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E Fleck

Publications and source records attributed to E Fleck.

At least 37 records · Page 2Linked to original sources
PubMed2001

Adenovirus-mediated overexpression and stimulation of the human angiotensin II type 2 receptor in porcine cardiac fibroblasts does not modulate proliferation, collagen I mRNA expression and ERK1/ERK2 activity, but inhibits protein tyrosine phosphatases.

The contribution of the angiotensin (Ang) II type 2 receptor (AT2R) to cardiac hypertrophy is still controversial. Here we examined the effect of overexpressing the human AT2R in cultured porcine cardiac fibroblasts (pFib) on proliferation, procollagen I mRNA expression, and - as putatively underlying signal-transduction pathways - on mitogen-activated protein kinase ERK1/ERK2 and phosphotyrosine phosphatase activities. As quantitated by 125I-(Sar1,Ile8)-Ang II binding, transduction of cardiac fibroblasts with the adenoviral AT2R expression vector led to a six- to tenfold higher AT2 than endogenous Ang II type 1 receptor (AT1R) expression. The overexpressed AT2R had the same apparent molecular mass as the endogenous AT2R in rat PC12W cells. Proliferation was not significantly lower in AT2R expressing pFib than in antisense-transduced controls (TA2) upon stimulation with Ang II (AT2R 110.5+/-4.8% vs. TA2 110.2+/-5.5%), Ang II plus the AT1R blocker Irbesartan (97.1+/-1.4% vs. 108.0+/-5.0; P=0.052) and the partial AT2R antagonist CGP42112 at the agonistic concentration of 50 nM (92.1+/-2.7% vs. 99.8+/-3.1%; P=0.053). Procollagen Ialpha2 (COL1A2) mRNA levels were quantitated by (a) northern blot analysis and (b) reverse transcriptase polymerase chain reaction. COL1A2/GAPDH (a) and COL1A2/beta-actin (b) ratios revealed no differences between AT2R-transduced fibroblasts and antisense controls when stimulated with Ang II (1 microM, 24 h) plus Irbesartan and 10 ng/ml transforming growth factor beta1. Ang II stimulation of the endogenous AT1R increased extracellular signal regulated kinase 1/2 activities. This response was reduced by Irbesartan, but PD123319 had no effect. Time course and magnitude of Ang II stimulated ERK1/ERK2 activation was identical in AT2R-transduced and control cells. Also, neither simultaneous nor Ang II pre-stimulation, suggested to induce gene expression of the MAP kinase phosphatase 1, modulated phorbol myristate acetate-stimulated ERK1/ERK2 activation in AT2R-transduced pFib, in AT2R-transduced human umbilical vein endothelial cells, and in PC12W cells. By the use of a tyrosine phosphatase assay we observed an inhibition of phosphotyrosine phosphatase activity by 30.8% (P=0.009, n=5) after 5 min Ang II stimulation of AT2R-expressing pFib. Immunoprecipitation-tyrosine phosphatase assays revealed that inhibition of phosphotyrosine phosphatase 1B, which regulates insulin signaling, contributed to this effect. In conclusion, stimulation of the overexpressed human AT2R in porcine cardiac fibroblasts inhibited tyrosine phosphatase activity but had no significant effect on fibroblast functions related to cardiac fibrosis. It is conceivable that possible antifibrotic AT2R effects are species specific and/or require the interaction between fibroblasts and cardiomyocytes, probably via paracrine factors, or mechanical load.

Adenoviridae↗
PubMed2001

[Comparison of various parameters for determining an index of myocardial perfusion reserve in detecting coronary stenosis with cardiovascular magnetic resonance tomography].

