Comparative efficacy of fibrinolytics and glycoprotein IIb/IIIa inhibitors in preventing coronary no-reflow: a network meta-analysis

Background

Coronary no-reflow is a potentially lethal complication of percutaneous coronary intervention (PCI). The optimal approach to preserve coronary reflow during primary PCI is still controversial.

Purpose

Therefore, we aimed to compare and rank the adjunctive use of fibrinolytic agents and glycoprotein IIb/IIIa inhibitors by network meta-analysis of randomized controlled trials.

Methods

Pairwise and network meta-analysis were performed using the random-effects model within a frequentist framework. The primary outcome was coronary TIMI flow grade immediately following the intervention.

Results

82 studies with a total of 20666 participants were identified, including 7 multi-arm studies. This enabled 94 pairwise comparisons of 35 different adjunctive anticoagulant regimens, all administered in the context of primary PCI. Overall, risk of bias in these studies was rated moderate, and heterogeneity was low with a global I2 value of 20.8%. The figure shows the ranking of the interventions in relation to no adjunctive treatment (NON) and placebo (PLA). In particular, Tirofiban (TIR) alone or in combination with Adenosin (ADE) Nicorandil (NIC) was effective in preventing coronary no-reflow. The route of its administration, intravenous (IV) vs intracoronary (IC), did not matter much. However, its timing as an early IV injection upstream of primary PCI was not beneficial. Eptifibatide (EPT) given as IC bolus followed by continuous IV infusion had an effect comparable to TIR, as well as, among the fibrinolytics, Pamiteplase (PAM) given IV and Urokinase (URO) given IC.

Conclusions

This comprehensive comparison of fibrinolytics and glycoprotein IIb/IIIa inhibitors demonstrates that TIR, EPT, PAM, and URO can effectively and equally prevent coronary no-reflow in primary PCI.

Funding Acknowledgement

Type of funding sources: None.

Genetically rheumatoid arthrits and risk of comorbidities: a Mendelian randomization study

Background

Ample observational evidence indicates that patients with rheumatoid arthritis (RA) are at increased risk of developing comorbid conditions, in particular cardiovascular disease. The pathogenesis of these comorbidities is still largely unknown. For effective preventive measures, it would however be important to discriminate between those that are causally linked with rheumatoid arthritis and those that are the results of concomitant treatments or other confounding factors.

Purpose

Our objective was to explore whether genetically determined manifestation of RA was associated with any comorbidities, in particular cardiovascular disease, by conducting a 2-sample Mendelian randomization (MR) study on publicly available summary statistics from genome-wide association study (GWAS) consortia.

Methods

Genetic instruments for RA were obtained from a GWAS of 14,361 autoantibody-positive individuals with RA and 43,923 controls of European descent (Okada et al. 2014). The CARDIoGRAMplusC4D consortium comprising 60,801 cases with coronary artery disease and 123,504 controls was used to evaluate the associations with cardiovascular outcomes applying inverse variance–weighted meta-analysis, weighted-median analysis, Mendelian randomization–Egger regression, and multivariable Mendelian randomization. Genetic instruments for RA were further tested for association with other etiologically related traits by using publicly available GWAS data.

Results

Genetic predisposition to RA was not associated with higher risk of coronary artery disease (beta coefficient [b] ± standard error [se] = 0.02±0.03; P=0.4913), and myocardial infarction (b ± se = 0.03±0.03; P=0.3338). In contrast, IgA nephropathy (b ± se = 0.47±0.18; P=0.0225) and triglyceride levels were significantly related as outcomes to genetically determined RA as exposure. Other significantly related outcomes were the manifestation of squamous cell lung cancer (b ± se = 0.17±0.08; P=0.0496), serous ovarian cancer (b ± se = 0.13±0.05; P=0.0202), and prostate cancer (b ± se = 0.06±0.02; P=0.0041).

Conclusions

Despite the high prevalence of coronary artery disease and myocardial infarction among RA patients in observational studies, cardiovascular outcomes were not significantly associated with RA by Mendelian randomization. This paradox might partly be explained by the traits such as IgA nephropathy and elevated triglyceride levels that could act as mediators for the increased cardiovascular risk by their causal link with genetically determined RA.

