bluuebunny/crossref_metadata_2025 huggingface dataset:
Bronchoalveolar lavage fluids of patients with lung injury activate the transcription factor nuclear factor-κB in an alveolar cell line
Authors: NYS M. , DEBY-DUPONT G. , HABRAKEN Y. , LEGRAND-POELS S. , LEDOUX D. , CANIVET J.-L. , DAMAS P. , LAMY M.
Published: August 2015

In bronchoalveolar lavage (BAL) fluid from ventilated patients, cytotoxic oxidant activity is correlated with neutrophil activation. The aim of the present study was to investigate the hypothesis that BAL fluid induces activation of the transcription nuclear factor-κB (NF-κB) in human alveolar cells, in correlation with inflammatory mediators. We measured endotoxin, inflammatory cytokines [interleukin-1β (IL-1β), IL-8], nitrated proteins and the activity of myeloperoxidase (MPO) in BAL fluid from ventilated patients developing bronchopneumonia (n = 19 samples) or with acute respiratory distress syndrome (ARDS) (n = 14), and from ARDS/infection-free patients (n = 11). We also exposed alveolar cells to the BAL fluid or to human MPO, H2O2 or HOCl, and tested nuclear extracts for the activation of NF-κB. IL-1β, IL-8, nitrated protein, MPO and endotoxin levels were significantly higher in BAL fluid from patients with bronchopneumonia than in that from the ARDS and ARDS/infection-free groups. A correlation was observed between IL-8 and MPO values (r = 0.82). The level of NF-κB activity induced by the BAL fluid was correlated with levels of IL-1β (P<0.001), IL-8 (P<0.005) and MPO (P<0.002), and with the neutrophil count (P<0.002), and was higher for BAL fluid from the bronchopneumonia group. NF-κB activation by MPO was also demonstrated. The activation of NF-κB by BAL fluid, especially that from bronchopneumonia patients, suggests that a similar phenomenon may occur in vivo, leading to potential amplification of the inflammatory reaction.
Augmented endothelial uptake of oxidized low-density lipoprotein in response to endothelin-1
Authors: MORAWIETZ Henning , DUERRSCHMIDT Nicole , NIEMANN Bernd , GALLE Jan , SAWAMURA Tatsuya , HOLTZ Juergen
Published: August 2015

Endothelin-1 (ET-1) may be involved in the development and progression of atherosclerosis. Furthermore, endothelin receptor blockade was shown to reduce the formation of atherosclerotic lesions in experimental studies. Another potent pro-atherosclerotic risk factor is oxidized low-density lipoprotein (oxLDL). Endothelial cells mediate the uptake of oxLDL by the recently identified lectin-like oxLDL receptor-1 (LOX-1), which accumulates in atherosclerotic lesions. In the present study, we analysed the effects of ET-1 on oxLDL uptake and LOX-1 expression in primary cultures of human umbilical vein endothelial cells (HUVEC). ET-1 stimulated uptake of oxLDL in HUVEC, which reached a maximum after 1h. In further studies, we found a similar induction of LOX-1 mRNA and protein expression in response to ET-1. The augmented oxLDL uptake and the increased LOX-1 expression in response to ET-1 are mediated by the endothelin receptor B. Our data support a new pathophysiological mechanism by which locally and systemically increased ET-1 levels, e.g. in hypertensive patients, could promote LOX-1-mediated oxLDL uptake in human endothelial cells. This mechanism could promote the development and progression of endothelial dysfunction and atherosclerosis. In addition, endothelin receptor blockade could be considered as a new anti-atherosclerotic therapeutic principle.
Endothelin-1 induces mucosal mast cell degranulation and tissue injury via ETA receptors
Authors: BOROS Mihály , SZALAY László , KASZAKI József
Published: August 2015

The effects of endothelin-1 (ET-1) on mucosal mast cells are of special interest, since they may be an important component of the tissue response that occurs during ischaemic preconditioning or ischaemia/re-oxygenation injuries. Increasing doses of ET-1 were administered intravenously to anaesthetized rats. In a second series of experiments, animals were pretreated with the ETA receptor antagonists BQ-610 or ETR-P1/fl peptide, or with the ETB receptor antagonist IRL-1038. Intestinal perfusion changes were recorded, and the proportion of degranulated mast cells and the degree of mucosal damage were determined in ileal biopsies. ET-1 induced dose-dependent alterations in the haemodynamic and morphological parameters, and caused significant mast cell degranulation. These changes were inhibited significantly by pretreatment with the ETA receptor antagonists, but not with the ETB receptor antagonist. We conclude that a cross-talk exists between endothelial cell-derived humoral mediators and the intestinal mast cell system.
The immunosuppressive drug mycophenolic acid reduces endothelin-1 synthesis in endothelial cells and renal epithelial cells
Authors: HAUG Cornelia , SCHMID-KOTSAS Alexandra , LINDER Theresia , JEHLE Peter M. , BACHEM Max G. , GRUENERT Adolf , ROZDZINSKI Eva
Published: August 2015

