bluuebunny/crossref_metadata_2025 huggingface dataset:
Point of care monitoring of oral anticoagulant therapy in children: comparison of CoaguChek Plus and Thrombotest methods with venous international normalised ratio
Authors: Ignjatovic Vera , Barnes Chris , Newall Fiona , Hamilton Simone , Burgess Janet , Monagle Paul
Published: July 2004

This paper reports the outcome of a research protocol aimed at optimising warfarin monitoring in a tertiary pediatric centre. The Thrombotest™ INR was the standard monitoring test employed to manage oral anticoagulant therapy in children at the Royal Children’s Hospital (RCH), Melbourne. This study compares the results of this standard method to the novel CoaguChek® INR monitor and the “gold standard” technique of venous INR sampling. The objectives were to determine 1) if point-of-care techniques of measuring the INR (Thrombotest and CoaguChek) are accurate and reliable compared to INR results obtained from venous sampling, processed in an accredited laboratory, and 2) if INR results generated by POC devices can be safely used to manage oral anticoagulant therapy in children. 18 children (10 females and 8 males) participated in the study. Ages ranged from 9 months to 21 years (Mean 11.9 years; SD 5.03 years). The agreement between CoaguChek and venous INR measurements (r = 0.885) was shown to be higher compared to Thrombotest and venous INR (r = 0.700). Compared to the venous INR, values obtained with Coaguchek and Thrombotest crossed into or out of the therapeutic range in 25% and 36% of cases respectively. In 88% of the CoaguChek cases and 57% Thrombotest cases, the difference from the venous result was less than 0.5. The CoaguChek method of INR monitoring is a more accurate and reliable method compared to Thrombotest, in the pediatric population tested, and can be safely used to manage oral anticoagulant therapy in children.
Pharmacokinetics of clopidogrel after administration of a high loading dose
Authors: Kastrati Adnan , Harlfinger Steffi , Gorchakova Olga , Lazar Andreas , von Beckerath Nicolas , Schömig Albert , Schömig Edgar , Taubert Dirk
Published: July 2004

The adenosine diphosphate (ADP) receptor P2Y12 blocking agent clopidogrel is clinically proven to be efficient in preventing thrombotic events. However, its therapeutic value is limited by an, as yet poorly explained, interindividual heterogeneity in platelet inhibition. To evaluate possible pharmacokinetic determinants of this response variability, we developed a sensitive and specific liquid chromatography tandem mass spectrometry (LC-MS/MS) assay for quantification of unmodified inactive clopidogrel, its inactive carboxyl metabolite, and its active thiol metabolite in plasma. Analyte concentrations and platelet aggregation were assessed in ten healthy volunteers receiving an oral load of 600 mg clopidogrel. Subjects showed marked inter-individual differences in maximal platelet inhibition and in plasma pharmacokinetics. Univariate regression revealed linear correlations between maximal antiplatelet effect and peak plasma concentrations (cmax) of unchanged clopidogrel (r=0.76; p=0.01), of the carboxyl metabolite (r=0.70; p=0.03), and of the thiol metabolite (r=0.73; p=0.02), as well as linear correlations between cmax values of clopidogrel and its metabolites. This indicates that the response variability is predominantly caused by individual differences in clopidogrel absorption and that other factors, such as ADP receptor reactivity or differences in bioactivation of clopidogrel, do not play a major role.
Platelet dysfunction during Bothrops jararaca snake envenomation in rabbits
Authors: Sano-Martins Ida , Santoro Marcelo
Published: July 2004

Despite being well established that snake envenomation causes blood coagulation and fibrinolysis disturbances, scant information is available about blood platelet disorders. Herein we show that experimentally Bothrops jararaca-envenomed rabbits presented thrombocytopenia, hypofibrinogenemia, elevation of von Willebrand factor plasma levels, platelet hypoaggregation in platelet rich plasma and whole blood, normoaggregation in washed platelet suspensions, decreased platelet ATP secretion, normal plasma levels of platelet factor 4, and constant intraplatelet serotonin levels. Furthermore, by flow cytometric analyses, platelets displayed a significant decrease in the expression of a GPIIb-IIIa epitope recognized by P2 monoclonal antibody (p< 0.05) and an increased expression of a ligandinduced binding site (LIBS-1) of GPIIIa (p< 0.05), but total GPIIb-IIIa expression, evaluated with specific polyclonal antibodies, was normal. Fibrinogen and fibrin(ogen) degradation product (FfDP) expression on platelet surface showed no significant alteration. Nonetheless, significant elevations of platelet P-selectin were noticed on circulating platelets. The percentage of circulating reticulated platelets and the survival time of biotinylated platelets of envenomed rabbits were not statistically different from control animals. We suggest that thrombin engendered by procoagulating components of B. jararaca venom has an essential role in the pathogenesis of platelet and coagulation disorders in this experimental model. Increased expression of P-selectin in the experimental group demonstrates that platelets of envenomed rabbits are indeed activated in circulation, and that decreased fibrinogen or increased FfDP levels are not the primary cause of platelet dysfunction. These results imply the existence of an inhibitor in plasma that interferes with platelet aggregation in bothropic envenomation.
Extrinsic coagulation pathway activation and metalloproteinase-2/TIMPs system are related to oxidative stress and atherosclerosis in hemodialysis patients
Authors: Pawlak Dariusz , Mysliwiec Michal , Pawlak Krystyna
Published: July 2004

Matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs), together with extrinsic coagulation pathway activation and increased oxidative stress (SOX) have all been implicated as important factors in atherosclerosis and vascular remodelling. The aim of the present study was to investigate whether the MMPs/TIMPs system is associated with activation of the extrinsic coagulation pathway in conditions of increased SOX in hemodialysis (HD) patients. In HD patients, with and without cardiovascular disease (CVD), and in controls, we compared pre-dialysis levels of MMP-2, MMP-9,TIMP-1,TIMP-2; the markers of extrinsic coagulation pathway-tissue factor (TF) and its inhibitor (TFPI), prothrombin fragment F1+2 (F1+2); a marker of SOX-Cu/Zn superoxide dismutase (Cu/Zn SOD) and a surrogate of atherosclerotic disease-intima media thickness (IMT). Hemodialysis patients, particularly those with CVD, showed a significant increase in values of MMP-2/TIMPs, markers of the extrinsic coagulation pathway, Cu/Zn SOD and IMT as compared to controls. The markers of coagulation activation positively correlated with the MMP-2/TIMPs system, whereas they did not correlate with MMP-9. In addition, both MMP-2/TIMPs as well as extrinsic coagulation parameters were related to the prevalence of increased SOX, IMT and CVD. Multiple stepwise regression analysis showed that low TIMP-2 followed by increased Cu/Zn SOD and MMP-2 levels independently and significantly predicted elevated IMT on maintenance HD patients. In conclusion, our data suggest that the MMP-2/TIMPs system and an activated extrinsic coagulation pathway could cooperate in conditions of elevated SOX and could influence arterial remodeling resulting in the presence of CVD in haemodialysis patients.
The catalytic subunit of pseutarin C, a group C prothrombin activator from the venom of Pseudonaja textilis, is structurally similar to mammalian blood coagulation factor Xa
Authors: Rao Veena , Swarup Sanjay , Kini Manjunatha
Published: July 2004

Pseutarin C, a group C prothrombin activator from Pseudonaja textilis venom, is a large protein complex consisting of catalytic and nonenzymatic subunits, which are functionally similar to the mammalian FXa-FVa complex. Here, we present the complete cDNA sequence of the catalytic subunit of pseutarin C. The cDNA of the catalytic subunit encodes a protein of 449 amino acids, which includes a 22-residue signal peptide, 18-residue propeptide and a mature protein of 409 amino acids. The deduced amino acid sequence shows 74-83% identity to group D prothrombin activators from snake venom and ∼42% identity to mammalian FX and has identical domain structure. The precursor of the catalytic subunit of pseutarin C has several unique features. The activation peptide of the catalytic subunit of pseutarin C is significantly smaller (27 as compared to 52 residues in mammalian FX) and does not contain any glycosylation sites. Unlike coagulation FXa, Ser52 and Asn45 of the light and heavy chains are O- and N-glycosylated in pseutarin C catalytic subunit. There is a 12-residue insertion in pseutarin C catalytic subunit close to the region that is implicated in binding to FVa. This is the first sequence of the catalytic subunit of a group C prothrombin activator.
The potential clinical and economic outcomes of pharmacogenetics-oriented management of warfarin therapy – a decision analysis
Authors: Chan Fredric , Wong Raymond , Cheng Gregory , You Joyce
Published: July 2004

Variant cytochrome P450 (CYP) 2C9 genotypes are associated with low maintenance dose requirement of warfarin therapy and increased risk of major bleeding events. The objective of the present study was to evaluate the potential clinical and economic outcomes of using CYP2C9 genotype data to guide the management of anticoagulation therapy and to identify influential factors affecting the cost-effectiveness of this treatment scheme. A decision tree was designed to simulate, over 12 months, the clinical and economic outcomes of patients newly started on warfarin associated with two alternatives: (1) no genotyping (non-genotyped group) and (2) CYP2C9 genotyping prior to initiation of warfarin therapy (genotyped group). Nongenotyped group patients would receive standard care of an anticoagulation clinic (AC). In the genotyped group, patients with at least one variant CYP2C9 allele would receive intensified anticoagulation service. Most of the clinical probabilities were derived from literature. The direct medical costs were estimated from the Diagnosis-Related Group charges and from literature. The total number of events and the direct medical cost per 100 patient-years in the genotyped and non-genotyped groups were 9.58 and USD155,700, and, 10.48 and USD 150,500, respectively. The marginal cost per additional major bleeding averted in the genotyped group was USD 5,778. The model was sensitive to the variation of the cost and reduction of bleeding rate in the intensified anticoagulation service. In conclusion, the pharmacogenetics-oriented management of warfarin therapy is potentially more effective in preventing bleeding with a marginal cost. The cost-effectiveness of this treatment scheme depends on the relative cost and effectiveness of a pharmacogenetics-oriented intensified anticoagulation service comparing to the standard AC care.
Postmenopausal hormone replacement and venous thromboembolism following hip and knee arthroplasty
Authors: Hurbanek Jason , Jaffer Amir , Morra Nariman , Karafa Matthew , Brotman Daniel
Published: July 2004

Hormone replacement therapy has been associated with venous thromboembolism. Controversy exists regarding the appropriate management of hormone replacement in the perioperative setting and in other situations – such as acute illness – predisposing to acute venous thromboembolism. We performed a case-control study to determine whether perioperative hormone replacement is associated with venous thromboembolism following hip and knee arthroplasty. 108 patients with postoperative venous thrombosis were matched by age, date and type of surgery, and surgeon with 210 controls without thrombosis. Perioperative hormone replacement use was no more prevalent in patients with postoperative thrombosis than those without. Eighteen (16.7%) women with post-operative thrombosis had taken perioperative hormone replacement compared to 49 (23.3%) of controls: odds ratio = 0.66; (95% CI 0.35–1.18; p=0.17). After multivariate analysis, the adjusted odds ratios were similar. Variables predicting post-operative thrombosis included: prior venous thromboembolism (OR = 2.3; p = 0.02), rheumatologic disease (OR = 2.2; p = 0.03), and absence of pharmacologic antithrombotic prophylaxis (OR = 13.4; p = 0.005). Cases and controls were otherwise similar. Users of hormone replacement were similar to non-users except that they were less likely to have coronary disease (OR 0.34; p = 0.03) or prior thrombosis (OR = 0.28; p = 0.04), and were younger (median age 67 versus 74 years; p <0.0001). We found no association between perioperative hormone replacement and post-operative thrombosis in patients undergoing major orthopaedic surgery. Routine discontinuation of these medications preoperatively – and possibly in other situations predisposing to thrombosis, such as acute medical illness – may be unnecessary in patients receiving appropriate pharmacologic antithrombotic prophylaxis.
Extracellular regulation of TGF-β activity in wound repair: growth factor latency as a sensor mechanism for injury
Authors: Blakytny Robert , Brunner Georg
Published: July 2004

