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W Seeger

Publications and source records attributed to W Seeger.

At least 91 records · Page 5Linked to original sources
PubMed2001

Ultrasonic versus jet nebulization of iloprost in severe pulmonary hypertension.

Inhalation of iloprost, a stable prostacyclin analogue, is a promising perspective in the treatment of pulmonary hypertension. In initial clinical studies, a conventional jet nebulizer system was successfully used to decrease pulmonary vascular resistance and pressure, requiring however, up to twelve inhalations of 12-15 min per day. The aim of this study was to investigate if the application of an equal dose of iloprost at a drastically reduced duration of inhalation with the use of a more efficient ultrasonic nebulizer, leads to comparable haemodynamic effects, without escalation of side effects. The physical features of the jet nebulizer system (Ilo-Neb) and the ultrasonic nebulizer (Multisonic Compact) were characterized by laser diffractometry and a Tc99m-tracer technique. Mass median aerodynamic diameters were 3.2 microm for the jet and 3.9 microm for the ultrasonic nebulizer. Total output (mean+/-SD) was 60+/-7 microL.min(-1) (jet) and 163+/-15 microL.min(-1)(ultrasonic), and efficiency of the devices was 39+/-3% (jet) and 86+/-5% (ultrasonic). Based on these data, a total inhalative dose of 2.8 microg iloprost was delivered by jet nebulization within 12 min and by ultrasonic nebulization within 4 min, in 18 patients with severe primary and secondary pulmonary hypertension (New York Heart Association class III and IV), in a randomized crossover design. Haemodynamics were assessed by right heart catheterization. Inhalation with the ultrasonic device and jet nebulizer, reduced mean+/-SEM pulmonary artery pressure from 54.3+/-2.1 to 47.1+/-2.0 and from 53.5+/-2.2 to 47.0+/-2.2 mmHg, respectively, and mean+/-SEM pulmonary vascular resistance from 1,073+/-109 to 804+/-87 and from 1,069+/-125 to 810+/-83 dyn.s.cm(-5), respectively. Both modes of aerosolization were well tolerated. In conclusion, due to the markedly higher efficiency and output of the ultrasonic device, wastage of drug is largely avoided and the duration of inhalation can be shortened to one-third, with comparable haemodynamic effects and without enforcing side effects.

Administration, Inhalation↗
PubMed2001

Subthreshold concentrations of anti-proteinase 3 antibodies (c-ANCA) specifically prime human neutrophils for fMLP-induced leukotriene synthesis and chemotaxis.

Anti-neutrophil cytoplasmic antibodies (ANCA) targeting proteinase 3 (PR3) possess a high sensitivity and specificity for Wegener's granulomatosis. Due to their capacity of directly activating neutrophils, a pathogenetic role for these autoantibodies has been proposed. We investigated the impact of subthreshold concentrations of monoclonal anti-PR3 antibodies (anti-PR3; 0.1 microg/mL) on neutrophil activation elicited by a secondary agent. Preincubation with anti-PR3 resulted in a massive amplification of N-formyl-methionyl-leucyl-phenylalanine (fMLP)-induced leukotriene (LT) generation, with a marked increase in the liberation of LTB4, LTA4, and 5-hydroxyeicosatetraenoic acid (5-HETE). This priming commenced within 2.5 min, with a maximum after 5-7.5 min. Moreover, anti-PR3 pretreatment markedly enhanced PMN movement toward fMLP. The priming effect of anti-PR3 toward fMLP challenge was reproduced by c-ANCA, but not by F(ab)2 fragments of the antibodies and isotype-matched control IgG. Generation of superoxide anion and release of elastase were suppressed in anti-PR3-pretreated neutrophils undergoing fMLP challenge. In contrast, neutrophil activation by platelet-activating factor (PAF) or the calcium ionophore A23187 remained unaffected. We conclude that subthreshold concentrations of anti-PR3 antibodies selectively modify neutrophil responses to fMLP, with enhancement of leukotriene generation and chemotaxis, but suppression of respiratory burst and degranulation. Such priming might contribute to localized neutrophil accumulation together with blunted host defense in Wegener's granulomatosis.

Animals↗
PubMed2000

Endotoxin-induced myocardial tumor necrosis factor-alpha synthesis depresses contractility of isolated rat hearts: evidence for a role of sphingosine and cyclooxygenase-2-derived thromboxane production.

