bluuebunny/crossref_metadata_2025 huggingface dataset:
Cyclic AMP Response Element–Binding Protein Mediates Reactive Oxygen Species–Induced c-
fos
Expression
Authors: Ichiki Toshihiro , Tokunou Tomotake , Fukuyama Kae , Iino Naoko , Masuda Satoko , Takeshita Akira
Published: June 2003

Although the cyclic AMP response element–binding protein (CREB) plays an important role in the survival of neuronal cells and T lymphocytes, the role of CREB in vascular smooth muscle cells (VSMCs) is incompletely characterized. We examined the role of CREB in VSMCs stimulated with reactive oxygen species. Activation of CREB was examined by Western blot analysis with an antibody that specifically recognizes phosphorylation at serine 133 of CREB, which is a critical marker of activation. Hydrogen peroxide (H
2
O
2
) time-dependently induced phosphorylation of CREB, with a peak at 15 minutes. The H
2
O
2
-induced phosphorylation of CREB was partially blocked by inhibition of either extracellular signal–regulated protein kinase kinase by PD98059 or of p38 mitogen-activated protein kinase (MAPK) by SB203580. AG1478, an epidermal growth factor receptor (EGFR) inhibitor, suppressed the H
2
O
2
-induced phosphorylation of CREB and tyrosine phosphorylation of EGFR. Overexpression of the dominant-negative form of CREB by an adenovirus vector suppressed H
2
O
2
-induced c-
fos
expression. These findings suggest that H
2
O
2
induces CREB phosphorylation through EGFR transactivation and mitogen-activated protein kinase pathways. CREB might be a novel redox-sensitive transcription factor involved in the regulation of VSMC gene expression.
Baroreflex Control of Muscle Sympathetic Nerve Activity After Carotid Body Tumor Resection
Authors: Timmers Henri J.L.M. , Karemaker John M. , Wieling Wouter , Marres Henri A.M. , Lenders Jacques W.M.
Published: June 2003

Bilateral carotid body tumor resection causes a permanent attenuation of vagal baroreflex sensitivity. We retrospectively examined the effects of bilateral carotid body tumor resection on the baroreflex control of sympathetic nerve traffic. Muscle sympathetic nerve activity was recorded in 5 patients after bilateral carotid body tumor resection (1 man and 4 women, 51±11 years) and 6 healthy control subjects (2 men and 4 women, 50±7 years). Baroreflex sensitivity was calculated from changes in R-R interval and muscle sympathetic nerve activity in response to bolus injections of phenylephrine and nitroprusside. In addition, sympathetic responses to the Valsalva maneuver and cold pressor test were measured. The integrated neurogram of patients and control subjects contained a similar pattern of pulse synchronous burst of nerve activity. Baroreflex control of both heart rate and sympathetic nerve activity were attenuated in patients as compared with control subjects [heart rate baroreflex sensitivity: 3.68±0.93 versus 11.61±4.72 ms/mm Hg (phenylephrine,
P
=0.011) and 2.53±1.36 versus 5.82±1.94 ms/mm Hg (nitroprusside,
P
=0.05); sympathetic baroreflex sensitivity: 3.70±2.90 versus 7.53±4.12 activity/100 beats/mm Hg (phenylephrine,
P
=0.10) and 3.93±4.43 versus 15.27±10.03 activity/100 beats/mm Hg (nitroprusside,
P
=0.028)]. The Valsalva maneuver elicited normal reflex changes in muscle sympathetic nerve activity, whereas heart rate responses were blunted in the patients with bilateral carotid body tumor resection. Maximal sympathetic responses to the cold pressor test did not differ between the two groups. Denervation of carotid sinus baroreceptors as the result of bilateral carotid body tumor resection produces chronic impairment of baroreflex control of both heart rate and sympathetic nerve activity. During the Valsalva maneuver, loss of carotid baroreflex control of heart rate is less well compensated for by the extra carotid baroreceptors than the control of muscle sympathetic nerve activity.
Role of Sodium-Calcium Exchanger in Modulating the Action Potential of Ventricular Myocytes From Normal and Failing Hearts
Authors: Armoundas Antonis A. , Hobai Ion A. , Tomaselli Gordon F. , Winslow Raimond L. , O’Rourke Brian
Published: June 2003

Increased Na
+
-Ca
2+
exchange (NCX) activity in heart failure and hypertrophy may compensate for depressed sarcoplasmic reticular Ca
2+
uptake, provide inotropic support through reverse-mode Ca
2+
entry, and/or deplete intracellular Ca
2+
stores. NCX is electrogenic and depends on Na
+
and Ca
2+
transmembrane gradients, making it difficult to predict its effect on the action potential (AP). Here, we examine the effect of [Na
+
]
i
on the AP in myocytes from normal and pacing-induced failing canine hearts and estimate the direction of the NCX driving force using simultaneously recorded APs and Ca
2+
transients. AP duration shortened with increasing [Na
+
]
i
and was correlated with a shift in the reversal point of the NCX driving force. At [Na
+
]
i
≥10 mmol/L, outward NCX current during the plateau facilitated repolarization, whereas at 5 mmol/L [Na
+
]
i
, NCX had a depolarizing effect, confirmed by partially inhibiting NCX with exchange inhibitory peptide. Exchange inhibitory peptide shortened the AP duration at 5 mmol/L [Na
+
]
i
and prolonged it at [Na
+
]
i
≥10 mmol/L. With K
+
currents blocked, total membrane current was outward during the late plateau of an AP clamp at 10 mmol/L [Na
+
]
i
and became inward close to the predicted reversal point for the NCX driving force. The results were reproduced using a computer model. These results indicate that NCX plays an important role in shaping the AP of the canine myocyte, helping it to repolarize at high [Na
+
]
i
, especially in the failing heart, but contributing a depolarizing, potentially arrhythmogenic, influence at low [Na
+
]
i
.
Shear Stress–Mediated Chromatin Remodeling Provides Molecular Basis for Flow-Dependent Regulation of Gene Expression
Authors: Illi Barbara , Nanni Simona , Scopece Alessandro , Farsetti Antonella , Biglioli Paolo , Capogrossi Maurizio C. , Gaetano Carlo
Published: June 2003