Several studies have demonstrated that endothelin-1 (ET-1) plays an important pathophysiological role in ischaemic renal failure and drug-induced renal injury, such as cyclosporine A (CsA)- and tacrolimus-associated nephrotoxicity. This study aimed to investigate whether the new immunosuppressive drug mycophenolic acid (MPA), which in contrast with CsA and tacrolimus lacks nephrotoxic side effects, modulates ET-1 synthesis in endothelial cells and renal epithelial cells. ET-1 release by cultured human umbilical vein endothelial cells (HUVEC), human renal artery endothelial cells (RAEC) and rabbit proximal tubule cells was measured with a specific ELISA. ET-1 mRNA expression was investigated by reverse transcription–PCR. MPA (2.5–50µg/ml) induced a significant decrease in ET-1 mRNA expression (minimum 51.8±3.8% of control; P<0.001) in HUVEC and RAEC. After a 48h incubation with MPA (1–50µg/ml), a significant decrease in ET-1 release per culture well (minimum 56.8±1.7%; P<0.001) and DNA content per culture well (minimum 58.7±1.9%; P<0.001) was observed with HUVEC and RAEC, whereas ET-1 release referred to the DNA content in the corresponding culture well did not differ significantly from controls. In rabbit proximal tubule cells, ET-1 release referred to the cell number in the corresponding culture well was also reduced after incubation with MPA (minimum 86.2±2.4%; P<0.05). This study provides evidence that, in contrast with CsA and tacrolimus, MPA does not stimulate ET-1 synthesis. The present results might explain the clinical observation that renal function often improves when CsA or tacrolimus is replaced by mycophenolate mofetil.
Role of endothelin-1 receptors in the sarcolemma membrane and the nuclear membrane in the modulation of basal cytosolic and nuclear calcium levels in heart cells
Authors: BKAILY Ghassan , MASSAAD Danie , CHOUFANI Sanaa , JACQUES Danielle , D'ORLÉANS-JUSTE Pedro
Published: August 2015

Our previous work in heart cells showed that the nuclear envelope membranes possess receptors, such as those for angiotensin II. Using non-working single cells from the hearts of 10-day chick embryos and the confocal microscopy technique, our present results show that stimulation of endothelin-1 (ET-1) receptors at the sarcolemma membrane induced a dose-dependent sustained increase in basal cytosolic and nuclear calcium levels that was insensitive to the ETA and ETB receptor antagonists BQ123 and BQ788. The cytosolic application of ET-1 induced a dose-dependent increase in the sustained basal nuclear Ca2+ concentration that was insensitive to BQ123 and BQ788. The ET-1 receptors at the nuclear envelope membrane were more sensitive to ET-1 than those located at the sarcolemma membrane of heart cells. Cytosolic application of ET-1 prevented sustained basal cytosolic Ca2+ uptake by the nuclei. The use of an ET-1 fluorescent probe demonstrated the presence of ET-1 receptors at both the sarcolemma membrane and the nuclear envelope membrane. Thus our results suggest that ET-1 receptors that are insensitive to BQ123 and BQ788 are present at both the sarcolemma and nuclear envelope membranes. Extracellular and cytosolic ET-1 may play a role in regulating basal cytosolic and nuclear Ca2+ levels in heart cells.
Acute endothelinA receptor antagonism improves coronary artery compliance in coronary artery disease patients
Authors: KYRIAKIDES Zenon S. , KREMASTINOS Dimitrios Th. , KOLOKATHIS Fotis , KOSTOPOULOU Anna , GEORGIADIS Michael , WEBB David J.
Published: August 2015

Endothelin (ET) exerts a tonic, stiffening effect on the common carotid artery in rats in vitro. This effect is mediated via the ETA receptor. The aim of this study was to examine the acute effects of ETA receptor antagonism on coronary artery compliance in humans. We examined 22 patients with stable angina after diagnostic coronary arteriography. Intracoronary BQ-123 (6µmol), an ETA receptor antagonist (14 patients), or saline (8 patients), was infused in an artery without significant lesion over 20min. The artery lumen area in the proximal arterial segment was measured at end diastole and end systole before and after BQ-123 or saline administration using an intravascular ultrasound catheter. Calculations were made of absolute (in mm2/mmHg×103) and normalized compliance index (in mmHg-1×103). Pulse pressure decreased from 64±21 to 61±17mmHg after BQ-123 administration and increased from 59±16 to 68±20mmHg after saline administration (F = 9.54, P = 0.006). The respective changes in absolute compliance index were from 24±18 to 39±25 and from 19±15 to 14±17 (F = 6.43, P = 0.02). Normalized compliance index changed from 2.5±2.0 to 3.6±2.4 and from 2.7±2.6 to 1.6±1.8 (F = 11.92, P = 0.002) respectively, in the two groups. Acute ETA receptor antagonism improves coronary artery compliance in coronary artery disease patients.
Coronary responses to endothelin-1 and acetylcholine during partial coronary ischaemia and reperfusion in anaesthetized goats
Authors: MARTÍNEZ Maria Angeles , FERNÁNDEZ Nuria , MONGE Luis , GARCÍA-VILLALÓN Angel Luis , SANZ Elena , DIÉGUEZ Godofredo
Published: August 2015

To examine coronary reactivity to acetylcholine and endothelin-1 (ET-1) during partial ischaemia and reperfusion, flow in the left circumflex coronary artery was measured electromagnetically, and coronary partial ischaemia was induced by stenosis of this artery in anaesthetized goats. In eight animals not treated with NG-nitro-L-arginine methyl ester (L-NAME), coronary stenosis reduced coronary flow by 45%, mean arterial pressure by 16% and coronary vascular conductance by 34%. During this ischaemia, coronary vasodilatation to acetylcholine (0.003–0.1µg) and sodium nitroprusside (SNP; 1–10µg) was markedly reduced, and coronary vasoconstriction to ET-1 (0.01–0.3nmol) was attenuated. After 30min of reperfusion, coronary flow, mean arterial pressure and coronary vascular conductance remained decreased, and the effects of acetylcholine, SNP and ET-1 were as in control animals. In six goats treated with NG-nitro-L-arginine methyl ester, coronary stenosis reduced coronary flow by 26% and coronary vascular conductance by 24%, but did not affect mean arterial pressure. During this ischaemia, coronary vasodilatation to acetylcholine and SNP was also markedly reduced, but vasoconstriction to ET-1 was unaffected. After 30min of reperfusion, coronary flow and coronary vascular conductance remained decreased and mean arterial pressure was normal; in addition, the effects of acetylcholine were lower, those of SNP were similar and those of ET-1 were higher than in control animals. Therefore partial ischaemia reduces the coronary vasodilator reserve and blunts coronary vasoconstriction to ET-1, and reperfusion does not alter the endothelium-dependent and -independent coronary vasodilatation or vasoconstriction to ET-1.
Expressed monophasic action potential alternans before the onset of ventricular arrhythmias induced by intracoronary bolus administration of endothelin-1 in dogs
Authors: MERKELY Béla , VÁGÓ Hajnalka , KISS Orsolya , ZIMA Endre , SZÜCS Gábor , GELLÉR László , Juhász-Nagy Alexander
Published: August 2015