BACKGROUND: Although endotoxin (lipopolysaccharides, LPS) is recognized as a mediator of septic cardiodepression, its cardiac effects are still not fully elucidated. METHODS AND RESULTS: Perfusion of isolated rat hearts with LPS for 180 minutes resulted in a decline of left ventricular contractility after 90 minutes, whereas coronary perfusion pressure remained unaffected. This cardiodepression was paralleled by a release of tumor necrosis factor (TNF)-alpha into the perfusate and preceded by myocardial TNF-alpha mRNA upregulation as quantified by real-time polymerase chain reaction. The cardiodepression was abrogated when LPS was perfused with a TNF-alpha antiserum or the ceramidase inhibitor N:-oleoylethanolamine. In contrast, the cardiac release of nitric oxide (NO) was not augmented by LPS. Immunohistochemical studies of LPS-perfused hearts revealed a positive staining for the constitutive (NOSIII) but not for the inducible NO synthase (NOSII). Accordingly, NOSII mRNA levels commenced to increase only at the very end of the LPS perfusion period. Progressive liberation of thromboxane (Tx) A(2) and prostacyclin was induced by LPS together with myocardial cyclooxygenase (Cox)-2 mRNA expression. Both nonselective inhibition of Cox by indomethacin and selective inhibition of the inducible Cox-2 by NS-398 abolished prostanoid release. Interestingly, the generation of TNF-alpha and the associated cardiodepression caused by LPS were reduced by indomethacin, NS-398 and the Tx-receptor antagonist daltroban. CONCLUSIONS: LPS depresses contractility of isolated rat hearts by inducing TNF-alpha synthesis and subsequently activating the sphingomyelinase pathway, whereas no evidence for a role of NOSII- or NOSIII-generated NO was found. Moreover, Cox-2-derived TxA(2) appears to facilitate TNF-alpha synthesis in response to LPS.

Animals↗
PubMed2000

Targeting lipopolysaccharides by the nontoxic polymyxin B nonapeptide sensitizes resistant Escherichia coli to the bactericidal effect of human neutrophils.

The nonapeptide of polymyxin B (PMBN) has been reported to sensitize various pathogenic gram-negative bacteria to the direct bactericidal effect of human serum. To investigate the impact of PMBN on human neutrophil-effected killing of the serum- and phagocytosis-resistant Escherichia coli strains C14 and O111, serum was coapplied with PMBN or with neutrophils, but this did not result in decreased numbers of viable bacteria. In contrast, the most potent bacterial killing occurred in the presence of neutrophils plus serum components plus PMBN. The effect of this on E. coli C14 was the appearance of inositol phosphates, diacylglycerol, respiratory burst, elastase liberation, and generation of lipid mediators (leukotriene B(4), 5-HETE, and platelet-activating factor). Strong neutrophil activation required early, but not late, complement components and was blocked by inhibition of phagocytosis with cytochalasin D. PMBN seems to cause dramatic support of natural host defense by complement-dependent sensitization of E. coli to the bactericidal efficacy of human neutrophils.

Anti-Bacterial Agents↗
PubMed2000

Inhaled iloprost to treat severe pulmonary hypertension. An uncontrolled trial. German PPH Study Group.

BACKGROUND: Inhaled aerosolized iloprost, a stable prostacyclin analogue, has been considered a selective pulmonary vasodilator in the management of pulmonary hypertension. OBJECTIVE: To assess the efficacy of inhaled iloprost in the treatment of life-threatening pulmonary hypertension. DESIGN: Open, uncontrolled, multicenter study. SETTING: Intensive care units and pulmonary hypertension clinics at six university hospitals in Germany. PATIENTS: 19 patients who had progressive right-heart failure despite receiving maximum conventional therapy (12 with primary pulmonary hypertension, 3 with pulmonary hypertension related to collagen vascular disease without lung fibrosis, and 4 with secondary pulmonary hypertension). INTERVENTION: Inhaled iloprost, 6 to 12 times daily (50 to 200 microg/d). MEASUREMENTS: Right-heart catheterization and distance walked in 6 minutes at baseline and after 3 months of therapy. RESULTS: During the first 3 months of therapy, New York Heart Association functional class improved in 8 patients and was unchanged in 7 patients. Four patients died, 3 of right-heart failure and 1 of sepsis. The acute hemodynamic response to inhaled iloprost was predominant pulmonary vasodilatation with little systemic effect at baseline and at 3 months (data available for 12 patients). Hemodynamic variables were improved at 3 months, and the distance walked in 6 minutes improved by 148 m (95% CI, 4.5 to 282 m; P = 0.048). Of the 15 patients who continued to use inhaled iloprost, 8 stopped: Four had lung transplantation, 1 switched to intravenous prostacyclin therapy, and 3 died. Seven patients are still receiving inhaled iloprost (mean +/-SD) duration of therapy, 536 +/- 309 days; mean dosage, 164 +/- 38 microg/d). CONCLUSIONS: Inhaled iloprost may offer a new therapeutic option for improvement of hemodynamics and physical function in patients with life-threatening pulmonary hypertension and progressive right-heart failure that is refractory to conventional therapy.

