure, high blood pressure




Aldosterone synthase gene (CYP11B2) C-344T polymorphism, plasma aldosterone, renin activity and blood pressure in a multi-ethnic population.

Barbato A, Russo P, Siani A, Folkerd EJ, Miller MA, Venezia A, Grimaldi C, Strazzullo P, Cappuccio FP.

Department of Community Health Sciences, St George's Hospital Medical School, London, UK.

BACKGROUND: The aldosterone synthase gene (CYP1B2) locus is a candidate region involved in the development of hypertension. OBJECTIVE: To study the relationship between the C-344T CYP1B2 polymorphism, plasma aldosterone, renin activity and blood pressure in a multi-ethnic population. DESIGN: Population-based, cross-sectional study of 1313 middle-aged men and women (456 white, 441 of African origin and 416 South Asian). Anthropometry, blood pressure, biochemistry, questionnaire data and timed urine collections were taken with standardized techniques. All were genotyped for the C-344T CYP11B2 polymorphism. RESULTS: The frequency of the C allele was significantly lower in people of African origin (0.21) than in white (0.46) and South Asian (0.43) (P < 0.001). After adjustment for age, sex and ethnicity the TT genotype was associated with 14% higher plasma aldosterone levels, 3.7 mmHg higher systolic and 2.1 mmHg higher diastolic blood pressure than CC (P for linear trend < 0.05). No significant interactions with age, sex, ethnicity, body mass index (BMI) and fractional excretion of sodium were found in the associations between genotype and both blood pressure and aldosterone levels. In a sub-sample of participants in which plasma renin activity was measured (n = 457), a significant excess of T alleles was found in those with a raised (>/= 750) aldosterone-to-renin ratio (ARR). CONCLUSION: In this multi-ethnic population, the C-344T CYP1B2 polymorphism is associated with blood pressure, plasma aldosterone levels and ARR. Although significant differences in allele frequencies were found between groups, ethnicity does not explain the results.

Online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15361760&dopt=Abstract blood pressure, high blood pressure




[Blood pressure volatility--a new parameter for determining blood pressure variability in type-1 diabetes mellitus]

[Article in Hungarian]

Ruzicska E, Nagy V, Sarman B, Skoumal R, Somogyi A.

Semmelweis Egyetem, Altalanos Orvostudomanyi Kar, II. Belgyogyaszati Klinika, Budapest.

INTRODUCTION: In diabetes the heart rate variability is decreased because of the autonomic neuropathy and parallel with this phenomenon the overnight blood pressure fall is lost. Presumably this change in the hemodynamic parameters is connected with the fact that the cardiovascular complications in type 1 diabetic patients are 2-4 times more frequent than in healthy patients. The volatility, as a new factor, is the dispersion of the proportion of the blood pressure values following each other. It exactly reflects the 24-hour blood pressure fluctuation, while the dipper/non-dipper determination differentiates only between the daytime and night-time average blood pressure values. The volatility follows the changes of the measured values in accordance to the frequency of the measurements during the whole day. AIM: Our aim was to compare the blood pressure variability of type 1 diabetic patients (DM) and healthy controls (C). PATIENTS AND METHODS: The authors examined 43 diabetic patients from our outpatient clinic and 45 healthy people. The blood pressures were measured with Meditech ABPM 02 monitor on workdays. The measurements started in the mornings. The frequency of the measurements was 20 minutes during the day and 50 minutes at night-time. The authors took the history of all the patients and detailed laboratory results. The patients also had ophthalmology examination, ECG and echocardiography tests. RESULTS: During the Ambulatory Blood Pressure Monitoring we found that the systolic volatility of blood pressure values was significantly lower in DM compared to C patients. Systolic volatility: 0.133 +/- 0.011 vs. 0.175 +/- 0.014 p < 0.026. Comparing only the normotonic C and DM group systolic volatility of blood pressure values were significantly lower in DM. Systolic volatility: 0.128 +/- 0.016 vs. 0.177 +/- 0.021 p < 0.036. CONCLUSION: It is an important new finding that in type 1 diabetic patient the volatility--a new parameter for determining blood pressure variability--is lower than in the healthy control group. At normotension state other parameters describing the blood pressure variability (like diurnal index or standard deviation) could not show this change.

