bluuebunny/crossref_metadata_2025 huggingface dataset:
Atherosclerosis in APOE*3-Leiden Transgenic Mice
Authors: Lutgens Esther , Daemen Mat , Kockx Mark , Doevendans Pieter , Hofker Marten , Havekes Louis , Wellens Hein , de Muinck Ebo D.
Published: June 2012

Background
—This study documents (1) the progression of atherosclerosis along the entire arterial tree in APOE*3-Leiden mice after 1, 4, 6, 9, and 12 months of a high-fat/high-cholesterol (HFC) diet and (2) the amount and phenotype of DNA-synthesizing and apoptotic cells in different lesion types after 6 months of HFC diet.

Methods and Results
—Diet duration was correlated with a craniocaudal progression of lesion development and with an increase in severity of the lesion. Typically, the lesions contained smooth muscle cells, macrophages, and T lymphocytes and were covered by an intact endothelium. Whereas DNA synthesis (BrdU uptake) was usually elevated in type II lesions (8.6±0.8% versus 1.0±0.2% in the nondiseased arterial wall;
P
<0.05), apoptosis was found primarily in advanced lesions (type IV, 1.3±0.1% and type V, 1.2±0.2% versus 0.04±0.04% in the nondiseased arterial wall [
P
<0.05]). Cell phenotyping revealed that the majority of DNA synthesis and apoptosis was confined to the macrophage-derived foam cell (68.6±3.0% and 82.2±4.6%, respectively).

Conclusions
—This study shows that in APOE*3-Leiden mice, duration of an HFC diet is associated with (1) a craniocaudal progression of lesion development and (2) an increased complexity of atherosclerotic lesions. Furthermore, DNA synthesis is predominant in early lesions, whereas apoptosis is present mainly in more advanced lesions. Both parameters of cell turnover are confined primarily to the macrophage-derived foam cell.
Exaggerated Endothelin Release in High-Altitude Pulmonary Edema
Authors: Sartori Claudio , Vollenweider Laurent , Löffler Bernd-Michael , Delabays Alain , Nicod Pascal , Bärtsch Peter , Scherrer Urs
Published: June 2012

Background
—Exaggerated pulmonary hypertension is thought to play an important part in the pathogenesis of high-altitude pulmonary edema (HAPE). Endothelin-1 is a potent pulmonary vasoconstrictor peptide that also augments microvascular permeability.

Methods and Results
—We measured endothelin-1 plasma levels and pulmonary artery pressure in 16 mountaineers prone to HAPE and in 16 mountaineers resistant to this condition at low (580 m) and high (4559 m) altitudes. At high altitude, in mountaineers prone to HAPE, mean (±SE) endothelin-1 plasma levels were ≈33% higher than in HAPE-resistant mountaineers (22.2±1.1 versus 16.8±1.1 pg/mL,
P
<0.01). There was a direct relationship between the changes from low to high altitude in endothelin-1 plasma levels and systolic pulmonary artery pressure (
r
=0.82,
P
<0.01) and between endothelin-1 plasma levels and pulmonary artery pressure measured at high altitude (
r
=0.35,
P
=0.05).

Conclusions
—These findings suggest that in HAPE-susceptible mountaineers, an augmented release of the potent pulmonary vasoconstrictor peptide endothelin-1 and/or its reduced pulmonary clearance could represent one of the mechanisms contributing to exaggerated pulmonary hypertension at high altitude.
Significance of Myocytes With Positive DNA In Situ Nick End-Labeling (TUNEL) in Hearts With Dilated Cardiomyopathy
Authors: Kanoh Motoo , Takemura Genzou , Misao Jun , Hayakawa Yukihiro , Aoyama Takuma , Nishigaki Kazuhiko , Noda Toshiyuki , Fujiwara Takako , Fukuda Kazunori , Minatoguchi Shinya , Fujiwara Hisayoshi
Published: June 2012

Background
—The presence of apoptotic myocytes has been reported in human hearts with dilated cardiomyopathy (DCM) on the basis of a positive finding of DNA in situ nick end-labeling (TUNEL). However, ultrastructural evidence of myocyte apoptosis has not been obtained.

Methods and Results
—A total of 80 endomyocardial biopsies were obtained from right and left ventricles of 20 patients with DCM and 20 normal control subjects. TUNEL-positive myocytes were found by light microscope in 15% of DCM specimens (controls, 0%,
P
<0.05), and the percentage of TUNEL-positive myocytes per section in DCM was 1.0±2.7% (mean±SD). According to TUNEL at the electron microscopic level (EM-TUNEL), immunogold particles, which label DNA breaks with 3′-OH terminals, were markedly accumulated in the bizarre-shaped nuclei, with widespread clumping of chromatin (so-called “hypertrophied nuclei”) of the myocytes obtained from DCM. Their ultrastructure was neither apoptotic nor necrotic but rather that of living cells.
Taq
polymerase–based DNA in situ ligation assay, which detects double-stranded DNA fragments more specifically than TUNEL, did not detect a positive reaction in any case. In mirror sections, all of the TUNEL-positive myocytes in DCM simultaneously expressed proliferating cell nuclear antigen, which is required for both DNA replication and repair, but Ki-67, a replication-associated antigen, was completely negative in all cases, which appeared to rule out cell proliferation activity.

Conclusions
—Most of the TUNEL-positive myocytes in hearts with DCM are not apoptotic but rather living cells with increasing activity of DNA repair.
Autonomic Modification of the Atrioventricular Node During Atrial Fibrillation
Authors: Mazgalev Todor N. , Garrigue Stéphane , Mowrey Kent A. , Yamanouchi Yoshio , Tchou Patrick J.
Published: June 2012

Background
—Postganglionic vagal stimulation (PGVS) by short bursts of subthreshold current evokes release of acetylcholine from myocardial nerve terminals. PGVS applied to the atrioventricular node (AVN) slows nodal conduction. However, little is known about the ability of PGVS to control ventricular rate (VR) during atrial fibrillation (AF).