Funding Acknowledgement

Type of funding source: Public hospital(s). Main funding source(s): Medical University of Vienna, Austria

Genetically determined atrial fibrillation and risk of stroke: a Mendelian randomization study

Background

Based on observational evidence, atrial fibrillation is a well-established risk factor of stroke to be considered for antithrombotic treatment in presence of additional clinical conditions derived from multivariate risk models. Although biologically plausible, it however still is unknown whether this association is causal and confined to the embolic stroke subtype.

Purpose

Our objective was to explore whether genetically determined manifestation of atrial fibrillation was associated with stroke and its etiologic subtypes by conducting a 2-sample Mendelian randomization (MR) study on publicly available summary statistics from GWAS consortia.

Methods

Genetic instruments for atrial fibrillation were obtained from the AFGen Consortium comprising 17,931 cases and 115,142 controls. Their associations with stroke and stroke subtypes were evaluated in the MEGASTROKE genome-wide association study data set (67 162 cases; 454 450 controls) applying inverse variance–weighted meta-analysis, weighted-median analysis, Mendelian randomization–Egger regression, and multivariable Mendelian randomization. The dataset of Nielsen et al. comprising a total of 60,620 cases with atrial fibrillation and 970,216 controls of European ancestry from six contributing studies was used as an independent validation sample. Genetic instruments for atrial fibrillation were further tested for association with etiologically related traits by using publicly available genome-wide association study data.

Results

Genetic predisposition to atrial fibrillation was associated with higher risk of any stroke (beta coefficient [b] ± standard error [se] = 0.22±0.04; P=0.0001), any ischemic stroke (b ± se = 0.24±0.05; P=0.0003), and cardioembolic stroke (b ± se = 0.76±0.10; P<0.0001), but not with small-vessel stroke or large artery stroke, see figure. Analyses in the validation sample showed similar associations (any stroke: b ± se = 0.19±0.04; P<0.0001; any ischemic stroke: b ± se = 0.21±0.04; P<0.0001; cardioembolic stroke: b ± se = 0.82±0.13; P<0.0001). Genetically determined atrial fibrillation was further weakly associated with chronic kidney disease (b ± se = 0.10±0.04; P=0.0261), but not with coronary artery disease and myocardial infarction or any other available phenotype.

Conclusions

Genetic predisposition to atrial fibrillation is associated with higher risk of any stroke, mainly driven by the ischemic and cardioembolic subtypes. In contrast, large artery and small-vessel strokes did not exhibit a causal relationship with atrial fibrillation.

Funding Acknowledgement

Type of funding source: Public hospital(s). Main funding source(s): Medical University of Vienna, Austria

P252 Incidental finding of a chronic left ventricular pseudoaneurysm years after surgical aortic valve replacement

Case presentation

A 35-years old female was referred to our outpatient clinic with unclear thoracic pain and dyspnea. Clinical chemistry testing was unremarkable. Electrocardiography (ECG) showed T-wave inversion in the anterior-lateral leads. Chest X-ray displayed an oval bulge on the left border of the heart. The physical exam revealed a systolic murmur on top of the closing click sound of a mechanical aortic valve prothesis which had been implanted nine years ago. Since that time, the patient had not had regular checkups and the actual consultation was motivated by her aggravating symptoms only.

Findings. In transthoracic echocardiography, the mechanical aortic valve prothesis exhibited an acceptable peak velocity of 2.7 m/s with a mean gradient of 18 mm Hg and only mild paravalvular regurgitation. The native mitral and tricuspid valves were functionally and morphologically normal. Left and right ventricle were of normal systolic and diastolic function and normal size. No signs of pericardial effusion were detected. However, a big (40x22mm) saccular structure with a narrow (10 mm) neck was visible at the apex of the left ventricle, see left panel of figure. At the neck, a bidirectional flow between the saccular structure and the left ventricle was detected with a peak velocity of 2,5 m/sec indicating the presence of a pseudoaneurysm. Its linings were calcified and free of discernable thrombus formation, although the flow inside was turbulent as evidenced in the contrast echocardiogram, see right panel of figure. Subsequently, CT-imaging confirmed the diagnosis and surgical resection of the pseudoaneurysm was successfully performed 10 days later. The surgeon noted that the walls of the resected cavity contained thrombotic masses despite respective negative findings on CT and echo. The postoperative course was uneventful, and the patient was discharged in good condition with normal left and right ventricular function and no regional left ventricular wall abnormalities. A year later, she was however re-admitted with prosthetic aortic valve stenosis due to thrombus formation on one the leaflets in the second trimester of a pregnancy.

