bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantum relativistic Toda chain at root ofunity: isospectrality, modified Q‐operator, and functional Bethe ansatz
Authors: Pakuliak Stanislav , Sergeev Sergei
Published: September 2002

We investigate an N‐state spin model called quantum
relativistic Toda chain and based on the unitary
finite‐dimensional representations of the Weyl algebra with q
being Nth primitive root of unity. Parameters of the
finite‐dimensional representation of the local Weyl algebra form
the classical discrete integrable system. Nontrivial dynamics of
the classical counterpart corresponds to isospectral
transformations of the spin system. Similarity operators are
constructed with the help of modified Baxter′s Q‐operators. The
classical counterpart of the modified Q‐operator for the initial
homogeneous spin chain is a Bäcklund transformation.
This transformation creates an extra Hirota‐type soliton in a
parameterization of the chain structure. Special choice of values
of solitonic amplitudes yields a degeneration of spin
eigenstates, leading to the quantum separation of variables, or
the functional Bethe ansatz. A projector to the separated
eigenstates is constructed explicitly as a product of modified
Q‐operators.
Amenability and coamenability of algebraic quantum groups
Authors: Bédos Erik , Murphy Gerard J. , Tuset Lars
Published: September 2002

We define concepts of amenability and coamenability for algebraic
quantum groups in the sense of Van Daele (1998). We show that
coamenability of an algebraic quantum group always implies amenability of its dual. Various necessary and/or sufficient conditions for amenability or
coamenability are obtained. Coamenability is shown to have
interesting consequences for the modular theory in the case that
the algebraic quantum group is of compact type.
Sur les fonctions séparément excessives
Authors: El Kadiri Mohamed
Published: September 2002

On considère deux résolvantes basiques sur deux espaces mesurables (E, ℰ) et (F, ℱ) associées à des semi‐groupes de noyaux (Pt) et (Qt). On montre que si E et F sont radoniens, alors toute fonction sur E × F séparément excessive pour les semi‐groupes (P t) et (Q t) est excessive pour le semi‐groupe (P t ⊗ Q t) (ou sa résolvante), ce qui généralise un résultat bien connu de Cairoli (1967).
On the Diophantine equation x2 + p2k+1 = 4yn
Authors: Arif S. Akhtar , Al-Ali Amal S.
Published: September 2002

It has been proved that if p is an odd prime, y > 1, k ≥ 0, n is an integer greater than or equal to 4, (n, 3h) = 1 where h is the class number of the field , then the equation x2 + p2k+1 = 4yn has exactly five families of solution in the positive integers x, y. It is further proved that when n = 3 and p = 3a2 ± 4, then it has a unique solution k = 0, y = a2 ± 1.
Multiple quantum products in toric varieties
Authors: Spielberg Holger
Published: September 2002

We generalize the author′s formula for Gromov‐Witten invariants of symplectic toric manifolds (1999) to those needed to compute
the quantum product of more than two classes directly, that is,
involving the pullback of the Poincaré dual of the point
class in the Deligne‐Mumford spaces .
Local completeness of ℓp(E), 1 ≤ p < ∞
Authors: Bosch C. , Gilsdorf T. , Gómez C. , Vera R.
Published: September 2002

We study the heredity of local completeness and the strict Mackey
convergence property from the locally convex space E to the space of absolutely p‐summable sequences on E, ℓp(E) for 1 ≤ p < ∞.
The monad induced by the hom‐functor in the category of topological spaces and its associated Eilenberg‐Moore algebras
Authors: Nailana Koena R.
Published: September 2002

We discuss the monad associated with the topology of pointwise
convergence. We also study examples of the Eilenberg‐Moore
algebras for this monad.
Solving the Dirichlet acoustic scattering problem for a surface with added bumps using the Green′s function for the original surface
Authors: Goldberg Maxim J. , Kim Seonja
Published: September 2002

We solve the Dirichlet problem for acoustic scattering from a
surface which has been perturbed by the addition of one or more
bumps. We build the solution for the bumpy case using the Green′s
function for the unperturbed surface, and the solution of a local
integral equation in which the integration is carried out only
over the added bumps. We conclude by giving an alternative
formulation of our method for the special case of a bump on a
plane.
Convergence theorems and stability results for Lipschitz strongly pseudocontractive operators
Authors: Liu Zeqing , Zhang Lili , Kang Shin Min
Published: September 2002

Suppose that X is an arbitrary real Banach space and T : X → X is a Lipschitz strongly pseudocontractive operator.
It is proved that under certain conditions the Ishikawa iterative
method with errors converges strongly to the fixed point of T and this iteration procedure is stable with respect to T.
Argument estimates of certain multivalent functions involving a linear operator
Authors: Cho Nak Eun , Patel J. , Mohapatra G. P.
Published: September 2002

The purpose of this paper is to derive some argument properties of certain multivalent functions in the open unit disk involving a linear operator. We also investigate their integral preserving property in a sector.
Some type of rotational scheme
Authors: Faried Nashat , Abdel-Kader Zeinab
Published: September 2002

The aim of this paper is to construct a rotational product scheme
in the product of Banach spaces with rotational schemes. Besides
we give an equivalent definition of the generalized Kolmogorov
diameters suggested by Aksoy and Nakamura in 1986, and give the
generalized Kolmogorov diameters of the product (∏ i∈n Di) of bounded subsets Di in the product of Banach spaces having schemes in terms of the generalized diameters of Di.
A note on a paper by Brenner
Authors: Tzermias Pavlos
Published: September 2002

We note that a result of Brenner (1962) follows from a theorem of
Lerch (1896) which also extends it.
Convex dynamics in Hele‐Shaw cells
Authors: Prokhorov Dmitri , Vasil′ev Alexander
Published: September 2002