The transforming growth factor-β (TGF-β) family of growth factors are major regulators of wound repair, scar formation, and fibrosis. One of the prominent features of TGF-β biology is the fact that this growth factor is secreted as a latent precursor, which may be directed to and stored at specific sites in the cellular microenvironment. Targeting and mobilization, and particularly extracellular activation of latent TGF-β control the biological action of this growth factor. This review will focus on mechanisms of extracellular TGF-β regulation relevant to and potentially operating in wound repair and scarring.
Interrelationships Between Human Apolipoprotein A-I and Apolipoproteins B-48 and B-100 Kinetics Using Stable Isotopes
Authors: Welty Francine K. , Lichtenstein Alice H. , Barrett P. Hugh R. , Dolnikowski Gregory G. , Schaefer Ernst J.
Published: July 2004

Objective—

Our purpose was to determine the relationship between apolipoprotein (apo) A-I and apoB-48 and apoB-100 metabolism in moderately hypercholesterolemic humans.

Methods and Results—

The kinetics of apoA-I within high-density lipoprotein (HDL), apoB-48 and apoB-100 within triglyceride-rich lipoproteins, and apoB-100 within intermediate-density lipoprotein and low density-lipoprotein (LDL) were examined with a primed constant infusion of [5,5,5-
2
H
3
] leucine in the fed state (hourly feeding) in 23 subjects after consumption of a 36% total fat diet. Lipoproteins were isolated by ultracentrifugation; apolipoproteins by SDS-PAGE gels; and isotope enrichment assessed by gas chromatograph/mass spectrometry. Kinetic parameters were calculated by multicompartmental modeling of the data with SAAM II. ApoA-I production rate (PR) was correlated with LDL apoB-100 pool size (PS;
r
=0.49;
P
=0.017) and LDL cholesterol (
r
=0.61;
P
=0.002), whereas apoA-I fractional catabolic rate (FCR) was inversely correlated with apoB-48 FCR (
r
=−0.40;
P
=0.05) but not with very low-density lipoprotein apoB-100 FCR.

Conclusions—

Two links exist between apoA-I and apoB kinetics: 1) when LDL apoB-100 PS is high, there is increased apoA-I PR; and 2) delayed chylomicron remnant clearance (represented by apoB-48 FCR) is associated with enhanced apoA-I FCR, a finding indicating that alterations in intestinal lipoproteins may be more important in determining HDL cholesterol levels than changes in liver lipoproteins.
Acyl-Coenzyme A:Cholesterol Acyltransferase-2 (ACAT-2) Is Responsible for Elevated Intestinal ACAT Activity in Diabetic Rats
Authors: Hori Masaharu , Satoh Maki , Furukawa Kohichiro , Sakamoto Yu-ichiro , Hakamata Hideki , Komohara Yoshihiro , Takeya Motohiro , Sasaki Yutaka , Miyazaki Akira , Horiuchi Seikoh
Published: July 2004

Objective—

Diabetes-induced dyslipidemia is seen in streptozotocin-induced diabetic rats. This is caused, in part, by elevated intestinal acyl-coenzyme A:cholesterol acyltransferase (ACAT) activity. Because two ACAT isozymes (ACAT-1 and ACAT-2) were identified, in the present study we determined which ACAT isozyme was involved in the elevated intestinal ACAT activity in diabetic rats.

Methods and Results—

We cloned a full-length cDNA of rat ACAT-2. Its overexpression in ACAT-deficient AC29 cells demonstrated that the ACAT activity is derived from the cloned cDNA, and a 45-kDa protein of rat ACAT-2 cross-reacts with an anti-human ACAT-2 antibody. The tissue distribution of rat ACAT-2 mRNA revealed its restricted expression to liver and small intestine. Immunohistochemical analyses using an anti-human ACAT-2 antibody demonstrated that ACAT-2 is localized in villus–crypt axis of rat small intestine. The intestinal ACAT activity in diabetic rats was significantly immunodepleted by an anti–ACAT-2 antibody but not by an anti–ACAT-1 antibody. Finally, intestinal ACAT-2 in diabetic rats significantly increased at both protein and mRNA levels as compared with that in control rats.

Conclusions—

Our data demonstrate that ACAT-2 isozyme is responsible for the increased intestinal ACAT activity of diabetic rats, suggesting an important role of ACAT-2 for dyslipidemia in diabetic patients.
Elevated Fluid Shear Stress Enhances Postocclusive Collateral Artery Growth and Gene Expression in the Pig Hind Limb
Authors: Pipp Frederic , Boehm Stefanie , Cai Wei-Jun , Adili Farzin , Ziegler Bela , Karanovic Gordana , Ritter Ralf , Balzer Jörn , Scheler Christian , Schaper Wolfgang , Schmitz-Rixen Thomas
Published: July 2004

Objective—

The role of fluid shear stress (FSS) in collateral vessel growth remains disputed and prospective in vivo experiments to test its morphogenic power are rare. Therefore, we studied the influence of FSS on arteriogenesis in a new model with extremely high levels of collateral flow and FSS in pig and rabbit hind limbs.