Discussion

This is an exceptional case of chronic left ventricular pseudoaneurysm following aortic valve replacement. Since the patient had no history of myocardial infarction or of other potential causes that could explain the formation of a pseudoaneurysm, it is likely to be a remnant of venting the left ventricle during the original surgical procedure. The patient had been unattended and asymptomatic for several years which allowed chronification as indicated by the calcifications of the inner linings. Still, immediate surgical repair was mandatory due to the high risk of rupture and thromboembolism.

Abstract P252 Figure.

P1702 Libman-Sacks endocarditis of the mitral valve combined with right atrial thrombus formation

Case presentation

A 46-years old female with a history of systemic lupus erythematosus (SLE) was admitted to hospital care after the manifestation of a tonic-clonic generalized seizure. Since this had been the first neurological event, a thorough diagnostic work-up was performed. CT- and MRI-imaging of the brain revealed cerebral microangiopathy and two small fresh ischemic lesions in the left frontal and temporobasal regions, respectively. While the microangiopathy could be reconciled with cerebral SLE-vasculitis, the ischemic lesions pointed to thromboembolism whose source could be potentially cardiogenic.

Findings. In fact, the transesophageal echocardiogram showed a small vegetation (5x8 mm) on the posteromedial cusp of the posterior mitral leaflet (P3) with moderate regurgitation, likely to represent Libman-Sacks endocarditis and a potential source of systemic embolization. In addition, a mass of was visible protruding from the fossa ovalis into the right atrium, see figure. It represented a thrombus according to MRI which was subsequently performed. Since no interatrial passage of microbubbles occurred, the foramen ovale was unlikely to be patent and to allow for paradoxical embolism into the brain. However, the right atrial thrombus was compatible with a history of repeated deep venous thrombosis and pulmonary embolism in the recent past.

Discussion

This case exemplifies the combination of Libman-Sacks endocarditis on the mitral valve with right atrial thrombus formation and ensuing embolism both into the venous and arterial system. It demonstrates the importance of closely monitoring and treating coagulopathies in SLE patients which makes them prone to thrombus formation both in the systemic and pulmonary circulation.

Abstract P1702 Figure.

P332Comparative efficacy of intracoronary agents for acute treatment of coronary no-reflow: a network meta-analysis

Background

Coronary no-reflow is a potentially lethal complication of percutaneous coronary intervention (PCI). There is a growing body of evidence on how to best prevent this condition by the proper stenting technique and other mechanical measures or adjunctive drug treatments. However, it is still controversial how to tackle coronary no-reflow when it occurs.

Purpose

We aimed to compare and rank intracoronary agents for acute treatment of coronary no-reflow by considering both indirect and direct evidence from the literature in a network meta-analysis.

Methods

We searched the databases PubMed, Embase and Central for randomised controlled trials of the acute treatment of coronary no-reflow following primary PCI in patients with ST-elevation myocardial infarction (STEMI) and non-STEMI. Trials with patients suffering from stable angina and/or receiving elective PCI, observational study design and no measure of coronary flow were excluded. Two blinded reviewers independently collected studies, assessed risk of bias with the Cochrane risk of bias tool and extracted data. The primary outcome was a measure of coronary flow immediately following the intervention (TIMI flow grade, TIMI frame count or myocardial bush grade), secondary outcome were major adverse cardiovascular events during follow-up. Pairwise and network meta-analysis were performed using the random-effects model within a frequentist framework.

