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Antidiuretic Hormone as a Marker for Bronchial Carcinoma. Scott Med J 2016. [DOI: 10.1177/003693307702200426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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XactMice: humanizing mouse bone marrow enables microenvironment reconstitution in a patient-derived xenograft model of head and neck cancer. Oncogene 2015; 35:290-300. [PMID: 25893296 PMCID: PMC4613815 DOI: 10.1038/onc.2015.94] [Citation(s) in RCA: 99] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2014] [Revised: 02/20/2015] [Accepted: 03/03/2015] [Indexed: 12/14/2022]
Abstract
The limitations of cancer cell lines have led to the development of direct patient derived xenograft (PDX) models. However, the interplay between the implanted human cancer cells and recruited mouse stromal and immune cells alters the tumor microenvironment and limits the value of these models. To overcome these constraints, we have developed a technique to expand human hematopoietic stem and progenitor cells (HSPCs) and use them to reconstitute the radiation-depleted bone marrow of a NOD/SCID/IL2rg−/− (NSG) mouse on which a patient’s tumor is then transplanted (XactMice). The human HSPCs produce immune cells that home into the tumor and help replicate its natural microenvironment. Despite previous passage on nude mice, the expression of epithelial, stromal, and immune genes in XactMice tumors aligns more closely to that of the patient tumor than to those grown in non-humanized mice – an effect partially facilitated by human cytokines expressed by both the HSPC progeny and the tumor cells. The human immune and stromal cells produced in the XactMice can help recapitulate the microenvironment of an implanted xenograft, reverse the initial genetic drift seen after passage on non-humanized mice, and provide a more accurate tumor model to guide patient treatment.
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Can angiotensin II cause renal hypertension when its plasma concentration is normal? CONTRIBUTIONS TO NEPHROLOGY 2015; 8:57-60. [PMID: 891218 DOI: 10.1159/000400614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Measurement of plasma renin concentration and angiotensin II in peripheral and renal venous plasma in the management of renovascular hypertension. CONTRIBUTIONS TO NEPHROLOGY 2015; 3:45-51. [PMID: 1026369 DOI: 10.1159/000399380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Athough in general, measurement of renal vein renin appears to give a good prediction as to the subsequent response to surgery, its main value lies in its ability to reflect changes in renal plasma flow; true changes in renin secretion rate being much more difficult to detect. Although it is a little early to say how much information can be derived from saralasin infusions, caution must be exercised in necessarily assuming that the test accurately reflects subsequent surgical response.
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A RAPID METHOD FOR THE DIAGNOSIS OF RENAL TUBERCULOSIS BY THE USE OF THE X-RAYED GUINEA PIG. ACTA ACUST UNITED AC 2010; 24:419-27. [PMID: 19868051 PMCID: PMC2125463 DOI: 10.1084/jem.24.4.419] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
It is possible to reduce the resistance of guinea pigs to tuberculosis by x-ray exposures, so that when animal inoculation is required for a diagnosis a much quicker result may be had than by the use of normal animals. In renal tuberculosis when it is necessary to resort to the use of animals, it ordinarily requires from 5 to 7 weeks, while by the use of x-rayed guinea pigs the diagnosis can be made in from 8 to 10 days. The resistance can be sufficiently lowered by one massive dose of x-ray administered either shortly before or after the inoculation of the material to be tested. The lesions are so marked in these animals that the diagnosis is certain after the interval indicated above.
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THE DEMONSTRATION OF A TUMOR GROWTH-INHIBITING FACTOR FROM NORMAL HUMAN CONNECTIVE TISSUE. ACTA ACUST UNITED AC 2010; 61:59-66. [PMID: 19870346 PMCID: PMC2133199 DOI: 10.1084/jem.61.1.59] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Extracts from fresh normal human connective tissue (rectus sheath) exhibited a decided inhibiting action on grafts of Rat Tumor 256 transplanted into test animals. There was complete inhibition of tumor growth in 66 per cent of the animals; there was a marked retardation in the rate of growth in another 15 per cent, the tumors in these instances being much smaller than the controls transplanted at the same time. In only one experiment was there failure to obtain a lasting growth-inhibitory effect. The tumors in these animals (19 per cent) although showing an initial retardation in growth, apparently overcame the restraint and at the end of 5 weeks were larger than the control series. Extracts from fresh normal human muscle tissue, on the other hand, showed no such inhibiting action on grafts of Rat Tumor 256.
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THE LYMPHOCYTE IN NATURAL AND INDUCED RESISTANCE TO TRANSPLANTED CANCER : II. STUDIES IN LYMPHOID ACTIVITY. ACTA ACUST UNITED AC 2010; 22:204-11. [PMID: 19867911 PMCID: PMC2125311 DOI: 10.1084/jem.22.2.204] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
The refractory state to transplanted cancer, induced by the subcutaneous injection of defibrinated blood, is accompanied in every case by a definite lymphoid crisis in the blood. The rise of lymphocytes is not present during the interval between the immunizing injection and the cancer inoculation but comes on sharply within twenty-four hours of the introduction of the cancer graft. In control animals where the graft leads to a definite take there is no such lymphoid response, but in instances of natural immunity the phenomenon is similar to that seen in artificially induced immunity, though the period of rise is often delayed for several days or a week. The lymphoid crisis is not merely an accompanying factor in the immune period; it is essential to the process. This is demonstrated by the fact that destruction of the lymphocytes by x-ray is accompanied by the loss of natural or induced resistance to the growth of inoculated cancer. The polymorphonuclear cells show a tendency to increase in the animals with growing tumors, but further study will be necessary before any conclusions regarding them can be drawn.