We showed previously a direct arrhythmogenic effect of the intracoronary infusion of endothelin-1 (ET-1). We aimed to examine the electrophysiological effects of intracoronary bolus administration of ET-1 using monophasic action potential (MAP) recordings. Eight mongrel dogs received boli of ET-1 (1 and 2nmol) into the left anterior descending coronary artery. These intracoronary ET-1 boli rapidly caused a marked decrease in coronary blood flow (1nmol, 78±7%; 2nmol, 89±7%). Ischaemic changes of MAP morphology, a decrease in upstroke velocity (baseline, 1.78±0.2V/s; 1nmol, 0.95±0.18V/s; 2nmol, 0.45±0.21V/s; P<0.01) and a decrease in MAP duration at 90% repolarization (MAPD90) [1nmol, from 191±3 to 176±5ms (P<0.05); 2nmol, from 212±4 to 180±8ms (P<0.05)] occurred after ET-1 bolus administration. However, at 7–10min after the 1nmol bolus, a significant increase in MAPD90 was observed (10min, in the left ventricular anterior epicardial region: from 191±3 to 206±6ms; P<0.05). The incidence of ventricular arrhythmias was as follows: after the 1nmol ET-1 bolus: ventricular tachycardia, 3/8 animals; ventricular fibrillation, 1/8; after the 2nmol ET-1 bolus: ventricular tachycardia, 5/7; ventricular fibrillation, 5/7. MAP alternans was present in each animal (1nmol, 18.2±5.8%; 2nmol, 10.8±2.5%). Thus electrophysiological and coronary blood flow changes indicate the predominance of an ischaemic arrhythmogenic effect of the bolus administration of ET-1 (shortening of action potential duration; appearance of MAP alternans), whereas the observed delayed prolongation of MAPD90 suggests a direct arrhythmogenic effect of ET-1. The expressed MAP alternans could have a pathogenic role in the onset of ventricular arrhythmias induced by an intracoronary bolus of ET-1.
Treatment with darusentan over 21 days improved cGMP generation in patients with chronic heart failure
Authors: PHILIPP Sebastian , MONTI Jan , PAGEL Ines , LANGENICKEL Thomas , NOTTER Thomas , RUSCHITZKA Frank , LÜSCHER Thomas , DIETZ Rainer , WILLENBROCK Roland
Published: August 2015

In heart failure, the cGMP to natriuretic peptide ratio is decreased and infusion of atrial natriuretic peptide (ANP) induces less cGMP generation. The ratio of the second messenger cGMP to plasma concentrations of ANP or brain natriuretic peptide (BNP) correlates with the effectiveness of natriuretic peptides. It was investigated whether blockade of the ETA receptor might improve the cGMP:NP ratio in heart failure. Patients with chronic heart failure (n = 142; mean age = 57 years) received oral treatment with the ETA antagonist darusentan (either 30, 100, 300mg/day or placebo) on top of standard therapy over a period of 21 days in a randomized, double-blind, placebo-controlled, multicentre study. Plasma concentrations of ANP, BNP and cGMP were determined before randomization and after 21 days of treatment. In parallel with decreased pulmonary and systemic vascular resistance, 3 weeks of oral treatment with the ETA receptor antagonist darusentan reduced BNP plasma levels and increased the cGMP:BNP ratio significantly. The improved cGMP:BNP ratio might reflect the ability of chronic ETA receptor blockade to facilitate the generation of the second messenger cGMP, which points towards a favourable modulation of the natriuretic peptide effector system, in addition to haemodynamic improvement in heart failure patients.
Chronic effects of an endothelin-converting enzyme inhibitor on cardiorenal and hormonal function in heart failure
Authors: WADA Atsuyuki , OHNISHI Masato , TSUTAMOTO Takayoshi , FUJII Masanori , MATSUMOTO Takehiro , YAMAMOTO Takashi , WANG Xinwen , KINOSHITA Masahiko
Published: August 2015

Endothelin (ET)-converting enzyme (ECE) is a rate-limiting step in ET-1 generation, and its expression and activity are increased significantly with the development of congestive heart failure (CHF). The selective enzymic inhibition of ET-1 formation thus seems to be a very important target in the prevention of CHF. We evaluated the chronic effects of a specific ECE inhibitor, FR901533 (0.3mg·kg-1·h-1, n = 5) on cardiac, hormonal, and body fluid balance in dogs with CHF induced by rapid right ventricular pacing (270beats/min, 22 days). Vehicle dogs were given placebo (n = 5). Despite no significant difference in blood pressure, FR901533 decreased pulmonary capillary wedge pressure and increased cardiac output compared with the vehicle. FR901533 prevented the reduction of urine flow rate and urinary sodium excretion in association with an increase in the glomerular filtration rate and renal plasma flow compared with the vehicle. FR901533 also suppressed significantly the elevation of plasma atrial natriuretic peptide and aldosterone levels which is an established prognostic factor in CHF. These results indicate that the role of ECE in CHF is important and that chronic ECE inhibition could possess therapeutic potential in the treatment of CHF not only on haemodynamics but also in the prevention of fluid retention.
Role of endothelin-1 in the development of a special type of cardiomyopathy
Authors: ZSÁRY A. , SZÜCS S. , SCHNEIDER T. , ROSTA A. , SÁRMÁN P. , FENYVESI T. , KARÁDI I.
Published: August 2015