For the assessment of myocardial perfusion with cardiac magnetic resonance imaging, different semiquantitative parameters of the first pass signal intensity time curves can be calculated and myocardial perfusion reserve indices can be determined. In this study we evaluated the feasibility of different perfusion parameters and their perfusion reserve indices for the detection of significant coronary artery stenosis. The signal intensity time curves of the first pass of a gadolinium-DTPA bolus injected via a central vein catheter before and after dipyridamole infusion were investigated in 15 patients with single vessel (stenosis > or = 75% area reduction) and five patients without significant coronary artery disease. For the distinction of ischemic and nonischemic myocardial segments, semiquantitative parameters, such as maximal signal intensity, contrast appearance time, time to maximal signal intensity and the steepness of the signal intensity curve's upslope determined by a linear fit, were assessed after correction for the input function. For each parameter a myocardial perfusion reserve index was calculated and cut off values for the detection of significant coronary stenosis were defined. The diagnostic accuracy of each parameter was then examined prospectively in 36 patients with coronary artery disease and compared with coronary angiography. Where as a distinction of ischemic and normal myocardium was possible with myocardial perfusion reserve indices, semiquantitative parameters at rest or after vasodilation alone did not allow such a distinction. The perfusion reserve index calculated from the upslope showed the most significant difference between ischemic and nonischemic myocardial segments (1.19 +/- 0.4 and 2.38 +/- 0.45, p < 0.001) followed by maximum signal intensity, time to maximum signal intensity and contrast apperance time. Sensitivity, specificity and diagnostic accuracy was 87, 82 and 85% for the detection of hypoperfusion induced by significant coronary artery stenoses using the perfusion reserve index calculated from the upslope. The steepness of the first pass signal intensity curve's upslope, determined by a linear fit, is a feasible parameter for the detection of significant coronary artery disease with MR. Based on a myocardial perfusion reserve index of this parameter, ischemic myocardium can be identified with high diagnostic accuracy.

Adult↗
PubMed2001

Integrins alphavbeta3 and alphavbeta5 mediate VSMC migration and are elevated during neointima formation in the rat aorta.

Neointima formation involves tissue expression of matrix proteins and growth factors. The role of alphavbeta3, but not alphavbeta5 integrin in vascular cells has been sufficiently investigated. The aim of the present study was to determine and compare the function of alphavbeta3 and alphavbeta5 integrins in rat aortic (RASMC) and human coronary vascular smooth muscle cells (HCSMC) and to characterize their expression accompanying neointima formation in vivo. RASMC and HCSMC express alphavbeta3 and alphavbeta5 integrin subunits. The alphavbeta5 integrin predominantly mediated adhesion of RASMCs to vitronectin and spreading on vitronectin via RGD-binding sequences. In contrast, the alphavbeta3 integrin did not contribute to the adhesion and spreading on fibronectin, vitronectin, gelatin or collagen I coated layers. PDGF-directed migration through gelatin coated membranes involved both alphavbeta3 and alphavbeta5 integrins. Selective blocking antibodies for alphavbeta3 and alphavbeta5 inhibited migration of RASMC and HCSMC by more than 60 % (p < 0.01). Integrin expression was studied in vivo in thoracic aorta of Sprague Dawley rats before and after balloon injury. In situ hybridization demonstrated low signals for alphav, beta3 and beta5 mRNA in uninjured aorta, which increased significantly at 14 days, localized predominantly in the neointima. Northern analysis of aorta after 14 days of injury also demonstrated an upregulation of alphav, beta3 and beta5 mRNA compared to uninjured aorta. Consistent with the increase in message levels, increased integrin protein expression was seen in the neointima after 7 and 14 days. This study provides evidence that alphavbeta3 and alphavbeta5 are elevated during neointima formation in the rat and indicates a novel role for alphavbeta5 participating in mechanisms regulating smooth muscle cell migration.

Animals↗
PubMed2001

TNFalpha induces expression of transcription factors c-fos, Egr-1, and Ets-1 in vascular lesions through extracellular signal-regulated kinases 1/2.