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TEMPERATURE EFFECT OF POPLITEAL VEIN LIGATION IN THROMBO-ANGIITIS OBLITERANS AND ARTERIOSCLEROSIS. Ann Surg 2007; 88:233-41. [PMID: 17865937 PMCID: PMC1398643 DOI: 10.1097/00000658-192808000-00009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Ligation of the Abdominal Aorta for Aneurysm: Complicated by Rupture into the Retroperitoneal Space. Ann Surg 2007; 119:457-67. [PMID: 17858365 PMCID: PMC1617896 DOI: 10.1097/00000658-194403000-00014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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The Similarity in Effect of Experimental High Intestinal Obstruction and High Complete Intestinal Fistula. Ann Surg 2007; 94:263-8. [PMID: 17866619 PMCID: PMC1391473 DOI: 10.1097/00000658-193108000-00011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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THE QUANTITATIVE DETERMINATION OF VASOCONSTRICTOR SPASM AS A BASIS FOR THERAPY IN PERIPHERAL ARTERIAL DISEASES. Ann Surg 2007; 96:754-66. [PMID: 17866867 PMCID: PMC1391795 DOI: 10.1097/00000658-193210000-00023] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Abstract
Right ventricular systolic dysfunction (RVSD) at baseline (pre-treatment) predicts early death in patients with pulmonary hypertension (PH). However, RVSD can only be detected reliably by prohibitively invasive or expensive techniques. N-terminal B-type natriuretic peptide concentration ([NT-proBNP]) correlates with RV function in PH; however, an [NT-proBNP] threshold that indicates RVSD in individual patients has not previously been determined. Twenty-five patients with PH (pulmonary arterial hypertension (n = 19) or chronic thromboembolic PH (n = 6)) underwent cardiovascular magnetic resonance (CMR) imaging and NT-proBNP measurement at baseline. [NT-proBNP] was correlated against RV dimensions and ejection fraction (RVEF) measured directly by CMR imaging. The ability of NT-proBNP to detect RVSD (defined as a CMR-derived RVEF >2 SDS below control values) was tested and predictors of [NT-proBNP] identified. [NT-proBNP] correlated negatively with RVEF. RVSD was present in nine out of 25 patients. An [NT-proBNP] threshold of 1,685 pg.mL(-1) was sensitive (100%) and specific (94%) in detecting RVSD. RVEF and RV mass index independently predicted [NT-proBNP]. In pulmonary hypertension, a baseline N-terminal B-type natriuretic peptide concentration of >1,685 ng.L(-1) suggests right ventricular systolic dysfunction, and thus an increased risk of early death. N-terminal B-type natriuretic peptide could prove useful as an objective, noninvasive means of identifying patients with pulmonary hypertension who have right ventricular systolic dysfunction at presentation.
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Elevated Troponin Levels Are Associated with Sympathoadrenal Activation in Acute Ischaemic Stroke. Cerebrovasc Dis 2006; 23:260-6. [PMID: 17199083 DOI: 10.1159/000098325] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2006] [Accepted: 08/22/2006] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND It has been hypothesised that elevated serum troponin levels in acute stroke are due to myocardial damage caused by sympathoadrenal activation, which, in turn, may be due particularly to insular damage. We aimed to determine the factors associated with troponin elevation in ischaemic stroke and the prognostic value of this finding. METHODS We studied 222 consecutive acute ischaemic stroke admissions. Serum troponin I and catecholamines were measured. Ischaemic damage on brain computed tomography (CT) scan was graded using the Alberta Stroke Program Early CT Score (ASPECTS). Electrocardiograms were classified using the Minnesota Code and the European Society of Cardiology/American College of Cardiology criteria for acute myocardial infarction. The Rankin scale was recorded at 30 days. RESULTS Forty-five patients (20%) had troponin I >0.2 microg/l. These troponin-positive patients had higher epinephrine levels (median 0.27 vs. 0.17 nmol/l; p = 0.0002) and were more likely to have electrocardiograms coded as definite or possible acute myocardial infarction (odds ratio 3.35; 95% CI 1.26-8.93), compared with those with troponin < or = 0.2 microg/l, in univariate analysis. There were no significant associations between troponin I score and ASPECTS or insular damage on brain CT. In logistic regression analyses, elevated troponin was significantly associated with age, elevated serum creatinine and epinephrine; however, increased troponin was not an independent predictor of death or dependency (Rankin >2) at 30 days. CONCLUSIONS Raised troponin I is associated with elevation of circulating epinephrine in acute ischaemic stroke. Activation of the sympathoadrenal system may be an important contributor to myocardial damage in these patients. Increased troponin is not associated with insular damage and does not independently predict poor outcome.