Shear stress (SS), the tangential component of hemodynamic forces, modulates the expression of several genes in endothelial cells. However, no information is available about its effect on chromatin structure, which plays a key role in gene transcription. In this study, a link between SS and chromatin remodeling was established in human umbilical vein endothelial cells (HUVECs). HUVECs were exposed to SS of 10 dyne/cm
2
per second, in the presence or absence of the histone deacetylase inhibitor trichostatin A, and assayed for histone H3 and histone H4 modifications. SS induced histone H3 serine phosphorylation at position 10 (S10) and lysine acetylation at position 14 (K14) but required trichostatin A to induce H3 phosphoacetylation and H4 acetylation. The phosphatidylinositol 3-kinase inhibitor wortmannin and the mitogen-activated protein kinase inhibitor PD98059 decreased SS-dependent histone H3 phosphorylation, without affecting its acetylation; the p38 inhibitor SB203580 reduced both H3 phosphorylation and acetylation, whereas the protein kinase A inhibitor PKI-tide reduced histone H3 acetylation. Remarkably, the abrogation of histone acetylation inhibited SS-dependent c-
fos
expression. SS also activated ribosomal S6 kinase-2 and mitogen- and stress-activated kinase-1 protein kinases and promoted the formation of a cAMP-responsive element–binding protein (CREB)/CREB-binding protein complex, providing the molecular basis for the increase in histone acetyltransferase activity observed in HUVECs exposed to SS. Finally, the effect of SS on chromatin remodeling was examined. In HUVECs exposed to SS, chromatin within c-
fos
and c-
jun
promoters was specifically immunoprecipitated by an antibody against acetylated histone H3 on K14. These results indicate that SS induces posttransduction modifications of histones; this is an early step toward the flow-dependent regulation of gene expression.
Roles of the Two Active Sites of Somatic Angiotensin-Converting Enzyme in the Cleavage of Angiotensin I and Bradykinin
Authors: Georgiadis Dimitris , Beau Fabrice , Czarny Bertrand , Cotton Joël , Yiotakis Athanasios , Dive Vincent
Published: June 2003

Somatic angiotensin-converting enzyme (ACE) contains two homologous domains, each bearing a functional active site. The in vivo contribution of each active site to the release of angiotensin II (Ang II) and the inactivation of bradykinin (BK) is still unknown. To gain insights into the functional roles of these two active sites, the in vitro and in vivo effects of compounds able to selectively inhibit only one active site of ACE were determined, using radiolabeled Ang I or BK, as physiological substrates of ACE. In vitro studies indicated that a full inhibition of the Ang I and BK cleavage requires a blockade of the two ACE active sites. In contrast, in vivo experiments in mice demonstrated that the selective inhibition of either the N-domain or the C-domain of ACE by these inhibitors prevents the conversion of Ang I to Ang II, while BK protection requires the inhibition of the two ACE active sites. Thus, in vivo, the cleavage of Ang I and BK by ACE appears to obey to different mechanisms. Remarkably, in vivo the conversion of Ang I seems to involve the two active sites of ACE, free of inhibitor. Based on these findings, it might be suggested that the gene duplication of ACE in vertebrates may represent a means for regulating the cleavage of Ang I differently from that of BK.
Vascular Endothelial Growth Factor-B Promotes In Vivo Angiogenesis
Authors: Silvestre Jean-Sébastien , Tamarat Radia , Ebrahimian Teni G. , Le-Roux Aude , Clergue Michel , Emmanuel Florence , Duriez Micheline , Schwartz Bertrand , Branellec Didier , Lévy Bernard I.
Published: June 2003

Vascular endothelial growth factors (VEGFs) and their receptors have emerged as central regulators of the angiogenic process. However, involvement of VEGF-B, one of these factors, in angiogenesis remains obscure. Mice received subcutaneous injection of Matrigel alone or Matrigel with human recombinant protein rhVEGF-B
167
or with rhVEGF-A
165
. After 14 days, cell ingrowth in the Matrigel plug was increased by 2.0- and 2.5-fold in rhVEGF-B
167
–treated and rhVEGF-A
165
–treated mice, respectively (
P
<0.01), in association with a raise in phospho-Akt/Akt (1.8-fold,
P
<0.01) and endothelial NO synthase (eNOS) (1.80- and 1.60-fold, respectively;
P
<0.05) protein levels measured by Western blot. VEGF-B–induced cell ingrowth was impaired by treatment with NOS inhibitor (
N
G
-nitro-
l
-arginine methyl ester; L-NAME, 10 mg/kg per day). Treatment with neutralizing antibody directed against the VEGF-B receptor VEGF-R1 (anti-VEGFR1, 10 μg) completely abrogated VEGF-B–related effects. Proangiogenic effect of VEGF-B was confirmed in a mouse model of surgically induced hindlimb ischemia. Plasmids containing human form of VEGF-A (phVEGF-A
165
) or VEGF-B (phVEGF-B
167
or phVEGF-B
186
) were administered by in vivo electrotransfer. Angiographic score at day 28 showed significant improvement in ischemic/nonischemic leg ratio by 1.4- and 1.5-fold in mice treated with phVEGF-B
167
and phVEGF-B
186
, respectively (
P
<0.05). Laser Doppler perfusion data also evidenced a 1.5-fold increase in phVEGF-B
167
–treated and phVEGF-B
186
–treated mice (
P
<0.05). Such an effect was associated with an upregulation of phospho-Akt/Akt and eNOS protein levels in the ischemic legs and was hampered by treatment with anti-VEGFR1. This study demonstrates for the first time that VEGF-B, in part through its receptor VEGF-R1, promotes angiogenesis in association with an activation of Akt and eNOS-related pathways.
Focal Adhesion Kinase Is Activated and Mediates the Early Hypertrophic Response to Stretch in Cardiac Myocytes
Authors: Torsoni Adriana S. , Constancio Sabata S. , Nadruz Wilson , Hanks Steven K. , Franchini Kleber G.
Published: June 2003