Administration, Inhalation↗
PubMed2000

Monocyte migration through the alveolar epithelial barrier: adhesion molecule mechanisms and impact of chemokines.

Alveolar monocyte influx requires adherence and transmigration through the vascular endothelium, extracellular matrix, and alveolar epithelium. For investigating the monocyte migratory process across the epithelial barrier, we employed both the A549 cell line and isolated human alveolar epithelial cells. Under baseline conditions, spontaneous bidirectional transepithelial monocyte migration was noted, which was dose-dependently increased in the presence of the monocyte chemoattractant protein-1. TNF-alpha stimulation of the alveolar epithelium provoked the polarized apical secretion of monocyte chemoattractant protein-1 and RANTES and up-regulation of ICAM-1 and VCAM-1 expression, accompanied by markedly enhanced transepithelial monocyte traffic in the basal-to-apical direction. Multiple adhesive interactions were noted to contribute to the enhanced monocyte traffic across the TNF-alpha-stimulated alveolar epithelium: these included the beta 2 integrins CD11a, CD11b, CD11c/CD18, the beta 1 integrins very late Ag (VLA)-4, -5, and -6, and the integrin-associated protein CD47 on monocytes, as well as ICAM-1, VCAM-1, CD47, and matrix components on the epithelial side. In contrast, spontaneous monocyte migration through unstimulated epithelium depended predominantly on CD11b/CD18 and CD47, with some additional contribution of VLA-4, -5, and -6. In summary, unlike transendothelial monocyte traffic, for which beta 1 and beta 2 integrins are alternative mechanisms, monocyte migration across the alveolar epithelium largely depends on CD11b/CD18 and CD47 but required the additional engagement of the beta 1 integrins for optimal migration. In response to inflammatory challenge, the alveolar epithelium orchestrates enhanced monocyte traffic to the apical side by polarized chemokine secretion and up-regulation of ICAM-1 and VCAM-1.

Cell Adhesion Molecules↗
PubMed2000

[Inhalative strategies for improvement of pulmonary hemodynamics and gas exchange in sepsis and severe pulmonary hypertension].

Chronic pulmonary hypertension and septic lung failure display different clinical features resulting in severe disturbances in the pulmonary circulation. In these diseases, the pulmonary bloodflow is impaired by a pathologic constriction of blood vessels that may lead to right ventricular overloading as well as serious worsening of gas exchange mainly caused by ventilation/perfusion mismatch. Various mechanisms deteriorating the vascular function may induce both an irreversible and a reversible contraction of pulmonary vessels, respectively. Two pharmacological approaches exist to reduce the vascular resistance: Reduction of the increased vascular tone by relaxation of vascular smooth muscle cells (effect of vasodilators). Inhibition of thrombus-mediated obliteration of the lung perfusion by use of anticoagulant and fibrinolytic drugs. Prevention of the structural reorganization of pulmonary vessels (vascular remodeling) by use of vasodilators with anti-inflammatory and anti-proliferative potency such as prostanoids. The systemic (intravenous or oral) application of vasodilative agents in sepsis and chronic pulmonary hypertension has, however, important side effects: Antagonism of the hypoxic pulmonary vasoconstriction aggravates the ventilation/perfusion mismatch (decrease in arterial oxygenation). Side effects of these vasodilators (systemic hypotension). The inhalative route of application is superior because of the pulmonary enrichment of the applied agent (pulmonary selectivity). Furthermore, a preferential deposition in the well-ventilated areas of the lung is achieved (intrapulmonary selectivity). Thus, the decrease in pulmonary-vascular resistance is paralleled by both optimized ventilation-perfusion matching and subsequently improved gas exchange. First clinical studies with inhaled nitric oxide and aerosolized prostacyclin have been performed in intubated and mechanically ventilated patients with septic lung failure. At present, the use of the long-acting prostacyclin analogue ilomedin for ambulant treatment of patients with chronic pulmonary hypertension is under investigation.