Methods and Results
—To quantify the effects and establish the mechanism of PGVS on the AVN, AF was simulated by random high right atrial pacing in 11 atrial-AVN rabbit heart preparations. Microelectrode recordings of cellular action potentials (APs) were obtained from different AVN regions. Five intensities and 5 modes of PGVS delivery were evaluated. PGVS resulted in cellular hyperpolarization, along with depressed and highly heterogeneous intranodal conduction. Compact nodal AP exhibited decremental amplitude and dV/dt and multiple-hump components, and at high PGVS intensities, a high degree of concealed conduction resulted in a dramatic slowing of the VR. Progressive increase of PGVS intensity and/or rate of delivery showed a significant logarithmic correlation with a decrease in VR (
P
<0.001). Strong PGVS reduced the mean VR from 234 to 92 bpm (
P
<0.001). The PGVS effects on the cellular responses and VR during AF were fully reproduced in a model of direct acetylcholine injection into the compact AVN via micropipette.

Conclusions
—These studies confirmed that PGVS applied during AF could produce substantial VR slowing because of acetylcholine-induced depression of conduction in the AVN.
Practice of Coronary Angioplasty in California in 1995
Authors: Rill Velisar , Brown David L.
Published: June 2012

Background
—This study seeks to analyze changes in the practice of PTCA in California between 1989 and 1995 by use of the Office of Statewide Health Planning and Development (OSHPD) data set.

Methods and Results
—All hospital discharges in 1995 with a procedure code for PTCA or stent were identified. The 1995 PTCA data were compared with previously published data from 1989 obtained from the same database. The number of PTCAs performed increased by 49% between 1989 and 1995, from 24 883 to 37 118. The percentage of female patients increased from 29.8% to 32.7% (
P
=0.0001). The percentage of diabetics increased from 14.4% to 21.6% (
P
=0.0001) between 1989 and 1995. Procedures on patients with a principal diagnosis of acute myocardial infarction increased from 19.3% of all PTCAs in 1989 to 27.5% of PTCAs in 1995 (
P
=0.0001). In-hospital mortality increased from 1.4% in 1989 to 1.9% in 1995 (
P
=0.0001). There were 3087 admissions with stent placement in 1995. In-hospital mortality after stent placement was 0.9% (
P
=0.0001 versus PTCA). Patients undergoing PTCA in hospitals performing >400 PTCAs in 1995 had a 4% incidence of death or emergency bypass surgery compared with a 6% incidence when PTCAs were performed in hospitals performing ≤400 PTCA in 1995 (
P
<0.0001). Patients undergoing stent implantation in hospitals performing >75 stent procedures in 1995 had a 1.3% incidence of death or emergency bypass compared with an incidence of 4% when the procedure was performed in a hospital performing ≤75 stent placements in 1995 (
P
<0.0001).

Conclusions
—The 1995 OSHPD data continue to suggest an inverse relationship between hospital PTCA and stent volume and adverse patient outcomes.
Prevalence of Myocardial Viability as Detected by Positron Emission Tomography in Patients With Ischemic Cardiomyopathy
Authors: Auerbach Martin Allen , Schöder Heiko , Hoh Carl , Gambhir Sanjiv Sam , Yaghoubi Shariar , Sayre Jim W. , Silverman Daniel , Phelps Michael E. , Schelbert Heinrich R. , Czernin Johannes
Published: June 2012

Background
—Detection of myocardial viability is important in patients with ischemic cardiomyopathy. Restoration of blood flow to viable myocardium is associated with improved left ventricular function and improved patient prognosis. However, the prevalence of viable myocardium in patients with ischemic cardiomyopathy is unknown.

Methods and Results
—To determine the prevalence of myocardial viability, clinical [
13
N]ammonia/
18
F-deoxyglucose PET studies performed in 283 patients (age, 63±10 years) with ischemic heart disease (mean ejection fraction, 26±8%) were visually analyzed for the presence and extent of viable and nonviable myocardium. The myocardium was divided into 19 segments. The extent of viable myocardium was considered “functionally” significant if ≥5 segments (≈25% of the left ventricular myocardium) exhibited a blood flow/metabolism mismatch and “prognostically” significant if 1 to 4 left ventricular segments did so. Of all patients, 41% had no evidence of viable myocardium, 55% had viable myocardium, and 4% had normal blood flow and metabolism within an enlarged left ventricle. Functionally significant viability was found in 27% and prognostically significant viability in 28% of the patients. Multivariate analysis revealed the presence of angina to be the only clinical parameter associated with the presence of functionally significant viability.

Conclusions
—Revascularization might improve patient prognosis in 55% and result in improved left ventricular function in 27% of all patients with ischemic cardiomyopathy.
Blood Flow Dynamics in Heart Failure
Authors: Shoemaker J. Kevin , Naylor Heather L. , Hogeman Cynthia S. , Sinoway Lawrence I.
Published: June 2012

Background
—Exercise intolerance in heart failure (HF) may be due to inadequate vasodilation, augmented vasoconstriction, and/or altered muscle metabolic responses that lead to fatigue.

Methods and Results
—Vascular and metabolic responses to rhythmic forearm exercise were tested in 9 HF patients and 9 control subjects (CTL) during 2 protocols designed to examine the effect of HF on the time course of oxygen delivery versus uptake (protocol 1) and on vasoconstriction during exercise with 50 mm Hg pressure about the forearm to evoke a metaboreflex (protocol 2). In protocol 1, venous lactate and H
+
were greater at 4 minutes of exercise in HF versus CTL (
P
<0.05) despite similar blood flow and oxygen uptake responses. In protocol 2, mean arterial pressure increased similarly in each group during ischemic exercise. In CTL, forearm blood flow and vascular conductance were similar at the end of ischemic and ambient exercise. In HF, forearm blood flow and vascular conductance were reduced during ischemic exercise compared with the ambient trial.