Methods and Results—

A side-to-side anastomosis was created between the distal stump of one of the bilaterally occluded femoral arteries with the accompanying vein. This clamps the collateral reentry pressure at venous levels and increases collateral flow, which is directed to a large part into the venous system. This decreases circumferential wall stress and markedly increases FSS. One week after anastomosis, angiographic number and size of collaterals were significantly increased. Maximal collateral flow exceeded by 2.3-fold that obtained in the ligature-only hind limb. Capillary density increased in lower leg muscles. Immunohistochemistry revealed augmented proliferative activity of endothelial and smooth muscle cells. Intercellular adhesion molecule-1 and vascular cell adhesion molecule (VCAM)-1 were upregulated, and monocyte invasion was markedly increased. In 2-dimensional gels, actin-regulating cofilin1 and cofilin2, destrin, and transgelin2 showed the highest degree of differential regulation.

Conclusions—

High levels of FSS cause a strong arteriogenic response, reinstate cellular proliferation, stimulate cytoskeletal rearrangement, and normalize maximal conductance. FSS is the initiating molding force in arteriogenesis.
cAMP-Response Element-Binding Protein Mediates Tumor Necrosis Factor-α–Induced Vascular Smooth Muscle Cell Migration
Authors: Ono Hiroki , Ichiki Toshihiro , Fukuyama Kae , Iino Naoko , Masuda Satoko , Egashira Kensuke , Takeshita Akira
Published: July 2004

Objective—

Migration of vascular smooth muscle cells (VSMCs) contributes to formation of vascular stenotic lesions such as atherosclerosis and restenosis after angioplasty. Previous studies have demonstrated that tumor necrosis factor-α (TNF-α) is a potent migration factor for VSMCs. cAMP-response element-binding protein (CREB) is the stimulus-induced transcription factor and activates transcription of target genes such as
c-fos
and interleukin-6. We examined whether CREB is involved in TNF-α–induced VSMC migration.

Methods and Results—

TNF-α induced CREB phosphorylation with a peak at 15 minutes of stimulation. Pharmacological inhibition of p38 mitogen-activated protein kinase (p38-MAPK) inhibited TNF-α–induced CREB phosphorylation. Adenovirus-mediated overexpression of dominant-negative form of CREB suppressed TNF-α–induced CREB phosphorylation and
c-fos
mRNA expression. VSMC migration was evaluated using a Boyden chamber. Overexpression of dominant-negative form of CREB suppressed VSMC migration as well as Rac1 expression induced by TNF-α. Overexpression of dominant-negative Rac1 also inhibited TNF-α–induced VSMC migration.

Conclusion—

Our results suggest that p38-MAPK/CREB/Rac1 pathway plays a critical role in TNF-α–induced VSMC migration and may be a novel therapeutic target for vascular stenotic lesion.
Angiogenic Effects of Adrenomedullin in Ischemia and Tumor Growth
Authors: Iimuro Satoshi , Shindo Takayuki , Moriyama Nobuo , Amaki Toshihiro , Niu Pei , Takeda Norifumi , Iwata Hiroshi , Zhang Yuelan , Ebihara Aya , Nagai Ryozo
Published: July 2004

Adrenomedullin (AM) is a novel vasodilating peptide involved in the regulation of circulatory homeostasis and implicated in the pathophysiology of cardiovascular disease. We tested the hypothesis that AM also possesses angiogenic properties. Using laser Doppler perfusion imaging, we found that AM stimulated recovery of blood flow to the affected limb in the mouse hind-limb ischemia model. AM exerted this effect in part by promoting expression of vascular endothelial growth factor (VEGF) in the ischemic limb, and immunostaining for CD31 showed the enhanced flow to reflect increased collateral capillary density. By enhancing tumor angiogenesis, AM also promoted the growth of subcutaneously transplanted sarcoma 180 tumor cells. However, heterozygotic AM knockout mice (

AM
+/−

) showed significantly less blood flow recovery with less collateral capillary development and VEGF expression than their wild-type littermates. Similarly, mice treated with AM22-52, a competitive inhibitor of AM, showed reduced capillary development, and growth of sarcoma 180 tumors was inhibited in

AM
+/−

and AM22-52–treated mice. Notably, administration of VEGF or AM rescued blood flow recovery and capillary formation in

AM
+/−

and AM22-52–treated mice. In cocultures of endothelial cells and fibroblasts, AM enhanced VEGF-induced capillary formation, whereas in cultures of endothelial cells AM enhanced VEGF-induced Akt activation. These results show that AM possesses novel angiogenic properties mediated by its ability to enhance VEGF expression and Akt activity. This may make AM a useful therapeutic tool for relieving ischemia; conversely, inhibitors of AM could be useful for clinical management of tumor growth.
Protein Kinase Cε Overexpression Alters Myofilament Properties and Composition During the Progression of Heart Failure
Authors: Goldspink Paul H. , Montgomery David E. , Walker Lori A. , Urboniene Dalia , McKinney Ronald D. , Geenen David L. , Solaro R. John , Buttrick Peter M.
Published: July 2004