Previously we reported that the rapid activation of the Fak/Src multicomponent signaling complex mediates load-induced activation of growth and survival signaling pathways in adult rat heart. In this study, we report that 5% to 20% (10-minute) cyclic stretch (1 Hz) of neonatal rat ventricular myocytes (NRVMs) was paralleled by increases of Fak phosphorylation at Tyr-397 (from 1.5- to 2.8-fold), as detected by anti-Fak-pY
397
phosphospecific antibody. Moreover, 15% cyclic stretch lasting from 10 to 120 minutes increased Fak phosphorylation at Tyr-397 by 2.5- to 3.5-fold. This activation was accompanied by a dramatic change in Fak localization in NRVMs from densely concentrated in the perinuclear regions in nonstretched cells to aggregates regularly distributed along the myofilaments in stretched cells. Furthermore, a 4-hour cyclic stretch enhanced the activity of an atrial natriuretic factor (ANF) promoter-luciferase reporter gene by 2.7-fold. Disrupting endogenous Fak/Src signaling either by expression of a dominant-negative Fak mutant with phenylalanine substituted for Tyr-397 or by treatment with a c-Src pharmacological inhibitor (PP-2) markedly attenuated stretch-induced Fak activation and clustering at myofilaments and inhibited stretch-induced ANF gene activation. On the other hand, overexpression of wild-type Fak potentiated the stretch-induced Fak phosphorylation but did not enhance either baseline or stretch-induced ANF promoter-luciferase reporter gene activity compared with the responses of nontransfected NRVMs. These findings identify Fak as an important element in the early responses induced by stretch in cardiac myocytes, indicating that it may coordinate the cellular signaling machinery that controls gene expression program associated with load-induced cardiac myocyte hypertrophy.
Effects of Adenovirus-Mediated Sorcin Overexpression on Excitation-Contraction Coupling in Isolated Rabbit Cardiomyocytes
Authors: Seidler Tim , Miller Stewart L.W. , Loughrey Christopher M. , Kania Astrid , Burow Annika , Kettlewell Sarah , Teucher Nils , Wagner Stefan , Kögler Harald , Meyers Marian B. , Hasenfuss Gerd , Smith Godfrey L.
Published: June 2003

To evaluate the effect of sorcin on cardiac excitation-contraction coupling, adult rabbit ventricular myocytes were transfected with a recombinant adenovirus coding for human sorcin (Ad-sorcin). A β-galactosidase adenovirus (Ad-LacZ) was used as a control. Fractional shortening in response to 1-Hz field stimulation (at 37°C) was significantly reduced in Ad-sorcin–transfected myocytes compared with control myocytes (2.10±0.05% [n=311] versus 2.42±0.06% [n=312], respectively;
P
<0.001). Action potential duration (at 20°C) was significantly less in the Ad-sorcin group (458±22 ms, n=11) compared with the control group (520±19 ms, n=10;
P
<0.05). In voltage-clamped, fura 2–loaded myocytes (20°C), a reduced peak-systolic and end-diastolic [Ca
2+
]
i
was observed after Ad-sorcin transfection. L-type Ca
2+
current amplitude and time course were unaffected. Caffeine-induced Ca
2+
release from the sarcoplasmic reticulum (SR) and the accompanying inward Na
+
-Ca
2+
exchanger (NCX) current revealed a significantly lower SR Ca
2+
content and faster Ca
2+
-extrusion kinetics in Ad-sorcin–transfected cells. Higher NCX activity after Ad-sorcin transfection was confirmed by measuring the NCX current-voltage relationship. β-Escin–permeabilized rabbit cardiomyocytes were used to study the effects of sorcin overexpression on Ca
2+
sparks imaged with fluo 3 at 145 to 160 nmol/L [Ca
2+
] using a confocal microscope. Under these conditions, caffeine-mediated SR Ca
2+
release was not different between the two groups. Spontaneous spark frequency, duration, width, and amplitude were lower in sorcin-overexpressing myocytes. In summary, sorcin overexpression in rabbit cardiomyocytes decreased Ca
2+
-transient amplitude predominately by lowering SR Ca
2+
content via increased NCX activity. The effect of sorcin overexpression on Ca
2+
sparks indicates an effect on the ryanodine receptor that may also influence excitation-contraction coupling.
Altered Expression of Small-Conductance Ca
2+
-Activated K
+
(SK3) Channels Modulates Arterial Tone and Blood Pressure
Authors: Taylor Mark S. , Bonev Adrian D. , Gross Tobias P. , Eckman Delrae M. , Brayden Joseph E. , Bond Chris T. , Adelman John P. , Nelson Mark T.
Published: June 2003

The endothelium is a critical regulator of vascular tone, and dysfunction of the endothelium contributes to numerous cardiovascular pathologies. Recent studies suggest that apamin-sensitive, small-conductance, Ca
2+
-activated K
+
channels may play an important role in active endothelium-dependent vasodilations, and expression of these channels may be altered in disease states characterized by vascular dysfunction. Here, we used a transgenic mouse (SK3
T/T
) in which SK3 expression levels can be manipulated with dietary doxycycline (DOX) to test the hypothesis that the level of expression of the SK subunit, SK3, in endothelial cells alters arterial function and blood pressure. SK3 protein was elevated in small mesenteric arteries from SK3
T/T
mice compared with wild-type mice and was greatly suppressed by dietary DOX. SK3 was detected in the endothelium and not in the smooth muscle by immunohistochemistry. In whole-cell patch-clamp experiments, SK currents in endothelial cells from SK3
T/T
mice were almost completely suppressed by dietary DOX. In intact arteries, SK3 channels contributed to sustained hyperpolarization of the endothelial membrane potential, which was communicated to the arterial smooth muscle. Pressure- and phenylephrine-induced constrictions of SK3
T/T
arteries were substantially enhanced by treatment with apamin, suppression of SK3 expression with DOX, or removal of the endothelium. In addition, suppression of SK3 expression caused a pronounced and reversible elevation of blood pressure. These results indicate that endothelial SK3 channels exert a profound, tonic, hyperpolarizing influence in resistance arteries and suggest that the level of SK3 channel expression in endothelial cells is a fundamental determinant of vascular tone and blood pressure.
Cerebral Hemodynamics in Asymptomatic and Symptomatic Patients With High-Grade Carotid Stenosis Undergoing Carotid Endarterectomy
Authors: Soinne Lauri , Helenius Johanna , Tatlisumak Turgut , Saimanen Eija , Salonen Oili , Lindsberg Perttu J. , Kaste Markku
Published: June 2003