Conclusions
—Intrinsic differences in skeletal muscle metabolism, not vasodilatory dynamics, must account for the augmented glycolytic metabolic responses to moderate-intensity exercise in class II and III HF. The inability to increase forearm vascular conductance during ischemic handgrip exercise, despite a normal pressor response, suggests that enhanced vasoconstriction of strenuously exercising skeletal muscle contributes to exertional fatigue in HF.
Preintervention Arterial Remodeling as an Independent Predictor of Target-Lesion Revascularization After Nonstent Coronary Intervention
Authors: Dangas George , Mintz Gary S. , Mehran Roxana , Lansky Alexandra J. , Kornowski Ran , Pichard Augusto D. , Satler Lowell F. , Kent Kenneth M. , Stone Gregg W. , Leon Martin B.
Published: June 2012

Background
—Pathological and intravascular ultrasound (IVUS) studies have documented arterial remodeling during atherogenesis. However, the impact of this remodeling process on the long-term outcome after percutaneous intervention is unknown.

Methods and Results
—We used preintervention IVUS to define positive and negative/intermediate remodeling in a total of 777 lesions in 715 patients treated with nonstent techniques. Positive remodeling (lesion external elastic membrane area greater than average reference) was present in 313 lesions; intermediate/negative remodeling (lesion external elastic membrane area less than or equal to reference) was present in the other 464. Baseline clinical and angiographic characteristics were similar, except for a slightly higher percentage of insulin-dependent diabetic patients (10.2% versus 6.1%;
P
=0.054) in the negative/intermediate-remodeling group. Angiographic success and in-hospital and short-term complications were comparable in the 2 groups. There was no significant correlation between remodeling (as a continuous variable) and final lumen area (
r
=0.06) or final lesion plaque burden (
r
=0.17). At 18±13 months of clinical follow-up, both groups had similar rates of death and Q-wave myocardial infarction: 3.4% and 2.5% for the negative/intermediate-remodeling group versus 2.7% and 2.7% for the positive-remodeling group. However, the target-lesion revascularization (TLR) rate was 20.2% for the negative/intermediate-remodeling group versus 31.2% for the positive-remodeling group (
P
=0.007), and remodeling, as a continuous variable, was strongly correlated with probability of TLR (
P
=0.0001). By multivariable logistic regression analysis, diabetes (OR=2.3), left anterior descending artery location (OR=1.8), and remodeling (OR=5.9) were independent predictors of TLR.

Conclusions
—Positive lesion-site remodeling is associated with a higher long-term TLR after a nonstent interventional procedure. Thus, long-term clinical outcome appears to be determined in part by preintervention lesion characteristics.
Cholesterol Reduction Rapidly Improves Endothelial Function After Acute Coronary Syndromes
Authors: Dupuis Jocelyn , Tardif Jean-Claude , Cernacek Peter , Théroux Pierre
Published: June 2012

Background
—Cholesterol lowering reduces coronary events. One mechanism could be improvement of endothelial function. In line with this hypothesis, this study investigates whether cholesterol reduction can result in rapid improvement of endothelial function after acute coronary syndromes.

Methods and Results
—Patients with acute myocardial infarction or unstable angina and total cholesterol levels at admission ≥5.2 mmol/L or LDL ≥3.4 mmol/L were randomized to placebo (n=30) or pravastatin 40 mg daily (n=30) for 6 weeks. Brachial ultrasound was used to measure endothelium-dependent flow-mediated dilatation (FMD) and response to endothelium-independent nitroglycerin. Changes in the levels of markers of platelet activation, coagulation factors, and plasma endothelin levels were also assessed. Total and LDL cholesterol levels were similar at admission and before randomization in both groups. With pravastatin, but not with placebo, they decreased by 23% (
P
<0.05) and 33% (
P
<0.01), respectively. FMD was unchanged with placebo, 5.43±0.74% (mean±SEM) to 5.84±0.81%, but increased with pravastatin, 4.93±0.81% to 7.0±0.79% (
P
=0.02), representing a 42% relative increase. Responses to nitroglycerin were similar during the time course of the study in the 2 groups. Markers of platelet activity, coagulation factors, and endothelin levels were not affected by pravastatin.

Conclusions
—Cholesterol reduction with pravastatin initiated early after acute coronary syndromes rapidly improves endothelial function after 6 weeks of therapy.
Continuous Infusion of Epoprostenol Improves the Net Balance Between Pulmonary Endothelin-1 Clearance and Release in Primary Pulmonary Hypertension
Authors: Langleben David , Barst Robyn J. , Badesch David , Groves Bertron M. , Tapson Victor F. , Murali Srinivas , Bourge Robert C. , Ettinger Neil , Shalit Eileen , Clayton Linda M. , Jöbsis Maria M. , Blackburn Shelmer D. , Crow James W. , Stewart Duncan J. , Long Walker
Published: June 2012

Background
—Primary pulmonary hypertension results from progressive narrowing of the precapillary pulmonary vasculature. A variety of endothelial abnormalities have been identified, including a net reduction in pulmonary clearance of the vasoconstrictor and smooth muscle mitogen endothelin-1. In many patients, net pulmonary release of endothelin-1 is observed. Chronic infusions of epoprostenol (prostacyclin) improve functional capacity, survival, and hemodynamics in patients with advanced primary pulmonary hypertension. We hypothesized that the epoprostenol infusions, as compared with conventional therapy, might alter the abnormal pulmonary endothelin-1 homeostasis.

Methods and Results
—Using a subset of patients from a larger randomized study comparing epoprostenol plus conventional therapy (n=11 in the present study) with conventional therapy alone (n=7 in the present study), we determined the ratio of plasma endothelin-1 levels in systemic arterial blood leaving the lung to levels in mixed venous blood entering the lung both before randomization and after 88 days of continuous therapy. There were no differences between the 2 groups before therapy, but by day 88, the epoprostenol-treated group had a greater proportion of patients (82%) with an arterial/venous ratio <1 than did the conventional therapy group, in which only 29% of patients had a ratio <1 (
P
<0.05).