We report characterization of a transgenic mouse that overexpresses constitutively active protein kinase Cε in the heart and slowly develops a dilated cardiomyopathy with failure. The hemodynamic, mechanical, and biochemical properties of these hearts demonstrate a series of temporal events that mark the progression of the disease. In the 3-month transgenic (TG) animals, contractile properties and gene expression measurements are normal, but an increase in myofibrillar Ca
2+
sensitivity and thin filament protein phosphorylation is noted. At 6 months, there is a decrease in the myofibrillar Ca
2+
sensitivity, a significant increase in β-myosin heavy chain mRNA and protein, normal cardiac function, but a blunted response to an inotropic challenge. The transition at 9 months is especially interesting because age-related changes appear to contribute to the decline in function seen in the TG heart. At this point, there is a decline in baseline function and maximum tension produced by the myofibrils, which is coincident with the onset of atrial myosin light chain isoform re-expression in the ventricles. In the 12-month TG mice, there is clear hemodynamic and geometric evidence of failure. Alterations in the composition of the myofibrils persist but the phosphorylation of myosin light chain 2v is dramatically different at this age compared with all others. We interpret these data to implicate the disruption of the myofibrillar proteins and their interactions in the propagation of dilated cardiac disease.
Thromboxane A
2
Receptor Signaling Inhibits Vascular Endothelial Growth Factor–Induced Endothelial Cell Differentiation and Migration
Authors: Ashton Anthony W. , Ware J. Anthony
Published: July 2004

Vascular endothelial growth factor (VEGF) is an important patho-physiological mediator of angiogenesis. VEGF-induced endothelial cell (EC) migration and angiogenesis often occur in complicated environments containing multiple agents capable of modifying the response. Thromboxane (TX) A
2
is released from multiple cell types and is a prime mediator of pathogenesis of many vascular diseases. Human EC express both TXA
2
receptor (TP) isoforms; however, the effects of individual TP isoforms on VEGF-induced EC migration and angogenesis are unknown. We report here that the TXA
2
mimetic [1S-(1α, 2β(5Z), 3α(1E, 3R), 4α]-7-[3-(3-hydroxy-4-(4′-iodophenoxy)-1-butenyl)-7-oxab icyclo-[2.2.1]heptan-2yl]-5′-heptenoic acid (IBOP) (100 nmol/L) is a potent antagonist (IC
50
30 nmol/L) of VEGF-induced EC migration and differentiation. TPβ, but not TPα, expression is required for the inhibition of VEGF-induced migration and angiogenesis. IBOP costimulation suppressed nitric oxide (NO) release from VEGF-treated EC through decreased activation of Akt, eNOS, and PDK1. TPβ costimulation also ablated the increase in focal adhesion formation in response to VEGF. This mechanism was characterized by decreased recruitment of focal adhesion kinase (FAK) and vinculin to the α
v
β
3
integrin and reduced FAK and Src activation in response to VEGF. Addition of NO donors together with transfection of a constitutively active Src construct could circumvent the blockade of VEGF-induced migration by TP; however, neither intervention alone was sufficient. Thus, TP stimulation appears to limit angiogenesis, at least in part, by inhibiting the pro-angiogenic cytokine VEGF. These data further support a role for antagonism of TP activation in enhancing the angiogenic response in tissues exposed to elevated TXA
2
levels in which revascularization is important.
Program of Cell Survival Underlying Human and Experimental Hibernating Myocardium
Authors: Depre Christophe , Kim Song-Jung , John Anna S. , Huang Yanhong , Rimoldi Ornella E. , Pepper John R. , Dreyfus Gilles D. , Gaussin Vinciane , Pennell Dudley J. , Vatner Dorothy E. , Camici Paolo G. , Vatner Stephen F.
Published: July 2004

Hibernating myocardium refers to chronically dysfunctional myocardium in patients with coronary artery disease in which cardiac viability is maintained and whose function improves after coronary revascularization. It is our hypothesis that long-term adaptive genomic mechanisms subtend the survival capacity of this ischemic myocardium. Therefore, the goal of this study was to determine whether chronic repetitive ischemia elicits a gene program of survival protecting hibernating myocardium against cell death. Accordingly, we measured the expression of survival genes in hibernating myocardium, both in patients surgically treated for hibernation and in a chronic swine model of repetitive ischemia reproducing the features of hibernation. Human hibernating myocardium was characterized by an upregulation of genes and corresponding proteins involved in anti-apoptosis (IAP), growth (VEGF, H11 kinase), and cytoprotection (HSP70, HIF-1α, GLUT1). In the swine model, the same genes and proteins were upregulated after repetitive ischemia, which was accompanied by a concomitant decrease in myocyte apoptosis. These changes characterize viable tissue, because they were not found in irreversibly injured myocardium. Our report demonstrates a novel mechanism by which the activation of an endogenous gene program of cell survival underlies the sustained viability of the hibernating heart. Potentially, promoting such a program offers a novel opportunity to salvage postmitotic tissues in conditions of ischemia.
Postconditioning: A Form of “Modified Reperfusion” Protects the Myocardium by Activating the Phosphatidylinositol 3-Kinase-Akt Pathway
Authors: Tsang Andrew , Hausenloy Derek J. , Mocanu Mihaela M. , Yellon Derek M.
Published: July 2004