Background and Purpose—

Asymptomatic patients with carotid stenosis benefit less from carotid endarterectomy (CEA) than symptomatic patients because the risk of embolic events is lower, but it is not known whether the hemodynamic effect of CEA is different between the groups. We evaluated hemodynamics of symptomatic and asymptomatic patient groups before and after CEA.

Methods—

Forty-six independent patients with a unilateral high-grade carotid stenosis, 23 asymptomatic and 23 symptomatic, underwent dynamic susceptibility contrast MRI (DSC-MRI) and transcranial Doppler ultrasound (TCD) evaluation before CEA and 3 and 100 days afterward. Quantitative perfusion parameters were calculated separately in selected regions of white and gray matter and watershed regions in each hemisphere, and mean transit time (MTT) maps were assessed visually by 2 independent observers. Vasomotor reactivity was determined with breath-holding index and flow impedance with pulsatility index ipsilaterally.

Results—

In contrast to the asymptomatic carotid stenosis group, symptomatic carotid stenosis patients had preoperatively increased MTT and lower cerebral blood flow values in the ipsilateral hemisphere, more in white matter and watershed regions than in gray matter. Visually detected perfusion deficits were associated with symptomatic status. The interhemispheric asymmetries were abolished by CEA. The improving trend over time was greater in the symptomatic carotid stenosis group and was best seen in MTT. On TCD, pulsatility index was lower in symptomatic carotid stenosis patients preoperatively, with no postoperative difference, whereas the breath-holding index improved only in the symptomatic carotid stenosis group after CEA.

Conclusions—

Patients with asymptomatic and symptomatic carotid stenosis differ significantly by means of DSC-MRI and TCD before and in response to CEA.
Detection of Hemosiderin Deposition by T2*-Weighted MRI After Subarachnoid Hemorrhage
Authors: Imaizumi Toshio , Chiba Masahiko , Honma Toshimi , Niwa Jun
Published: June 2003

Background and Purpose—

Subarachnoid hemorrhage (SAH) is very difficult to diagnose several months after its onset. We thus investigated subarachnoid hemosiderin deposition well after SAH by T2*-weighted MRI, a sensitive method for hemosiderin detection.

Methods—

To investigate how hemosiderin deposition as confirmed by T2*-weighted MRI contributes to the determination of prior SAH and how the extent of hemosiderin deposition is associated with a number of clinical factors, we retrospectively analyzed 58 patients >3 months after SAH associated with ruptured aneurysms. We also investigated 209 healthy volunteers as controls.

Results—

T2*-weighted MRI demonstrated subarachnoid hemosiderin deposition in 72.4% of the SAH patients, whereas no deposition was seen in the healthy volunteer group. The hemosiderin was preferentially deposited in the subarachnoid space near a ruptured aneurysm. Odds ratios (ORs) were estimated from logistic regression analyses correlating hemosiderin deposition with other factors. Age (≥54 years) (OR, 5.1; 95% CI, 1.03 to 25.0;
P
=0.046), Fisher grade 3 on initial CT (OR, 8.0; 95% CI, 1.26 to 50.4;
P
=0.027), and Karnofsky Scale score ≤80% 6 months after onset of SAH (OR, 12.8; 95% CI, 1.97 to 83.3;
P
=0.0077) were all found to be independently associated with hemosiderin deposition levels.

Conclusions—

T2*-weighted MRI is an effective means of diagnosing prior SAH and may also reveal the location of a ruptured aneurysm. The extent of hemosiderin deposition was significantly associated with several factors, including age, CT findings, and poor prognosis.
Stroke MRI in Intracerebral Hemorrhage
Authors: Schellinger Peter D. , Fiebach Jochen B. , Hoffmann Katrin , Becker Kristina , Orakcioglu Berk , Kollmar Rainer , Jüttler Eric , Schramm Peter , Schwab Stefan , Sartor Klaus , Hacke Werner
Published: June 2003

Background and Purpose—

Cerebral ischemia has been proposed as a contributing mechanism to secondary neuronal injury after intracerebral hemorrhage (ICH). The search for surrogate parameters that allow treatment stratification for spontaneous ICH continues. We sought to assess the presence and prognostic effect of perihemorrhagic ischemic changes and hypoperfusion in a prospective stroke MRI study.

Methods—

We performed stroke MRI in 32 patients with hyperacute ICH (mean, 16.9±17.2 mL) within 6 hours after symptom onset (mean, 3.1±1.3 hours). Clinical data at baseline (National Institutes of Health Stroke Scale) and on day 90 (Barthel Index, modified Rankin Scale) were assessed. Perihemorrhagic perfusion- and diffusion-weighted imaging changes were assessed in a 1-cm-wide area around the clot.

Results—

Despite a mild perihemorrhagic mean transit time prolongation of 0.7±1.1 second, there were no significant perihemorrhagic apparent diffusion coefficient or mean transit time changes indicating irreversible ischemia or hypoperfusion. ICH size, time to imaging, or clinical severity at baseline or outcome were not reflected by changes of relative apparent diffusion coefficient or perfusion-weighted imaging. ICH size correlated with baseline clinical severity (
r
=0.51,
P
=0.005). There was a significant association (
P
=0.0494) and a significant negative correlation (
r
=−0.468,
P
=0.0103) of perihemorrhagic perfusion change with time from symptom onset not associated with ICH size.