Conclusions
—These results suggest that continuous epoprostenol therapy may have a beneficial effect on the balance between endothelin-1 clearance and release in many patients with primary pulmonary hypertension and may provide one explanation for the salutary effect of epoprostenol in this disease.
Thrombin-Induced Platelet Activation Is Inhibited by High- and Low-Molecular-Weight Heparin
Authors: De Candia E. , De Cristofaro R. , Landolfi R.
Published: June 2012

Background
—Thrombin binds to platelet glycoprotein Ib (Gp Ib), and this interaction contributes to platelet activation. Thrombin ligation to Gp Ib was recently shown to be inhibited by heparin, thus raising the hypothesis, investigated in this article, that heparin might inhibit thrombin-induced platelet activation.

Methods and Results
—Aggregation of gel-filtered platelets by 1 nmol/L thrombin was reduced by both high-molecular-weight (MW) (14 500-Da) and low-MW (4500-Da) heparin, with IC
50
values of 1.65±0.26 and 5.13±0.8 μmol/L, respectively. Homogeneous-MW fractions (16 000- to 13 000-Da range) were used to evaluate the heparin effect on intracytoplasmic calcium release by thrombin. Calcium mobilization by 1 nmol/L thrombin was reduced as a function of heparin concentration, and the inhibitory effect was correlated to the MW of heparin fractions (IC
50
values were 1.9±0.39, 6.07±0.83, and 14.8±0.43 μmol/L for 16 000-, 9000-, and 3000-Da heparin, respectively). Platelet aggregation and calcium mobilization by ADP and by the thrombin receptor–activating peptide were not affected by heparin. The activation of Gp Ib–depleted platelets by α-thrombin was not inhibited by heparin. Moreover, platelet stimulation by heparin binding site phosphopyridoxylated thrombin, which has a severe impairment of Gp Ib ligation, was not affected by heparin. Finally, heparin did not interfere with the hydrolysis by thrombin of the protease-activated receptor 1.

Conclusions
—These results demonstrated that heparin, by inhibiting the thrombin–Gp Ib interaction, is able to interfere with thrombin-induced platelet activation. The extent of the inhibitory effect is directly related to the MW of heparin fractions.
Association Between Myocardial Infarction and the Mast Cells in the Adventitia of the Infarct-Related Coronary Artery
Authors: Laine Petri , Kaartinen Maija , Penttilä Antti , Panula Pertti , Paavonen Timo , Kovanen Petri T.
Published: June 2012

Background
—Histamine, a product of mast cells, is an effective vasoconstrictor of atherosclerotic coronary arteries. Because it has been suggested that coronary spasm plays a role in acute coronary syndromes such as myocardial infarction (MI), we quantified and characterized the mast cells in the adventitia of infarct-related coronary arteries.

Methods and Results
—In a series of 17 autopsied MI patients, we identified the segment of the left coronary artery with ruptured plaque responsible for the infarction. More distal segments from the infarct-related coronary artery, either with nonruptured plaques or with normal intima, were also studied. Corresponding segments taken from left coronary arteries obtained from 17 patients who had died of noncardiac causes served as controls. Adventitial mast cells in the infarct-related and the control coronary arteries were identified immunohistochemically by staining for tryptase. In the infarct-related coronary arteries, we also stained for chymase and histamine. Moreover, T lymphocytes and macrophages were identified immunohistochemically and counted. In the infarct-related coronary arteries, significantly larger numbers of mast cells were present in the adventitia backing ruptured plaques (98±40 mast cells/mm
2
, mean±SD) than in the adventitia backing nonruptured plaques (41±12 mast cells/mm
2
;
P
<0.001) or backing normal intima (19±8 mast cells/mm
2
;
P
<0.001). No such difference was found among the 3 different segments in the control coronary arteries. The majority of mast cells contained not only tryptase but also chymase. Mast cells were the only cells in the coronary adventitia that contained histamine. The proportion of adventitial mast cells that were degranulated was highest in the segments with ruptured plaques. The numbers of adventitial macrophages and T lymphocytes were also increased in the segments with plaque rupture.

Conclusions
—In infarct-related coronary arteries, the number of degranulated mast cells in the adventitia backing ruptured plaques is increased. Histamine released from the degranulated mast cells may reach the media, where it may locally provoke coronary spasm and thus contribute to the onset of MI.
Increased Protein Kinase C Activity and Expression of Ca
2+
-Sensitive Isoforms in the Failing Human Heart
Authors: Bowling Nancy , Walsh Richard A. , Song Guojie , Estridge Thomas , Sandusky George E. , Fouts Rebecca L. , Mintze Karen , Pickard Todd , Roden Robert , Bristow Michael R. , Sabbah Hani N. , Mizrahi Jacques L. , Gromo Gianni , King George L. , Vlahos Chris J.
Published: June 2012

Background
—Increased expression of Ca
2+
-sensitive protein kinase C (PKC) isoforms may be important markers of heart failure. Our aim was to determine the relative expression of PKC-β1, -β2, and -α in failed and nonfailed myocardium.

Methods and Results
—Explanted hearts of patients in whom dilated cardiomyopathy or ischemic cardiomyopathy was diagnosed were examined for PKC isoform content by Western blot, immunohistochemistry, enzymatic activity, and in situ hybridization and compared with nonfailed left ventricle. Quantitative immunoblotting revealed significant increases of >40% in PKC-β1 (
P
<0.05) and -β2 (
P
<0.04) membrane expression in failed hearts compared with nonfailed; PKC-α expression was significantly elevated by 70% in membrane fractions (
P
<0.03). PKC-ε expression was not significantly changed. In failed left ventricle, PKC-β1 and -β2 immunostaining was intense throughout myocytes, compared with slight, scattered staining in nonfailed myocytes. PKC-α immunostaining was also more evident in cardiomyocytes from failed hearts with staining primarily localized to intercalated disks. In situ hybridization revealed increased PKC-β1 and -β2 mRNA expression in cardiomyocytes of failed heart tissue. PKC activity was significantly increased in membrane fractions from failed hearts compared with nonfailed (1021±189 versus 261±89 pmol · mg
−1
· min
−1
,
P
<0.01). LY333531, a selective PKC-β inhibitor, significantly decreased PKC activity in membrane fractions from failed hearts by 209 pmol · min
−1
· mg
−1
(versus 42.5 pmol · min
−1
· mg
−1
in nonfailed,
P
<0.04), indicating a greater contribution of PKC-β to total PKC activity in failed hearts.