We study geometric properties of a contracting bubble
driven by a homogeneous source at infinity and surface tension.
The properties that are preserved during the time evolution are
under consideration. In particular, we study convex dynamics of
the bubble and prove that the rate of the area change is
controlled by variation of the bubble logarithmic capacity. Next
we consider injection through a single finite source and study
some isoperimetric inequalities that correspond to the convex and
α‐convex dynamics.
Null controllability of a nonlinear heat equation
Authors: Aniculăesei G. , Aniţa S.
Published: September 2002

We study the internal exact null controllability of a nonlinear
heat equation with homogeneous Dirichlet boundary condition. The
method used combines the Kakutani fixed‐point theorem and the
Carleman estimates for the backward adjoint linearized system.
The result extends to the case of boundary control.
Strongly nonlinear potential theory on metric spaces
Authors: Aïssaoui Noureddine
Published: September 2002

We define Orlicz‐Sobolev spaces on an arbitrary metric space with
a Borel regular outer measure, and we develop a capacity theory
based on these spaces. We study basic properties of capacity and
several convergence results. We prove that each Orlicz‐Sobolev
function has a quasi‐continuous representative. We give estimates
for the capacity of balls when the measure is doubling. Under
additional regularity assumption on the measure, we establish
some relations between capacity and Hausdorff measures.
A characterization of regular saddle surfaces in the hyperbolicand spherical three‐space
Authors: Kalikakis Dimitrios E.
Published: September 2002

We prove that the class of regular saddle surfaces in the
hyperbolic or spherical three‐space coincides with the class of regular surfaces with
curvature not greater than the curvature of the surrounding space.
We also show that a similar result for nonregular surfaces is
incorrect.
Elliptic problems with nonmonotone discontinuities at resonance
Authors: Nikolaos Halidias
Published: September 2002

Using the critical point theory of Chang (1981) for locally
Lipschitz functionals, we prove an existence theorem for some
elliptic problems at resonance with no Carathéodory forcing
term.

Elliptic problems with nonmonotone discontinuities at resonance (Erratum)dx.doi.org/10.1155/S108533750430905X
On dynamics of viscoelastic multidimensional medium with variable boundary
Authors: Orlov V. P.
Published: September 2002

We prove the existence and uniqueness theorems for solutions of
an initial‐boundary value problem to the system of equations,
which describes dynamics of viscoelastic continuous medium with a
variable boundary and a memory along the trajectories of
particles in classes of summable functions.
Positive solutions of higher order quasilinear elliptic equations
Authors: Montenegro Marcelo
Published: September 2002

The higher order quasilinear elliptic equation −Δ(Δp(Δu)) = f(x, u) subject to Dirichlet boundary
conditions may have unique and regular positive solution. If the
domain is a ball, we obtain a priori estimate to the radial
solutions via blowup. Extensions to systems and general domains
are also presented. The basic ingredients are the maximum
principle, Moser iterative scheme, an eigenvalue problem, a
priori estimates by rescalings, sub/supersolutions, and
Krasnosel′skiĭ fixed point theorem.
Attractors for Nonautonomous Multivalued Evolution Systems Generated by Time‐Dependent Subdifferentials
Authors: Yamazaki Noriaki
Published: September 2002

In a real separable Hilbert space, we consider nonautonomous
evolution equations including time‐dependent subdifferentials and
their nonmonotone multivalued perturbations. In this paper, we
treat the multivalued dynamical systems associated with
time‐dependent subdifferentials, in which the solution is not
unique for a given initial state. In particular, we discuss the
asymptotic behaviour of our multivalued semiflows from the
viewpoint of attractors. In fact, assuming that the
time‐dependent subdifferential converges asymptotically to a
time‐independent one (in a sense) as time goes to infinity, we
construct global attractors for nonautonomous multivalued
dynamical systems and its limiting autonomous multivalued
dynamical system. Moreover, we discuss the relationship between
them.
On principal eigenvalues for periodic parabolic Steklov problems
Authors: Godoy T. , Dozo E. Lami , Paczka S.
Published: September 2002

Let Ω be a C2+γ domain in ℝN,
N ≥ 2, 0 < γ < 1. Let T > 0 and let L be a uniformly
parabolic operator Lu = ∂u/∂t − ∑i,j (∂/∂xi) (aij(∂u/∂xj)) + ∑jbj (∂u/∂xi) + a0u, a0 ≥ 0, whose coefficients, depending on
(x, t) ∈ Ω × ℝ, are T periodic in t and
satisfy some regularity assumptions. Let A be the N × N
matrix whose i, j entry is aij and let ν be the unit
exterior normal to ∂Ω. Let m be a T‐periodic
function (that may change sign) defined on ∂Ω whose
restriction to ∂Ω × ℝ belongs to
for some large enough q.
In this paper, we give necessary and sufficient conditions on m
for the existence of principal eigenvalues for the periodic
parabolic Steklov problem Lu = 0 on Ω × ℝ,
〈A∇u, ν〉 = λmu on
∂Ω × ℝ, u(x, t) = u(x, t + T), u > 0 on
Ω × ℝ. Uniqueness and simplicity of the
positive principal eigenvalue is proved and a related maximum
principle is given.
An inverse problem for a nonlinear Schrödingerequation
Authors: Ton Bui An
Published: September 2002

We study the dependence on the control q of the interval of
definition of the solution u of the Cauchy problem ιu′ + Δ u = −λ|u| 2u − ιqu
in
ℝ 2 × (0, T), u(x, 0) = ω
in
ℝ 2, and we prove a version of Fibich′s conjecture.
Feedback laws for an inverse problem of the above equation with
experimental data, measured on a portion of the boundary of an
open, bounded subset of ℝ 2
are established.
Unit root testing in the presence of innovation variance breaks: a simple solution with increased power
Authors: Cook Steven
Published: September 2002

The Dickey‐Fuller unit root test is known to suffer severe
oversizing in the presence of innovation variance breaks. In this
paper, forward and reverse Dickey‐Fuller regressions are proposed
as a means of correcting this size distortion. The results of
Monte Carlo experimentation show such an approach to result in
both satisfactory size properties and increased power relative to
previously suggested solutions.
Network flow optimization for restoration of images
Authors: Zalesky Boris A.
Published: September 2002