Conclusions—

Perihemorrhagic hypoperfusion probably is a consequence of reduced metabolic demand (diaschisis) rather than a sign of ischemia. We found no evidence for a perihemorrhagic and potentially salvageable ischemic penumbra in hyperacute ICH. Further studies should address metabolic, toxic, apoptotic, and microvascular aspects.
Effects of a Selective CD11b/CD18 Antagonist and Recombinant Human Tissue Plasminogen Activator Treatment Alone and in Combination in a Rat Embolic Model of Stroke
Authors: Zhang Li , Zhang Zheng Gang , Zhang Rui Lan , Lu Mei , Krams Michael , Chopp Michael
Published: June 2003

Background and Purpose—

We evaluated the neuroprotective effect of UK-279,276 (also referred to as recombinant neutrophil inhibitory factor), a selective CD11b/CD18 antagonist, in combination with thrombolytic therapy on focal cerebral ischemia.

Methods—

Male Wistar rats (n=88) were subjected to embolic middle cerebral artery occlusion. Animals were randomly assigned to the following groups (n=11 in each group): vehicle treatment alone at 2 or 4 hours, UK-279,276 treatment alone at 2 or 4 hours, recombinant human tissue plasminogen activator (rhtPA) treatment alone at 2 or 4 hours, or the combination of UK-279,276 and rhtPA at 2 or 4 hours. Infarct volume, neurological function, hemorrhagic transformation, neutrophil accumulation, and parenchymal fibrin deposition were measured 7 days after middle cerebral artery occlusion.

Results—

Treatment with UK-279,276 significantly (
P
<0.05) improved neurological severity scores, an index of neurological functional deficit, but had no effect on infarct volume compared with vehicle-treated animals. Treatment with rhtPA alone at 2 but not 4 hours significantly (
P
<0.05) reduced infarct volume and improved neurological function compared with vehicle-treated animals. Combination treatment with UK-279,276 and rhtPA at 2 or 4 hours significantly (
P
<0.01) reduced infarct volume and enhanced recovery of neurological function compared with control. Neutrophil accumulation and fibrin deposition in the brain parenchyma of combination-treated rats at 2 and 4 hours after stroke were significantly reduced (
P
<0.05) compared with corresponding vehicle-treated control groups. The neuroprotective effect of the combined treatments was superior to the additive effects from each treatment of rhtPA or UK-279,276 alone.

Conclusions—

These data suggest that the combination treatment with UK-279,276 and rhtPA may extend the window of thrombolytic therapy for the acute treatment of stroke.
Risk of Ischemic Stroke Among Users of the Oral Contraceptive Pill
Authors: Siritho Sasitorn , Thrift Amanda G. , McNeil John J. , You Roger X. , Davis Stephen M. , Donnan Geoffrey A.
Published: June 2003

Background and Purpose—

Use of oral contraceptives has increased, and there is uncertainty about the stroke risk associated with their use. Our aim was to investigate this issue.

Methods—

Using case-control techniques, we identified consecutive women with ischemic stroke from 4 Melbourne hospitals. All patients were between 15 and 55 years of age and had no prior stroke. Neighborhood-based control subjects were individually age-matched (±5 years) and geographically matched to subject cases. A questionnaire administered to participants elicited information about prior exposure to various potential risk factors, including the oral contraceptive pill (OCP).

Results—

We included 234 cases and 234 controls (mean age, 42 years). Compared with noncurrent use, current use of the OCP, in doses of ≤50 μg estrogen, was not associated with an increased risk of ischemic stroke (odds ratio [OR] 1.76; 95% CI, 0.86 to 3.61;
P
=0.124). Factors associated with an increased risk of ischemic stroke were a history of hypertension (OR, 2.18; 95% CI, 1.22 to 3.91), transient ischemic attack (OR, 8.17; 95% CI, 1.69 to 39.6), previous myocardial infarction (OR, 5.64; 95% CI, 1.04 to 30.61), and diabetes mellitus (OR, 5.42; 95% CI, 1.42 to 20.75); family history of stroke (OR, 2.22; 95% CI, 1.12 to 4.43); and smoking >20 cigarettes per day (OR, 3.68; 95% CI, 1.22 to 11.09).

Conclusions—

There was no evidence for an association between ischemic stroke and use of the OCP in low doses (≤50 μg estrogen) in young Australian women. Other modifiable risk factors such as hypertension, diabetes mellitus, and smoking are important.
Angiotensin-Converting Enzyme Gene Polymorphism and Carotid Artery Wall Thickness
Authors: Sayed-Tabatabaei Fakhredin A. , Houwing-Duistermaat Jeanine J. , van Duijn Cornelia M. , Witteman Jacqueline C.M.
Published: June 2003

Background and Purpose—

Many studies have investigated the association between the angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism and carotid artery intima-media thickness (IMT); however, most studies were small and conducted in selective samples. The aim of this study was to evaluate this association by performing a meta-analysis on published articles.

Methods—

We searched Medline for articles studying the association between the ACE I/D polymorphism and carotid IMT. Twenty-six studies were found; 23 articles containing 9833 subjects were qualified to enter the meta-analysis. We classified those articles on the basis of their samples into high-risk and low-risk populations and white and Asian ethnic groups. IMT was used as a continuous variable, and data were analyzed with the Cochrane Review Manager.

Results—

A significant positive association was present between the D allele and common carotid IMT (weighted mean difference between DD and II genotypes, 0.23 mm×10
−1
;
P
<0.01). The association was stronger among high-risk populations. The point estimates of DD versus II were higher than those of ID versus II.