Conclusions
—In failed human heart, PKC-β1 and -β2 expression and contribution to total PKC activity are significantly increased. This may signal a role for Ca
2+
-sensitive PKC isoforms in cardiac mechanisms involved in heart failure.
l
-Arginine Normalizes Coronary Vasomotion in Long-Term Smokers
Authors: Campisi Roxana , Czernin Johannes , Schöder Heiko , Sayre James W. , Schelbert Heinrich R.
Published: June 2012

Background
—Noninvasive measurements of myocardial blood flow (MBF) with PET revealed an abnormal coronary vasomotor response to cold pressor test in healthy long-term smokers. If coronary endothelial dysfunction accounted for this abnormality, we hypothesized that it could be reversed by
l
-arginine as the substrate for NO synthase.

Methods and Results
—MBF was quantified with
13
N-labeled ammonia and PET in 11 healthy smokers (age, 45±10 years; 27±10 years of smoking) and in 12 age-matched nonsmokers on 2 separate days. On day 1, MBF was measured at rest and, after intravenous
l
-arginine, during cold pressor test. On day 2, MBF was measured during cold pressor test and then at rest during
l
-arginine. Baseline rate-pressure product (RPP) (6559±1590 versus 7144±1157 bpm×mm Hg) and MBF (0.65±0.14 versus 0.73±0.13 mL · g
−1
· min
−1
) were similar in nonsmokers and smokers. Cold pressor test increased RPP similarly in both groups (53±26% versus 46±26%), whereas MBF increased in nonsmokers (to 0.93±0.25 mL · g
−1
· min
−1
;
P
<0.05) but not in smokers (0.80±0.16 mL · g
−1
· min
−1
). The percent MBF increase differed between nonsmokers and smokers (44±25% versus 11±14%;
P
=0.0017). However, after
l
-arginine, the magnitude of MBF response to cold pressor test no longer differed between groups (48±36% versus 48±28%), whereas RPP again increased similarly in the 2 groups (59±30% versus 44±16%).
l
-Arginine had no effect on resting MBF in smokers or nonsmokers.

Conclusions
—Our findings implicate the coronary endothelium as the major site of the abnormal vasomotor response in long-term smokers. Cold pressor test combined with PET imaging may allow the noninvasive identification of coronary endothelial dysfunction in humans.
Poor Response to Activated Protein C as a Prominent Risk Predictor of Advanced Atherosclerosis and Arterial Disease
Authors: Kiechl Stefan , Muigg Armin , Santer Peter , Mitterer Manfred , Egger Georg , Oberhollenzer Martin , Oberhollenzer Friedrich , Mayr Agnes , Gasperi Arno , Poewe Werner , Willeit Johann
Published: June 2012

Background
—The potential role of activated protein C (APC) resistance in arterial thrombosis and disease is a matter of ongoing controversy.

Methods and Results
—In the present population-based survey, a random sample of 826 men and women underwent high-resolution duplex ultrasound scanning of the carotid and femoral arteries. Response to APC was expressed in APC ratios. Subjects were tested for the factor V Leiden mutation. The risk of carotid stenosis increased gradually with decreasing response to APC (adjusted OR [95% CI] for a 1-U decrease of response to APC, 1.6 [1.2 to 2.2]), as did the risk of femoral artery stenosis (1.7 [1.3 to 2.3]) and prevalent cardiovascular disease (1.4 [1.1 to 2.0]). The association between low APC ratio and atherosclerotic vascular disease applied equally to subjects with the factor V Leiden mutation and those without. Our study identified various nongenetic determinants of poor response to APC in the general population, including behavioral, hormonal, and environmental factors.

Conclusions
—The present study revealed an independent and gradual association between low response to APC and both advanced atherosclerosis (stenosis) and arterial disease. Resistance to APC due to factor V Leiden mutation was only one facet of this relationship.
Heterogeneity of Coronary Flow Reserve in the Examination of Multiple Individual Allograft Coronary Arteries
Authors: Wolford Thomas L. , Donohue Thomas J. , Bach Richard G. , Drury John H. , Caracciolo Eugene A. , Kern Morton J. , Miller Leslie W.
Published: June 2012

Background
—Epicardial and resistance vessel function in the transplanted heart has been evaluated primarily in regions supplied by a single vessel. Heterogeneity of flow among multiple perfusion fields as a marker of early endothelial dysfunction in the microcirculation has not been evaluated previously. This study tested the hypothesis that increased variability of coronary flow reserve (CFR) among multiple vascular regions would be associated with allograft coronary vasculopathy.

Methods and Results
—One hundred six posttransplant patients undergoing cardiac catheterization had measurement of CFR in at least 3 major epicardial vessels. Patients were divided into those with minimal angiographic abnormalities (n=37) and those with no angiographic abnormalities (n=69). The ranges, coefficients of variation, and univariate and multivariate regression analyses of CFR were computed to determine the major clinical factors influencing the degree of variability. The abnormal angiographic group was older (54±11 versus 47±13 years;
P
<0.003), had older hearts (35±11 versus 27±10 years;
P
<0.005), and were further posttransplant (1626±1022 versus 931±984 days;
P
<0.0009). There was no difference in global CFR between groups (normal, 3.4±0.8 versus abnormal, 3.4±0.7;
P
=NS). The coefficient of variation of CFR was higher for the abnormal group (16.3±8.6% versus 11.0±5.5%;
P
<0.0006). Univariate and multivariate predictors of increased variability in CFR included angiographic abnormalities, patient age, and body mass index. Both angiographic abnormalities and an elevated CV of CFR were predictive of a combined end point of death, congestive heart failure, or subsequent development of ≥50% coronary stenosis.