Results

8 studies with a total of 540 participants were identified, including 4 multi-arm studies. This enabled 19 pairwise comparisons of 12 different treatments, all administered via intracoronary route (ADE=adenosine, DIL=diltiazem, DIP=dipyridamole, NIT= nitroglycerin, NPR=nitroprusside, PLA=placebo, TIR=tirofiban, U+V=urokinase combined with verapamil, URA=urapidil, URO=urokinase, VER=verapamil X+T= Xuesaitong combined with tirofiban). Overall, risk of bias in these studies was rated moderate. For graphical representation of the network for the primary outcome, see left panel of the figure. It exhibited a low level of inconsistency and heterogeneity with a global I2 value of 20.9%. Among the different treatments, URA, X+T, and TIR were more effective in re-establishing coronary flow with the caveat that the results of URA depended on one singular trail with a large variance, see right panel of the figure. NIT was even slightly worse than placebo in the primary outcome, the other agents were equivalent with placebo. In terms of major cardiovascular events during follow-up, TIR exhibited a protective effect compared with placebo at borderline statistical significance (OR 0.3843 [95% CI 0.1488; 0.9923]. For URA, data on secondary outcome were not available.

Conclusions

Urapidil and Tirofiban are potentially effective candidate drugs for larger randomised controlled trials, which are needed to validate the sparse evidence that is available to date on the acute treatment of coronary no-reflow.

Influence of pentoxifylline on cytokine levels and inflammatory parameters in septic shock

OBJECTIVE

To evaluate the influence of pentoxifylline (PTX), a phosphodiesterase inhibitor, on cytokines and inflammatory proteins in patients suffering from septic shock.

DESIGN

Prospective study comparing a therapy group to a matched control group.

SETTING

Medical intensive care unit at a university hospital.

PATIENTS

Twenty four patients fulfilling the criteria of septic shock were included in this study. Twelve patients received PTX (therapy group) and 12 patients matched for diagnosis, age and gender served as the control group.

INTERVENTIONS

Pentoxifylline at 1 mg/kg per hour over 24 h in the therapy group.

MEASUREMENTS AND RESULTS

Cytokine levels [tumor necrosis factor-alpha (TNF)], soluble TNF receptor [TNF-R], and interleukin-6 [IL-6] and inflammatory proteins [C-reactive protein, alpha-1-antitrypsin (AAT), fibronectin, and haptoglobin], as well as hemodynamic parameters and the APACHE III score were evaluated before initiation of therapy and 24 h-later. After 24 h, TNF levels were significantly lower in the therapy group (p = 0.013), while IL-6 levels were significantly higher in the therapy group (p = 0.030). Within the 24 h TNF declined significantly in the therapy group (p = 0.006), while IL-6 showed a significant increase (p = 0.043). AAT and the APACHE III score tended to differ significantly after 24 h between the groups [AAT levels higher in the therapy group (p = 0.05), APACHE III score lower (p = 0.05)]. In the therapy group, the systemic vascular resistance index was significantly higher after 24 h (p = 0.0026) whereas the cardiac index declined (p = 0.035).

CONCLUSIONS

PTX does influence TNF levels in septic shock patients. Nevertheless, inhibiting a single mediator in severe septic shock cannot stop the inflammatory overreaction.

Measuring extracellular matrix turnover in the serum of patients with idiopathic or ischemic dilated cardiomyopathy and impact on diagnosis and prognosis

Circulating levels of extracellular matrix components were measured by radioimmunoassays and tested if they were useful for clinical staging in chronic heart failure. In 41 patients with dilated cardiomyopathy (33 idiopathic and 8 ischemic cases), the serum concentrations of procollagen type III aminoterminal peptide (PIIINP), type I collagen telopeptide (ICTP), and basement membrane laminin were significantly higher than in 30 healthy controls regardless of the underlying etiology. Patients with serum values of PIIINP, ICTP, and laminin > 7 micrograms/L, 7.6 micrograms/L, and 2.3 U/ml, respectively, were at higher relative risk for advanced clinical stage, poor hemodynamic condition, hyponatremia, heart transplantation, and death during follow-up than patients with low levels, with the exception that serum laminin > 2.3 U/ml was not significantly associated with hyponatremia and heart transplantation. Despite their interdependence on liver function, circulating levels of PIIINP and ICTP were independent predictors of mortality. In 17 of the 41 patients with cardiomyopathy whose explanted hearts were available for histologic evaluation, serum PIIINP, ICTP, and laminin significantly correlated with the myocardial area fractions of their tissue analogues (PIIINP vs myocardial collagen type III, r = 0.784, p = 0.0013; serum ICTP vs myocardial collagen type I, r = 0.603, p = 0.0527; and serum laminin vs myocardial laminin, r = 0.605, p = 0.0411). In conclusion, the increase in extracellular matrix turnover, which may partially be derived from fibrosis in the myocardium, can be measured in the serum of patients with dilated cardiomyopathy, and has an impact on risk stratification and prognosis.