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The Lymphocyte as a Factor in Natural and Induced Resistance to Transplanted Cancer. Proc Natl Acad Sci U S A 2006; 1:435-7. [PMID: 16576038 PMCID: PMC1090849 DOI: 10.1073/pnas.1.7.435] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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SYMPATHETIC INHIBITION OF THE LARGE INTESTINE IN HIRSCHSPRUNG'S DISEASE. J Clin Invest 2006; 9:247-62. [PMID: 16693931 PMCID: PMC435694 DOI: 10.1172/jci100302] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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THE MEASUREMENT OF SYMPATHETIC VASOCONSTRICTOR ACTIVITY IN THE LOWER EXTREMITIES. J Clin Invest 2006; 9:235-46. [PMID: 16693930 PMCID: PMC435693 DOI: 10.1172/jci100301] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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N-terminal pro B type natriuretic peptide, but not the new putative cardiac hormone relaxin, predicts prognosis in patients with chronic heart failure. Heart 2003; 89:879-81. [PMID: 12860863 PMCID: PMC1767758 DOI: 10.1136/heart.89.8.879] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
OBJECTIVE To determine whether the plasma concentration of the putative new cardiac hormone relaxin is predictive of clinical outcome in patients with chronic heart failure (CHF). DESIGN Plasma relaxin and N-terminal pro B type natriuretic peptide (NT pro BNP) concentrations were measured in 87 patients admitted in an emergency with CHF caused by left ventricular systolic dysfunction. These were related to death and death or readmission with CHF over the following year. SETTING Western Infirmary, Glasgow, UK. MAIN OUTCOME MEASURES Plasma concentrations of relaxin and NT pro BNP; time to death or hospitalisation caused by heart failure. RESULTS Plasma concentrations of both relaxin and NT pro BNP were greatly increased. Of the 43 patients with NT pro BNP above the group median concentration, 23 (53%) died and 30 (70%) died or were hospitalised with CHF. Among the 44 with concentrations below the median, these numbers were 5 (11%) and 12 (27%), respectively (p < 0.0001 and p < 0.0001, respectively). Plasma NT pro BNP concentration remained an independent predictor of an adverse clinical outcome in a multivariate analysis. Of the 42 patients with a relaxin concentration above the median, 13 (31%) died and 20 (48%) died or were hospitalised. Below the median, these numbers were 15 of 45 (33%) and 22 of 45 (49%) (p = 0.76 and p = 0.84, respectively). CONCLUSIONS NT pro BNP is a powerful and independent predictor of outcome in CHF, whereas relaxin, also secreted by the heart in increased amounts in CHF, is not.
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Effects of adrenomedullin on angiotensin II stimulated atrial natriuretic peptide and arginine vasopressin secretion in healthy humans. Br J Clin Pharmacol 2001; 52:165-8. [PMID: 11488773 PMCID: PMC2014530 DOI: 10.1046/j.0306-5251.2001.01428.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AIMS Adrenomedullin is a newly described peptide that has widespread tissue distribution. Its presence in cardiovascular (including vascular endothelial cells, smooth muscle cells, and cardiac atria and ventricles) and renal tissues, together with its vasodilatory and natriuretic properties, suggest a role in blood pressure regulation and fluid and electrolyte balance. METHODS Nine normal volunteers were studied to determine whether or not adrenomedullin influenced plasma atrial natriuretic peptide and arginine vasopressin concentrations during systemic angiotensin II infusion. RESULTS A significant (P = 0.02) augmentation of atrial natriuretic peptide concentrations, but no suppression of arginine vasopressin concentrations, was found with coinfusion of adrenomedullin and angiotensin II when compared with vehicle and angiotensin II. CONCLUSIONS Despite its vasodilator and natriuretic action, adrenomedullin significantly augmented angiotensin II-stimulated plasma atrial natriuretic peptide concentrations in healthy humans. This provides further evidence of a synergistic interaction between adrenomedullin and atrial natriuretic peptide and suggests that adrenomedullin may have a role in fluid and electrolyte balance and blood pressure regulation.
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Left ventricular dysfunction, natriuretic peptides, and mortality in an urban population. BRITISH HEART JOURNAL 2001. [DOI: 10.1136/hrt.86.1.21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
OBJECTIVETo report the mortality of left ventricular systolic dysfunction (LVD), assessed objectively by echocardiography, and its association with natriuretic peptide hormones in a random sample of 1640 men and women aged 25–74 years from a geographical, urban population.METHODSLeft ventricular function was measured by echocardiography in 1640 attendees studied in 1992–3. LVD was defined as a left ventricular ejection fraction (LVEF) ⩽ 30%. Plasma concentrations of N-terminal atrial natriuretic peptide (N-ANP) and brain natriuretic peptide (BNP) were measured by standard radioimmunoassays. Mortality was documented at four years.RESULTSThe four year all cause mortality rate in the whole cohort was 4.9% (80 deaths). It was 21% (nine deaths) in those with an LVEF ⩽ 30% and 4% in those whose LVEF was > 30% (p < 0.001). The median (interquartile range) BNP concentration in those who died was 16.9 pg/ml (8.8–27) and 7.8 pg/ml (3.4–13) in survivors (p < 0.0001). Similarly, N-ANP had a median concentration of 2.35 ng/ml (1.32–3.36) in those with a fatal outcome and 1.27 ng/ml (0.9–2.0) in those alive at four years (p < 0.0001). Subjects with an LVEF ⩽ 40% also had a significant mortality rate of 17% if they also had a BNP concentration ⩾ 17.9 pg/ml compared with 6.8% if their BNP was below this concentration (p = 0.013). Multivariate analysis revealed the independent predictors of four year all cause mortality to be increasing age (p < 0.001), a BNP concentration ⩾ 17.9 pg/ml (p = 0.006), the presence of ischaemic heart disease (p = 0.03), and male sex (p = 0.04).CONCLUSIONSLVD is associated with a considerable mortality rate in this population. BNP also independently predicts outcome. In addition to its role as a diagnostic aid in chronic heart failure and LVD, it provides prognostic information and clarifies the meaning of a given degree of LVD.
