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Biomedical subjects

Raila Ehlers

Publications and source records attributed to Raila Ehlers.

12 recordsLinked to original sources

GP IIb/IIIa inhibition with eptifibatide lowers levels of soluble CD40L and RANTES after percutaneous coronary intervention.

Platelets are the most abundant blood source of CD40L, a proinflammatory and prothrombotic costimulatory molecule implicated in atherosclerosis. Agonist stimulation results in the secretion of a soluble form of CD40L (sCD40L) and GP IIb/IIIa receptor inhibition blocks secretion of sCD40L in vitro. However, the effect of GP IIb/IIIa inhibition on sCD40L levels in humans is unknown. Plasma sCD40L and inflammatory markers were measured (t = 0, 0.5, 2, and 24 hr post-PCI) in a cohort of patients receiving abciximab (n = 15), eptifibatide (n = 15), or no GP IIb/IIIa inhibitor (n = 15). PCI in the absence of GP IIb/IIIa inhibitor was associated with a small but measurable rise in sCD40L and the platelet-derived chemokine RANTES. In contrast, eptifibatide significantly lowered baseline sCD40L (P = 0.018) and RANTES (P = 0.006) levels. This effect was not observed with abciximab. GP IIb/IIIa inhibition with eptifibatide lowers levels of sCD40L and RANTES post-stenting, possibly conferring anti-inflammatory as well as antithrombotic effects.

Abciximab↗

Targeting platelet-leukocyte interactions: identification of the integrin Mac-1 binding site for the platelet counter receptor glycoprotein Ibalpha.

The firm adhesion and transplatelet migration of leukocytes on vascular thrombus are dependent on the interaction of the leukocyte integrin Mac-1 (alphaMbeta2, CD11b/CD18) and the platelet counter receptor glycoprotein (GP) Ibalpha. Previous studies have established a central role for the I domain, a stretch of approximately 200 amino acids within the alphaM subunit, in the binding of GP Ibalpha. This study was undertaken to establish the molecular basis of GP Ibalpha recognition by alphaMbeta2. The P201-K217 sequence, which spans an exposed loop and amphipathic alpha4 helix in the three-dimensional structure of the alphaMI domain, was identified as the binding site for GP Ibalpha. Mutant cell lines in which the alphaMI domain segments P201-G207 and R208-K217 were switched to the homologous, but non-GP Ibalpha binding, alphaL domain segments failed to support adhesion to GP Ibalpha. Mutation of amino acid residues within P201-K217, H210-A212, T213-I215, and R216-K217 resulted in the loss of the binding function of the recombinant alphaMI domains to GP Ibalpha. Synthetic peptides duplicating the P201-K217, but not scrambled versions, directly bound GP Ibalpha and inhibited alphaMbeta2-dependent adhesion to GP Ibalpha and adherent platelets. Finally, grafting critical amino acids within the P201-K217 sequence onto alphaL, converted alphaLbeta2 into a GP Ibalpha binding integrin. Thus, the P201-K217 sequence within the alphaMI domain is necessary and sufficient for GP Ibalpha binding. These observations provide a molecular target for disrupting leukocyte-platelet complexes that promote vascular inflammation in thrombosis, atherosclerosis, and angioplasty-related restenosis.

Amino Acid Sequence↗

Heart failure.

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Cardiac Output, Low↗

Relationship between minor myocardial damage and inflammatory acute-phase reaction in acute coronary syndromes.

BACKGROUND: In severe acute coronary syndromes (ACS) elevation of markers of inflammation and acute phase reaction (APR) like C-reactive protein (CRP) as well as a release of troponin have been reported. Using a high sensitivity troponin T (TnT) test we investigated whether an APR occurs in ACS only in the presence of ischemic myocardial damage. METHODS: In 85 patients with ACS C-reactive protein (CRP), serum amyloid A (SAA), fibrinogen, thrombin antithrombin III complexes (TAT) and kallikrein were determined vs. high sensitive TnT (> or =0.02 ng/ml) initially and 2 d later vs. 45 patients with stable angina pectoris and 42 controls. RESULTS: In stable angina pectoris, markers of inflammation and coagulation were slightly elevated (p < 0.05). Initially in ACS elevations of CRP to 1.2 +/- 0.3 mg/dl, SAA to 4.8 +/- 2.6 mg/dl and fibrinogen to 448 +/- 21 mg/dl (all p < 0.01 vs. controls) were found followed by a significant APR (p < 0.01). In the subgroup of TnT positive ACS patients, an APR with increased CRP (4.1 +/- 1.3 mg/dl), SAA (20.4 +/- 8.3 mg/dl), and fibrinogen (641 +/- 45 mg/dl) was detectable (all p < 0.05 vs. TnT negative patients). In contrast, patients without TnT release showed APR markers comparable to patients with stable angina pectoris. CONCLUSION: Our findings demonstrate an association between myocardial injury in ACS and acute phase reaction as evidenced by several molecular markers. A highly sensitive TnT-test identified myocardial injury in about all patients with APR while a standard TnT cut-off (0.1 ng/ml) missed 32% of these patients. Thus, the APR in patients with ACS is strongly associated with at least minor ischemic myocardial damage and prior findings of an APR independent from myocardial injury are probably based on less sensitive troponin tests.