Emergency intubation with the Combitube in two cases of difficult airway management

The airway was managed successfully in two cases of difficult intubation using the Combitube, a new device for emergency intubation, which combines the functions of an oesophageal obturator airway and a conventional endotracheal airway. One patient could not be intubated due to lockjaw; in the other patient, the vocal cords could not be seen because of continued vomiting. The cases illustrate the benefit of the Combitube during emergency intubation for different problems and its effectiveness as an alternative to traditional intubation techniques.

The human cardiac mast cell: localization, isolation, phenotype, and functional characterization

We have isolated and characterized the human cardiac mast cell (CMC) and compared this novel mast cell (MC type with MC obtained from uterus, skin, and lung. Heart tissue was obtained from 14 patients with cardiomyopathy (CMP, heart transplantation). CMC were isolated by enzymatic digestion using collagenase, pronase-E, hyaluronidase, and DNAse. Substantial amounts of CMC (0.5% to 1.5% of isolated cells) were found in the atrial appendages but not in ventricular digests or other sites of the heart (< 0.1%). In situ staining of atrial tissue revealed the presence of CMC in the myocardium (2.16 +/- 0.7 MC/mm2), endocardium (2.24 +/- 0.9 MC/mm2), and epicardium. As assessed by combined toluidine blue/immunofluorescence staining with monoclonal antibodies (MoAbs), isolated CMC expressed surface IgE, the receptor for stem cell factor (c-kit receptor/CD117), the p24 antigen (CD9), the Pgp-1 homing receptor (CD44), the pan leukocyte antigen (CD45), and the ICAM-1 antigen (CD54). CMC were not recognized by MoAbs to lymphocyte function associated antigen 2 (LFA-2; CD2), T-cell receptor (TcR; CD3), T4 antigen (CD4), LFA-1 alpha-chain (CD11a), C3biR alpha-chain (CD11b), CR4 alpha-chain (CD11c), LPS-R related Ag (CD14), 3-FAL/x-hapten (CD15), Fc gamma RIII (CD16), lactosylceramid (CDw17), the B-cell antigen CD19, or CR1 (CD35). In situ expression of leukocyte antigens on CMC was demonstrable by indirect immunoperoxidase staining technique and double-labeling immunohistochemistry. Almost all CMC (90%) reacted with MoAbs against tryptase and chymase and thus were MCTC. Cardiac mast cells were also stained by the heparin-binding dye Berberine sulfate and expressed measurable amounts of histamine (4.6 +/- 1.4 pg per cell). Cross linking of either IgE receptor or SCF receptor (c-kit) on CMC resulted in histamine secretion (non-specific release: < 6% of total histamine, alpha IgE induced: 12% to 52%; SCF-induced release: 9% to 18%), whereas neither substance P (a skin MC agonist) nor the basophil agonist FMLP showed an effect on CMC. Together, the CMC is an MCTC primarily located in the appendage of the atrium. This novel type of MC exhibits surface membrane antigen and functional properties similar to those of lung and uterus MC.