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Abstract
OBJECTIVE To report the mortality of left ventricular systolic dysfunction (LVD), assessed objectively by echocardiography, and its association with natriuretic peptide hormones in a random sample of 1640 men and women aged 25-74 years from a geographical, urban population. METHODS Left ventricular function was measured by echocardiography in 1640 attendees studied in 1992-3. LVD was defined as a left ventricular ejection fraction (LVEF) </= 30%. Plasma concentrations of N-terminal atrial natriuretic peptide (N-ANP) and brain natriuretic peptide (BNP) were measured by standard radioimmunoassays. Mortality was documented at four years. RESULTS The four year all cause mortality rate in the whole cohort was 4.9% (80 deaths). It was 21% (nine deaths) in those with an LVEF </= 30% and 4% in those whose LVEF was > 30% (p < 0.001). The median (interquartile range) BNP concentration in those who died was 16.9 pg/ml (8.8-27) and 7.8 pg/ml (3.4-13) in survivors (p < 0.0001). Similarly, N-ANP had a median concentration of 2.35 ng/ml (1.32-3.36) in those with a fatal outcome and 1.27 ng/ml (0.9-2.0) in those alive at four years (p < 0.0001). Subjects with an LVEF </= 40% also had a significant mortality rate of 17% if they also had a BNP concentration >/= 17.9 pg/ml compared with 6.8% if their BNP was below this concentration (p = 0.013). Multivariate analysis revealed the independent predictors of four year all cause mortality to be increasing age (p < 0.001), a BNP concentration >/= 17.9 pg/ml (p = 0.006), the presence of ischaemic heart disease (p = 0.03), and male sex (p = 0.04). CONCLUSIONS LVD is associated with a considerable mortality rate in this population. BNP also independently predicts outcome. In addition to its role as a diagnostic aid in chronic heart failure and LVD, it provides prognostic information and clarifies the meaning of a given degree of LVD.
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ADEPT: Addition of the AT1 receptor antagonist eprosartan to ACE inhibitor therapy in chronic heart failure trial: hemodynamic and neurohormonal effects. Am Heart J 2001; 141:800-7. [PMID: 11320369 DOI: 10.1067/mhj.2001.114802] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
BACKGROUND Persistent activation of the renin-angiotensin-aldosterone-system (RAAS) is known to occur in patients with chronic heart failure (CHF) despite treatment with angiotensin-converting enzyme inhibitor (ACE) therapy. When added to ACE inhibitors, angiotensin II type 1 (AT1) antagonists may allow more complete blockade of the RAAS and preserve the beneficial effects of bradykinin accumulation not seen with AT1 receptor blockade alone. METHODS Thirty-six patients with stable New York Heart Association class II-IV CHF receiving ACE inhibitor therapy were randomly assigned in a double-blind manner to receive either eprosartan, a specific competitive AT1 receptor antagonist (400 to 800 mg daily, n = 18) or placebo (n = 18) for 8 weeks. The primary outcome measure was left ventricular ejection fraction (LVEF) as measured by radionuclide ventriculography, and secondary measures were central hemodynamics assessed by Swan-Ganz catheterization and neurohormonal effects. RESULTS There was no change in LVEF with eprosartan therapy (mean relative LVEF percentage change [SEM] +10.5% [9.3] vs +10.1% [5.0], respectively; difference, 0.4; 95% confidence interval [CI], -20.8 to 21.7; P =.97). Eprosartan was associated with a significant reduction in diastolic blood pressure and a trend toward a reduction in systolic blood pressure compared with placebo (-7.3 mm Hg [95% CI, -14.2 to -0.4] diastolic; -8.9 mm Hg [95% CI, -18.6 to 0.8] systolic). No significant change in heart rate or central hemodynamics occurred during treatment with eprosartan compared with placebo. A trend toward an increase in plasma renin activity was noted with eprosartan therapy. Eprosartan was well tolerated, with an adverse event profile similar to placebo, whereas kidney function remained unchanged. CONCLUSIONS When added to an ACE inhibitor, eprosartan reduced arterial pressure without increasing heart rate. There was no change in LVEF after 2 months of therapy with eprosartan.
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Abstract
Insulin resistance is of pathogenic importance in several common human disorders including type 2 diabetes, hypertension, obesity and hyperlipidemia, but the underlying mechanisms are unknown. The spontaneously hypertensive rat (SHR) is a model of these human insulin resistance syndromes. Quantitative trait loci (QTLs) for SHR defects in glucose and fatty acid metabolism, hypertriglyceridemia, and hypertension map to a single region on rat chromosome 4. Genetic analysis of an SHR derived from a National Institutes of Health colony led to the identification of a causative mutation in the SHR Cd36. We have investigated glucose and fatty acid metabolism in the stroke-prone SHR (SHRSP). We demonstrate defects in insulin action on 2-deoxy-D-glucose transport (SHRSP 3.3 +/- 1.5 vs. 21.0 +/- 7.4 pmol x min(-1) x [20 microl packed cells](-1), SHRSP vs. WKY, respectively, P = 0.01) and inhibition of catecholamine-stimulated lipolysis (P < 0.05 at all concentrations of insulin) in adipocytes isolated from SHRSP. In contrast, basal levels of catecholamine-stimulated nonesterified free fatty acid (NEFA) release and plasma levels of NEFA are similar in SHRSP and WKY. These results are in agreement with the data on the SHR.4 congenic strain, which suggested that the QTL containing Cd36 mutations accounted for the entire defect in basal catecholamine action but only for approximately 40% of the SHR defect in insulin action. In the SHR, both abnormalities appear consequent of defective Cd36 expression. Because Cd36 sequence and expression are apparently normal in SHRSP, it is likely that the molecular mechanism for defective insulin action in this strain is caused by a gene(s) different than Cd36.