Online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=14579675&dopt=Abstract blood pressure, high blood pressure




Endobronchial adrenaline: should it be reconsidered? Dose response and haemodynamic effect in dogs.

Efrati O, Ben-Abraham R, Barak A, Modan-Moses D, Augarten A, Manisterski Y, Barzilay Z, Paret G.

The Department of Pediatric Pulmonology, Chaim Sheba Medical Center, Tel Hashomer 52621, Israel. oryefraty hotmail.com

BACKGROUND: Tracheal drug administration is a route for drug delivery during cardiopulmonary resuscitation when intravenous access is not immediately available. However, tracheal adrenaline (epinephrine) injection has been recently shown to be associated with detrimental decrease in blood pressure. This was attributed to exaggerated early beta2 mediated effects unopposed by alpha-adrenergic vasoconstriction. We hypothesized that endobronchial adrenaline administration is associated with better drug absorption, which may abolish the deleterious drop of blood pressure associated with tracheal drug administration. OBJECTIVE: To determine haemodynamic variables after endobronchial adrenaline administration in a non-arrest canine model. DESIGN: Prospective, randomized, laboratory study. METHODS: Adrenaline (0.02, 0.05, 0.1 mg/kg) diluted with normal saline was injected into the bronchial tree of five anaesthetized dogs. Injection of 10-ml saline served as control. Heart rate, blood pressure and arterial blood gases were monitored for 60 min after drug instillation. The protocol was repeated after 1 week. RESULTS: Adrenaline at a dose of 0.02 mg/kg produced only a minor initial decrease in diastolic (from 90 +/- 5 to 78 +/- 3 mmHg, P=0.05), and mean blood pressure (from 107 +/- 4 to 100 +/- 3 mmHg, P=0.05), in all dogs. This effect lasted less then 30 s following the drug administration. In contrast, higher adrenaline doses (0.05 and 0.1 mg/kg) produced an immediate increase in diastolic (from 90 +/- 5 to 120 +/- 7 mmHg; and from 90 +/- 5 to 170 +/- 6 mmHg, respectively), and mean blood pressure (from 107 +/- 4 to 155 +/- 10 mmHg; and from 107 +/- 4 to 219 +/- 6 mmHg, respectively). All adrenaline doses resulted in an immediate increase in systolic blood pressure and pulse. Endobronchial administration of saline (control) affected none of the haemodynamic variables. CONCLUSIONS: In a non-arrest model, endobronchial adrenaline administration, as opposed to the effect of tracheal adrenaline, produced only a minor decrease in diastolic and mean blood pressure. We suggest that endobronchial adrenaline administration should be investigated further in a CPR low-flow model when maintaining adequate diastolic pressure may be crucial for survival.

Online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=14580742&dopt=Abstract blood pressure, high blood pressure




Association between course of blood pressure within the first 24 hours and functional recovery after acute ischemic stroke.

Vlcek M, Schillinger M, Lang W, Lalouschek W, Bur A, Hirschl MM.

Department of Emergency Medicine, General Hospital, University of Vienna, Vienna, Austria.

STUDY OBJECTIVE: The relation between course of blood pressure within the first 24 hours after acute stroke and early neurologic outcome remains a matter of dispute. We investigate this relation with adjustment for other influencing variables. METHODS: Three hundred seventy-two patients with the diagnosis of ischemic stroke were included to evaluate the relation between blood pressure course and early neurologic outcome. The following data were collected: age; sex; history of hypertension, diabetes mellitus, hyperlipidemia, coronary heart disease, peripheral vascular disease, and stroke; smoking habits; preadmission blood pressure, blood pressure on admission, and blood pressure 24 hours later; antihypertensive treatment; and stroke localization. We assessed outcome at day 5 after admission as dependent or independent (Rankin Scale score <or=2) and applied multivariate logistic regression analysis to investigate the effect of blood pressure changes on outcome, with adjustment for other baseline variables. RESULTS: Relative changes of systolic and diastolic blood pressure within hospital admission to 24 hours after admission revealed significant differences of patients' neurologic outcome only for diastolic blood pressure changes from admission to 24 hours. A diastolic blood pressure decrease more than 25% from admission until 24 hours after admission was associated with a 3.8-fold increased adjusted odds (95% confidence interval 1.2 to 12.1) for poor neurologic outcome on day 5 (Rankin Scale score 3 to 5). CONCLUSION: Excessive diastolic blood pressure reduction was associated with an increased risk for an impaired neurologic outcome in patients with ischemic stroke. The association between both characteristics was independent from concomitant risk factors, stroke localization, and possible antihypertensive treatment.