The network flow optimization approach is offered for restoration
of gray‐scale and color images corrupted by noise. The Ising
models are used as a statistical background of the proposed
method. We present the new multiresolution network flow minimum
cut algorithm, which is especially efficient in identification of
the maximum a posteriori (MAP) estimates of corrupted images. The
algorithm is able to compute the MAP estimates of large‐size
images and can be used in a concurrent mode. We also consider the
problem of integer minimization of two functions,
U1(x) = λ∑i|yi − xi|+∑i,j  βi,j|xi − xj|
and
, with parameters
λ, λi, βi,j > 0
and vectors
x = (x1, …, xn),
y = (y1, …, yn) ∈ {0,…,L−1}n.
Those functions constitute the energy ones for the Ising model of
color and gray‐scale images. In the case L = 2, they coincide,
determining the energy function of the Ising model of binary
images, and their minimization becomes equivalent to the network
flow minimum cut problem. The efficient integer minimization of
U1(x), U2(x)
by the network flow
algorithms is described.
Relativistic wave equations with fractional derivatives andpseudodifferential operators
Authors: Závada Petr
Published: September 2002

We study the class of the free relativistic covariant equations
generated by the fractional powers of the d′Alembertian operator
(□1/n). The equations corresponding to n = 1 and 2
(Klein‐Gordon and Dirac equations) are local in their nature, but
the multicomponent equations for arbitrary n > 2
are nonlocal. We
show the representation of the generalized algebra of Pauli and
Dirac matrices and how these matrices are related to the algebra
of SU (n)
group. The corresponding representations of the
Poincaré group and further symmetry transformations on the
obtained equations are discussed. The construction of the related
Green functions is suggested.
Mechanical analogy for the wave‐particle: helix on a vortex filament
Authors: Dmitriyev Valery P.
Published: September 2002

The small amplitude‐to‐thread ratio helical configuration of a
vortex filament in the ideal fluid behaves exactly as de Broglie
wave. The complex‐valued algebra of quantum mechanics finds a
simple mechanical interpretation in terms of differential
geometry of the space curve. The wave function takes the meaning
of the velocity, with which the helix rotates about the screw
axis. The helices differ in type of the screw—right‐ or
left‐handed. Two kinds of the helical waves deflect in the
inhomogeneous fluid vorticity field in the same way as spin
particles in the Stern‐Gerlach experiment.
A Green′s function for a convertible bond using the Vasicek model
Authors: Mallier R. , Deakin A. S.
Published: September 2002

We consider a convertible security where the underlying stock
price obeys a lognormal random walk and the risk‐free
rate is given by the Vasicek model. Using a Laplace transform in
time and a Mellin transform in the stock price, we derive a
Green′s function solution for the value of the convertible bond.
Long-Term Treatment With

N
ω

-Nitro-
l
-Arginine Methyl Ester Causes Arteriosclerotic Coronary Lesions in Endothelial Nitric Oxide Synthase-Deficient Mice
Authors: Suda Osamu , Tsutsui Masato , Morishita Tsuyoshi , Tanimoto Akihide , Horiuchi Masataka , Tasaki Hiromi , Huang Paul L. , Sasaguri Yasuyuki , Yanagihara Nobuyuki , Nakashima Yasuhide
Published: September 2002

Background—

N
ω

-nitro-
l
-arginine methyl ester (
l
-NAME) is widely used to inhibit endothelial synthesis of NO in vivo. However, it is controversial whether the long-term vascular effects of
l
-NAME are mediated primarily by inhibition of endothelial NO synthesis. We addressed this point in mice that are deficient in the endothelial NO synthase gene (eNOS-KO mice).

Methods and Results—

Wild-type and eNOS-KO mice received
l
-NAME in drinking water for 8 weeks. In wild-type mice, long-term treatment with
l
-NAME caused significant medial thickening and perivascular fibrosis in coronary microvessels but not in large coronary arteries. Importantly, in eNOS-KO mice, treatment with
l
-NAME also caused an extent of medial thickening and perivascular fibrosis in coronary microvessels that was comparable to that in wild-type mice and that was not prevented by supplementation of L-arginine. Vascular NO and cGMP levels were not significantly reduced by
l
-NAME treatment, and no expression of inducible or neuronal NO synthase was noted in microvessels of eNOS-KO mice, suggesting an involvement of NO-independent mechanisms. Treatment with
l
-NAME caused an upregulation of vascular ACE and an increase in cardiac lucigenin chemiluminescence that were comparable in both strains and that were abolished by simultaneous treatment with temocapril (ACE inhibitor) or CS866 (angiotensin II type 1 receptor antagonist) along with the suppression of vascular lesion formation.

Conclusions—

These results provide the first direct evidence that the long-term vascular effects of
l
-NAME are not mediated by simple inhibition of endothelial NO synthesis. Direct upregulation of local ACE and increased oxidative stress appear to be involved in the long-term vascular effects of
l
-NAME in vivo.
Mucosal Administration of Heat Shock Protein-65 Decreases Atherosclerosis and Inflammation in Aortic Arch of Low-Density Lipoprotein Receptor-Deficient Mice
Authors: Maron Ruth , Sukhova Galina , Faria Ana-Maria , Hoffmann Ethan , Mach Francois , Libby Peter , Weiner Howard L.
Published: September 2002

Background—

Increasing evidence supports the involvement of inflammation and immunity in atherogenesis as well as the role of autoimmunity to heat shock proteins (HSPs) in the progression of atherosclerosis. Mucosal administration of autoantigens decreases organ-specific inflammation and disease in several models of autoimmunity (diabetes, arthritis, and encephalomyelitis) and is also being tested in human clinical trials.