Conclusions—

Our meta-analysis showed evidence of a positive association between the D allele of the ACE gene and common carotid IMT. The overall results were concordant in both ethnic groups.
Infection and the Risk of Spontaneous Cervical Artery Dissection
Authors: Guillon Benoît , Berthet Karine , Benslamia Lamia , Bertrand Marion , Bousser Marie-Germaine , Tzourio Christophe
Published: June 2003

Background and Purpose—Several constitutional and environmental risk factors may be involved in the occurrence of spontaneous cervical artery dissection (SCAD). This work explored the association between recent infection and SCAD in an hospital-based case-control study.

Methods—Forty-seven patients with SCAD and 52 with ischemic stroke from another cause were prospectively and consecutively recruited by 2 neurology departments. A specially designed questionnaire was used to assess the history of an acute infection that could have occurred within a month before the vascular event.

Results—Acute infection was more frequent in patients with SCAD (31.9%) than in control subjects (13.5%) (crude odds ratio, 3.0; 95% confidence interval, 1.1 to 8.2;P=0.032). This association was stronger in patients with multiple (odds ratio, 6.4) than single artery (odds ratio, 2.1) dissection.

Conclusions—Recent infection is a risk factor and could be a trigger for SCAD.
Left Ventricular Hypertrophy Is Associated With Asymptomatic Cerebral Damage in Hypertensive Patients
Authors: Selvetella Giulio , Notte Antonella , Maffei Angelo , Calistri Valentina , Scamardella Virginia , Frati Giacomo , Trimarco Bruno , Colonnese Claudio , Lembo Giuseppe
Published: June 2003

Background and Purpose—

It has been demonstrated that left ventricular hypertrophy (LVH) confers an increased risk for major cerebrovascular events. However, it is still uncertain whether there is an association between LVH and asymptomatic cerebrovascular damage in hypertensive patients. In this study, we investigated the relation between LVH, evaluated by both echocardiography (Echo-LVH) and electrocardiography (ECG-LVH), and preclinical cerebral damage, as identified by magnetic resonance imaging.

Methods—

One hundred ninety-five consecutive patients were enrolled in the study. We evaluated other risk factors such as age, sex, presence of diabetes, cholesterol levels, smoking status, heart rate, and systolic and diastolic blood pressure. Asymptomatic cerebrovascular damage was considered silent cerebral lesions: punctate lesions, lacunes, and territorial lesions. Patients were divided into 2 groups according to the presence of asymptomatic brain lesions.

Results—

The 2 groups of patients differed only in terms of age and systolic pressure. More importantly, the prevalence of Echo-LVH (83% versus 47.7%,
P
<0.001) and ECG-LVH (56% versus 22%,
P
<0.001) was significantly higher in patients with asymptomatic brain lesions. A multivariate analysis allowed us to recognize LVH as the only independent predictor for the presence of ischemic lacunes (
P
<0.001). Moreover, we evaluated the impact of left ventricular geometry on asymptomatic cerebrovascular damage, and we found that hypertensives with concentric hypertrophy displayed more pronounced asymptomatic cerebrovascular damage compared with patients with eccentric hypertrophy.

Conclusions—

Our study demonstrates that LVH is associated with cerebral damage even in the absence of clinical symptoms. Thus, the presence of cardiac damage provides important prognostic clues about the presence of asymptomatic cerebral damage.
Can Patients Be Anticoagulated After Intracerebral Hemorrhage?
Authors: Eckman Mark H. , Rosand Jonathan , Knudsen Katherine A. , Singer Daniel E. , Greenberg Steven M.
Published: June 2003

Background and Purpose—

Warfarin increases both the likelihood and the mortality of intracerebral hemorrhage (ICH), particularly in patients with a history of prior ICH. In light of this consideration, should a patient with both a history of ICH and a clear indication for anticoagulation such as nonvalvular atrial fibrillation be anticoagulated? In the absence of data from a clinical trial, we used a decision-analysis model to compare the expected values of 2 treatment strategies—warfarin and no anticoagulation—for such patients.

Methods—

We used a Markov state transition decision model stratified by location of hemorrhage (lobar or deep hemispheric). Effectiveness was measured in quality-adjusted life years (QALYs). Data sources included English language literature identified through MEDLINE searches and bibliographies from selected articles, along with empirical data from our own institution. The base case focused on a 69-year-old man with a history of ICH and newly diagnosed nonvalvular atrial fibrillation.

Results—

For patients with prior lobar ICH, withholding anticoagulation therapy was strongly preferred, improving quality-adjusted life expectancy by 1.9 QALYs. For patients with prior deep hemispheric ICH, withholding anticoagulation resulted in a smaller gain of 0.3 QALYs. In sensitivity analyses for patients with deep ICH, anticoagulation could be preferred if the risk of thromboembolic stroke is particularly high.

Conclusions—

Survivors of lobar ICH with atrial fibrillation should not be offered long-term anticoagulation. Similarly, most patients with deep hemispheric ICH and atrial fibrillation should not receive anticoagulant therapy. However, patients with deep hemispheric ICH at particularly high risk for thromboembolic stroke or low risk of ICH recurrence might benefit from long-term anticoagulation.
Long-Term Relative Survival in Elderly Patients After Carotid Endarterectomy
Authors: Norman Paul E. , Semmens James B. , Laurvick Crystal L. , Lawrence-Brown Michael
Published: June 2003

Background and Purpose—

Octogenarians were not included in the major trials of carotid endarterectomy. Concern has been expressed about the role of carotid endarterectomy in this age group. This concern is based in part on uncertainty about the long-term survival of elderly patients after carotid endarterectomy. The aim of the present study was to assess relative survival in those patients ≥80 years of age undergoing carotid endarterectomy.

Methods—

A population-based record linkage study of all patients who underwent carotid endarterectomy from 1988 to 1998 in Western Australia was undertaken. Long-term relative survival after carotid endarterectomy was assessed against age- and sex-matched controls.

Results—

During the period 1988 to 1998, 1796 (1306 male, 490 female) cases were identified. There were 151 patients ≥80 years of age. The cumulative survival at 5 years was 64.9% for those ≥80 years of age compared with 80.1% for those <80 years of age. Relative survival at 5 years was 118% (95% CI, 102 to 134) for those ≥80 years of age compared with 94.7% (95% CI, 92 to 97) for those <80 years of age.