Acute Disease↗
PubMed2000

Immunostaining for cell picking and real-time mRNA quantitation.

Microdissection techniques allow a cell-type or even cell-specific mRNA analysis within complex tissues. Furthermore, valid mRNA quantitation can be performed by real-time reverse transcriptase-polymerase chain reaction from a few isolated cells obtained from cryosections. For a more precise access to many cell types, this technique has to be complemented by a cell-type-specific immunostaining. To evaluate its effect on mRNA quantitation, we analyzed alveolar macrophages (AMs) from control rat lungs and those undergoing stimulation with lipopolysaccharide and interferon-gamma nebulization. Whereas AMs from the left lung were directly harvested for mRNA extraction by bronchoalveolar lavage, tissue sections of the right lung were stained with an optimized immunofluorescence protocol detecting AMs. Fifteen AM profiles per sample were picked by laser-assisted sampling technique. Normalizing to a standard gene, nitric oxide synthase II (NOSII) and tumor necrosis factor (TNF)-alpha mRNA were quantified by real-time reverse transcriptase-polymerase chain reaction. In stimulated lungs, the percentage of picked samples positive for NOSII or TNF-alpha mRNA increased significantly. Moreover, a marked increase in the ratio of target gene mRNA to standard gene mRNA was noted for both NOSII and TNF-alpha in picked AMs from stimulated lungs, which matched very well the increase detected in the lavaged AMs undergoing direct RNA extraction. Thus, when using an optimized protocol for immunofluorescence, this approach may be reliably combined with laser-assisted cell picking and real-time mRNA quantitation in a few immunohistochemically characterized cell profiles within complex tissues.

Animals↗
PubMed2000

Rat pulmonary cyclooxygenase-2 expression in response to endotoxin challenge: differential regulation in the various types of cells in the lung.

Cyclooxygenase (Cox), the key enzyme of prostanoid synthesis, consists of the two isoforms Cox-1 and Cox-2, both recently noted to be constitutively expressed in rat lungs with a distinct profile of cellular distribution. The responsiveness of pulmonary Cox-1 and Cox-2 expression to intravascular endotoxin lipopolysaccharide (LPS) administration was investigated in isolated, ventilated rat lungs, buffer-perfused with or without admixture of rat plasma. Immunohistochemical staining intensity was measured by a previously described method of silver enhancement and epipolarization image analysis. Both the Cox-1 mRNA, quantified in the whole lung homogenate, and the cellular localization of Cox-1 were unchanged in response to LPS. In contrast, time- and dose-dependent up-regulation of Cox-2 mRNA (lung homogenate) occurred, and differential LPS reactivity at the cellular level was observed. Up-regulation of Cox-2 in cell types expressing this enzyme already under baseline conditions was noted in bronchial epithelial cells, bronchial and vascular smooth muscle cells, cells within the BALT and myocytes of the large hilar veins. De novo induction of Cox-2 occurred in endothelial cells and the majority of alveolar macrophages. Down-regulation of Cox-2 was observed in perivascular and peribronchial macrophage-like cells. Moreover, differential impact of plasma components was noted: for the large majority of cells, CD14 surface expression correlated with Cox-2 responsiveness to LPS independent of plasma, whereas the presence of plasma components was a prerequisite for the LPS response in CD14-negative cells. LPS did not provoke physiological changes in the perfused lungs, but markedly enhanced baseline prostanoid generation. We conclude that LPS-induced Cox-2 regulation occurs in a complex, cell-specific manner, which may be relevant for pathogenetic sequelae in septic lung injury and acute respiratory failure.

Animals↗
PubMed2000

A comparison of the acute hemodynamic effects of inhaled nitric oxide and aerosolized iloprost in primary pulmonary hypertension. German PPH study group.