Migration, proliferation and differentiation of vascular smooth muscle cells (VSMC) and macrophages are important pathological responses that contribute to the development and progression of vascular lesions. Cytokines such as TNFalpha are present at sites of vascular injury and regulate a variety of cellular functions of inflammatory cells and VSMC. Cell migration, proliferation and differentiation require de novo gene transcription resulting from extracellular signals being transduced to the nucleus, where multiple genes are regulated to participate in lesion formation. In VSMC and macrophages, TNFalpha induces activation of the extracellular signal-regulated kinases 1/2 (ERK 1/2), which transmit signals from the cytosol to the nucleus. Potential nuclear targets of TNFalpha-activated ERK 1/2 include the transcription factors Ets-1, Egr-1, and c-fos, which are known to regulate cellular growth, differentiation, and migration. The aim of this study was to investigate the expression of the transcription factors Ets-1, Egr-1 and c-fos in different types of vascular lesions, their regulation by TNFalpha and the role of ERK 1/2 in these signaling events. Atherosclerotic lesions from fructose-fed LDL-receptor deficient mice and neointimal lesions from rat aortae 2 weeks post balloon injury demonstrated the presence and colocalization of TNFalpha, phosphorylated and activated ERK 1/2, and transcription factors Ets-1, Egr-1 and c-fos. Neointimal lesions consisted primarily of VSMC, whereas atherosclerotic lesions predominantly contained macrophages. In cultured rat aortic VSMC, TNFalpha (100 U/ml) stimulated a rapid and transient expression of Ets-1, Egr-1 and c-fos with a maximal induction 1 h after stimulation. In cultured RAW 264.7 mouse macrophages, TNFalpha similarly induced the expression of Ets-1, Egr-1, and c-fos. Induction of these transcription factors was mediated via ERK 1/2 activation, since the ERK 1/2-pathway inhibitor PD98059 (10-30 microM) significantly inhibited their TNFalpha-induced expression. TNFalpha induced ERK 1/2 activation in both cell types. These findings underscore the importance of the ERK 1/2 pathway in the expression of TNFalpha-regulated transcription factors, which may participate in different forms of vascular lesion formation.

Animals↗
PubMed2001

Effect of the angiotensin II type 2-receptor gene (+1675 G/A) on left ventricular structure in humans.

OBJECTIVES: Our study goal was to analyze whether gene variants of angiotensin II type 2-receptor (AT2-R) modulate the effects of angiotensin II on the left ventricle (LV). BACKGROUND: Experimental data suggest that angiotensin II modifies ventricular growth responses via angiotensin II type 1-receptors (AT1-R) and AT2-R. METHODS: In 120 white, young male subjects with normal or mildly elevated blood pressure, we assessed plasma angiotensin II and aldosterone concentrations (RIA), 24-h urinary sodium excretion, 24-h ambulatory blood pressure and LV structure (two-dimensional guided M-mode echocardiography). The intronic +1675 G/A polymorphism of the X-chromosomal located AT2-R gene was investigated by single-strand conformational polymorphism analysis and DNA-sequencing. RESULTS: Hypertensive subjects with the A-allele had a greater LV posterior (11.0 +/- 1.3 vs. 9.9 +/- 1.3 mm, p < 0.001), septal (11.8 +/- 1.4 vs. 10.1 +/- 1.2 mm, p < 0.001) and relative wall thickness (0.44 +/- 0.06 vs. 0.39 +/- 0.06, p < 0.01) as well as LV mass index (138 +/- 23 vs. 120 +/- 13 g/m2, p < 0.001) than those with the G-allele. Confounding factors (i.e., body mass index and surface area, plasma angiotensin II, sodium excretion, systolic and diastolic ambulatory blood pressure) were similar between the two genotypes. In normotensive subjects, relative wall thickness (0.36 +/- 0.05 vs. 0.35 +/- 0.05) and LV mass index (115 +/- 21 vs. 112 +/- 17 g/m2) were nearly identical across the two genotypes, with similar confounding variables. CONCLUSIONS: Our data indicate that the X-chromosomal located +1675 G/A-polymorphism of the AT2-R gene is associated with LV structure in young male humans with early structural changes of the heart due to arterial hypertension.

Adult↗
PubMed2001

Activation of the cardiac renin-angiotensin system and increased myocardial collagen expression in human aortic valve disease.

OBJECTIVES: We sought to determine whether the cardiac renin-angiotensin system (RAS) is activated in human aortic valve disease depending on left ventricular function, and we analyzed the concomitant regulation of the extracellular matrix components. BACKGROUND: In animal models with pressure or volume load, activation of the cardiac RAS increases fibrosis. In human aortic valve disease, the ventricular collagen protein content is increased, but only scarce data on the activation state of the cardiac RAS and its effects on collagen and fibronectin messenger ribonucleic acid (mRNA) are available. METHODS: In left ventricular biopsies from patients with aortic valve stenosis (AS) and aortic valve regurgitation and from control subjects, we quantitated mRNAs for angiotensin-converting enzyme (ACE), chymase, transforming growth factor-beta1 (TGF-beta1), collagen I, collagen III and fibronectin by reverse-transcription polymerase chain reaction. Proteins were localized by immunohistochemistry; ACE activity was determined by high performance liquid chromatography; and TGF-beta protein by quantitative enzyme immunoassay. RESULTS: Protein, ACE and TGF-beta1 mRNA were significantly increased in patients with AS and AR (1.5- to 2.1-fold) and correlated with each other. The increase occurred also in patients with normal systolic function. Collagen I and III and fibronectin mRNAs were both upregulated about twofold in patients with AS and AR. In AS, collagen and fibronectin mRNA expression levels were positively correlated with left ventricular end-diastolic pressure and inversely with left ventricular ejection fraction (LVEF). CONCLUSIONS: In human hearts, pressure and volume overload increases cardiac ACE and TGF-beta1 in the early stages. This activation of the cardiac RAS may contribute to the observed increase in collagen I and III and fibronectin mRNA expression. The increase in extracellular matrix already exists in patients with a normal LVEF, and it increases with functional impairment.