Brief intermittent episodes of ischemia and reperfusion, at the onset of reperfusion after a prolonged period of ischemia, confer cardioprotection, a phenomenon termed “ischemic postconditioning” (Postcond). We hypothesized that this phenomenon may just represent a modified form of reperfusion that activates the reperfusion injury salvage kinase (RISK) pathway. Isolated perfused rat hearts were subjected to: (a) 35 minutes of ischemia and 120 minutes of reperfusion, and infarct size was determined by tetrazolium staining; or (b) 35 minutes of ischemia and 7 minutes of reperfusion, and the phosphorylation states of Akt, endothelial NO synthase (eNOS), and p70S6K were determined. Postcond reduced infarct size from 51.2±3.4% to 31.5±4.1% (
P
<0.01), an effect comparable with ischemic preconditioning (IPC; 27.5±2.3%;
P
<0.01). Of interest, the combined protective effects of IPC and Postcond were not additive (30.1±4.8% with IPC+Postcond;
P
=NS). Inhibiting phosphatidylinositol 3-kinase (PI3K) at reperfusion using LY or Wortmannin (Wort) during the first 15 minutes of reperfusion completely abolished Postcond-induced protection (31.5±4.1% with Postcond versus 51.7±4.5% with Postcond+LY,
P
<0.01; 56.2±10.1% with Postcond+ Wort;
P
<0.01), suggesting that Postcond protects the heart by activating PI3K-Akt. Western blot analysis demonstrated that Postcond induced a significant increase in phosphorylation of Akt, eNOS, and p70S6K in an LY- and Wort-sensitive manner. In conclusion, we show for the first time that ischemic Postcond protects the myocardium by activating the prosurvival kinases PI3K-Akt, eNOS, and p70S6K in accordance with the RISK pathway.
Subcortical Ca
2+
Waves Sneaking Under the Plasma Membrane in Endothelial Cells
Authors: Isshiki Masashi , Mutoh Akiko , Fujita Toshiro
Published: July 2004

Subplasmalemmal Ca
2+
, dynamically equilibrated with extracellular Ca
2+
, affects numerous signaling molecules, effectors, and events within this restricted space. We demonstrated the presence of a novel Ca
2+
wave propagating beneath the plasma membrane in response to acute elevation of extracellular [Ca
2+
], by targeting a Ca
2+
sensor, cameleon, to the endothelial plasmalemma. These subcortical waves, spatially distinct from classical cytosolic Ca
2+
waves, originated in localized regions and propagated throughout the subplasmalemma. Translocation of an expressed GFP fused with a PH domain of PLCδ from the plasma membrane to the cytosol accompanied these subcortical waves, and U73122 attenuated not only the GFP-PHδ translocation, but also the peak amplitude of the subcortical Ca
2+
waves; this finding suggests the involvement of local IP
3
production through PLC-mediated PIP
2
hydrolysis in the initiation of these waves. Changes in NO production as well as PKCβ-GFP translocation from the cytosol to the plasma membrane, but not of GFP-PLA
2
to perinuclear endomembranes, were associated with the subplasmalemmal Ca
2+
changes. Thus, extracellular Ca
2+
maintains the basal PLC activity of the plasma membrane, is involved in the initiation of compartmentalized subcortical Ca
2+
waves, and regulates Ca
2+
-dependent signaling molecules residing in or translocated to the plasma membrane. The full text of this article is available online at http://circres.ahajournals.org.
Creation of a Genetic Calcium Channel Blocker by Targeted Gem Gene Transfer in the Heart
Authors: Murata Mitsushige , Cingolani Eugenio , McDonald Amy D. , Donahue J. Kevin , Marbán Eduardo
Published: July 2004

Calcium channel blockers are among the most commonly used therapeutic drugs. Nevertheless, the utility of calcium channel blockers for heart disease is limited because of the potent vasodilatory effect that causes hypotension, and other side effects attributable to blockade of noncardiac channels. Therefore, focal calcium channel blockade by gene transfer is highly desirable. With a view to creating a focally applicable genetic calcium channel blocker, we overexpressed the ras-related small G-protein Gem in the heart by somatic gene transfer. Adenovirus-mediated delivery of Gem markedly decreased L-type calcium current density in ventricular myocytes, resulting in the abbreviation of action potential duration. Furthermore, transduction of Gem resulted in a significant shortening of the electrocardiographic QTc interval and reduction of left ventricular systolic function. Focal delivery of Gem to the atrioventricular (AV) node significantly slowed AV nodal conduction (prolongation of PR and AH intervals), which was effective in the reduction of heart rate during atrial fibrillation. Thus, these results indicate that gene transfer of Gem functions as a genetic calcium channel blocker, the local application of which can effectively modulate cardiac electrical and contractile function.
Effects of
Hsp70.1
Gene Knockout on the Mitochondrial Apoptotic Pathway After Focal Cerebral Ischemia
Authors: Lee Seung-Hoon , Kwon Hyung-Min , Kim Young-Ju , Lee Kyung-Mi , Kim Manho , Yoon Byung-Woo
Published: July 2004

Background and Purpose—

Murine heat-shock protein 70 (HSP70) protein, which is produced from 2 genes,
hsp70.1
and
hsp70.3
, is known to protect the brain against ischemic injury. However, little information is available on the antiapoptotic mechanism of HSP70.1 protein after cerebral ischemia. To evaluate the role of HSP70.1 protein in ischemia, we analyzed the mitochondrial apoptotic pathway using
hsp70.1
knockout (KO) mice and their wild-type (WT) mice.

Methods—

hsp70.1
KO and WT mice underwent focal ischemia for 120 minutes. DNA fragmentation was evaluated by TUNEL staining. Cytochrome
c
release and the activation of caspase-3 were analyzed by Western blotting and immunohistochemistry.

Results—

hsp70.1
mRNA was not detected in
hsp70.1
KO mice after ischemia, and HSP70 protein expression was markedly suppressed versus WT mice. KO mice showed a significantly greater infarction volume and DNA fragmentation in the cortex than WT mice at 24 hours after ischemia. At 8 hours, cytochrome
c
release into the cytoplasm was markedly higher in KO mice than in WT mice. Caspase-3 activation was also significantly enhanced in KO mice versus WT mice, as evidenced by higher levels of activated caspase-3 and cleaved gelsolin.