The role of endothelin-1 (ET-1) in certain pathological states is still unclear. We have investigated the effect of anthracyclines (maximum dose, 450mg/m2 of body surface) on left ventricular systolic and diastolic function and how it influences the level of plasma ET-1 in 21 patients (12 female and nine male) with Hodgkin and non-Hodgkin lymphoma. We also studied the association between plasma ET-1 concentration and echocardiographic parameters. Serum ET-1 was measured by ELISA. Left ventricular function was analysed by echocardiography: ejection fraction (EF), velocity–time integral, E- and A-waves, E:A ratio, deceleration time (DT) and Doppler index were all measured. Statistical analysis was made by the Wilcoxon rank test. EF and serum ET-1 level decreased significantly (EF, 56.29±5.0% to 48.57±5.9%, P<0.0001; ET-1, 6.45±4.0pg/ml to 2.9±1.0pg/ml, P<0.0001). DT increased significantly (179.8±47.8ms to 215.5±66.7ms, P<0.01) after anthracycline therapy. There was no difference in other echocardiographic parameters before and after therapy. The decrease in serum ET-1 concentration might be a result of anthracycline's direct cytotoxic effect and the decreasing level of ET-1 can play a role in the reduction of EF. However, more studies are needed to evaluate the presence and severity of endothelial damage.
Influence of endothelin receptor antagonists on myocardial protein kinase C isoforms in uraemic cardiomyopathy
Authors: WOLF Sabine C. , AMEND Thorsten , RISLER Teut , AMANN Kerstin , BREHM Bernhard R.
Published: August 2015

Increased endothelin-1 (ET-1) levels were found in patients with chronic renal failure and these correlate with the severity of renal failure. Increased mortality due to cardiovascular problems is observed in patients with elevated ET-1 concentrations. The aim of this study was to find out the influence of ET-1 and ET receptor antagonists on myocardial protein kinase C (PKC) regulation in uraemic cardiomyopathy. Male rats were subtotally nephrectomized and treated with an ETA-receptor antagonist (30mg·kg-1·day-1, LU302146) or an ETAB-receptor antagonist (30mg·kg-1·day-1, LU302872) for 12 weeks. One group was left untreated (SNX) and one group was sham-operated (sham). Systolic blood pressure, myocardial weight and the changes of the protein kinase C isoforms in the heart were determined. PKC isoforms α and δ were investigated by Western blot analysis using specific antibodies. In the SNX group, systolic blood pressure rose to 154±5mmHg after 12 weeks. The ETA receptor antagonist prevented this increase in blood pressure, but ETAB antagonism did not. Left ventricular weight increased in SNX; this increase was inhibited by the ETA receptor antagonist. In comparison with the sham group, PKC isoform α increased by 19% in SNX animals. When the SNX animals were treated with ETA or ETAB antagonists, PKC isoform α levels decreased by 31%. PKC isoform δ levels decreased by 35% in SNX animals. Treatment with both ETA or ETAB antagonists increased PKC isoform δ levels to normal. In the myocardium of uraemic rats PKC isoforms are differentially regulated with an increase in α isoform but a decrease in δ isoform. ET receptor blockers normalize these PKC isoforms.
Stimulation of peroxisome-proliferator-activated receptor α (PPAR α) attenuates cardiac fibrosis and endothelin-1 production in pressure-overloaded rat hearts
Authors: OGATA Takehiro , MIYAUCHI Takashi , SAKAI Satoshi , IRUKAYAMA-TOMOBE Yoko , GOTO Katsutoshi , YAMAGUCHI Iwao
Published: August 2015

Endothelin-1 (ET-1) production is increased in hypertrophied hearts accompanied with fibrosis. ET-1 is a potent mitogen of fibroblasts and ET receptor antagonists are reported to inhibit the proliferation of fibroblasts and cardiac fibrosis. Peroxisome-proliferator-activated receptor α (PPARα), one of the nuclear hormone receptors, suppresses activator protein-1 (AP-1), one of the nuclear transcription factors. Activation of PPARα is reported to inhibit thrombin-induced ET-1 production by repressing the AP-1 signalling pathway in vascular endothelial cells. We investigated effects of the PPARα activator fenofibrate (80mg/kg per day, per os) on mRNA levels of ET-1, collagen type I and type III and histological features of myocardial fibrosis in hypertrophied rat hearts due to pressure-overload by abdominal aortic banding (AB). The treatment with fenofibrate or vehicle was started 7 days before the AB operation. Four days after the AB operation, fenofibrate treatment significantly reduced ET-1 mRNA expression compared with vehicle treatment in AB rat hearts. Collagen type I and type III mRNA expression, and interstitial and perivascular fibrosis were attenuated in the fenofibrate-treated AB rat group. Since the ET-1 gene has AP-1 response elements in the 5´-flanking region, it is suggested that myocardial fibrosis is effectively inhibited by fenofibrate through suppression of AP-1-mediated ET-1 gene augmentation in the pressure-overloaded heart caused by aortic banding in rats.
Interaction of endogenous endothelin-1 and inhaled nitric oxide in term and preterm infants
Authors: TRUOG William E. , PALLOTTO Eugenia , CLARK Perry , BANKS Beverly , KAFTAN Harold A. , EKEKEZIE Ikechukwu I. , NORBERG Mike , BALLARD Roberta A.
Published: August 2015