Aged↗
PubMed2001

Spectrum of clinical phenotypes and gene variants in cardiac myosin-binding protein C mutation carriers with hypertrophic cardiomyopathy.

OBJECTIVES: We studied the clinical and genetic features of hypertrophic cardiomyopathy (HCM) caused by mutations in the myosin-binding protein C gene (MYBPC3) in 110 consecutive, unrelated patients and family members of European descent. BACKGROUND: Mutations in the MYBPC3 gene represent the cause of HCM in approximately 15% of familial cases. MYBPC3 mutations were reported to include mainly nonsense versus missense mutations and to be characterized by a delayed onset and benign clinical course of the disease in Japanese and French families. We investigated the features that characterize MYBPC3 variants in a large, unrelated cohort of consecutive patients. METHODS: The MYBPC3 gene was screened by single-strand conformational polymorphism analysis and sequencing. The clinical phenotypes were analyzed using rest and 24-h electrocardiography, electrophysiology, two-dimensional and Doppler echocardiography and angiography. RESULTS: We identified 13 mutations in the MYBPC3 gene: one nonsense, four missense and three splicing mutations and five small deletions and insertions. Of these, 11 were novel, and two were probably founder mutations. Patients with MYBPC3 mutations presented a broad range of phenotypes. In general, the 16 carriers of protein truncations had a tendency toward earlier disease manifestations (33 +/- 13 vs. 48 +/- 9 years; p = 0.06) and more frequently needed invasive procedures (septal ablation or cardioverter-defibrillator implantation) compared with the 9 carriers of missense mutations or in-frame deletions (12/16 vs. 1/9 patients; p < 0.01). CONCLUSIONS: Multiple mutations, which include missense, nonsense and splicing mutations, as well as small deletions and insertions, occur in the MYBPC3 gene. Protein truncation mutations seem to cause a more severe disease phenotype than missense mutations or in-frame deletions.

Adolescent↗
PubMed2001

Clinical validation of new pacing-sensing configurations for atrial automatic capture verification in pacemakers.

INTRODUCTION: This study evaluated an atrial automatic capture verification scheme based on atrial evoked response (AER). Atrial pacing was between Atip and Can (Atip-Can) using different coupling capacitances (CCs). Independent pairs of sensing electrodes between Aring and Vtip (Aring-Vtip) or between Aring and a separate indifferent electrode (Aring-Indiff) were used to reduce pacing-induced afterpotentials. METHODS AND RESULTS: A custom-made external pacing system was used to perform automatic step-up and step-down pacing (0.1 to 7.1 V at 0.5 msec, step size of 0.1 V) using different CCs (2 or 15 microF). Intracardiac signals from Aring-Indiff and Aring-Vtip were independently recorded and analyzed both in real time and off-line to detect AER. Every paced beat also was visually inspected and compared with surface ECG to verify the captures. With the intracardiac signals properly filtered, AER detection was based on the signal within a window of 12 to 65 msec after the stimulus. Data from 27 patients (4 chronic and 23 acute implantations; age 65.6+/-13.9 years) were analyzed. Bipolar atrial lead measurements using a standard pacing system analyzer were as follows (mean +/- SD): impedance 695+/-227 ohms, P wave amplitude 4.2+/-2.3 mV, slew rate 1.1+/-0.9 V/sec, and pacing threshold at 0.5 msec 1.0+/-0.5 V. The results with CC = 2 microF showed that of 9,500 atrial paced beats, correct capture verification rates were 99.8% (Aring-Indiff) and 99.4% (Aring-Vtip). Similar results were achieved with CC = 15 microF (99.7% and 99.5%, respectively). CONCLUSION: AER can be reliably detected using independent pacing (Atip-Can) and sensing (Aring-Vtip or Aring-Indiff) electrodes. Therefore, atrial automatic capture verification by AER detection is feasible.