Conclusions—

These findings suggest that the deletion of the
hsp70.1
gene increases cytochrome
c
release into the cytoplasm and subsequent caspase-3 activation, thereby exacerbating apoptosis after focal cerebral ischemia.
Poststroke Neurological Improvement Within 7 Days Is Associated With Subsequent Deterioration
Authors: Aslanyan Stella , Weir Christopher J. , Johnston S. Claiborne , Lees Kennedy R.
Published: July 2004

Background and Purpose—

Improvement in the National Institutes of Health Stroke Scale (NIHSS) 24 hours after stroke has been associated with subsequent neurological deterioration. We hypothesized that a similar association would be apparent for events occurring after 7 days, when acute changes from edema and herniation are less common. We evaluated the degree of NIHSS improvement at 7 days (recovery) as a predictor of subsequent neurological deterioration from day 7 to day 90.

Methods—

We studied all patients of the Glycine Antagonist (gavestinel) In Neuroprotection (GAIN) International Trial with ischemic stroke alive at day 7, excluding patients with hemorrhagic events and deaths from nonstroke-related causes. The GAIN International Trial was a randomized, double-blind, placebo-controlled, and parallel-group trial; because the study drug had no effect on stroke outcome, treatment groups were combined for this analysis. Neurological deterioration was assessed by the combined measure, including: (1) stroke-related events recorded as “serious adverse events,” (2) recurrent stroke recorded on a separate case report form, and (3) any NIHSS worsening.

Results—

Among 1187 patients included, 25% had >65% recovery. Deterioration was more prevalent in the group with >65% early recovery (15.5% versus 10.3%;
P
=0.01). Logistic regression modeling indicated that recovery was associated with subsequent neurological deterioration (odds ratio, 1.2; 95% CI, 1.1 to 1.3, per 10% recovery) after adjusting for age, NIHSS at 7 days, and stroke subtype.

Conclusions—

Substantial neurological recovery at 7 days is associated with subsequent neurological deterioration.
Informed Consent for Thrombolytic Therapy for Patients With Acute Ischemic Stroke Treated in Routine Clinical Practice
Authors: Rosenbaum Julie R. , Bravata Dawn M. , Concato John , Brass Lawrence M. , Kim Nancy , Fried Terri R.
Published: July 2004

Background and Purpose—

Little is known about informed consent for tissue plasminogen activator (tPA). Our objectives were to determine how frequently informed consent is obtained when tPA is given to stroke patients in clinical practice and whether the person providing consent (patient or surrogate) was the appropriate decision-maker.

Methods—

This retrospective cohort included acute stroke patients given tPA in 10 Connecticut hospitals (1996–1998). Consent was defined as any documentation of discussion about risks and benefits of tPA. Patients had adequate decision-making capacity if they were alert, oriented, and without aphasia or neglect (patient was appropriate decision-maker). Patients with any of these deficits were considered to have diminished capacity (surrogate was appropriate decision-maker).

Results—

Among 63 patients who received tPA, 53 (84%) had informed consent documented; 16/53 (30%) gave their own consent. Among patients with adequate decision-making capacity, 5/8 (63%) had consent by surrogate. Among patients with diminished capacity, 7/38 (18%) provided their own consent.

Conclusions—

A substantial percentage of patients who received tPA for stroke had no consent documented. Surrogates often provided consent when the patients had capacity; conversely, patients with diminished capacity sometimes provided their own consent. Given the urgency and weight of the decision regarding tPA, more explicit informed consent and capacity assessment should be considered for treatment protocols.
Rates and Determinants of Site-Specific Progression of Carotid Artery Intima-Media Thickness
Authors: Mackinnon Andrew D. , Jerrard-Dunne Paula , Sitzer Matthias , Buehler Alexandra , von Kegler Stefan , Markus Hugh S.
Published: July 2004

Background and Purpose—

Carotid intima-media thickness (IMT) progression rates are increasingly used as an intermediate outcome for vascular risk. The carotid bifurcation (BIF) and internal carotid artery (ICA) are predilection sites for atherosclerosis. IMT measures from these sites may be a better estimate of atherosclerosis than common carotid artery (CCA) IMT. The study aim was to evaluate site-specific IMT progression rates and their relationships to vascular risk factors compared with baseline IMT measurements.

Methods—

In a community population (n=3383), ICA-IMT, BIF-IMT, CCA-IMT, and vascular risk factors were evaluated at baseline and at 3-year follow-up.

Results—

Mean (SD) IMT progression was significantly greater at the ICA (0.032 [0.109] mm/year) compared with the BIF (0.023 [0.108] mm/year) and the CCA (0.001 [0.040] mm/year) (
P
<0.001). Only ICA-IMT progression significantly correlated with baseline vascular risk factors (age, male gender, hypertension, diabetes, and smoking). Change in risk factor profile over follow-up, estimated using the Framingham risk score, was a predictor of IMT progression only. For all arterial sites, correlations were stronger, by a factor of 2 to 3, for associations with baseline IMT compared with IMT progression.

Conclusions—

Progression rates at the ICA rather than the CCA yield greater absolute changes in IMT and better correlations with vascular risk factors. Vascular risk factors correlate more strongly with baseline IMT than with IMT progression. Prospective data on IMT progression and incident vascular events are required to establish the true value of progression data as a surrogate measure of vascular risk.
Admission Fibrinolytic Profile Is Associated With Symptomatic Hemorrhagic Transformation in Stroke Patients Treated With Tissue Plasminogen Activator
Authors: Ribo Marc , Montaner Joan , Molina Carlos A. , Arenillas Juan F. , Santamarina Esteban , Quintana Manuel , Alvarez-Sabín José
Published: July 2004

Background and Purpose—

Symptomatic intracranial hemorrhage (SICH) is the most feared complication after tissue plasminogen activator (tPA) stroke treatment. Endogenous fibrinolysis inhibitors play an essential role in the coagulation/fibrinolysis balance and may be involved in the bleeding process. We aim to determine the predictive value of pretreatment levels of fibrinolysis inhibitors (PAI-1, lipoprotein(a), TAFI, and homocysteine) on SICH.