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Investigation of estrogen status and increased stroke sensitivity on cerebral blood flow after a focal ischemic insult. J Cereb Blood Flow Metab 2000; 20:931-6. [PMID: 10894176 DOI: 10.1097/00004647-200006000-00005] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Recently the authors have shown that female stroke-prone spontaneously hypertensive rats (SHRSPs) in proestrus (high endogenous estrogen), sustain more than 20% smaller infarcts after middle cerebral artery occlusion (MCAO) compared with SHRSPs in metestrus (low endogenous estrogen). Because estrogen has vasodilator properties, the authors investigated whether the estrous state influences cerebral blood flow (CBF) after MCAO. CBF was measured 2.5 hours after a distal MCAO by [14C]iodo-antipyrine autoradiography in conscious SHRSPs either in metestrus or in proestrus. There were no significant differences in CBF when analyzed either at predetermined anatomic regions or by cumulative distribution analysis of areas with flow <25 mL/100 g/min. As a positive internal control, the authors compared results in SHRSPs with those in their normotensive reference strain, Wistar Kyoto rat. SHRSPs displayed more severe and widespread ischemia than Wistar Kyoto rats. Thus, the absence of demonstrable CBF differences between estrous states appears to be unrelated to the CBF measurement paradigm. In conclusion, the smaller infarct size afforded in proestrus in SHRSPs is unlikely to be due to an influence on CBF.
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Abstract
OBJECTIVE Adrenomedullin inhibits angiotensin II stimulated aldosterone production in vitro and in vivo in experimental animals. The aim of this study was to investigate the effect of adrenomedullin on angiotensin II and adrenocorticotrophic hormone-stimulated aldosterone production in vivo in healthy humans. DESIGN AND METHODS Seven volunteers were studied in a quiet, temperature-controlled laboratory. After 35 min of rest, an infusion of placebo or adrenomedullin (3 pmol/kg per min) was given over 60 min; 15 min after starting this first infusion, a second infusion of angiotensin II (0.96 fmol/kg per min) or adrenocorticotrophic hormone (0.1 mIU/kg per min) was co-infused and continued for 45 min. RESULTS Adrenomedullin significantly inhibited angiotensin II stimulated aldosterone production: the increment in aldosterone on the placebo day was 691 pmol/l compared with 552 pmol/l on the adrenomedullin day (P< 0.004). Adrenomedullin did not inhibit adrenocorticotrophic hormone-stimulated aldosterone or cortisol release. CONCLUSION Adrenomedullin selectively inhibits angiotensin II-stimulated aldosterone production.
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Titration of vasodilator therapy in chronic heart failure according to plasma brain natriuretic peptide concentration: randomized comparison of the hemodynamic and neuroendocrine effects of tailored versus empirical therapy. Am Heart J 1999; 138:1126-32. [PMID: 10577444 DOI: 10.1016/s0002-8703(99)70079-7] [Citation(s) in RCA: 172] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
BACKGROUND Most patients with chronic heart failure (CHF) receive the same dose of angiotensin-converting enzyme (ACE) inhibitors because there is currently no measure of treatment efficacy. We sought to determine whether titration of vasodilator therapy according to plasma brain natriuretic peptide (BNP) concentration may be of value in the individual optimization of vasodilator therapy in CHF. METHODS AND RESULTS Twenty patients with mild to moderate CHF receiving stable conventional therapy including an ACE inhibitor were randomly assigned to titration of ACE inhibitor dosage according to serial measurement of plasma BNP concentration (BNP group) or optimal empirical ACE inhibitor therapy (clinical group) for 8 weeks. Only the BNP-driven approach was associated with significant reductions in plasma BNP concentration throughout the duration of the study and a significantly greater suppression when compared with empiric therapy after 4 weeks [-42.1% (-58.2, -19.7) vs -12.0% (-31.8, 13.8), P =.03]. Both treatment strategies were well tolerated and associated with favorable neurohormonal and hemodynamic effects; however, in comparison between groups, mean heart rate fell (P =.02) and plasma renin activity rose (P =.03) in the BNP group when compared with the clinical group. CONCLUSIONS Plasma BNP concentration may be chronically reduced by tailored vasodilator therapy in CHF. Furthermore, titration of vasodilator therapy according to plasma BNP was associated with more profound inhibition of the renin-angiotensin-aldosterone system and significant fall in heart rate when compared with empiric therapy.
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Structural and functional assessment of small arteries in patients with chronic heart failure. Clin Sci (Lond) 1999; 97:671-9. [PMID: 10585894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Abstract
The physiological response to a chronically failing heart is the implementation of compensatory mechanisms intended to support blood pressure. These mechanisms, which are not fully understood, increase peripheral vascular tone, thus increasing the strain on the weakened myocardium. This study investigated the structure and function of small arteries from heart failure patients and controls without heart failure in an attempt to identify abnormalities associated with heart failure which may be related to these mechanisms. Small arteries were dissected from gluteal biopsies and studied using wire myography. Arterial morphological parameters were measured and concentration-response curves constructed for a number of vasoconstrictor and vasodilator agonists. Plasma concentrations of neuroendocrine hormones were also measured. There were no morphological differences between small arteries from control subjects and those from patients with chronic heart failure. In heart failure patients, vasoconstrictor responses to endothelin-1 were significantly reduced, although plasma endothelin-1 levels were increased. Arteries from heart failure patients also showed evidence of an impaired neuronal uptake mechanism, since blockade by cocaine had no effect on noradrenaline-induced vasoconstriction in these vessels. These results suggest that small-artery structure is not altered in chronic heart failure and so cannot account for the heightened vascular resistance in this syndrome. However, abnormal neuronal uptake and impaired vasoconstriction in response to endothelin-1 may be associated with the complex compensatory phenomenon involved in heart failure.