Adult↗
PubMed2001

The immediate and long-term effect of optimal balloon angioplasty on the absolute coronary blood flow velocity reserve. A subanalysis of the DEBATE study. Doppler Endpoints Balloon Angioplasty Trial Europe.

BACKGROUND: There are limited data regarding the immediate and long-term effect of balloon angioplasty on the coronary flow reserve evaluated in a multicentre setting. METHODS AND RESULTS: A total of 86 patients with one-vessel disease and normal left ventricular function were analysed before and after optimal balloon angioplasty (diameter stenosis <35%) and at 6-month follow-up. Coronary flow reserve was assessed with a Doppler guide wire. A low coronary flow reserve ( 2.5 (46% vs 23% and 36% vs 16%, respectively; P<0.05) due to a trend towards restenosis (29% vs 16%; P=0.15) or a low coronary flow reserve at follow-up due to persistent elevated baseline blood flow velocity. Patients without restenosis showed a decrease or increase of coronary flow reserve during follow-up, determined by alterations of hyperaemic blood flow velocity. CONCLUSIONS: Patients with an impaired coronary flow reserve directly after optimal balloon angioplasty showed a higher target lesion revascularization rate compared to patients with a coronary flow reserve >2.5. This patient group consists of patients prone to develop restenosis, while other patients are characterized by a persistently low coronary flow reserve, probably secondary to disturbed autoregulation and/or diffuse mild coronary atherosclerosis. Coronary flow reserve alterations in patients without restenosis were related to changes in hyperaemic blood flow velocity, suggesting that this phenomenon relates to epicardial remodelling.

Adult↗
PubMed2001

Is contrast-related vasodilatation after intra-coronary iodixanol and iopromide in vivo endothelium-dependent?

AIMS: Goals of the study were the assessment of the correlation between flow-dependent and contrast-related vasodilatation, comparison of iodixanol to iopromide and evaluation of the impact of plaque on vasodilatation in coronary arteries. METHODS AND RESULTS: A controlled randomized paired cross-over comparison between iodixanol (320mgI.ml(-1)) and iopromide (300mgI.ml(-1)) was performed in 10 consecutive patients. Vessel area (Visions Five-64 F/X intra-vascular ultrasound-catheter, Endosonics and blood flow velocity measurements (0.014inches Doppler guide wire, Cardiometrics were recorded simultaneously at an identical position, at baseline, after i.c. bolus injection of 10ml physiologic saline (flow-dependent vasodilatation), and after application of contrast agent 1 and contrast agent 2 as randomized. The action of iodixanol and iopromide on the vascular wall did not differ and was equal to local flow-dependent vasodilatation induced by a saline bolus (correlation 0.95-- 0.98). The increase in local luminal area after injection of saline, iodixanol and iopromide in morphologically normal vessels (approximately 2.5mm(2)) was absent in atherosclerotic segments. Both contrast agents and saline demonstrated a nearly identical flow increase. CONCLUSION: If iodixanol or iopromide are used as contrast agents, contrast-related vessel area increase in vivo seems to be endothelium-dependent.

Adult↗
PubMed2001

Doxazosin inhibits monocyte chemotactic protein 1-directed migration of human monocytes.

Monocyte chemotactic protein 1 (MCP-1)-directed transendothelial migration of monocytes plays a key role in the early development of atherosclerosis. Migration of monocytes requires degradation of extracellular matrices, a process that involves matrix metalloproteinases (MMP) and tissue inhibitors of MMPs (TIMP). Recent studies suggest that the alpha1-adrenergic receptor antagonist doxazosin (Dox) might have antiatherosclerotic effects, although the underlying mechanisms are poorly understood. The purpose of the present study was to determine the effects of Dox on MCP-1-directed monocyte migration, MMP-9 activity, and TIMP-1 expression. MCP-1 (50 ng/ml) stimulated migration of human peripheral blood monocytes (HPBM) 2.7+/-0.42-fold and THP-1 human monocytes 5.9+/-0.83-fold compared with unstimulated control. Dox inhibited MCP-1-induced migration in a dose-dependent manner, with a maximal reduction at 10 microM of 69.5+/-5.9% in HPBM and 72.2+/-3.2% in THP-1 cells. Dox blocked migration even after pretreatment with phenoxybenzamine, an irreversible alpha1-adrenergic receptor antagonist (HPBM: phenoxybenzamine 1 microM + Dox 10 microM, 71.9+/-2.2% inhibition; THP-1 cells: phenoxybenzamine 1 microM + Dox 10 microM: 78+/-7.7% inhibition), suggesting that the antimigratory activity of Dox is mediated through a novel mechanism unrelated to its blocking of the alpha1-adrenergic receptor. Dox (10 microM) inhibited MMP-9 activity by 67.6+/-10.5%, whereas MMP-9 protein levels were not affected. Also, Dox increased PMA-induced-tissue inhibitor of MMPs-1 (TIMP-1) expression by 134.4+/-6.6%. Dox 10 microM. The present study demonstrates a potential novel antiatherosclerotic action of Dox by blocking MCP-1-directed monocyte migration, which might be partly mediated by inhibition of MMP-9 activity.