Methods and Results—

We examined the effect of nasal or oral administration of mycobacterial HSP-65 on atherosclerotic lesion formation in mice lacking the receptor for LDL that were maintained on a high-cholesterol diet. Animals were nasally or orally treated for 1 week with HSP-65, and a high-cholesterol diet was started after the last treatment. The mice were mucosally treated once a week for 8 or 12 weeks, at which time pathological analysis was performed. We found a significant decrease in the size of atherosclerotic plaques, a reduction in macrophage-positive area in the aortic arch, increased interleukin-10 expression, and a reduced number of T cells in nasally treated animals compared with control animals. A similar trend was observed in orally treated mice, but it was not significant.

Conclusions—

Our results demonstrate that nasal vaccination with HSP reduces the inflammatory process associated with atherosclerosis and provides a new immunologic approach for the treatment of atherosclerosis.
Guanylyl Cyclase-A Inhibits Angiotensin II Type 1A Receptor-Mediated Cardiac Remodeling, an Endogenous Protective Mechanism in the Heart
Authors: Li Yuhao , Kishimoto Ichiro , Saito Yoshihiko , Harada Masaki , Kuwahara Koichiro , Izumi Takehiko , Takahashi Nobuki , Kawakami Rika , Tanimoto Keiji , Nakagawa Yasuaki , Nakanishi Michio , Adachi Yuichiro , Garbers David L. , Fukamizu Akiyoshi , Nakao Kazuwa
Published: September 2002

Background—

Guanylyl cyclase (GC)-A, a natriuretic peptide receptor, lowers blood pressure and inhibits the growth of cardiac myocytes and fibroblasts. Angiotensin II (Ang II) type 1A (AT
1A
), an Ang II receptor, regulates cardiovascular homeostasis oppositely. Disruption of GC-A induces cardiac hypertrophy and fibrosis, suggesting that GC-A protects the heart from abnormal remodeling. We investigated whether GC-A interacts with AT
1A
signaling in the heart by target deletion and pharmacological blockade or stimulation of AT
1A
in mice.

Methods and Results—

We generated double-knockout (KO) mice for GC-A and AT
1A
by crossing GC-A-KO mice and AT
1A
-KO mice and blocked AT
1
with a selective antagonist, CS-866. The cardiac hypertrophy and fibrosis of GC-A-KO mice were greatly improved by deletion or pharmacological blockade of AT
1A
. Overexpression of mRNAs encoding atrial natriuretic peptide, brain natriuretic peptide, collagens I and III, transforming growth factors β
1
and β
3
, were also strongly inhibited. Furthermore, stimulation of AT
1A
by exogenous Ang II at a subpressor dose significantly exacerbated cardiac hypertrophy and dramatically augmented interstitial fibrosis in GC-A-KO mice but not in wild-type animals.

Conclusions—

These results suggest that cardiac hypertrophy and fibrosis of GC-A-deficient mice are partially ascribed to an augmented cardiac AT
1A
signaling and that GC-A inhibits AT
1A
signaling-mediated excessive remodeling.
Resveratrol, a Polyphenolic Phytoalexin Present in Red Wine, Enhances Expression and Activity of Endothelial Nitric Oxide Synthase
Authors: Wallerath Thomas , Deckert Göran , Ternes Thomas , Anderson Henrik , Li Huige , Witte Klaus , Förstermann Ulrich
Published: September 2002

Background—

Estrogens can upregulate endothelial nitric oxide synthase (eNOS) in human endothelial cells by increasing eNOS promoter activity and enhancing the binding activity of the transcription factor Sp1. Resveratrol, a polyphenolic phytoalexin found in grapes and wine, has been reported to act as an agonist at the estrogen receptor. Therefore, we tested the effect of this putative phytoestrogen on eNOS expression in human endothelial cells.

Methods and Results—

Incubation of human umbilical vein endothelial cells (HUVEC) and HUVEC-derived EA.hy 926 cells with resveratrol for 24 to 72 hours upregulated eNOS mRNA expression in a time- and concentration-dependent manner (up to 2.8-fold). eNOS protein expression and eNOS-derived NO production were also increased after long-term incubation with resveratrol. Resveratrol increased the activity of the eNOS promoter (3.5-kb fragment) in a concentration-dependent fashion, with the essential trans-stimulated sequence being located in the proximal 263 bp of the promoter sequence. In addition, eNOS mRNA was stabilized by resveratrol. The effect of resveratrol on eNOS expression was not modified by the estrogen receptor antagonists ICI 182780 and RU 58668. In electrophoretic mobility shift assays, nuclear extracts from resveratrol-incubated EA.hy 926 cells showed no enhanced binding activity of the eNOS promoter-relevant transcription factors Sp1, GATA, PEA3, YY1, or Elf-1. In addition to its long-term effects on eNOS expression, resveratrol also enhanced the production of bioactive NO in the short-term (after a 2-minute incubation).

Conclusions—

In concert with other effects, the stimulation of eNOS expression and activity may contribute to the cardiovascular protective effects attributed to resveratrol.
Benefit of Clopidogrel in Patients With Acute Coronary Syndromes Without ST-Segment Elevation in Various Risk Groups
Authors: Budaj Andrzej , Yusuf Salim , Mehta Shamir R. , Fox Keith A.A. , Tognoni Gianni , Zhao Feng , Chrolavicius Susan , Hunt David , Keltai Matyas , Franzosi Maria Grazia
Published: September 2002

Background—

The Clopidogrel in Unstable angina to prevent Recurrent Events (CURE) trial demonstrated that clopidogrel, given early and continued long term, was superior to placebo in patients with non-ST–elevation acute coronary syndromes receiving aspirin. The purpose of the present analysis was to estimate the treatment effect Zof clopidogrel in patients who were stratified according to their risk of future cardiovascular events.