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Nonadherence with angiotensin-converting enzyme inhibitor therapy: a comparison of different ways of measuring it in patients with chronic heart failure. J Am Coll Cardiol 1999; 34:2072-7. [PMID: 10588226 DOI: 10.1016/s0735-1097(99)00439-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
OBJECTIVES This study was designed to compare different proposed methods of assessing adherence with angiotensin-converting enzyme (ACE) inhibitor (ACEI) therapy in chronic heart failure. BACKGROUND The use of ACEIs in chronic heart failure gives us a unique opportunity to assess a patient's adherence by measuring whether the expected biochemical effect of an ACEI is present in the patient's bloodstream. In fact, there are several different ways of assessing ACE in vivo: these are serum ACE activity itself, plasma N-acetyl-seryl-aspartyl-lysyl-proline (AcSDKP), urine AcSDKP, plasma angiotensin I (AI), plasma angiotensin II (AII), or the AII/AI ratio. METHODS Patients with chronic heart failure (n = 39) were randomized to regimens of ACEI nonadherence for one week, ACEI adherence for one week or two versions of partial adherence for one week, after which the above six tests were performed. RESULTS All six tests significantly distinguished between full nonadherence for one week and full or partial adherence. Only plasma AcSDKP produced a significantly different result between partial adherence and either full adherence or full nonadherence for one week. In terms of their ability to distinguish full nonadherence from full adherence, plasma AcSDKP was 89% sensitive and 100% specific with an area under its ROC of 0.95. Corresponding figures for urine AcSDKP were 92%, 97% and 0.95 and for serum ACE they were 86%, 95% and 0.90. CONCLUSIONS All six tests distinguished full nonadherence from all other forms of adherence. The rank order of performance was plasma AcSDKP, urine AcSDKP, serum ACE, AII/AI ratio and plasma AII followed by plasma AI.
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No acute additive effect of losartan in a patient already on an ACE inhibitor for heart failure. J Hum Hypertens 1999; 13:797-8. [PMID: 10578227 DOI: 10.1038/sj.jhh.1000922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Abstract
BACKGROUND Cardiac cachexia is a syndrome of generalised wasting which caries a poor prognosis and is associated with raised plasma concentrations of tumour necrosis factor alpha (TNFalpha). TNFalpha increases secretion of leptin, a hormone which decreases food intake and increases energy expenditure. OBJECTIVE To determine whether an inappropriate increase in plasma leptin concentration contributes to the cachexia of chronic heart failure. DESIGN Retrospective case-control study. SETTING Tertiary referral cardiology unit. PATIENTS 110 human subjects comprising 29 cachectic chronic heart failure patients, 22 non-cachectic chronic heart failure patients, 33 patients with ischaemic heart disease but normal ventricular function, and 26 healthy controls. INTERVENTIONS Measurement of: body fat content by skinfold thickness (cachectic males < 27%, females < 29%); plasma leptin, TNFalpha, and noradrenaline (norepinephrine); central haemodynamics in chronic heart failure patients at right heart catheterisation. MAIN OUTCOME MEASURES Plasma leptin concentration corrected for body fat content, plasma TNFalpha and noradrenaline concentration, and central haemodynamics. RESULTS Mean (SEM) plasma leptin concentrations were: 6.2 (0.6) ng/ml (cachectic heart failure), 16.9 (3.6) ng/ml (non-cachectic heart failure), 16.8 (3.0) ng/ml (ischaemic heart disease), and 18.3 (3.5) ng/ml (control) (p < 0.001 for cachectic heart failure v all other groups). Plasma leptin concentration remained significantly lower in the cachectic heart failure group even after correcting for body fat content and in spite of significantly increased TNFalpha concentrations. Thus plasma leptin was inappropriately low in cachectic chronic heart failure in the face of a recognised stimulus to its secretion. There was no significant correlation between plasma leptin, New York Heart Association class, ejection fraction, or any haemodynamic indices. CONCLUSIONS Leptin does not contribute to the cachexia of chronic heart failure. One or more leptin suppressing mechanisms may operate in this syndrome-for example, the sympathetic nervous system.