Acute Disease↗

Simvastatin reduces neointimal thickening in low-density lipoprotein receptor-deficient mice after experimental angioplasty without changing plasma lipids.

BACKGROUND: Statins exert antiinflammatory and antiproliferative actions independent of cholesterol lowering. To determine whether these actions might affect neointimal formation, we investigated the effect of simvastatin on the response to experimental angioplasty in LDL receptor-deficient (LDLR-/-) mice, a model of hypercholesterolemia in which changes in plasma lipids are not observed in response to simvastatin. METHODS AND RESULTS: Carotid artery dilation (2.5 atm) and complete endothelial denudation were performed in male C57BL/6J LDLR-/- mice treated with low-dose (2 mg/kg) or high-dose (20 mg/kg) simvastatin or vehicle subcutaneously 72 hours before and then daily after injury. After 7 and 28 days, intimal and medial sizes were measured and the intima to media area ratio (I:M) was calculated. Total plasma cholesterol and triglyceride levels were similar in simvastatin- and vehicle-treated mice. Intimal thickening and I:M were reduced significantly by low- and high-dose simvastatin compared with vehicle alone. Simvastatin treatment was associated with reduced cellular proliferation (BrdU), leukocyte accumulation (CD45), and platelet-derived growth factor-induced phosphorylation of the survival factor Akt and increased apoptosis after injury. CONCLUSIONS: Simvastatin modulates vascular repair after injury in the absence of lipid-lowering effects. Although the mechanisms are not yet established, additional research may lead to new understanding of the actions of statins and novel therapeutic interventions for preventing restenosis.

Angioplasty↗

Comparison of C-reactive protein and terminal complement complex in patients with unstable angina pectoris versus stable angina pectoris.

Elevated C-reactive protein (CRP) can identify patients with coronary artery disease who are prone to future acute events. We investigated whether elevated CRP is related to the activation of the terminal complement cascade in 66 patients with unstable angina pectoris (UAP), in 45 patients with stable angina pectoris, and in 42 controls. CRP, additional acute phase reactants, the terminal complement complex (sC5b-9), leukocytes, and troponin T were measured. In 47 patients with UAP the CRP values were regarded as elevated (>0.3 mg/dl). In patients with UAP and elevated CRP, the plasma levels of sC5b-9 were markedly higher than in patients with UAP and lower CRP (245 +/- 14 vs 188 +/- 19 ng/ml, p <0.02) and in patients with stable angina pectoris with slightly (0.4 +/- 0.1 mg/dl) increased CRP (sC5b-9 173 +/- 21 vs 130 +/- 7 ng/ml [controls; p <0.05]). A further acute phase reaction was present only in patients with UAP and elevated CRP already on admission (p <0.01). sC5b-9 was not related to troponin release. Thus, elevated CRP levels are associated with activation of the plaque destabilizating terminal complement system in patients with UAP during the acute phase reaction. This may explain the prognostic value of CRP in acute coronary syndromes (ACS).

Acute-Phase Reaction↗

Absence of paradoxical thrombin activation by fibrin-specific thrombolytics in acute myocardial infarction: comparison of single-bolus tenecteplase and front-loaded alteplase.

OBJECTIVES: Thrombolytic therapy in patients with acute myocardial infarction is hampered by bleeding complications and procoagulant effects favoring early reocclusion. TNK-tPA was shown in vitro to have considerable fibrin specificity. We investigated the effects of tenecteplase (TNK-tPA) and alteplase (rt-PA) on the haemostasis and fibrinolytic system. METHODS AND RESULTS: We enrolled 30 patients with AMI into the study. Twenty patients received front-loaded rt-PA up to 100 mg; 10 patients were given TNK-tPA in a single bolus up to 50 mg. All patients received aspirin and intravenous heparin. During the first 2 days, the following parameters were repetitively determined: thrombin-antithrombin III complexes (TAT), antithrombin III (ATIII), prothrombin fragment F 1 + 2 (F 1 + 2), kallikrein-like activity (KK), activated factor XII (FXIIa), plasmin alpha 2-antiplasmin complexes (PAP), fibrinogen, D-dimers (DD), tissue-type plasminogen activator (t-PA). A total of 75 healthy persons served as control group. TAT increased significantly after rt-PA but not after TNK-tPA (3 h: 38.1 +/- 29.4 versus 10.5 +/- 4.2 microg/l; p < 0.01), indicating paradoxical thrombin activation. F 1 + 2 increased transiently after rt-PA but not after TNK-tPA. Fibrinogen was significantly lower after rt-PA versus TNK-tPA (3 h: 163 +/- 27 versus 380 +/- 54 mg/dl; p < 0.05). KK activities in the rt-PA group were significantly (p < 0.01) increased over 48 h versus TNK-tPA. PAP and D-dimers were lower over the time course of 48 h in the tenecteplase group versus rt-PA. CONCLUSIONS: This study indicates that tenecteplase has higher fibrin specificity not only in vitro but also in vivo versus alteplase. TNK-tPA consecutively has no paradoxical systemic procoagulant effect due to the lower extent of activation of the kallikrein-factor XII system than alteplase.