Adrenergic alpha-Antagonists↗
PubMed2001

Peroxisome proliferator-activated receptor-gamma ligands inhibit nuclear but not cytosolic extracellular signal-regulated kinase/mitogen-activated protein kinase-regulated steps in vascular smooth muscle cell migration.

Vascular smooth muscle cell (VSMC) migration involves adhesion, locomotion, and invasion regulated by various signaling molecules, among which the extracellular signal-regulated kinase (ERK)/mitogen-activated protein kinases (MAPK) play a critical role. We have shown that the peroxisome proliferator-activated receptor-gamma (PPAR-gamma) ligands troglitazone and rosiglitazone inhibit VSMC migration downstream of ERK MAPK. The purpose of the current study was to more specifically determine which step(s) in VSMC migration are targeted by inhibition of the ERK MAPK pathway or activation of PPAR-gamma. VSMC adhesion was not affected by the ERK MAPK pathway inhibitor PD98059 or PPAR-gamma ligands. Phosphorylation and activation of myosin light chain kinase (MLCK) play important roles in cell locomotion. Platelet-derived growth factor (PDGF)-induced MLCK phosphorylation (1.7-fold) was completely blocked by PD98059 at 30 microM (p < 0.05), but not by troglitazone or rosiglitazone. PDGF-directed migration (5.8-fold) was inhibited by PD98059 (-88% at 30 microM) and the MLCK inhibitor ML9 (0.1-1 microM, -84% at 1 microM) (all p < 0.05). The transcription factor Ets-1 mediates matrix metalloproteinase induction required for tissue invasion by VSMC. PDGF (20 ng/ml) stimulated an Ets-1 protein expression (14-fold at 60 min) in VSMC, which was inhibited by PD98059 (-72% at 30 microM), troglitazone (-69% at 20 microM), and rosiglitazone (-54% at 10 microM) (all p < 0.05). Immunohistochemistry of rat aortae 2 h after balloon injury showed a dramatic upregulation of Ets-1, which was markedly inhibited in animals that had received troglitazone treatment. In contrast, phosphorylated ERK MAPK was not affected by troglitazone. These data are consistent with PPAR-gamma ligands exerting their anti-migratory effects downstream of ERK MAPK activation by blocking nuclear events, such as Ets-1 expression, required for cell invasion in response to arterial injury.

Animals↗
PubMed2001

Angiotensin II induces migration and Pyk2/paxillin phosphorylation of human monocytes.