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How often are angiotensin II and aldosterone concentrations raised during chronic ACE inhibitor treatment in cardiac failure? Heart 1999; 82:57-61. [PMID: 10377310 PMCID: PMC1729098 DOI: 10.1136/hrt.82.1.57] [Citation(s) in RCA: 142] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
OBJECTIVE Angiotensin II (AII) and aldosterone are not always fully suppressed during chronic angiotensin converting enzyme (ACE) inhibitor treatment. In congestive heart failure (CHF) such failure of hormonal suppression is associated with increased mortality. This study examined how common AII and aldosterone increases are observed during routine clinical practice. PATIENTS AND METHODS 91 patients with symptomatic (mean New York Heart Association class 2.7) CHF (mean (SD) left ventricular ejection fraction 29.9 (8)%, range 9-46%) were studied 4-6 hours after ACE inhibitor dosing. A representative range of ACE inhibitors (enalapril, lisinopril, captopril, perindopril, and fosinopril) was examined. RESULTS Supine measurements showed a wide range of AII (10.5 (25.5) pg/ml), aldosterone (130.8 (136) pg/ml), and serum ACE (12.1 (13.3) EU/l; excludes captopril data) concentrations on diuretics. AII concentrations > 10 pg/ml were seen in 15% of patients, and aldosterone concentrations > 144 pg/ml were seen in 38% of patients. AII concentrations were significantly correlated (p < 0.001) with ACE but not with aldosterone concentrations. Aldosterone concentrations were not significantly correlated with ACE concentrations. CONCLUSIONS AII "reactivation" occurred in 15% and failure of aldosterone suppression in 38% of routine CHF patients taking ACE inhibitor treatment. AII "reactivation" was associated with both low and high levels of ACE activity, which suggests that multiple different mechanisms are at play. In patients with high plasma ACE concentrations, non-compliance should be considered along with inadequate dose titration. In patients with low plasma ACE and high AII concentrations, non-ACE mediated production of AII may be operative. Raised aldosterone concentrations appear to be more common than AII "reactivation". It is important to establish the cause of detectable or increased AII concentrations in a heart failure patient treated with an ACE inhibitor. The measurement of serum ACE may help to identify the likely cause as poor compliance or inadequate dose.
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Endothelin B receptors are functionally important in mediating vasoconstriction in the systemic circulation in patients with left ventricular systolic dysfunction. J Am Coll Cardiol 1999; 33:932-8. [PMID: 10091818 DOI: 10.1016/s0735-1097(98)00663-9] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
OBJECTIVES This study was designed to assess the functional importance of endothelin (ET)B receptors in patients with left ventricular systolic dysfunction (LVSD) by comparing the hemodynamic effects of ET-1, a nonselective ET(A) and ET(B) agonist, with ET-3, a selective ET(B) receptor agonist. BACKGROUND Knowledge of the functional importance of ET(B) receptors in mediating vasoconstriction in chronic heart failure will help determine whether antagonists at both ET(A) and ET(B) receptors are required to fully prevent vasoconstriction to endogenously produced ET-1. METHODS We infused ET-1 (5 and 15 pmol/min) and ET-3 (5 and 15 pmol/min) into two separate groups of eight patients with LVSD with similar baseline hemodynamic indices. Hemodynamics were measured using a pulmonary thermodilution catheter and an arterial line. RESULTS Endothelin-1 infusion led to systemic vasoconstriction, with a rise in mean arterial pressure (mean +/- SEM 100 +/- 3 to 105 +/- 3 mm Hg, p < 0.02) and systemic vascular resistance (1,727 +/- 142 to 2,055 +/- 164 dyn/s/cm(-5), p < 0.001) and a fall in cardiac index (2.44 +/- 0.21 to 2.22 +/- 0.20 liters/min/m , p < 0.01). Endothelin-3 infusion also led to systemic vasoconstriction, with a rise in mean arterial pressure (99 +/- 6 to 105 +/- 6 mm Hg, p < 0.01) and systemic vascular resistance (1,639 +/- 210 to 1,918 +/- 245 dyn/s/cm(-5), p < 0.01) and a fall in cardiac index (2.66 +/- 0.28 to 2.42 +/- 0.24 liters/min/m2, p < 0.05). Pulmonary hemodynamic measurements did not change significantly in either group. CONCLUSIONS Both ET-1 and ET-3 infusions led to systemic vasoconstriction; the hemodynamic changes observed were of a similar magnitude at the same molar concentration. This suggests that ET(B) receptors are functionally important in mediating vasoconstriction, at least in the systemic circulation, in patients with LVSD.
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Disparity between studies of the stability of BNP in blood: comparison of endogenous and exogenous peptide. Heart 1999; 81:212-3. [PMID: 9922362 DOI: 10.1136/hrt.81.2.212] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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Telemetry for cardiovascular monitoring in a pharmacological study: new approaches to data analysis. Hypertension 1999; 33:248-55. [PMID: 9931112 DOI: 10.1161/01.hyp.33.1.248] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Radio-telemetry systems offer the ability to measure blood pressure and heart rate in experimental models of hypertension without the stress artifacts induced by some other methods. We therefore aimed to develop improved, nonparametric regression methods for radio-telemetry data and to use these to assess the effects of pharmacological interventions on cardiac and vascular hypertrophy in the stroke-prone spontaneously hypertensive rat. One control group and 5 groups treated either with losartan (alone or in combination with NG-nitro-L-arginine methyl ester [ L-NAME]), perindopril (also alone or in combination with L-NAME), or hydralazine plus hydrochlorothiazide were monitored for 4 weeks. Cardiac hypertrophy was assessed by the left ventricle plus septum weight to body weight ratio and vascular hypertrophy by flow-cytometry analysis of vascular smooth muscle cell polyploidy. Hemodynamic series were split into trend and cyclic components by the seasonal and trend decomposition procedure based on Loess and compared between groups by Loess regression modeling. Systolic and diastolic blood pressures were reduced systematically by losartan and perindopril (P<10(-10)) but to a lesser extent by hydralazine plus hydrochlorothiazide (P<10(-8)), and diurnal variation was reduced in the latter group (P<10(-6)). L-NAME significantly reduced the hypotensive effect only of losartan. Vascular and cardiac hypertrophy were significantly attenuated with losartan or perindopril, but were unchanged with other treatments. The new analysis proposed here identifies differential effects on trends and cyclic variation and associations with regression of end-organ damage for losartan and perindopril compared with hydralazine plus hydrochlorothiazide. The method offers a powerful tool for detailed investigation of radio-telemetry data.