Endomyocardial HLA expression is increased to the same extent in idiopathic and secondary dilated cardiomyopathy

In a total of 22 failing hearts from human transplant recipients, the expression of major histocompatibility complex (MHC) molecules, the CD phenotype of infiltrating mononuclear cells, and the number of fibroblasts were analyzed by immunohistochemistry. Compared with 10 non-failing control hearts, significantly higher morphometric area fractions of HLA-ABC and HLA-DR with a concomitant increase of CD3-, CD4- and CD8-positive cells were found to be comparable in 12 patients with idiopathic dilated cardiomyopathy and in 10 patients with secondary heart failure. Furthermore, the similarity of T-cell activation in idiopathic and secondary variants of the disease were substantiated by the following observations: (1) the site-specific distribution of MHC molecules and mononuclear cells in the myocardium was comparable in idiopathic and secondary dilated cardiomyopathy; (2) 6 individuals with lymphocytic aggregates in their myocardium in association with the highest levels of HLA-ABC expression were equally distributed among idiopathic and secondary patient subsets; and (3) expression of HLA-ABC and HLA-DR correlated with that of an endothelial cell marker, von Willebrand factor, in failing myocardia of both study groups. In conclusion, no difference was found in increased MHC molecule expression in failing myocardium of idiopathic and secondary variants of dilated cardiomyopathy, and these entities were not differentially associated with infiltration by increased numbers of T lymphocytes. Hence, we postulate that these immunopathological features are consequences rather than causative factors of myocardial degeneration and dilatation.(ABSTRACT TRUNCATED AT 250 WORDS)

Serum-soluble CD4 as clinical and immunological marker in patients with dilated cardiomyopathy

Serological markers of cell-mediated immunity, i.e., soluble CD4, soluble interleukin-2 (Il-2) receptor and beta 2-microglobulin, were determined in 60 patients with dilated cardiomyopathy. Compared with normal healthy donors (n = 30) and controls who had coronary artery disease with preserved left ventricular function (n = 20), significantly increased levels associated with the New York Heart Association functional classes have been found in the cardiomyopathy patients, irrespectively of the etiology. Out of the immunological variables tested, serum-soluble CD4 most closely reflected the clinical and hemodynamic stage, predicted the presence of lymphocytic aggregates in the myocardium and correlated with the CD4/CD8 ratios of endomyocardial lymphocytes (r = 0.6, P < 0.05). Conversely, focal mononuclear infiltration of the myocardium was associated with significantly elevated CD4/CD8 ratios (2.1 +/- 0.6 vs. 1.3 +/- 0.2, P < 0.05), higher total numbers and percentages of endomyocardial lymphocytes expressing the pan T-markers CD2 and CD3, more CD45RO/UCHL1-positive cells and more CD4-positive T-helper cells, compared with non-reactive cases the lymphocytes of which were scattered throughout the myocardium. In conclusion, in a subset of cardiomyopathy patients lymphocytic clusters in the myocardium indicated an enhanced cellular immune response predominantly mediated by CD4-positive T-helper lymphocytes with active memory function. This immunopathological condition in the heart can be monitored by serum-soluble CD4.

Specific activation of human mast cells by the ligand for c-kit: comparison between lung, uterus and heart mast cells

Recent data suggest that stem cell factor (SCF or c-kit ligand, KL) is a major regulator of human mast cells (MCs). In the present study, MCs derived from the lung (n = 8), uterus (n = 14) and heart (n = 4) were analyzed for expression of c-kit receptor and for responses to recombinant SCF. MCs of all organs tested were recognized by mAbs to c-kit (YB5.B8, SR-1) as assessed by combined toluidine blue/immunofluorescence staining. Activation by rhSCF (10 ng/ml, 60 min) resulted in histamine release from lung MCs (SCF 12.8 +/- 2.7% histamine release; control 2.8 +/- 0.8%, p < 0.01), uterus MCs (SCF 16.8 +/- 5.8%; control 5.2 +/- 2.5%, p < 0.01) and heart MCs (SCF 18.4 +/- 2.6%; control 1.7 +/- 0.23%, p < 0.01). Short-term pre-incubation with rhSCF (15 min) did not result in histamine secretion (p > 0.05), but in an increase (lung 2.4 +/- 1.0 fold; uterus 2.1 +/- 1.1 fold, and heart 2.0 +/- 0.4 fold) of alpha IgE-induced mediator release (p < 0.05). The effects of SCF were dose-dependent (maximum responses at 10-100 ng/ml) and dependent on extracellular calcium. A monoclonal antibody to SCF was found to inhibit the effects of SCF on MCs. Furthermore, MCs could be desensitized specifically by pre-incubation of MCs with rhSCF in Ca-free medium. Together, these data suggest that SCF triggers mediator secretion from MCs in various organs via binding to the c-kit receptor.