Methods and Results—

Patients (n=12 562) who presented within 24 hours after the onset of symptoms were randomized to receive clopidogrel (300 mg followed by 75 mg daily) or placebo in addition to aspirin for 3 to 12 months. Treatment effect was analyzed in various risk groups according to the Thrombolysis in Myocardial Infarction (TIMI) risk score. The TIMI risk model was validated in the CURE population (C statistic, 0.634). The primary composite outcome of cardiovascular death, myocardial infarction, or stroke increased proportionally with increasing risk according to the TIMI risk score. The impact of clopidogrel versus placebo on the rate of the primary outcome was as follows: low-risk group (TIMI score 0 to 2), 4.1% versus 5.7% (relative risk [RR], 0.71; 95% confidence interval [CI], 0.52 to 0.97;
P
< 0.04), intermediate-risk group (TIMI score 3 to 4), 9.8% versus 11.4% (RR, 0.85; 95% CI, 0.74 to 0.98;
P
<0.03), and high-risk group (TIMI score 5 to 7), 15.9% versus 20.7% (RR, 0.73; 95% CI, 0.60 to 0.90;
P
<0.004). There was no evidence of statistical heterogeneity among the groups.

Conclusions—

The benefit of clopidogrel demonstrated in the CURE trial is consistent in low-, intermediate-, and high-risk patients with acute coronary syndromes (as stratified by TIMI risk score), thus supporting its use in all patients with documented non–ST elevation acute coronary syndromes.
Characterization of Human Atherosclerosis by Optical Coherence Tomography
Authors: Yabushita Hiroshi , Bouma Brett E. , Houser Stuart L. , Aretz H. Thomas , Jang Ik-Kyung , Schlendorf Kelly H. , Kauffman Christopher R. , Shishkov Milen , Kang Dong-Heon , Halpern Elkan F. , Tearney Guillermo J.
Published: September 2002

Background—

High-resolution visualization of atherosclerotic plaque morphology may be essential for identifying coronary plaques that cause acute coronary events. Optical coherence tomography (OCT) is an intravascular imaging modality capable of providing cross-sectional images of tissue with a resolution of 10 μm. To date, OCT imaging has not been investigated in sufficient detail to assess its accuracy for characterizing atherosclerotic plaques. The aim of this study was to establish objective OCT image criteria for atherosclerotic plaque characterization in vitro.

Methods and Results—

OCT images of 357 (diseased) atherosclerotic arterial segments obtained at autopsy were correlated with histology. OCT image criteria for 3 types of plaque were formulated by analysis of a subset (n=50) of arterial segments. OCT images of fibrous plaques were characterized by homogeneous, signal-rich regions; fibrocalcific plaques by well-delineated, signal-poor regions with sharp borders; and lipid-rich plaques by signal-poor regions with diffuse borders. Independent validation of these criteria by 2 OCT readers for the remaining segments (n=307) demonstrated a sensitivity and specificity ranging from 71% to 79% and 97% to 98% for fibrous plaques, 95% to 96% and 97% for fibrocalcific plaques, and 90% to 94% and 90% to 92% for lipid-rich plaques, respectively (overall agreement, κ=0.83 to 0.84). The interobserver and intraobserver reliabilities of OCT assessment were high (κ values of 0.88 and 0.91, respectively).

Conclusions—

Objective OCT criteria are highly sensitive and specific for characterizing different types of atherosclerotic plaques. These results represent an important step in validating this new intravascular imaging modality and will provide a basis for the interpretation of intracoronary OCT images obtained from patients.
Tissue and Serum Angiogenic Activity Is Associated With Low Prevalence of Ischemic Complications in Patients With Giant-Cell Arteritis
Authors: Cid Maria C. , Hernández-Rodríguez José , Esteban María-José , Cebrián Mireia , Gho Yong Song , Font Carme , Urbano-Márquez Alvaro , Grau Josep M. , Kleinman Hynda K.
Published: September 2002

Background—

Vascular inflammatory lesions from patients with giant-cell arteritis show a remarkable amount of neovascularization, but its clinical implications have never been investigated.

Methods and Results—

To assess the clinical relevance of neovascularization in giant-cell arteritis, angiogenesis was measured in temporal artery sections from 31 patients with biopsy-proven giant-cell arteritis by staining endothelial cells with
Ulex europaeus
lectin. Angiogenesis was highly variable among these patients. Patients without ischemic complications had higher tissue angiogenesis scores than patients with ischemic events (5.69±0.6 versus 2.91±0.6,
P
=0.003). Angiogenesis was also more prominent in patients with a strong acute phase response (score: 5.31±0.6) compared with those with a weak systemic inflammatory reaction (2.30±0.44;
P
=0.0007). Serum angiogenic activity was studied in an additional series of 38 biopsy-proven patients. Sera from patients without ischemic events tended to be more active in stimulating human umbilical vein endothelial cell growth (optical density ×1000, 270±15 versus 192±14,
P
=0.065) and differentiation into capillary-like structures (107±5 versus 84±8 relative units,
P
=0.0058) than patients with ischemic complications. Sera from patients without ischemic events had more in vivo full angiogenic activity tested in the chick chorioallantoic membrane than sera from patients with ischemic complications.

Conclusion—

Inflammation-induced angiogenic activity may play a compensatory role for ischemia in patients with giant-cell arteritis.
Electrically Unexcitable Scar Mapping Based on Pacing Threshold for Identification of the Reentry Circuit Isthmus
Authors: Soejima Kyoko , Stevenson William G. , Maisel William H. , Sapp John L. , Epstein Laurence M.
Published: September 2002

Background—

We hypothesized that delineating electrically unexcitable scar (EUS) within low-voltage infarct regions will locate reentry circuit isthmuses by defining their borders. The pacing threshold and electrogram amplitude that best determines EUS is unknown.