Online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=14581913&dopt=Abstract blood pressure, high blood pressure




Effects of blood pressure on neuropsychological functioning in Alzheimer's disease.

Davis RN, Massman PJ, Doody RS.

Department of Psychology, University of Houston, Houston, TX 77204-5022, USA. robnd uh.edu

Blood pressure is often lower among patients with Alzheimer's disease (AD) compared to nondemented older adults. Lower blood pressure in AD correlates with reduced cerebral blood flow and cortical atrophy, but its effect on neuropsychological functioning is unclear. We assessed the effects of blood pressure on tests of dementia severity, attention, memory, language, verbal and nonverbal reasoning, motor/psychomotor functioning, and activities of daily living (ADL) among probable AD patients (n=609). As hypothesized, lower systolic blood pressure (SBP) predicted reduced attention (Digits Forward and Backward), memory (Visual Reproduction I), and ADLs. Unexpectedly, lower pulse pressure (SBP-DBP) predicted greater dementia severity (Mini-Mental State Examination, MMSE), attention (Digits Forward and Backward), memory (Logical Memory I and Visual Reproduction I), and ADLs. These findings may reflect a tendency for less severely demented patients to exhibit normal age-related changes in blood pressure, whereas abnormal patterns may develop with increased dementia severity.

Online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=14591475&dopt=Abstract blood pressure, high blood pressure




[Reference values of arterial pressure depending on age, assessed by 24-hour ambulatory monitoring]

[Article in Polish]

Wasilewska A, Zoch-Zwierz WM, Tomaszewska B, Wiercinski R, Biernacka A, Porowski T.

I Klinika Chorob Dzieci Akademii Medycznej w Bialymstoku.

24-hour blood pressure monitoring has been ever more widely used in children. However, percentile ranks for healthy children have not been prepared yet. The aim of the study was to define percentile ranks of blood pressure measured by ambulatory blood pressure monitoring in healthy children aged 7-17 years depending on sex in children from the Province of Podlasie. The examinations were carried out in a group of 540 children: group I-girls--265, group II boys--275, who were divided into subgroups according to age. Blood pressure was measured by ambulatory blood pressure monitors: BR-102 f. Schiller, Poland LTD and Quiet Tycos, USA according to the principles in force. The results showed that mean systolic blood pressure (RRs) increased with age from 103.2 to 117.7 mm Hg in girls and from 98.8 to 125.6 mm Hg in boys. The differences were statistically significant (p > 0.05). Diastolic blood pressure (RRr) increased less (p > 0.05). Mean systolic blood pressure at night was 9-10% and diastolic pressure 10-11% lower, irrespective of sex. The range of normal blood pressure values (5-95 centile) was established. In group I in the youngest girls the range of RRs was 89-110 mmHg, that of RRr was from 51 to 75 mm Hg while in group II in the youngest boys RRs range was from 95 to 108 mm Hg and RRr--from 52 to 73 mm Hg. In group I and II in the oldest girls and boys the values were higher. The percentile ranks (5-95) were prepared for systolic and diastolic blood pressure based on blood pressure monitoring during 24-hours and separately during activity (day) and resting time (night). CONCLUSIONS: 1. Systolic blood pressure in children aged 7-17 years increases with age more than diastolic blood pressure. 2. Percentile ranks for healthy children aged 7-17 years depending on age, sex and daily time period were established.

Online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=14593955&dopt=Abstract blood pressure, high blood pressure