Conclusions—

Long-term relative survival after carotid endarterectomy in patients ≥80 years of age was better than that of an age-matched population. The likelihood of living long enough to gain benefit from a carotid endarterectomy is not jeopardized by being too old.
Local Intra-arterial Fibrinolysis of Thromboemboli Occurring During Neuroendovascular Procedures With Recombinant Tissue Plasminogen Activator
Authors: Hähnel Stefan , Schellinger Peter D. , Gutschalk Alexander , Geletneky Karsten , Hartmann Marius , Knauth Michael , Sartor Klaus
Published: June 2003

Background and Purpose—

There is a lack of systematic data regarding local intra-arterial fibrinolysis (LIF) of thromboemboli occurring during neuroendovascular procedures with the use of recombinant tissue plasminogen activator (rtPA). We report our technique for treating LIF of intracerebral thromboemboli occurring during neuroendovascular procedures.

Methods—

Nine of 723 patients (1.2%) who underwent neuroendovascular procedures during the period from January 1997 to September 2002 suffered thromboembolic complications. These patients were treated by LIF with a maximum dose of 0.9 mg rtPA per kilogram body weight. Recanalization was categorized as successful (Thrombolysis in Myocardial Infarction [TIMI] grade 2 or 3) versus unsuccessful (TIMI grade 0 or 1), and clinical outcome was categorized as independent (Rankin Scale score 0 to 2) versus dependent or dead (Rankin Scale score 3 to 6).

Results—

The minimum time between thrombus detection and beginning of LIF was 10 minutes, and the maximum time was 90 minutes. Successful recanalization was achieved in 4 of 9 patients (44%). All 9 patients suffered cerebral ischemic infarctions, and none of the patients sustained intracerebral hemorrhage. Two patients (22%) died from malignant brain infarctions. Four patients (44%) remained moderately disabled, and 3 patients (33%) were severely disabled 3 months after LIF.

Conclusions—

Although we used relatively high doses of rtPA, the recanalization rates and clinical outcome of LIF in our patients were not satisfactory. Strategies for the prevention of thromboemboli during neuroendovascular procedures must be improved, and novel fibrinolytic or thrombolytic techniques should be developed.
Use of the Original, Modified, or New Intracerebral Hemorrhage Score to Predict Mortality and Morbidity After Intracerebral Hemorrhage
Authors: Cheung Raymond Tak Fai , Zou Liang-Yu
Published: June 2003

Background and Purpose—

A simple clinical scale of intracerebral hemorrhage (ICH), comprising the Glasgow Coma Scale score, age, infratentorial origin, ICH volume, and intraventricular hemorrhage, was recently shown to predict 30-day mortality. We studied how well the original ICH Score would predict morbidity and mortality and determined whether modification would improve the predictions.

Methods—

Patients admitted to a regional hospital with acute ICH in 1999 were reviewed. Independent predictors of mortality or good outcome (modified Rankin score ≤2) at 30 days were identified by logistic regression to devise a new ICH Score for comparison with the original Score. A modified Score was created by substituting National Institutes of Health Stroke Scale (NIHSS) for the Glasgow Coma Scale.

Results—

The mortality rate was 22%, and 35% had good outcome. Independent factors for mortality were high NIHSS score, intraventricular hemorrhage, subarachnoid extension, and narrow pulse pressure. Independent factors for good outcome were low NIHSS score and low admission temperature. For all ICH Scores, no patient had a maximum score of 6. Cutoff values of ≥3 and <3 provided the best Youden’s index of diagnostic test in all ICH Scores for mortality and good outcome, respectively. The original and modified ICH Scores predict mortality equally well. The new and modified ICH Scores are slightly better for prediction of good outcome.

Conclusions—

All 3 ICH Scores are simple clinical grading scales. As reliable predictors of good outcome and/or mortality, they are useful in clinical research studies and standardization of clinical protocols.
Reliability of Assessing Percentage of Diffusion-Perfusion Mismatch
Authors: Coutts Shelagh B. , Simon Jessica E. , Tomanek Anna I. , Barber Philip A. , Chan Jean , Hudon Mark E. , Mitchell J. Ross , Frayne Richard , Eliasziw Michael , Buchan Alastair M. , Demchuk Andrew M.
Published: June 2003

Background and Purpose—

Emergent neurovascular imaging holds promise in identifying new and optimum target populations for thrombolysis in stroke. Recent research has focused on patients with diffusion-weighted MRI (DWI)-perfusion-weighted MRI (PWI) mismatch as a marker of tissue at risk of infarction and a means to select the most suitable candidates for thrombolysis. The present study sought to estimate the reliability of assessing the percentage of DWI-PWI mismatch.

Methods—

Thirteen patients with acute strokes had DWI and PWI within 7 hours of symptom onset. Six raters independently created relative mean transit time (rMTT) maps and then compared them with DWI images to assess the percentage of mismatch (PWI>DWI) in 10% increments. The MR scans were reassessed by 4 raters, tracing around the lesions to calculate the volume percentage of mismatch.

Results—

Visual assessment had an interrater reliability of 0.68 (95% CI, 0.52 to 1.0; SEM=21.6%) and an intrarater reliability of 0.80 (95% CI, 0.47 to 1.0; SEM=16.9%). Hand-drawn assessment had an interrater reliability of 0.66 (95% CI, 0.45 to 1.0; SEM=26.2%) and an intrarater reliability of 0.94 (95% CI, 0.81 to 1.0; SEM=10.9%).