Methods and Results—

The change in dimension of the virtual electrode was estimated in 11 patients and observed to increase by 4.4±2.5 mm as stimulus strength increases from threshold (2.9±1.8 mA) to 10 mA. EUS was defined as a threshold >10 mA. In 14 consecutive patients, mapping and ablation of ventricular tachycardia (VT) were performed using an electroanatomic mapping system. During sinus rhythm, unipolar pacing was performed at sites with bipolar electrogram amplitude <1.5 mV. EUS regions were marked on the maps. Reentry circuit isthmuses were identified by entrainment mapping or pace mapping, and ablation was performed. EUS was identified in the infarct in all 14 patients (11.8±13.9 cm
2
). All 20 VT circuit isthmuses identified were adjacent to EUS. Although electrogram amplitude correlated with pacing threshold (
r
=0.64,
P
<0.0001), many isthmuses had very low-amplitude electrograms, and EUS could not be identified from electrogram amplitude alone. RF ablation lines connecting selected EUS regions abolished all inducible VTs in 10 patients (71%); spontaneous VT was markedly reduced during follow-up (from 142±360 to 0.9±2.0 episodes per month,
P
=0.002).

Conclusions—

This new method of identifying EUS provides complimentary information to the electrogram amplitude in delineating potential reentry circuit paths, potentially facilitating ablation during sinus rhythm.
Repeated Three-Dimensional Magnetic Resonance Imaging of Atherosclerosis Development in Innominate Arteries of Low-Density Lipoprotein Receptor-Knockout Mice
Authors: Hockings Paul D. , Roberts Toby , Galloway Graham J. , Reid David G. , Harris Dorothy A. , Vidgeon-Hart Martin , Groot Pieter H.E. , Suckling Keith E. , Benson G. Martin
Published: September 2002

Background—

In vivo methods to evaluate the size and composition of atherosclerotic lesions in animal models of atherosclerosis would assist in the testing of antiatherosclerotic drugs. We have developed an MRI method of detecting atherosclerotic plaque in the major vessels at the base of the heart in low-density lipoprotein (LDL) receptor-knockout (LDLR
−/−
) mice on a high-fat diet.

Methods and Results—

Three-dimensional fast spin-echo magnetic resonance images were acquired at 7 T by use of cardiac and respiratory triggering, with ≈140-μm isotropic resolution, over 30 minutes. Comparison of normal and fat-suppressed images from female LDLR
−/−
mice 1 week before and 8 and 12 weeks after the transfer to a high-fat diet allowed visualization and quantification of plaque development in the innominate artery in vivo. Plaque mean cross-sectional area was significantly greater at week 12 in the LDLR
−/−
mice (0.14±0.086 mm
2
[mean±SD]) than in wild-type control mice on a normal diet (0.017±0.031 mm
2
,
P
<0.01). In the LDLR
−/−
mice, but not control mice, increase in plaque burden at week 12 relative to week 1 was also highly significant (
P
=0.001). Lumen cross section was not significantly different between time points or groups. MRI and histological assessments of plaque size were closely correlated (
R
=0.8). The lumen of proximal coronary arteries could also be visualized.

Conclusions—

This is the first report of in vivo detection of aortic arch atherosclerosis in any animal model. The method could significantly assist rapid evaluation of experimental antiatherosclerotic therapies.
Plaque Gruel of Atheromatous Coronary Lesion May Contribute to the No-Reflow Phenomenon in Patients With Acute Coronary Syndrome
Authors: Kotani Jun-ichi , Nanto Shinsuke , Mintz Gary S. , Kitakaze Masafumi , Ohara Tomoki , Morozumi Takakazu , Nagata Seiki , Hori Masatsugu
Published: September 2002

Background—

No-reflow associated with direct angioplasty (PCI) of patients with acute coronary syndromes (ACS) is associated with unfavorable results.

Methods and Results—

We used a new thrombectomy device to treat 51 lesions in 48 consecutive ACS patients (40 male and 8 female; mean age 63 years) and conducted a microscopic analysis of aspirates and blood samples retrieved from the culprit coronary artery. The first aspirate was collected before PCI and the second was collected separately after percutaneous transluminal coronary angioplasty or stenting, including samples from the no-reflow lumen. Light microscopy showed that the materials obtained from the pre-PCI aspiration consisted of thrombus in 37.5%, thrombus and atheroma in 35.0%, and atheromatous plaque in 27.5%. The materials collected from the post-PCI aspiration were thrombus in 8.3%, thrombus and atheroma in 41.7%, and atheromatous plaque in 50.0%. We then compared the 9 lesions (19.1%) with no-reflow to those without no-reflow. There was no difference in the pre-PCI aspirates. However, after PCI, there was more atheromatous plaque retrieved from patients with no-reflow (
P
<0.001) as well as significantly more platelet and fibrin complex, macrophages, and cholesterol crystals in the blood aspirated from no-reflow cases. Aspiration of these elements improved the no-reflow in 7 of 9 lesions to TIMI-3 flow.

Conclusions—

No-reflow after angioplasty may be caused by gruel that formed from an atheroma attributable to mechanical plaque disruption during intervention.
Normal Coronary Flow Reserve After Arterial Switch Operation for Transposition of the Great Arteries
Authors: Oskarsson Gylfi , Pesonen Erkki , Munkhammar Peter , Sandström Staffan , Jögi Peeter
Published: September 2002

Background—

Recent studies performed with positron emission tomography have suggested that coronary flow reserve (CFR) is moderately to severely reduced after the arterial switch operation (ASO). These findings are of great concern but have not been confirmed by other methods.

Methods and Results—

Eleven symptom-free children were studied between 4 and 11 (median 6.0) years after the ASO. Flow velocity in the left anterior descending (LAD) and right coronary arteries (RCA) was measured with a 0.014-inch Doppler FloWire (Cardiometrics) before and after intracoronary injection of adenosine (0.5 μg/kg) and nitroglycerin (5 μg/kg). CFR was defined as the ratio of hyperemic to basal average peak velocity (APV). The median (range) CFR in the LAD was 3.7 (3.0 to 4.8) and 3.4 (2.9 to 4.8) in the RCA. The increase in APV after intracoronary injection of nitroglycerin was 300% (240% to 420%) in the LAD and 260% (190% to 460%) in the RCA. APV at rest was 15.0 (14.0 to 21.0) cm/s in the LAD and 16.0 (9.6 to 30.0) cm/s in the RCA. A linear relation was found between right ventricular systolic pressure and resting APV in the RCA (
r
=0.77,
P
=0.0056), and between resting APV and CFR (
r
=-0.61,
P
<0.05) in the RCA.