OBJECTIVE: We sought to compare the acute hemodynamic effects of inhaled nitric oxide (NO) and aerosolized iloprost in primary pulmonary hypertension (PPH). BACKGROUND: Inhalation of the stable prostacyclin analogue iloprost has recently been described as a novel therapeutic strategy for PPH and may offer an alternative to continuous intravenous infusion of prostacyclin or inhalation of NO. METHODS: During right heart catheterization, 35 patients with PPH sequentially inhaled 40 ppm of NO and 14 to 17 microg of iloprost, and the effects on hemodynamics and blood gases were monitored. RESULTS: Both NO and iloprost caused significant increases in cardiac output, mixed-venous oxygen saturation and stroke volume as well as significant decreases in pulmonary artery pressure and pulmonary vascular resistance, whereas only inhaled iloprost significantly increased the arterial PO2 (p = 0.01). Compared with inhaled NO, aerosolized iloprost was more effective in reducing pulmonary artery pressure (-8.3 +/- 7.5 mm Hg vs. -4.3 +/- 8.8 mm Hg; p = 0.0001) and the pulmonary vascular resistance (-447 +/- 340 dynes x s x cm(-5) vs. -183 +/- 305 dyne x s x cm(-5); p < 0.0001). Furthermore, aerosolized iloprost caused a significantly greater increase of the cardiac output compared with NO (+0.7 +/- 0.6 liter/min vs. +0.3 +/- 0.4 liter/min; p = 0.0002) and had a more pronounced effect on the mixed-venous oxygen saturation (p = 0.003). CONCLUSIONS: During acute drug testing, aerosolized iloprost was more potent than inhaled NO as a pulmonary vasodilator in PPH at the doses used in this study.

Administration, Inhalation↗
PubMed2000

Immunostaining and laser-assisted cell picking for mRNA analysis.

Isolation of single cells or cell clusters from complex tissue sections has become possible by microdissection techniques. Employing laser-assisted cell picking, cell-specific mRNA analysis of a few isolated cell profiles may be performed. However, microscopic discrimination of different cell types in routinely stained tissue sections is limited, whereas immunostaining enables a more precise access to cells of interest. This approach was noted to interfere with mRNA recovery. To define optimal conditions for mRNA amplification from immunodetected cells, we systematically investigated several potential affectors. Kind of fixation, antibodies and staining reagents, incubation and total processing time, and digestion with proteinase K turned out to influence mRNA stability. We present rapid protocols for immunohistochemistry and immunofluorescence with total incubation times of approximately 25 to 40 minutes and 10 to 20 minutes, respectively, and suggest mRNA amplification without a preceding extraction step. Applying these protocols to oligocellular clusters containing approximately 20 cell profiles and nuclei each from lung and kidney tissue, the highest efficiency rates of mRNA amplification were obtained when combining short-term formalin fixation, reduction of antibody incubation time, application of immunofluorescence, and digestion with proteinase K. Thus, the successful combination of immunostaining and laser-assisted cell picking remarkably improves cell type-specific analysis of gene expression within complex tissues.

Alkaline Phosphatase↗
PubMed2000

Blockade of leucocyte function-associated antigen-1 (LFA-1) decreases lymphocyte trapping in the normal pulmonary vasculature: studies in the isolated buffer-perfused rat lung.

Adhesion molecules regulate the migration of lymphocytes in lymphoid and non-lymphoid organs. In the lung, little is known about lymphocyte sticking and migration through the pulmonary vascular endothelium in physiological or pathological situations. Therefore the isolated buffer-perfused rat lung was used to investigate the mobilization of lymphocytes out of the normal lung into the venous effluent and to the bronchoalveolar space. The lymphocyte subset composition was characterized in the venous effluent, the lung tissue and the bronchoalveolar lavage (BAL) using immunocytology. Lymphocytes continuously left the normal lung at a total of 5.0 +/- 0.7 x 106 cells within the first hour of perfusion. The injection of 200 x 106 lymphocytes via the pulmonary trunk increased the venous release of lymphocytes by 170%. To investigate the effect of LFA-1 and CD44 on the adhesion of lymphocytes to the pulmonary endothelium, lymphocytes preincubated with an anti-LFA-1 MoAb, which blocks the interaction of LFA-1 and intercellular adhesion molecule-1 (ICAM-1), or lymphocytes preincubated with an anti-CD44 MoAb, were injected. The injection of LFA-1-blocked lymphocytes led to an increase by 70% of injected cells recovered in the perfusate within the first hour, whereas anti-CD44 treatment of injected lymphocytes had no effect. The LFA-1-blocked lymphocytes showed higher numbers of T and B cells in the effluent. Thus, the present experiments demonstrate that LFA-1 influences the trapping of lymphocytes in the vasculature of the healthy rat lung.

Animals↗
PubMed2000

[Inhaled prostacyclin and iloprost in severe pulmonary hypertension secondary to pulmonary fibrosis].