[Tramadol in postoperative pain therapy. Patient-controlled analgesia versus continuous infusion]

Patient-controlled analgesia (PCA) is a well-proven procedure for individual pain relief in the post-operative period. Despite its superior approach regarding pharmacokinetic and pharmacodynamic considerations, PCA equipment is not available to many in the clinical practice. The goal of this study was to compare the efficacy and safety of PCA with continuous infusion (CI), an easily feasible method, using tramadol (T) as a centrally acting opioid with minor side effects on circulation and ventilation.

METHODS

The study was conducted on 20 ASA I or II patients aged 20-60 years undergoing gynecological operations under standardized general anesthesia. They were randomly allocated to two groups receiving i.v. T for postoperative pain relief via Lifecare PCA 4200 Infuser. Group 1 (G1, PCA, n = 10): loading dose 3 mg/kg T, demand dose 30 mg T, lock-out time 5 min, concurrent infusion 5 mg/h T; group 2 (G2, CI, n = 10): loading dose 3 mg/kg T, continuous infusion 0.35 mg/kg per h T. If the analgesia was inadequate, additional doses of 50 mg T were available in G2. During a mean trial period of 20 h, the heart rate, blood pressure, respiratory rate and blood gas analysis were documented. The plasma levels of T and beta-endorphins were determined. The quality of analgesia was assessed by using a verbal and a visual analogue scale.

RESULTS

The mean applied doses of T were 339 +/- 100 mg and 364 +/- 46 mg (G1 and G2, respectively) after 6 h and 565 +/- 243 mg and 707 +/- 139 mg (G1 and G2, respectively) in total (NS). Interindividual differences were substantial in G1. Five patients in G2 required an additional dose of 50 mg T. Pain scores decreased rapidly in both groups. The pain relief achieved was comparable and excellent after 6 h. The next morning, G2 reported significantly better analgesia in accordance with the higher availability of T as CI during the sleeping period. Mean plasma T levels were 994 +/- 440 ng/ml and 1170 +/- 357 ng/ml (G1 and G2, respectively). No correlation was found between T-levels and pain scores. The plasma levels of beta-endorphins were substantially elevated after the operation. They returned to normal during T-administration in both groups. No correlation was found between plasma levels of beta-endorphins and pain scores or T-consumption. Hemodynamic changes were minor and without clinical significance. PaO2 and paCO2 remained within small deviations from the physiological range. The respiratory rate, which was initially increased, dropped slightly in both groups. A high incidence of nausea and vomiting was observed, starting in the early phase of the loading dose.

CONCLUSIONS

T is well suitable for postoperative pain relief after major gynecological surgery using both PCA and CI. PCA ensures adjustment of the medication to the individual demand, whereas CI provides better analgesia after sleeping periods. We recommend antiemetic prophylaxis before treatment with T.

Autologous and allogenic natural cell mediated cytotoxicity at the single cell level: divergent effects of interferons and interleukin 2 on binding and lysis

In order to evaluate their divergent effects on binding and lysis of the NCMC, rH IFN-alpha and rH IL-2 were used for the in vitro-preincubation of normal donors' PBL, which were then tested as effector cells against K562 and the long-term cultured melanoma cell line RIMA in the SCCA. Both lymphokines significantly augmented the cytolysis of K562 without relevant influence on the conjugate formation. However, against RIMA IFN-alpha additionally amplified the binding affinity. This in keeping with the other authors' opinion that IFNs have target-specific effects at the single cell level, with the principal activation of already conjugated pre-killer cells against all the target cell lines tested. We performed a therapy-follow-up of the i.p. administration of rH IFN-gamma to patients with ovarian carcinomas in vivo. With the SCCA we detected a significant correlation of the duration of therapy with the autologous cytotoxicity in the ascitic compartment. In one case the increase of this parameter was even exponential. However, the countercurrent trend of the conjugate formation delayed and reduced the activation of the autologous total killer activity. This relative stagnation resulted in the inadequate clinical response of two patients. Moreover, we observed a discrepancy in the development of the autologous and allogeneic SCCA-parameters suggesting strong effects of the peritumorally administered IFN directly on the effusion tumor cells.