Angiotensin (Ang) II has been shown to enhance the development of atherosclerotic lesions. Migration of monocytes is an early critical step in the atherosclerotic process. To elucidate mechanisms by which Ang II promotes atherogenesis, we investigated its effects on human monocyte migration. Ang II induced migration of human peripheral blood monocytes (HPBM) and human THP-1 monocytes at concentrations between 0.01 and 1 micromol/L, with a 3.6+/-0.6-fold induction in HPBM and a 4.8+/-0.9-fold induction in THP-1 cells at 1 micromol/L Ang II (both P<0.01 versus unstimulated cells). Addition of the Ang II receptor type 1 (AT1-R) antagonist losartan (1 to 100 micromol/L) suppressed Ang II-induced migration of HPBM and THP-1 monocytes in a dose-dependent manner, demonstrating an AT1-R-mediated mechanism. Ang II-directed migration was also blocked by the Src kinase inhibitor PP2 (10 micromol/L), by the extracellular-regulated protein kinase (ERK 1/2) inhibitor PD98059 (30 micromol/L), and by the p38-MAPK inhibitor SB203580 (10 micromol/L), indicating that Src, ERK 1/2, and p38 are all involved in Ang II-induced migration of HPBM and human THP-1 monocytes. The proline-rich tyrosine kinase 2 (Pyk2) and paxillin are 2 cytoskeleton-associated proteins involved in cell movement, phosphorylated by Ang II in other cell types, and abundantly expressed in monocytes. Ang II (1 micromol/L) induced Pyk2 and paxillin phosphorylation in human THP-1 monocytes, peaking after 10 minutes for Pyk2 with a 6.7+/-0.9-fold induction and after 2 minutes for paxillin with a 3.2+/-0.4-fold induction. Ang II-induced phosphorylation of both proteins was suppressed by losartan and the Src inhibitor PP2, whereas no effect was observed with PD98059 and SB203580. This study demonstrates a novel proatherogenic action of Ang II on human monocytes by stimulating their migration, through an AT1-R-dependent process, involving signaling through Src, ERK 1/2, and p38. Furthermore, the promigratory actions of Ang II in human monocytes are associated with the phosphorylation of 2 cytoskeleton-associated proteins, Pyk2 and paxillin.

Angiotensin II↗
PubMed2001

Selective expression of the proprotein convertases furin, pc5, and pc7 in proliferating vascular smooth muscle cells of the rat aorta in vitro.

The aim of this study was to investigate whether transformation of quiescent vascular smooth muscle cells (VSMCs) into proliferating secretory cells is accompanied by an expression of processing enzymes that activate de novo-synthesized growth factors. Three enzymes belonging to the family of the kexin/subtilisin-like mammalian proprotein convertases (PCs), furin, PC5, and PC7, were found to be upregulated after balloon denudation in vivo. To determine their importance in these cell processes, we investigated their gene regulation using a short-term organ culture system. After incubation of rat aorta for 4 and 24 hr in serum-free medium, we demonstrated a significant induction of VSMC proliferation. The affected subset of VSMCs, positive for alpha-smooth muscle actin, also expressed proliferating cell nuclear antigen (PCNA). Our results revealed a parallel upregulation of furin, PC5, and PC7 in PCNA-immunolabeled cells. As a substrate model for comparison with PCs we used nerve growth factor (NGF). NGF is known to be activated by PCs. As shown by Northern blotting analysis, NGF mRNA concentration was significantly increased in cultured explants. NGF was released into the culture medium. In conclusion, both PCs and NGF are coordinately modulated on induction of VSMC proliferation.

Animals↗
PubMed2001

Patient information: involving the user group.

A review within an acute hospital trust identified problems with in-house information, including a lack of patient involvement, poor quality print and over-use of technical language. A project was set up to improve the quality of the trust's information leaflets.

Educational Status↗
PubMed2000

[Long-term outcome after coronary emergency intervention].

BACKGROUND AND OBJECTIVE: Coronary angioplasty (CAG) has become an acceptable method of treating an acute coronary syndrome (myocardial infarction [MI] or unstable angina [UA]). It was the aim of this study to determine whether the results of such emergency treatment differed from those after elective CAG. PATIENTS AND METHODS: Results of emergency CAG in 581 patients (aged 60 +/- 11 years; 77% males) admitted to the authors' hospital between July 1994 and December 1996 were compared with those of elective CAG in 2,460 patients (aged 61 +/- 10, admitted during the same period. Follow-up information was obtained after 22.4 +/- 11 months in 93.2% of the patients by examination, written answers to annual questionnaires, data being collected on survival, repeat cardia catheterizations, other interventions, aorto-coronary bypass, occurrence of myocardial infarction, the patients' general state and drugs received. RESULTS: 19 of 517 patients (3.7%) of the group who had undergone elective CAG had died during the follow-up period, compared with 107 of 2436 of the emergency cohort (4.4%; not significant). There were also no significant differences regarding repeat cardiac catheterization, interventions, coronary bypass or re-admission. The proportion of subsequent emergency CAG among all CAGs was 16.8% in the emergency cohort, 8.8% after elective angiography (p < 0.001). CONCLUSION: Coronary angiography performed in patients with an acute coronary syndrome has no prognostic significance regarding mortality and morbidity after the acute phase of the disease.

Aged↗