Conclusions
—These data demonstrate that increased variability of CFR is associated with discernible allograft coronary arteriopathy and is predictive of outcome in patients after heart transplantation.
Autoantibodies Activating Human β
1
-Adrenergic Receptors Are Associated With Reduced Cardiac Function in Chronic Heart Failure
Authors: Jahns Roland , Boivin Valérie , Siegmund Christian , Inselmann Gerhard , Lohse Martin J. , Boege Fritz
Published: June 2012

Background
—Autoantibodies against synthetic peptides of β-adrenergic receptors have been observed in human cardiomyopathy. However, it has never been shown that such antibodies really interact with native human β-adrenergic receptors, nor has the clinical impact of such an interaction been investigated in larger groups of patients.

Methods and Results
—We screened 104 patients with dilated or ischemic cardiomyopathy (NYHA functional classes II to IV) and 108 healthy subjects for IgG antibodies reacting with β-receptor peptides. Such IgGs were further analyzed for binding and functional interactions with native recombinant human β-adrenergic receptors. Antibodies reacting with synthetic receptor peptides were present in 51% of the patients. However, only a subgroup directed against the second extracellular receptor domain also recognized native human β-adrenergic receptors situated in a cell membrane. All antibodies of this subgroup impaired receptor ligand binding and enhanced receptor-mediated signaling, which could be blocked by 5 μmol/L bisoprolol in vitro. Their prevalence was 1% in healthy subjects and 10% in ischemic cardiomyopathy, whereas it amounted to 26% in dilated cardiomyopathy and was associated with a significantly poorer left ventricular function.

Conclusions
—Our data show that activating autoantibodies against human β-adrenergic receptors exist in ≈25% of patients with dilated cardiomyopathy. Counteraction of such autoantibodies might contribute to the beneficial effects of β-adrenergic receptor blockade in chronic heart failure.
Characterization of Atrioventricular Nodal Reentry With Continuous Atrioventricular Node Conduction Curve by Double Atrial Extrastimulation
Authors: Kuo Chi-Tai , Lin Kuo-Hung , Cheng Nye-Jan , Chu Po-Hsien , Hsu Tsu-Shiu , Chiang Cheng-Wen , Lee Ying-Shiung
Published: June 2012

Background
—Characterization of typical atrioventricular nodal reentrant tachycardia (AVNRT) with continuous AVN conduction (A
1
A
2
/A
2
H
2
) curves by double atrial extrastimulation (A
1
A
2
A
3
) has never been systematically studied.

Methods and Results
—This study was composed of 33 patients with typical AVNRT and continuous AVN conduction curves (group 1) and 103 patients with AVNRT and discontinuous AVN conduction curves (group 2). Using A
1
A
2
A
3
with predefined fast pathway–conducted A
2
, we examined the effects of slow pathway ablation on the A
2
A
3
/A
3
H
3
curves in both groups. In group 1, anterograde AVN effective refractory period (272±33 versus 277±47 ms,
P
>0.05) and AVN Wenckebach block cycle length (320±45 versus 343±59 ms,
P
>0.05) remained unchanged after ablation. A
2
H
2
max was shorter in group 1 than group 2 (237±89 versus 395±72 ms,
P
<0.05) at baseline. It shortened in group 2 (395±72 versus 221±78 ms,
P
<0.001) but remained unchanged in group 1 (237±89 versus 214±59 ms,
P
>0.05) after ablation. A
1
A
2
A
3
could further disclose discontinuous A
2
A
3
/A
3
H
3
curves in 29 patients of group 1. A
3
H
3
max shortened in both groups (375±81 versus 238±82 ms,
P
<0.001, and 419±104 versus 220±78 ms,
P
<0.001, respectively) in a similar fashion. Successful ablation resulted in loss of the left portion of the A
2
A
3
/A
3
H
3
curves in the 4 patients of group 1 with continuous A
2
A
3
/A
3
H
3
curves.

Conclusions
—Use of A
1
A
2
A
3
could expose discontinuous A
2
A
3
/A
3
H
3
curves in most patients with continuous A
1
A
2
/A
2
H
2
curves. Significant shortening of A
3
H
3
max after ablation may be indicative of successful elimination of AVNRT.
Chimeric DNA-RNA Hammerhead Ribozyme to Proliferating Cell Nuclear Antigen Reduces Stent-Induced Stenosis in a Porcine Coronary Model
Authors: Frimerman Aaron , Welch Peter J. , Jin Xiaomei , Eigler Neal , Yei Soonpin , Forrester James , Honda Hidehiko , Makkar Raj , Barber Jack , Litvack Frank
Published: June 2012

Background
—Stent-induced coronary restenosis is a major clinical and public health problem. Proliferating cell nuclear antigen (PCNA) is an important regulator of cell division, and blocking of its expression after angioplasty may limit intimal proliferation.

Methods and Results
—We cloned the porcine
PCNA
gene and constructed a chimeric hammerhead ribozyme to a segment of the gene with human homology. In vitro studies with both cultured porcine and human vascular smooth muscle cells demonstrated uptake of ribozyme within the nucleus and significant inhibition of cellular proliferation. The ribozyme was then delivered locally into pig coronaries in a stent model. At 30 days, histomorphometric analysis showed neointimal thickness of 0.51±0.20 mm in the ribozyme group versus 0.71±0.27 and 0.66±0.25 mm in stent controls and scrambled ribozyme control, respectively (
P
=0.002,
P
=0.03). Quantitative angiographic analysis showed late loss of 1.4±0.5 mm for ribozyme versus 1.9±0.4 and 2.0±0.4 mm for the controls (
P
=0.05 and
P
=0.02).