IFN-beta 2/IL-6 augments the activity of human natural killer cells

MHC nonrestricted cytotoxic cells play an important role in the killing of tumor cells in vitro and potentially in vivo. The activity of these cells is regulated by several cytokines such as IL-2 and IFN. In the present study we provide first evidence that IL-6 significantly augments the cytotoxic activity of human NK cells. IL-6 is produced by many different cells and is also known as IFN-beta 2, B cell stimulatory factor 2, hybridoma growth factor, hepatocyte-stimulating factor, and 26 kDa protein. IL-6 stimulates the activity of human CD3- NK cells but not that of CD3+ non-MHC-restricted cytotoxic T lymphocytes. As is the case with IL-2, the IL-6-mediated augmented cytotoxicity was a result of a more efficient lysis, but was not caused by an increased effector to target cell binding. Moreover, the effect of IL-6 on NK cell activity was blocked by a mAb directed against IL-2, and IL-6 itself was found to be a potent inducer of IL-2 production in cultured human PBMC. Thus it may be concluded that IL-6 enhances the cytotoxic activity of NK cells via IL-2. This newly recognized property of IL-6, which is produced by almost any cell, may be of importance in host defense against microbes and malignancies and therefore could contribute to improve the adoptive immunotherapy by using lymphokine-activated killer cells.

IFN-beta 2/IL-6 augments the activity of human natural killer cells

MHC nonrestricted cytotoxic cells play an important role in the killing of tumor cells in vitro and potentially in vivo. The activity of these cells is regulated by several cytokines such as IL-2 and IFN. In the present study we provide first evidence that IL-6 significantly augments the cytotoxic activity of human NK cells. IL-6 is produced by many different cells and is also known as IFN-beta 2, B cell stimulatory factor 2, hybridoma growth factor, hepatocyte-stimulating factor, and 26 kDa protein. IL-6 stimulates the activity of human CD3- NK cells but not that of CD3+ non-MHC-restricted cytotoxic T lymphocytes. As is the case with IL-2, the IL-6-mediated augmented cytotoxicity was a result of a more efficient lysis, but was not caused by an increased effector to target cell binding. Moreover, the effect of IL-6 on NK cell activity was blocked by a mAb directed against IL-2, and IL-6 itself was found to be a potent inducer of IL-2 production in cultured human PBMC. Thus it may be concluded that IL-6 enhances the cytotoxic activity of NK cells via IL-2. This newly recognized property of IL-6, which is produced by almost any cell, may be of importance in host defense against microbes and malignancies and therefore could contribute to improve the adoptive immunotherapy by using lymphokine-activated killer cells.

[Human natural killer activity in selected test systems and tissue compartments: natural killer cell modulation by biological response modifiers]

In order to evaluate the effect of biological response modifiers on NK- and NK-like activity, interferons were tested in the single cell cytotoxicity assay (SCCA) with various effector/target combinations. alpha Interferon (IFN-alpha) significantly augmented the cytolysis of K 562 in vitro by non-adherent peripheral blood lymphocytes of normal donors without any influence on the binding capacity. Similarly, in vivo, the intraperitoneal administration of gamma Interferon (IFN-gamma) to patients with ovarian carcinomas resulted in a significant increase in the autologous cytotoxicity in the ascitic compartment. Nevertheless the autologous total killer activity was not improved owing to the countercurrent trend of the conjugate formation. Moreover, we detected a discrepancy in the development of the autologous and allogenic parameters as a result of the strong effects of the peritumorally administered IFN on the effusion tumour cells. In order to investigate the role of epidermal NK-like activity in immunosurveillance we tested epidermal cells as effectors against K 562 and the long-term cultured melanoma cell line RIMA. The SCCA detected the ability of conjugate formation without any cytotoxicity, augmentable significantly and in a dose-related manner by IFN-gamma, as the only one of ten tested biological response modifiers.