The peptide endothelin-1 (ET-1) plays an unknown role in the pathogenesis and progression of two important neonatal pulmonary disorders, chronic lung disease (CLD) of prematurity and persistent pulmonary hypertension of the newborn (PPHN). Inhaled nitric oxide (INO) is a proven vasodilator therapy in PPHN and is an experimental therapy in CLD. We sought to determine the effects, if any, of the interaction of inhaled INO with ET-1 in these two separate disorders. Infants (n = 21) with PPHN (mean gestation age, 39.4 weeks; mean birth weight, 3470g) were treated with INO. All infants were <72h of age at baseline. Plasma obtained at baseline and after 24h of INO therapy was assessed for ET-1. The change in ET-1 levels with INO was inversely correlated with change in arterial partial pressure of O2 (r =-0.71, P = 0.0003). A separate group of 33 patients with CLD (mean gestational age, 27 weeks; mean birth weight, 740g; mean age, 19 days) had tracheal aspirate levels of ET-1 obtained before, during, and after 7 days' administration of INO. Values were normalized by soluble secretory component of IgA. Tracheal aspirate ET-1 levels were detectable before INO therapy. There was no significant change during or after treatment with INO. There was not a significant correlation between baseline fractional inspired O2 and ET-1 levels. There was a non-significant trend in the correlation between the change in ET-1 and the change in interleukin-8 levels in tracheal aspirate. This report confirms the presence of ET-1 in tracheal aspirate of premature infants who are developing CLD and reaffirms the presence of ET-1 in plasma of infants with PPHN. Short-term INO therapy was associated with a decrease in plasma ET-1 levels in PPHN, but did not affect tracheal aspirate ET-1 in CLD. Given the vasconstrictive, profibrotic, and proinflammatory properties of ET-1, specific ET-1 receptor antagonists could be considered as candidates for trials as adjunct therapy in either or both of these disorders.
Differential expression of neutral endopeptidase-24.11 (neprilysin) and endothelin-converting enzyme in human prostate cancer cell lines
Authors: USMANI Badar A. , HARDEN Ben , MAITLAND Norman J. , TURNER Anthony J.
Published: August 2015

Neutral endopeptidase-24.11 (neprilysin; NEP/CD10) is a cell surface metallopeptidase expressed by prostatic epithelial cells that degrades various bioactive peptides including endothelin. Endothelin-converting enzyme (ECE), the key enzyme of endothelin biosynthesis, catalyses the final processing step in the pathway. Neuropeptide substrates of NEP, including endothelin, have been implicated in the growth of androgen-independent prostate cancer. We have surveyed the expression of NEP and ECE in a range of prostate cancer cell lines. Western analysis reveals that ECE-1 is expressed abundantly in all the malignant cell lines tested, except for LNCaP. In contrast, LNCaP cells express high levels of NEP, while NEP was not detected in PC-3, DU145 and other metastatic cell lines that were tested. Of the normal immortalized prostate epithelial cell lines, PNT1a shows equivalent amounts of NEP and ECE. PNT2-C2 shows poor NEP expression but an abundance of ECE. P4E6, by comparison, has low levels of both ECE and NEP. These differences in expression may render these cell lines useful in experimental models for future study. Benign prostatic hyperplasia primary epithelial cells express much higher levels of NEP than malignant primary epithelial cells, but neither show ECE expression. On the other hand, surrounding stromal cell populations have detectable ECE levels. An absence of ECE in malignant and benign prostatic hyperplasia cells of primary epithelial origin suggests an important role for stromal interaction and paracrine production of ECE within the host. The upregulation of ECE expression in metastatic cells in culture may be indicative of its role in metastatic progression. A differential profile of ECE and NEP could contribute to an abundance of mitogenic peptides aiding the progression of androgen-independent prostate cancer.
Haemodynamic and hormonal changes during haemorrhage in conscious dogs treated with an endothelin-A receptor antagonist
Authors: HÖHNE Claudia , FRANCIS Roland C.E. , KACZMARCZYK Gabriele , BOEMKE Willehad
Published: August 2015

This study compares the haemodynamic and hormonal responses during haemorrhage of conscious dogs pre-treated with an endothelin-A (ET-A) receptor inhibitor. The dogs were studied in two different randomized groups: the control group and a group that was given the ET-A receptor antagonist ABT-627 (as a bolus of 1mg·kg of body weight-1 followed by 0.01mg·kg body weight-1·min-1 intravenously). The time-course was the same for both groups: after a 1h baseline period (pre-haemorrhage), blood (25ml·kg of body weight-1) was withdrawn within 5min. Haemodynamics were continuously recorded and hormone levels measured after 1h (post-haemorrhage). Thereafter, the blood withdrawn was retransfused within 5min and haemodynamics again observed for 1h (post-retransfusion). In ABT-627-treated dogs, the decrease in mean arterial pressure from 87±3 to 64±3mmHg (P<0.05 versus pre-haemorrhage), and cardiac output from 2.1±0.1 to 1.3±0.1l·min-1 (P<0.05 versus pre-haemorrhage) and the increase in systemic vascular resistance from 3286±174 to 4211±230dyn·s·cm-5 (P<0.05 versus pre-haemorrhage) during acute haemorrhage are comparable with controls. During haemorrhage in controls, vasopressin levels increased from 0±0 to 13±2pg·ml-1 (P<0.05 versus pre-haemorrhage), angiotensin II levels increased from 9±1 to 28±9pg·ml-1 (P<0.05 versus pre-haemorrhage) and adrenaline levels increased from 134±22 to 426±74pg·ml-1 (P<0.05 versus pre-haemorrhage) whereas noradrenaline levels did not change (approx. 200 pg·ml-1). In ABT-627-treated dogs, vasopressin levels increased from 0.2±0.0 to 22.2±6.1pg·ml-1 (P<0.05 versus pre-haemorrhage and P<0.05 versus control), angiotensin II levels increased from 8±1 to 37±8pg·ml-1 (P<0.05 versus pre-haemorrhage), noradrenaline levels increased from 147±16 to 405±116pg·ml-1 (P<0.05 versus pre-haemorrhage) and adrenaline levels did not change (200 pg·ml-1) during haemorrhage. We conclude from our results that dogs receiving the selective ET-A inhibitor ABT-627 seem to show a different hormonal response after haemorrhage compared with controls, displaying considerably higher noradrenaline concentrations. Independent of ET-A receptor inhibition, cardiac output during haemorrhage was maintained within the control range. This may indicate that the organism is defending blood flow (cardiac output) over blood pressure during haemorrhage, and that this defence strategy is not compromised by ET-A receptor inhibition.
Impact of parainfluenza-3 virus infection on endothelin receptor density and function in guinea pig airways
Authors: D'APRILE Angela C. , FERNANDES Lynette B. , RIGBY Paul J. , GOLDIE Roy G.
Published: August 2015