Methods—

Consecutive tPA-treated stroke patients with middle cerebral artery occlusion were studied. Baseline blood samples were obtained just before tPA administration and fibrinolysis inhibitors were determined. A second computed tomography (CT) scan was obtained at 24 hours or when a neurological worsening occurred to rule out SICH.

Results—

Seventy-seven patients (40% women, age 75 years) were studied. Median admission National Institutes of Health Stroke Scale was 17 (range, 7 to 22) and mean time to treatment was 160 minutes. Six patients (7.9%) presented with a SICH. In analyses based on clinical and CT variables, no relation could be found with SICH. When laboratory data were analyzed, patients who experienced SICH showed lower baseline PAI-1 (21.7±3.5 ng/mL versus 31.8±12.1 ng/mL;
P
<0.01) and higher TAFI (216.7±78.4% versus 162.1±54.2%;
P
=0.03). Homocysteine and lipoprotein(a) were not related to SICH. The only factors associated with SICH were TAFI >180% (OR, 12.9; CI, 1.41 to 118.8;
P
=0.02) and PAI-1 <21.4 ng/mL (OR, 12.75; CI, 1.17 to 139.2;
P
=0.04). The combination of admission PAI-1 <21.4 ng/mL and TAFI >180% had a sensibility of 75% and a specificity of 97.6% (
P
<0.01) predicting SICH, with a positive predictive value of 75% and negative predictive value of 97.6%.

Conclusions—

Baseline PAI-1 and TAFI levels predict SICH after stroke tPA therapy. In the future, these biomarkers could be used to improve thrombolysis safety.
The Duty to Prevent Emotional Harm at Work: Arguments from Science and Law, Implications for Policy and Practice
Authors: Shain Martin
Published: July 2004

Although science and law employ different methods to gather and weigh evidence, their conclusions are remarkably convergent with regard to the effect that workplace stress has on the health of employees. Science, using the language of probability, affirms that certain stressors predict adverse health outcomes such as disabling anxiety and depression, cardiovascular disease, certain types of injury, and a variety of immune system disorders. Law, using the language of reasonable foreseeability, affirms that these adverse outcomes are predictable under certain conditions, typically defined in relation to what a reasonable person should know. Society is arguably in a position to establish standards for the abatement of certain types of workplace stress. As part of this process, we need to conceptualize an ideal form of conduct that exemplifies the standards to which both law and science urge us to aspire. For this purpose, the concept of the neighbor at work is proposed.
The Intellectual Assembly Line is Already Here
Authors: Vanderburg Willem H.
Published: July 2004

The universal attempt to link computers by means of business process reengineering, enterprise integration, and the management of technology is creating large systems that structure and control the flows of information within institutions. Human work associated with these systems must be reorganized in the image of these technologies. The transformation of office work now parallels that of factory work as a result of the intellectual assembly line: Each so-called knowledge worker adds and transforms information in a manner almost entirely prescribed by the system, which, in turn, takes this information to the next work station and so on. The result is a loss of control coupled with growing demands and a new kind of organizational structure. It would appear that the implications for human health are possibly even greater than those associated with traditional assembly-line work.
Job Socialization: The Carry-Over Effects of Work on Political and Leisure Activities
Authors: Karasek Robert A.
Published: July 2004

A model of job socialization based on the joint effect of decision latitude and psychological demands are developed to predict how behaviors learned on the job would carry over to leisure and political activities out-side of work. The model is tested with a longitudinal national random sample of the Swedish male work force (1:1,000) in 1968 and 1974 (n longitudinal = 1,508), including both expert and self-reports job data and 92% (1968) and 85% (1968-1974) response rates. Workers with more “active” jobs (high decision latitude and high demands) become more “active” in their political and leisure activity from 1968 to 1974 (p < .001). Cross-sectional analyses and work experience cohort results (1968) are consistent. Associations are unaffected by control for education and father’s education, limiting an alternative explanation via personal background. The content of work may substantially affect political behavior, culture, and the economic equilibrium of service-oriented societies.
A Vacuum in Political and Economic Labor Policy?
Authors: Karasek Robert A.
Published: July 2004

A vacuum is arising in the social policy of advanced countries. It is due to the fact that both of the currently dominant bases for social policy, market-oriented policy, and its presumed antagonist, welfare state policy, have the same and an insufficiently broad production value model at their core. The solution is to create a true new alternative, work quality policy, based on a re-understanding of work organization and the alternative forms of value it can create. Understanding work organization’s consequences can help resolve current dilemmas relating to (a) economic growth based on low production cost instead of skill development, (b) hidden costs of work intensity and job insecurity, (c) true service sector productivity, and (d) current fragility of democratic institutions.
Residency in the United States, Subjective Well-Being, and Depression in an Older Mexican-Origin Sample
Authors: Cuellar Israel , Bastida Elena , Braccio Sara Maria
Published: July 2004

Objective: To compare the mental health and well-being of Mexican immigrants with native-born Mexican Americans living in the Lower Rio Grande Valley of Texas. Methods: A randomly stratified sample of 353 Hispanics aged 45 and older were interviewed. The immigrant group ( n = 148) was compared with native-born Mexican Americans ( n = 205). Results: The findings showed that the native-born group was not significantly different from the immigrant group on measures of depression, health status, life satisfaction, or self-esteem. The immigrant group was found to report significantly more stress than the Mexican American group. Income, age, gender, and acculturation were significant predictors of well-being, whereas immigration status and years of residency were not. Discussion: The well-being of Mexican immigrants in the United States is confounded by such variables as income, age, gender, and acculturation, along with various other contextual factors that characterize their life experiences in the United States.