Aged↗

Echocardiographic evidence of right ventricular remodeling after transplantation.

Right ventricular (RV) failure is a significant source of mortality after cardiac transplantation. The use of RV assist devices (RVAD) as a bridge to recovery has been reported. However, early changes of RV structure and anatomy after RVAD implantation have yet to be described. We report a case of RV failure after transplantation requiring RVAD implantation. After 3 weeks of gradual weaning of inotropic and RVAD support, the device was explanted successfully. Transesophageal echocardiography documents RV hypertrophy and remodeling between RVAD implantation and removal, suggesting a rapid adaptive response of the right ventricle in the presence of pulmonary hypertension.

Adult↗

The effect of remifentanil or fentanyl on postoperative vomiting and pain in children undergoing strabismus surgery.

UNLABELLED: Postoperative vomiting (POV) after strabismus surgery in children results in discomfort and prolonged hospital stays. Opioids increase the incidence of POV. Remifentanil has a context-sensitive half-life of 3 to 4 min, and how this short half-life influences POV in those patients is unknown. We conducted a prospective, double-blinded study in 81 ASA status I or II children from 2 to 12 yr of age undergoing elective strabismus surgery under general anesthesia. Patients were randomized to receive either remifentanil (bolus 1 microg/kg; infusion 0.1-0.2 microg x kg(-1) x min(-1)) or fentanyl (2 microg/kg, and 1 microg/kg every 45 min). POV episodes were recorded for 25 h. Pain scores were obtained by using an objective pain scale for 60 min during recovery. The number of patients who experienced POV did not differ significantly between groups (49% vs 48%). However, in the Remifentanil group, POV episodes were significantly less frequent (0.95 vs 2.2 episodes). In contrast, fentanyl was associated with lower pain scores during the first 30 min of recovery. We conclude that children undergoing strabismus surgery under balanced anesthesia with remifentanil, compared with fentanyl, showed less frequent POV. However, early postoperative analgesia was better with fentanyl. IMPLICATIONS: Opioids increase the incidence of postoperative vomiting (POV). Remifentanil is characterized by the shortest half-life of all opioids used in anesthetic practice. Therefore, we studied the effect of remifentanil on POV compared with the longer-acting opioid fentanyl in children undergoing strabismus surgery.

Analgesics, Opioid↗

Correlation between ST-T-segment changes with markers of hemostasis in patients with acute coronary syndromes.

BACKGROUND: Disturbance of the hemostatic and the inflammatory system plays an important role in the pathophysiology of acute coronary syndromes (ACS). Their markers have been shown to predict further coronary events in patients with ACS. The prognostic value of the admission electrocardiogram (ECG), which is commonly used to evaluate ischemia, was studied previously. We investigated the correlation between serum markers of the hemostatic/inflammatory system and ECG changes in ACS. METHODS: A standard 12-lead ECG was obtained from 85 patients with ACS on admission (0d). Markers of the hemostatic and inflammatory system were measured on admission and after 2 days (2d). RESULTS: Patients with ST-T-changes had higher fibrinogen and thrombin-antithrombin III complex (TAT) levels than patients without ECG alterations at both times (fibrinogen: 0d: 492 +/- 38 vs. 357 +/- 36 mg/dl, p < 0.01; 2d: 633 +/- 55 vs. 440 +/- 50 mg/dl, p < 0.02; TAT: 0d: 7.2 +/- 1.3 vs. 3.6 +/- 0.7 microg/l, p < 0.05; 2d: 5.3 +/- 0.9 vs. 3.2 +/- 0.5 microg/l, p < 0.05). Tissue-type plasminogen activator (TPA) was elevated in patients with ECG changes initially (10.1 +/- 0.6 vs. 7.2 +/- 0.7 ng/ml, p < 0.02). D-dimers, the acute-phase proteins C-reactive protein, serum amyloid A and the soluble adhesion molecules showed no significance. CONCLUSIONS: The data reveal a correlation between electrocardiographic changes and hemostasis in patients with ACS. The association of myocardial damage and a disturbed hemostatic system might stratify patients who are at high risk of suffering further coronary events.

Acute Disease↗