We examined the impact of parainfluenza-3 (P-3) respiratory tract viral infection on the density and function of endothelin (ET) receptor subtypes (ETA and ETB) in guinea pig tracheal smooth muscle. Total specific binding of [125I]ET-1 and the relative proportions of ETA and ETB binding sites for this ligand were assessed at day 0 (control) and at 2, 4, 8 and 16 days post-inoculation. At day 0, the proportions of ETA and ETB binding sites were 30% and 70% respectively. Total specific binding was significantly reduced at day 4 post-inoculation (32% reduction, n = 8–12, P<0.05) and was largely due to a corresponding fall in ETB receptor density at this time point (38% reduction, n = 8–12, P<0.05). The density of ETA receptors also fell significantly at day 8 post-inoculation (33% reduction, n = 6–12, P<0.05). By day 16 post-inoculation, the densities of ETA and ETB receptors had recovered to control values. The ratio of ETA:ETB receptor subtypes did not alter with P-3 infection. While P-3 infection reduced the density of tracheal smooth muscle ETA and ETB receptors, the contractile sensitivity and maximum response to carbachol and ET-1 was not altered in tissue from day 4 post-inoculation compared with the control. There seems to be a significant functional reserve for both receptor subtypes in this species that buffers the impact of P-3 infection on airway smooth muscle responsiveness to ET-1.
Role of endothelin-converting enzyme, chymase and neutral endopeptidase in the processing of big ET-1, ET-1(1-21) and ET-1(1-31) in the trachea of allergic mice
Authors: DE CAMPO Benjamin A. , GOLDIE Roy G. , JENG Arco Y. , HENRY Peter J.
Published: August 2015

The present study examined the roles of endothelin-converting enzyme (ECE), neutral endopeptidase (NEP) and mast cell chymase as processors of the endothelin (ET) analogues ET-1(1–21), ET-1(1–31) and big ET-1 in the trachea of allergic mice. Male CBA/CaH mice were sensitized with ovalbumin (10µg) delivered intraperitoneal on days 1 and 14, and exposed to aerosolized ovalbumin on days 14, 25, 26 and 27 (OVA mice). Mice were killed and the trachea excised for histological analysis and contraction studies on day 28. Tracheae from OVA mice had 40% more mast cells than vehicle-sensitized mice (sham mice). Ovalbumin (10µg/ml) induced transient contractions (15±3% of the Cmax) in tracheae from OVA mice. The ECE inhibitor CGS35066 (10µM) inhibited contractions induced by big ET-1 (4.8-fold rightward shift of dose-response curve; P<0.05), but not those induced by either ET-1(1–21) or ET-1(1–31). The chymase inhibitors chymostatin (10µM) and Bowman-Birk inhibitor (10µM) had no effect on contractions induced by any of the ET analogues used. The NEP inhibitor CGS24592 (10µM) inhibited contractions induced by ET-1(1–31) (6.2-fold rightward shift; P<0.05) but not ET-1(1–21) or big ET-1. These data suggest that big ET-1 is processed predominantly by a CGS35066-sensitive ECE within allergic airways rather than by mast cell-derived proteases such as chymase. If endogenous ET-1(1–31) is formed within allergic airways, it is likely to undergo further conversion by NEP to more active products.
Effects of benazepril, an angiotensin-converting enzyme inhibitor, combined with CGS 35066, a selective endothelin-converting enzyme inhibitor, on arterial blood pressure in normotensive and spontaneously hypertensive rats
Authors: BATTISTINI Bruno , AYACH Bilal , MOLEZ Stéphanie , BLOUIN Andre , JENG Arco Y.
Published: August 2015

Continuous intra-arterial administration of a selective endothelin-converting enzyme (ECE) inhibitor CGS 35066 at a dose of 30mg/kg decreased the mean arterial blood pressure (MABP) in conscious unrestrained normotensive rats and spontaneously hypertensive rats (SHRs). At that dose, the magnitude of the antihypertensive effects was greater in SHRs than in normotensive rats. Additional administration of an angiotensin-converting enzyme (ACE) inhibitor benazapril (lotensin) further reduced MABP in normotensive rats and completely blocked hypertension in SHRs. However, when the selective ECE inhibitor was subsequently removed, blood pressure was less inhibited in normotenive rats whereas it remained strongly inhibited in SHRs by the ACE inhibitor alone. These results imply that simultaneous treatment with benazepril and CGS 35066 gave additive antihypertensive effects in normotensive rats but not in SHRs, when both compounds were administered at a dose of 30mg/kg. Our results suggest that: (i) the endothelin (ET) system together with the renin–angiotensin system contribute to the maintenance of blood pressure in normal healthy rats; (ii) while an ECE inhibitor acts as an antihypertensive agent on its own, the sole efficacy of ACE inhibitor at that dose is sufficient to block MABP without the participation of the ET system in SHR.
Oral administration of an inhibitor of endothelin-converting enzyme attenuates cerebral vasospasm following experimental subarachnoid haemorrhage in rabbits
Authors: KWAN Aij-Lie , LIN Chih-Lung , CHANG Chih-Zen , WINARDI Daniel , YEN Chun-Po , Wu Shu-Chuan , LEE Kevin S. , KASSELL Neal F. , HOWNG Shen-Long , SAVAGE Paula , JENG Arco Y.
Published: August 2015