Conclusions—

The CFR and coronary vasoreactivity to nitroglycerin in children treated for transposition of the great arteries with the ASO was within normal limits. Increased right ventricular pressure and myocardial hypertrophy can cause increased resting coronary flow velocity in the RCA and affect CFR negatively.
Management of Vasovagal Syncope
Authors: Krediet C.T. Paul , van Dijk Nynke , Linzer Mark , van Lieshout Johannes J. , Wieling Wouter
Published: September 2002

Background—

Posture-related vasovagal syncope is by far the most frequent cause of transient loss of consciousness, and present pharmacological and cardiac pacing treatment remains unsatisfactory. A simple maneuver to prevent or diminish vasovagal reactions would be beneficial.

Methods and Results—

Twenty-one patients with recurrent syncope (age 17 to 74 years, 11 males) who were referred for routine tilt-table testing and had a positive test were included. They were instructed to perform leg crossing and muscle tensing for at least 30 seconds at the onset of a tilt table-provoked impending faint. Continuously measured blood pressure and heart rate at nadir and during the maneuver were compared. Ten months after the test, a telephone follow-up was performed. The physical counter-maneuver, performed in 20 of 21 subjects, increased blood pressure and heart rate. Systolic blood pressure rose from 65±13 to 106±16 mm Hg (mean±SD,
P
<0.001), and diastolic blood pressure rose from 43±9 to 65±10 mm Hg (
P
<0.001). During the maneuver, prodromal symptoms disappeared in all patients, and none lost consciousness. After terminating the maneuver, symptoms did not return in 5 subjects during the test. At follow-up, 13 of 20 patients reported that they applied the maneuver in daily life and benefited from it.

Conclusions—

Leg crossing combined with tensing muscles at the onset of prodromal symptoms can postpone and in some subjects prevent vasovagal syncope.
Long-Term Use of Contraceptive Depot Medroxyprogesterone Acetate in Young Women Impairs Arterial Endothelial Function Assessed by Cardiovascular Magnetic Resonance
Authors: Sorensen Morten B. , Collins Peter , Ong Paul J.L. , Webb Carolyn M. , Hayward Christopher S. , Asbury Elizabeth A. , Gatehouse Peter D. , Elkington Andrew G. , Yang Guang Z. , Kubba Ali , Pennell Dudley J.
Published: September 2002

Background—

Depot medroxyprogesterone acetate (DMPA) inhibits proliferation of ovarian follicles, resulting in anovulation and a decrease in circulating estrogen; the latter action is potentially disadvantageous to cardiovascular health. We therefore investigated the vascular effects of long-term contraceptive DMPA in young women.

Methods and Results—

Endothelium-dependent (hyperemia-induced flow-mediated dilatation [FMD]) and -independent (glyceryl trinitrate [GTN]) changes in brachial artery area were measured using cardiovascular magnetic resonance in 13 amenorrheic DMPA users (>1 year use; mean age 29±4 years) and in 10 controls (mean age 30±4 years,
P
=0.25) with regular menstrual cycles after validation of the technique. FMD and GTN responses were measured just before repeat MPA injection and 48 hours later (n=12) in DMPA users and during menstruation and midcycle (n=9) in controls. Serum-estradiol levels (S-estradiol) were measured at both visits. FMD was reduced in DMPA users compared with controls during menstruation (1.1% versus 8.0%, respectively
P
<0.01) without differences in GTN responses. S-estradiol levels in DMPA users were significantly lower than in controls during menstruation (58 versus 96 pmol/L,
P
<0.01). High levels of circulating MPA 48 hours after injection were not linked to an additional impairment in FMD (2.0% versus 3.1%,
P
=0.23). Estradiol levels were significantly correlated to FMD (
r
=0.43,
P
<0.01).

Conclusions—

Endothelium-dependent arterial function measured by cardiovascular magnetic resonance is impaired in chronic users of DMPA, and hypoestrogenism may be the mechanism of action. DMPA might adversely affect cardiovascular health, and in particular its use in women with cardiovascular disease should be additionally evaluated.
Magnetic Resonance Imaging to Assess the Hemodynamic Effects of Pulmonary Valve Replacement in Adults Late After Repair of Tetralogy of Fallot
Authors: Vliegen Hubert W. , van Straten Alexander , de Roos Albert , Roest Arno A.W. , Schoof Paul H. , Zwinderman Aeilko H. , Ottenkamp Jaap , van der Wall Ernst E. , Hazekamp Mark G.
Published: September 2002

Background—

Pulmonary regurgitation (PR) late after total correction for tetralogy of Fallot may lead to progressive right ventricular (RV) dilatation and an increased incidence of severe arrhythmias and sudden death. Timing of pulmonary valve replacement (PVR) is subject to discussion, because the effect of PVR on RV function in adults is unclear. In this study, MRI was used to assess the effect of PVR on RV function and PR. Clinical improvement was established by means of the NYHA classification.

Methods and Results—

Twenty-six adult patients were included. Cardiac MRI was performed at a median of 5.1±3.4 months before and 7.4± 2.4 months after PVR. Mean preoperative PR was 46±10% (range, 25% to 64%). After PVR, 20 of 26 patients (77%) showed no residual PR, 5 patients showed mild residual PR, and 1 patient showed moderate PR. RV end-diastolic volume (RV-EDV) decreased from 305±87 to 210±62 mL (
P
<0.001), and RV end-systolic volume (RV-ESV) decreased from 181±67 to 121±58 mL (
P
<0.001). No significant change was found in RV-EF (42% versus 42%). However, RVEF corrected for regurgitations and shunting increased from 25.2±8.0% to 43.3±13.7% (
P
<0.001). Mean validity class improved from 2.0 to 1.3 (
P
<0.001).