Conclusions
—Chimeric hammerhead ribozyme to PCNA inhibits smooth muscle cell proliferation in vitro and reduces both histomorphometric and angiographic restenosis in the porcine coronary stent model when delivered locally.
Long-Term Prognostic Value of Dobutamine-Atropine Stress Echocardiography in 1737 Patients With Known or Suspected Coronary Artery Disease
Authors: Poldermans Don , Fioretti Paolo M. , Boersma Eric , Bax Jeroen J. , Thomson Ian R. , Roelandt Jos R. T. C. , Simoons Maarten L.
Published: June 2012

Background
—The purpose of this study was to assess the long-term value of dobutamine-atropine stress echocardiography (DSE) for prediction of late cardiac events in patients with proven or suspected coronary artery disease.

Methods and Results
—Clinical data and DSE results were analyzed in 1734 consecutive patients undergoing DSE between 1989 and 1997. Seventy-four patients who underwent revascularization within 3 months of DSE and 1 patient lost to follow-up were excluded; the remaining 1659 (median age, 62 years; range, 14 to 99 years) were followed up for 36 months (range, 6 to 96 months). Wall motion abnormalities at rest and the presence and extent of stress-induced wall motion abnormalities (ischemia) were scored for each patient. Cardiac events were related to clinical and ECG data and DSE results. Four hundred twenty-eight cardiac events occurred in 366, documented cardiac death in 108 (total death, 247), nonfatal infarction in 128, and late revascularization in 192 patients. In a multivariable Cox proportional-hazards model, the ratio of documented cardiac death or (re)infarction was increased in the presence of stress-induced ischemia (hazard ratio, 3.3; 95% CI, 2.4 to 4.4) and extensive rest wall motion abnormalities (hazard ratio, 1.9; 95% CI, 1.3 to 2.6). The number of ischemic segments was predictive for late cardiac events. A normal DSE carried a relatively good prognosis, with an annual event rate of cardiac death or infarction of 1.3% over a 5-year period.

Conclusions
—In a large group of patients, DSE has an added value for predicting late cardiac events during long-term follow-up, improving the separation between high- risk and very-low-risk patients.
New Noninvasive Method for Coronary Flow Reserve Assessment
Authors: Caiati Carlo , Montaldo Cristiana , Zedda Norma , Bina Alessandro , Iliceto Sabino
Published: June 2012

Background
—We tested the hypothesis that blood flow velocity could be recorded in the left anterior descending coronary artery (LAD) during transthoracic echocardiography by use of second harmonic echo Doppler modality along with contrast enhancement (intravenous Levovist) at rest and after pharmacologically induced maximal vasodilation to assess coronary flow reserve (CFR) with a totally noninvasive approach.

Methods and Results
—Fifty-six consecutive patients undergoing coronary angiography underwent transthoracic contrast-enhanced pulsed-wave Doppler recording of blood flow velocity in the LAD by use of harmonic color Doppler as a guide at rest and after maximal vasodilation by dipyridamole infusion. Contrast enhancement with the harmonic mode greatly improved the success rate of recording adequate pulsed-wave Doppler signal in the LAD. CFR was (mean±SD) 1.54±0.7 in patients with (group 1) and 2.79±0.9 in patients without (group 2) significant LAD stenosis (lumen narrowing >70%) (
P
<0.001); sensitivity and specificity in detecting significant LAD stenosis were 86% and 90%, respectively. There was close agreement between CFRs determined by this new method and intracoronary Doppler flow wire.

Conclusions
—Contrast-enhanced transthoracic echo Doppler with the harmonic mode is a feasible and promising technique for assessing CFR in a totally noninvasive way.
Mediterranean Diet, Traditional Risk Factors, and the Rate of Cardiovascular Complications After Myocardial Infarction
Authors: de Lorgeril Michel , Salen Patricia , Martin Jean-Louis , Monjaud Isabelle , Delaye Jacques , Mamelle Nicole
Published: June 2012

Background
—The Lyon Diet Heart Study is a randomized secondary prevention trial aimed at testing whether a Mediterranean-type diet may reduce the rate of recurrence after a first myocardial infarction. An intermediate analysis showed a striking protective effect after 27 months of follow-up. This report presents results of an extended follow-up (with a mean of 46 months per patient) and deals with the relationships of dietary patterns and traditional risk factors with recurrence.

Methods and Results
—Three composite outcomes (COs) combining either cardiac death and nonfatal myocardial infarction (CO 1), or the preceding plus major secondary end points (unstable angina, stroke, heart failure, pulmonary or peripheral embolism) (CO 2), or the preceding plus minor events requiring hospital admission (CO 3) were studied. In the Mediterranean diet group, CO 1 was reduced (14 events versus 44 in the prudent Western-type diet group,
P
=0.0001), as were CO 2 (27 events versus 90,
P
=0.0001) and CO 3 (95 events versus 180,
P
=0.0002). Adjusted risk ratios ranged from 0.28 to 0.53. Among the traditional risk factors, total cholesterol (1 mmol/L being associated with an increased risk of 18% to 28%), systolic blood pressure (1 mm Hg being associated with an increased risk of 1% to 2%), leukocyte count (adjusted risk ratios ranging from 1.64 to 2.86 with count >9×10
9
/L), female sex (adjusted risk ratios, 0.27 to 0.46), and aspirin use (adjusted risk ratios, 0.59 to 0.82) were each significantly and independently associated with recurrence.

Conclusions
—The protective effect of the Mediterranean dietary pattern was maintained up to 4 years after the first infarction, confirming previous intermediate analyses. Major traditional risk factors, such as high blood cholesterol and blood pressure, were shown to be independent and joint predictors of recurrence, indicating that the Mediterranean dietary pattern did not alter, at least qualitatively, the usual relationships between major risk factors and recurrence. Thus, a comprehensive strategy to decrease cardiovascular morbidity and mortality should include primarily a cardioprotective diet. It should be associated with other (pharmacological?) means aimed at reducing modifiable risk factors. Further trials combining the 2 approaches are warranted.
Inhibition of Inositol(1,4,5)Trisphosphate Generation by Endothelin-1 During Postischemic Reperfusion
Authors: Woodcock Elizabeth A. , Reyes Nancy , Jacobsen Alexander N. , Du Xiao-Jun
Published: June 2012

Background
—Reperfusion of ischemic rat hearts in the presence of thrombin or norepinephrine but not endothelin-1 causes the generation of inositol 1,4,5-trisphosphate (Ins 1,4,5P
3
) and arrhythmias. The present study investigates the effect of endothelin-1 on these responses.