Increasing evidence has implicated endothelin-1 (ET-1), a potent vasoconstrictive peptide, in the pathophysiology of cerebral vasospasm after subarachnoid haemorrhage (SAH). Endothelin-converting enzyme-1 (ECE-1), the protease involved in the final step of post-translational processing of ET-1, cleaves the inactive precursor big ET-1 at the Trp21–Val 22 peptide bond. In our previous study, we found that an inhibitor of ECE-1, CGS 26303, could prevent and reverse the arterial narrowing after SAH in rabbits. CGS 26393, a prodrug of CGS 26303, is an orally active, long-acting inhibitor of ECE-1. The present study examined the effects of CGS 26393 on the prevention and reversal of cerebral vasospasm after SAH. New Zealand white rabbits were subjected to experimental SAH by injecting autologous blood into the cisterna magna. In the prevention study, the drug was given orally 1h before the induction of SAH. All drug treatments in the reversal study were initiated at 23h after induction of SAH. One of three dosages (3, 10 or 30mg/kg) of CGS 26393 or vehicle was administrated orally twice daily, and all animals were sacrificed by perfusion and fixation 48h after SAH. Basilar arteries were removed and sectioned, and cross-sectional areas were measured. Cerebrospinal fluid (CSF) was collected prior to perfusion. Oral administration of CGS 26393 attenuated SAH-induced cerebral vasospasm in a dose-dependent manner in both the prevention and reversal groups. These effects achieved statistical significance at all dosages when compared with the SAH-only or SAH plus vehicle groups. Moreover, the attenuation of vasospasm following oral administration of CGS 26393 was more efficacious than that obtained with bolus injections of CGS 26303. The levels of free CGS 26303 in the CSF were increased in a dose-dependent manner in all three CGS 26393-treated groups. This study provides the first evidence that oral administration of an inhibitor of ECE-1, CGS 26393, is capable of preventing and reversing cerebral vasospasm following SAH. These findings also reinforce evidence demonstrating that treatment with an ECE-1 inhibitor is a potentially viable therapeutic approach for reducing cerebral vasospasm after SAH.
Effect of castration on endothelin receptors
Authors: PADLEY Robert J. , DIXON Douglas B. , WU-WONG J. Ruth
Published: August 2015

Endothelin (ET) plays a pivotal role in the pathogenesis of cell growth disorders such as cancer. Atrasentan (ABT-627), a selective antagonist for the ET receptor A (ETA), has shown benefit in controlling disease progression in men with hormone refractory prostate cancer who have undergone aggressive hormone ablation therapy. It is not known how hormone ablation affects ET-binding sites, although ET-1 and ETA expression are found to be elevated in prostate cancer patients. In this study, we examined the effect of castration on ET receptor binding in male beagle dogs. Three dogs were surgically castrated and another three sham-operated. The animals were sacrificed 1 week after operation and membranes were prepared from the prostate, heart, brain, kidney, liver and lung for ET-1, ET-3 and angiotensin II (A-II, as a control) binding studies. No significant difference in A-II binding was observed between castrated and sham-operated animals. However, ET-1 and ET-3 binding to prostate and brain membranes were altered significantly. From saturation binding studies using ET-1 in the prostate, the Kd and Bmax values increased from 0.043nM and 0.094pmol/mg respectively in sham-operated dogs to 0.104nM and 0.311pmol/mg respectively in castrated animals. These results indicate that surgical castration in dogs produces a change in the ET receptor density in the prostate and brain, and may have implications for the effect of hormone ablation therapy on ET receptor expression in prostate cancer patients.
DC-SIGN (dendritic cell-specific ICAM-grabbing non-integrin) and DC-SIGN-related (DC-SIGNR): friend or foe?
Authors: SOILLEUX Elizabeth J.
Published: August 2015

C-type lectins are calcium-dependent carbohydrate-binding proteins with a wide range of biological functions, many of which are related to immunity. DC-SIGN (dendritic cell-specific ICAM-grabbing non-integrin, where ICAM is intercellular adhesion molecule) is a recently described mannose-specific C-type lectin expressed by dendritic cells. Dendritic cells are potent antigen-presenting cells capable of activating T-lymphocytes. DC-SIGN, which is expressed by dendritic cells, binds to ICAM-3 on T-lymphocytes, therefore playing an important role in the activation of T-lymphocytes. DC-SIGN can also bind HIV, and the virus may remain bound to DC-SIGN for protracted periods. DC-SIGN may deliver bound HIV to permissive cell types, mediating infection with high efficiency. A closely related C-type lectin, DC-SIGN-related molecule (DC-SIGNR) has also been described. DC-SIGNR is expressed by restricted subsets of endothelial cells, but has similar ICAM-3 and HIV-binding properties to DC-SIGN. This review describes the mapping of DC-SIGN and DC-SIGNR to chromosome 19p13.3 adjacent to the previously described C-type lectin, CD23 [the low-affinity receptor for immunoglobulin E (FcERII)]. The similar genomic organization of these three genes is discussed and consideration is given to the evolutionary duplications that may underlie this arrangement. Both DC-SIGN and DC-SIGNR possess a neck region, made up of multiple repeats, which supports the ligand-binding domain. Consideration is given to the biological reasons underlying the considerable polymorphism in the numbers of repeats in DC-SIGNR, but not DC-SIGN. The expression patterns of both DC-SIGN and DC-SIGNR are discussed in detail, with particular attention to the expression of both molecules in the placenta, which may have implications for the vertical transmission of HIV. Since dendritic cells may be important in determining the phenotype of many immune responses, via effects on T-lymphocytes, the differential expression of DC-SIGN by particular dendritic cell subsets may have important implications for the immunobiological functions of DC-SIGN. Similarly, the expression of DC-SIGNR by very restricted subsets of endothelial cells may give clues to the function of DC-SIGNR. Finally, the role of DC-SIGN in pathology, particularly in infective and neoplastic processes, is discussed, followed by speculation about likely future developments in this field.
Dissociation of augmented physiological, hormonal and cognitive responses to hypoglycaemia with sustained caffeine use
Authors: WATSON J.M. , SHERWIN R.S. , DEARY I.J. , SCOTT L. , KERR D.
Published: August 2015