Conclusions—

In adult patients with PR and RV dilatation, late after total correction of tetralogy of Fallot, MRI measurements show remarkable hemodynamic improvement of RV function after PVR and improvement of validity. We therefore advocate a less restrictive management concerning PVR in these patients.
Serum Immunoglobulin G Antibodies to Chlamydial Heat Shock Protein 60 but Not to Human and Bacterial Homologs Are Associated With Coronary Artery Disease
Authors: Mahdi Olaimatu S. , Horne Benjamin D. , Mullen Kelly , Muhlestein Joseph B. , Byrne Gerald I.
Published: September 2002

Background—

Evidence for an association between
Chlamydia pneumoniae
infection and coronary artery disease (CAD) has been reported by numerous studies, cross-reactive heat shock protein (Hsp) antibody responses have been causally linked to CAD, and the severity of chlamydial disease pathogenesis correlates with Hsp serology. Our aim was to determine if chlamydial Hsp (cHsp) antibody responses are predictive of CAD.

Methods and Results—

Patients were recruited in a case-control study: 250 cases had angiographically significant CAD (stenosis ≥70%), and 250 controls had normal coronary arteries (stenosis <10%). Serum immunoglobulin G reactivity to Hsp10 and Hsp60 antigens (chlamydial,
Escherichia coli
, and human), and
C pneumoniae
whole organisms were measured by ELISA. Univariate analysis confirmed that classical CAD risk factors were predictors of CAD. Univariate analysis showed that cHsp60 (
P
= 0.001, OR 3.9), cHsp10 (
P
=0.045, OR 3.8),
E coli
Hsp60 (
P
=0.04, OR 1.5) and
C pneumoniae
(
P
=0.03, OR 1.8) ELISA optical density (OD) values were significantly different between cases and controls. Multivariate analysis found that only upper-quintile cHsp60 seroreactivity remained a significant predictor of CAD after controlling for classical CAD risk factors and seroreactivity to the other antigens (cHsp60 OD,
P
=0.005, OR 3.9 per OD unit; cHsp60 quintile, 5 versus 1 to 4;
P
=0.01, OR 2.1).

Conclusions—

The presence of elevated anti-cHsp60 immunoglobulin G antibodies, but not anti-human or anti–
E coli
homologs, was independently associated with CAD. This finding argues against previous suggestions that cross-reactive or autoimmune Hsp60 responses may contribute to disease progression. High anti-cHsp60 antibody response appears to identify the subset of patients with chlamydial infection and significant CAD.
Effects of Atorvastatin on Stroke in Patients With Unstable Angina or Non-Q-Wave Myocardial Infarction
Authors: Waters David D. , Schwartz Gregory G. , Olsson Anders G. , Zeiher Andreas , Oliver Michael F. , Ganz Peter , Ezekowitz Michael , Chaitman Bernard R. , Leslie Sally J. , Stern Theresa
Published: September 2002

Background—

This report describes the effect of intensive cholesterol lowering with atorvastatin on the incidence of nonfatal stroke, a secondary end point, in a randomized, placebo-controlled trial of patients with unstable angina or non-Q-wave myocardial infarction. The primary end point, a composite of death, nonfatal myocardial infarction, resuscitated cardiac arrest, or recurrent symptomatic myocardial ischemia with objective evidence requiring emergency rehospitalization, was reduced from 17.4% in the placebo group to 14.8% in the atorvastatin group over the 16 weeks of the trial (
P
=0.048).

Methods and Results—

Strokes were adjudicated by a blinded end-point committee using standard clinical and imaging criteria. The outcomes of nonfatal stroke and fatal plus nonfatal stroke were analyzed by time to first occurrence during the 16-week trial. Of 38 events (in 36 patients) adjudicated as fatal or nonfatal strokes, 3 were classified as hemorrhagic, one as embolic, and 29 as thrombotic or embolic; 5 could not be categorized. Nonfatal stroke occurred in 9 patients in the atorvastatin group and 22 in the placebo group (relative risk, 0.40; 95% confidence intervals, 0.19 to 0.88;
P
=0.02). Fatal or nonfatal stroke occurred in 12 atorvastatin patients and 24 placebo patients (relative risk, 0.49; 95% confidence intervals, 0.24 to 0.98;
P
=0.04). All 3 hemorrhagic strokes occurred in the placebo group.

Conclusion—

Intensive cholesterol lowering with atorvastatin over 16 weeks in patients with acute coronary syndromes reduced the overall stroke rate by half and did not cause hemorrhagic stroke. These findings need to be confirmed in future trials.
Myocardial Infarction in Parents Who Lost a Child
Authors: Li Jiong , Hansen Dorthe , Mortensen Preben Bo , Olsen Jørn
Published: September 2002

Background—

The association between psychological stress and coronary heart disease remains unclear. We conducted a prospective follow-up study based on national registers to investigate if the death of a child, one of the most severe stressors, increases the risk of myocardial infarction (MI) in parents.

Methods and Results—

From 1980 to 1996, 19 361 parents who lost a child (<18 years of age) in Denmark were recruited to the exposed cohort, and 295 540 parents matched on family structure were selected for the unexposed cohort. The Cox proportional hazards model was used to evaluate the relative risk (RR) of myocardial infarction (MI). The average RRs for a fatal MI and any first MI among the exposed were 1.36 (95% CI, 0.98 to 1.88) and 1.28 (95% CI, 1.08 to 1.51), respectively. The two cohorts had similar MI risk during the first 6 years of follow-up. From the 7th to the 17th year of follow-up, the exposed cohort had a RR of 1.58 (95% CI, 1.08 to 2.30) for fatal MI and a RR of 1.31 (95% CI, 1.09 to 1.57) for first MI. Parents who lost a child unexpectedly, especially from sudden infant death syndrome, experienced higher RRs.

Conclusions—

The death of a child was associated with an increased risk of MI in bereaved parents.