Methods and Results
—Ins 1,4,5P
3
generation was quantified by use of [
3
H] labeling and high-performance liquid chromatography as well as by mass analysis. Twenty minutes of global ischemia followed by 2 minutes of reperfusion increased [
3
H]Ins 1,4,5P
3
from 2828±265 to 5033±650 cpm/g tissue in the presence of thrombin 2.5 IU/mL and to 4561±286 cpm/g tissue in response to release of norepinephrine (n=4,
P
<0.01) in both cases. Reperfusion in the presence of endothelin-1 alone caused no change in Ins 1,4,5P
3
(2762±240 cpm/g tissue), but when added together with thrombin or norepinephrine, endothelin-1 reduced the Ins 1,4,5P
3
responses to 2313±197 and 1764±168 cpm/g tissue, respectively (n=4,
P
<0.01 in both cases). Similar inhibitory interactions between endothelin-1 10 nmol/L and thrombin 2.5 IU/mL were observed under normoxic conditions in nonperfused ventricle, eliminating the possibility that excessive vasoconstriction was responsible. In parallel studies, endothelin-1 suppressed the development of reperfusion arrhythmias initiated by either thrombin (ventricular fibrillation, 75% to 39%, n=16 to 18) or norepinephrine (83% to 8%, n=12 to 22) (
P
<0.01 in both cases).

Conclusions
—Inhibition of Ins 1,4,5P
3
generation during myocardial reperfusion by endothelin-1 represents a novel antiarrhythmic mechanism.
Attenuated Acute Cardiac Rejection in NOS2 −/− Recipients Correlates With Reduced Apoptosis
Authors: Koglin Jörg , Granville David J. , Glysing-Jensen Troels , Mudgett John S. , Carthy Chris M. , McManus Bruce M. , Russell Mary E.
Published: June 2012

Background
—The mechanisms through which NOS2-mediated pathways regulate graft failure in acute cardiac rejection are ill defined. To determine whether apoptosis promoted by NOS2 may contribute, we used a heterotopic transplant model to study mouse cardiac allografts placed in recipients with targeted gene deletion of NOS2.

Methods and Results
—Using 5 different indexes of apoptosis, we showed that mouse cardiac allografts placed in NOS2 −/− recipients (n=7) had reduced apoptotic activity compared with those in NOS2 +/+ controls (n=8). There were significantly fewer TUNEL-positive nuclei per high-powered field (
P
<0.01), less DNA fragmentation (antinucleosome ELISA;
P
<0.05), lower corrected transcript levels for caspase-1 and -3 (
32
P reverse transcriptase–polymerase chain reaction;
P
<0.01), and reduced caspase-3 activity (cleavage of DEVD-pNA [
P
<0.001] and poly [ADP-ribose] polymerase) in grafts from NOS2 −/− recipients. This concordant reduction in apoptotic indexes paralleled the improved histological outcome of grafts transplanted into NOS2 −/− recipients (assessed as rejection scores;
P
=0.012). To identify pathways controlled by NOS2, we compared intragraft transcript levels of potential triggers and regulators. Whereas Fas ligand/Fas and tumor necrosis factor (TNF)-α/TNF receptor-1 levels were not altered by NOS2 deficiency, transcript levels for p53 were significantly lower in grafts from NOS2 −/− recipients, coinciding with a significant increase in the antiapoptotic Bcl-2/Bax balance and decrease in Bcl-X
l
levels.

Conclusions
—Using NOS2 knockout mice, we demonstrated that NOS2-mediated pathways can promote acute rejection, at least in part, by inducing apoptotic cell death. When NOS2 is present, p53 might control NOS2-mediated apoptosis by stimulating Bax and repressing Bcl-2 and Bcl-X
l
expression, which may activate the cell death program in the rejecting heart.
Reactive Oxygen Species Play an Important Role in the Activation of Heat Shock Factor 1 in Ischemic-Reperfused Heart
Authors: Nishizawa Junichiro , Nakai Akira , Matsuda Katsuhiko , Komeda Masashi , Ban Toshihiko , Nagata Kazuhiro
Published: June 2012

Background
—The myocardial protective role of heat shock protein (HSP) has been demonstrated. Recently, we reported that ischemia/reperfusion induced a significant activation of heat shock factor (HSF) 1 and an accumulation of mRNA for HSP70 and HSP90. We examined the role of reactive oxygen species (ROSs) in the induction of stress response in the ischemic-reperfused heart.

Methods and Results
—Rat hearts were isolated and perfused with Krebs-Henseleit buffer by the Langendorff method. Whole-cell extracts were prepared for gel mobility shift assay using oligonucleotides containing the heat shock element. Induction of mRNA for HSP70 and HSP90 was examined by Northern blot analysis. Repetitive ischemia/reperfusion, which causes recurrent bursts of free radical generation, resulted in burst activation of HSF1, and this burst activation was significantly reduced with either allopurinol 1 mmol/L (an inhibitor of xanthine oxidase) or catalase 2×10
5
U/L (a scavenger of H
2
O
2
). Significant activation of HSF1 was observed on perfusion with buffer containing H
2
O
2
150 μmol/L or xanthine 1 mmol/L plus xanthine oxidase 5 U/L. The accumulation of mRNA for HSP70 or HSP90 after repetitive ischemia/reperfusion was reduced with either allopurinol or catalase.

Conclusions
—Our findings demonstrate that ROSs play an important role in the activation of HSF1 and the accumulation of mRNA for HSP70 and HSP90 in the ischemic-reperfused heart.