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ACE (I/D) genotype as a predictor of the magnitude and duration of the response to an ACE inhibitor drug (enalaprilat) in humans. Circulation 1998; 98:2148-53. [PMID: 9815869 DOI: 10.1161/01.cir.98.20.2148] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND We have investigated the possible effects of contrasting ACE (I/D) genotypes on the responses to the ACE inhibitor enalaprilat in normotensive men. METHODS AND RESULTS Subjects with DD (n=12) and II (n=11) ACE genotypes received an intravenous infusion of enalaprilat or placebo. Pressor responses to stepwise, incremental doses of angiotensin I were measured at 1 and 10 hours after dosing. The dose required to raise mean blood pressure by 20 mm Hg (PD20) was calculated individually, and the ratio of PD20 during enalaprilat to that during placebo (dose ratio, DR) was used for assessment of the extent of ACE inhibition. The pressor response was significantly attenuated at 1 hour after enalaprilat in both groups, but significant attenuation was evident at 10 hours after dose only in the II subjects. The DRs at both 1 hour (median, 5.43 versus 2.82, P=0.0035) and 10 hours (2.06 versus 0.84, P=0.0008) after enalaprilat were significantly higher in II subjects than in DD subjects. CONCLUSIONS The effect of enalaprilat was significantly greater and lasted longer in normotensive men homozygous for the II ACE genotype. By multivariate analysis, ACE (I/D) genotype and plasma angiotensin II levels were predictive of >50% of the variation in response to ACE inhibition.
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Endothelin-1 has haemodynamic effects at pathophysiological concentrations in patients with left ventricular dysfunction. Cardiovasc Res 1998; 39:563-70. [PMID: 9861298 DOI: 10.1016/s0008-6363(98)00084-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
OBJECTIVES Plasma levels of immunoreactive endothelin-1 (ET-1) are raised in chronic heart failure. Whether plasma ET-1 contributes to the haemodynamic derangement found in chronic heart failure is not known. We investigated the effects of exogenous ET-1 on the pulmonary and systemic vasculature in patients with left ventricular systolic dysfunction (LVD), with or without overt heart failure. METHODS ET-1 was infused at 1, 5 and 15 pmol/min into a distal pulmonary artery of ten patients with LVD to achieve plasma concentrations of ET-1 similar to those found in patients with heart failure and pulmonary hypertension. Haemodynamics were measured using a pulmonary thermodilution catheter and an arterial line. Intravascular Doppler and local pulmonary angiography were used to assess local pulmonary blood flow in the first four patients. RESULTS Systemic haemodynamic changes occurred with ET-1 infusion: mean arterial pressure (100 +/- 3 [standard error of the mean]) to 107 +/- 3 mmHg; p < 0.01) and systemic vascular resistance (1699 +/- 118 to 2033 +/- 135 dynes s/cm5; p < 0.001) rose, while the cardiac index fell from 2.43 +/- 0.17 to 2.20 +/- 0.16 l/min/m2 (p < 0.002). Mean pulmonary artery pressure (21 +/- 2 mmHg) and pulmonary vascular resistance (151 +/- 14 to 147 +/- 14 dynes s/cm5) did not change however. CONCLUSIONS Exogenous ET-1, when infused to achieve plasma concentrations similar to those in severe heart failure and pulmonary hypertension, causes systemic but not pulmonary vasoconstriction.
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Abstract
BACKGROUND In previous studies on the use of natriuretic peptides to detect left-ventricular systolic dysfunction, a higher rate of cardiac disorders in the control groups than in the study groups could have led to bias. We investigated the effectiveness of plasma N-terminal atrial natriuretic peptide (NT-ANP) and brain natriuretic peptide (BNP) concentrations to show left-ventricular systolic dysfunction in a random sample of the general population. METHODS We randomly selected 2000 participants aged 25-74 years from family physicians' lists in Glasgow, UK. We sent all participants questionnaires. 1653 respondents underwent echocardiography and electrocardiography. We took a left-ventricular ejection fraction of 30% or less to show left-ventricular systolic dysfunction. NT-ANP and BNP were measured in plasma by RIAs. FINDINGS 1252 participants had analysable electrocardiograms and echocardiograms, completed questionnaires, and available blood samples. Median concentrations of NT-ANP and BNP were significantly higher in participants with left-ventricular systolic dysfunction (2.8 ng/mL [IQR 1.8-4.6] and 24.0 pg/mL [18.0-33.0]) than in those without (1.3 ng/mL [0.9-1.8] and 7.7 pg/mL [3.4-13.0]; each p < 0.001). Among participants with left-ventricular systolic dysfunction, both symptomatic and asymptomatic subgroups had raised NT-ANP and BNP concentrations. A BNP concentration of 17.9 pg/mL or more gave a sensitivity of 77% and specificity of 87% in all participants, and 92% and 72% in participants aged 55 years or older. INTERPRETATION Measurement of BNP could be a cost-effective method of screening for left-ventricular systolic dysfunction in the general population, especially if its use were targeted to individuals at high risk.
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