Conclusions—

Results from the present study suggest that quantifying mismatch by the human eye is reproducible but not reliable among observers. This raises doubts about using mismatch for clinical decision making and clinical trial enrollment.
Endogenous CCL2 (monocyte chemotactic protein-1) modulates human immunodeficiency virus type-1 replication and affects cytoskeleton organization in human monocyte–derived macrophages
Authors: Fantuzzi Laura , Spadaro Francesca , Vallanti Giuliana , Canini Irene , Ramoni Carlo , Vicenzi Elisa , Belardelli Filippo , Poli Guido , Gessani Sandra
Published: June 2003

CC chemokine ligand 2 (CCL2) is constitutively expressed at high levels in human peripheral blood monocytes, and its expression is further up-modulated during their differentiation into macrophages as well as in the course of HIV infection. To investigate the role of endogenous CCL2 on HIV replication and macrophage function, CCL2's activity was neutralized by specific antibodies. Infection of monocyte-derived macrophages with laboratory-adapted HIV-1 or primary viral isolates in the continuous presence of anti-CCL2 antibody resulted in significantly lower p24 Gag antigen release with respect to control cultures. Interestingly, CCL2 neutralization did not affect the early steps of the HIV life cycle but resulted in the intracellular accumulation of p24 Gag antigen. Simultaneously, remarkable changes in cell morphology and size occurred in cell cultures maintained in the presence of anti-CCL2 antibody. These results suggest that CCL2 may represent an autocrine factor important for enhancing virion production likely by affecting the macrophage cytoskeleton. (Blood. 2003;102:2334-2337)
A novel MyD-1 (SIRP-1α) signaling pathway that inhibits LPS-induced TNFα production by monocytes
Authors: Smith Rosemary E. , Patel Vanshree , Seatter Sandra D. , Deehan Maureen R. , Brown Marion H. , Brooke Gareth P. , Goodridge Helen S. , Howard Christopher J. , Rigley Kevin P. , Harnett William , Harnett Margaret M.
Published: June 2003

MyD-1 (CD172) is a member of the family of signal regulatory phosphatase (SIRP) binding proteins, which is expressed on human CD14+ monocytes and dendritic cells. We now show a novel role for MyD-1 in the regulation of the innate immune system by pathogen products such as lipopolysaccharide (LPS), purified protein derivative (PPD), and Zymosan. Specifically, we demonstrate that ligation of MyD-1 on peripheral blood mononuclear cells (PBMCs) inhibits tumor necrosis factor alpha (TNFα) secretion but has no effect on other cytokines induced in response to each of these products. In an attempt to understand the molecular mechanisms underlying this surprisingly selective effect we investigated signal transduction pathways coupled to MyD-1. Ligation of the SIRP was found to recruit the tyrosine phosphatase SHP-2 and promote sequential activation of phosphatidylinositol (PI) 3-kinase, phospholipase D, and sphingosine kinase. Inhibition of LPS-induced TNFα secretion by MyD-1 appears to be mediated by this pathway, as the PI 3-kinase inhibitor wortmannin restores normal LPS-driven TNFα secretion. MyD-1-coupling to this PI 3-kinase-dependent signaling pathway may therefore present a novel target for the development of therapeutic strategies for combating TNFα production and consequent inflammatory disease. (Blood. 2003;102:2532-2540)
Green fluorescent protein selectively induces HSP70-mediated up-regulation of COX-2 expression in endothelial cells
Authors: Zhang Fan , Hackett Neil R. , Lam George , Cheng Joseph , Pergolizzi Robert , Luo Lan , Shmelkov Sergey V. , Edelberg Jay , Crystal Ronald G. , Rafii Shahin
Published: June 2003

Reporter genes, including green fluorescent protein (GFP), have been used to monitor the expression of transgenes introduced into vascular cells by gene transfer vectors. Here, we demonstrate that GFP by itself can selectively induce expression of certain genes in endothelial cells. Elevation of the cytoplasmic concentration of GFP in endothelial cells, specifically, resulted in a robust upregulation of heat shock protein 70 (HSP70). GFP induced both mRNA and protein expression of HSP70 in a dose-dependent manner. GFP-mediated up-regulation of HSP70 resulted in induction of cyclooxygenase-2 (COX-2) followed by prostaglandin E2 (PGE2) production. GFP-mediated up-regulation of HSP70 is independent of mitogen-activated protein kinase and phosphatidylinositol-3-kinase signaling cascades because inhibition of these pathways had no effect on HSP70 increases. Adenoviral delivery of GFP into murine vasculature significantly enhanced blood flow, suggesting that sufficient PGE2 is produced to induce vasodilation. Identification of the molecular partners that interact with GFP will increase our understanding of the vascular-specific factors that regulate stress angiogenesis and hemostasis.
Phenotype and hematopoietic potential of side population cells throughout embryonic development
Authors: Nadin Brian M. , Goodell Margaret A. , Hirschi Karen K.
Published: June 2003

Adult murine bone marrow hematopoietic stem cells (HSCs) can be purified by sorting Hoechst 33342-extruding side population (SP) cells. Herein we investigated whether SP cells reside within embryonic tissues and exhibit hematopoietic progenitor activity. We isolated yolk sac (YS) and embryonic tissues 7.5 to 11.5 days after coitus (dpc), resolved an SP in each, and demonstrated that these SP cells exhibit distinct phenotypic and functional characteristics throughout development. YS and embryonic SP isolated 8.0 dpc expressed vascular endothelial-cadherin (VE-cadherin) and vascular endothelial receptor 2 (Flk-1), markers not expressed by bone marrow SP but expressed by endothelial cells and progenitors. SP at this stage did not express CD45 or produce hematopoietic colonies in vitro. In contrast, SP isolated 9.5 to 11.5 dpc contained a significantly higher proportion of cells expressing cKit and CD45, markers highly expressed by bone marrow SP. Furthermore, YS SP isolated 9.5 to 11.5 dpc demonstrated 40- to 90-fold enrichment for hematopoietic progenitor activity over unfractionated tissue. Our data indicate that YS and embryonic SP cells detected prior to the onset of circulation express the highest levels of endothelial markers and do not generate blood cells in vitro; however, as development progresses, they acquire hematopoietic potential and phenotypic characteristics similar to those of bone marrow SP. (Blood. 2003;102:2436-2443)