In patients with Type I diabetes and healthy volunteers, ingestion of modest amounts of caffeine augments the usual symptomatic and counter-regulatory responses to hypoglycaemia. The aim of the present study was to determine whether these are lost with sustained caffeine use, i.e. does tolerance develop? Eleven healthy caffeine consumers underwent two identical hyperinsulinaemic glucose clamp procedures. For 7 days prior to each clamp, subjects consumed a caffeine-free diet supplemented with 200mg of caffeine capsules twice daily (caffeine-replete) or placebo (caffeine-withdrawn). During each clamp, blood glucose was held for 80min at 4.5mmol/l and then 2.5mmol/l. At 85min, subjects were given a 200mg caffeine capsule. Measurements were taken of symptoms, plasma catecholamine, middle cerebral artery blood velocity (VMCA) and cognition. Following the acute caffeine challenge and during hypoglycaemia, VMCA fell only in the caffeine-withdrawn condition [-5.1 (-7.3, -3.0)cm/s compared with -1.9 (-4.0, +0.2) cm/s in caffeine-replete condition; P<0.04; values are differences (95% confidence intervals)]. Plasma catecholamine levels and global cognitive performance were unaffected by caffeine status, whereas tests of executive intellectual function were better preserved during hypoglycaemia in the caffeine-replete condition (P<0.05). The influence of caffeine on hypoglycaemic symptomatic awareness depended upon the duration of the hypoglycaemic stimulus. At onset, symptoms were more intense in caffeine-withdrawn state (P<0.01); however, with increasing duration of hypoglycaemia, symptom intensity was greater in caffeine-replete condition (P<0.05). Thus previous caffeine consumption influences the physiological and symptomatic responses to acute hypoglycaemia, but complete tolerance does not develop with sustained use.
CX3CR1-expressing inflammatory dendritic cells contribute to the progression of steatohepatitis
Authors: Sutti Salvatore , Locatelli Irene , Bruzzì Stefania , Jindal Aastha , Vacchiano Marco , Bozzola Cristina , Albano Emanuele
Published: August 2015

Liver monocytes play a major role in the development of NASH (non-alcoholic steatohepatitis). In inflamed tissues, monocytes can differentiate in both macrophages and dendritic cells. In the present study, we investigated the role of moDCs (monocyte-derived inflammatory dendritic cells) in experimental steatohepatitis induced in C57BL/6 mice by feeding on a MCD (methionine/choline-deficient) diet. The evolution of steatohepatitis was characterized by an increase in hepatic CD45+/CD11b+ myeloid cells displaying the monocyte/macrophage marker F4-80+. In the early phases (4 weeks of treatment), Ly6Chigh/CD11b+/F4-80+ inflammatory macrophages predominated. However, their frequency did not grow further with the disease progression (8 weeks of treatment), when a 4-fold expansion of CD11b+/F4-80+ cells featuring the fractalkine receptor (CX3CR1) was evident. These CX3CR1+ cells were also characterized by the combined expression of inflammatory monocyte (Ly6C, CD11b) and dendritic cell (CD11c, MHCII) markers as well as by a sustained TNFα (tumour necrosis factor α) production, suggesting monocyte differentiation into inflammatory moDCs. The expansion of TNFα-producing CX3CR1+ moDCs was associated with an elevation in hepatic and circulating TNFα level and with the worsening of parenchymal injury. Hydrogen sulfide (H2S) has been shown to interfere with CX3CR1 up-regulation in monocyte-derived cells exposed to pro-inflammatory stimuli. Treating 4-week-MCD-fed mice with the H2S donor NaHS while continuing on the same diet prevented the accumulation of TNFα-producing CX3CR1+ moDCs without interfering with hepatic macrophage functions. Furthermore, NaHS reduced hepatic and circulating TNFα levels and ameliorated transaminase release and parenchymal injury. Altogether, these results show that inflammatory CX3CR1+ moDCs contributed in sustaining inflammation and liver injury during steatohepatitis progression.
Remediation of Residual /r/ Errors: A Case Study Using the SATPAC Approach
Authors: Flipsen, Peter , Sacks Stephen
Published: August 2015

Residual speech production errors may occur in up to 1–2% of the adult population. Although they don't usually interfere with message intelligibility, potential negative impacts have been documented. The current report discusses the challenges of remediating these errors and errors related to /r/ in particular. It then presents an alternative intervention approach (called SATPAC) that uses a combination of nonwords, a bunched /r/ (rather than the more commonly targeted retroflex /r/), multimodal feedback (including visual and tactile), and homework. A case study is presented to illustrate the potential success of this approach.
“Minute to Win It”: Using Elevator Speeches to Advocate in Educational Speech-Language Pathology and Audiology
Authors: Ellis Kellie C. , Gottfred Catherine , Freiberg Christine
Published: August 2015

Elevator speeches, or brief talks in which individuals pitch an idea, sell a solution to a problem, or raise awareness of an issue, have gained increasing popularity within the business world. While school-based professionals may not view themselves as having to “sell,” audiologists and speech-language pathologists are in the business of “selling” our ability to create change for students with communication disorders. Elevator speeches serve as a viable advocacy tool and can be used influence decision-makers and bring about meaningful change in our professions. This article equips readers with knowledge of how to craft a winning elevator speech, provides examples of instances in which school-based professionals could use elevator speeches, and presents information on how to assess the success of elevator speeches.
Recent review on image clustering
Authors: Ahmed Nasir
Published: August 2015

In this review, image clustering problem is discussed starting from global learning based clustering approaches such as Kmeans to the recent challenges in this domain. In global learning based clustering models, cluster evaluation criteria was formulated on whole image datasets. In local learing based clustering models, local neighbourhood information in image data matrices were utilised. However, performances of local learning based clustering models may face limitations for image datasets that contain images with pose, illumination, or occlusion variations. Further, both global learning and local learning approaches were combined in clustering models. Still, image clustering performances are not significantly improved. I elaborate challenges in image clustering problem by categorising image datasets as Gaussian‐like or multimodal. Clustering performances on 14 benchmark image datasets of almost all state‐of‐the‐art clustering models are optimal only for Gaussian‐like image datasets. Thus, image clustering performance has direct correlation with the distribution of image datasets. Further, by employing optimal image descriptor, clustering performances are data dependent. Almost all exiting clustering models are based on second‐order statistics. Owing to which, multimode image patterns may not be effectively handled even by exploiting both local and global information in image data matrices.