Pulmonary hypertension is a life-threatening complication of lung fibrosis. Vasodilator therapy is difficult owing to systemic side effects and pulmonary ventilation-perfusion mismatch. We compared the effects of intravenous prostacyclin and inhaled NO and aerosolized prostacyclin in randomized order and, in addition, tested for effects of oxygen and systemic calcium antagonists (CAAs) in eight patients with lung fibrosis and pulmonary hypertension. Aerosolized prostaglandin (PG)I2 caused preferential pulmonary vasodilatation with a decrease in mean pulmonary arterial pressure from 44.1 +/- 4.2 to 31.6 +/- 3.1 mmHg, and pulmonary vascular resistance (RL) from 810 +/- 226 to 386 +/- 69 dyn.s.cm-5 (p < 0.005, respectively). Systemic arterial pressure, arterial oxygen saturation, and pulmonary right-to-left-shunt flow, measured by multiple inert gas analysis, were not significantly changed. Inhaled NO similarly resulted in selective pulmonary vasodilatation, with RL decreasing from 726 +/- 217 to 458 +/- 81 dyn.s.cm-5. In contrast, both intravenous PGI2 and CAAs were not pulmonary selective, resulting in a significant drop in arterial pressure. In addition PGI2 infusion caused a marked increase in shunt flow. Long-term therapy with aerosolized iloprost (long-acting PGI2 analog) resulted in unequivocal clinical improvement from a state of immobilization and severe resting dyspnea in a patient with decompensated right heart failure. We concluded that, in pulmonary hypertension secondary to lung fibrosis, aerosolization of PGI2 or iloprost causes marked pulmonary vasodilatation with maintenance of gas exchange and systemic arterial pressure. Long-term therapy with inhaled iloprost may be life saving in decompensated right heart failure from pulmonary hypertension secondary to lung fibrosis.

Administration, Inhalation↗
PubMed2000

[Prevalence of stroke and transitory ischemic attacks in obstructive sleep apnea: a retrospective analyis so f 187 consecutive patients].

BACKGROUND: Obstructive sleep apnea (OSA) is presumed to be significantly associated with cerebrovascular disease; however, there are no consistent epidemiological data providing proof of such a link. Hence, the aim of the present study was to determine the prevalence of stroke and transient ischemic attack (TIA) in patients with OSA. PATIENTS AND METHODS: 187 consecutive patients with a polysomnographically verified diagnosis of OSA who had been admitted to our sleep laboratory during 1/98-3/00 were retrospectively analysed. RESULTS: The prevalence of stroke and TIA was 7%. This rate was lower if compared with those for coronary artery disease and arterial hypertension in the same study cohort (14% and 53% respectively). The 13 OSA patients with stroke were elderly overweight men (age: 64 +/- 1.7 years, BMI: 31.4 +/- 1.1 kg/m2). They had quite severe OSA (AHI: 43 +/- 5/h) and almost all of them suffered from arterial hypertension. In all cases, the insult was caused by cerebral or brain stem ischemia. None of the patients presented with persistent neurological deficits. The mean latency period between the occurrence of stroke or TIA and the diagnosis of OSA was 41.9 +/- 11.3 months. CONCLUSION: In summary, the prevalence of stroke or TIA in our series of 187 consecutive OSA patients was 7%. Further prospective studies controlling for confounding factors such as age, body weight and arterial hypertension are needed to clarify the risk potential of OSA for the development of cerebrovascular disorders.

Aged↗
PubMed2000

Antisense oligomers for selective suppression of MCP-1 synthesis in human pulmonary endothelial cells.

Endothelial synthesis of the C-C chemokine monocyte chemotactic protein-1 (MCP-1) has been implicated in the regulation of monocyte recruitment for extravascular pools under both physiologic and inflammatory conditions. We designed and characterized five antisense phosphorothioate oligodeoxynucleotides (PS-ODN) targeting MCP-1 secretion by human pulmonary artery endothelial cells (HPAEC) and pulmonary microvascular endothelial cells (HMVEC-L). The most effective PS-ODN (MCP-1 AS 2) dose-dependently suppressed the secretion of MCP-1 but not the secretion of the C-X-C chemokine interleukin-8 (IL-8) in both HPAEC and HMVEC-L in the nanomolar concentration range. Mismatch controls bearing 2 or 4 bp substitutions showed markedly reduced inhibitory capacity. MCP-1 mRNA levels were not affected even at the highest PS-ODN doses employed (ribonuclease protection assay), suggesting a translational arrest of MCP-1 production. Accordingly, PS-ODN exhibited no nonspecific side effects on immediate-early gene regulation of the transcription factor nuclear factor-kappaB (NF-kappaB), as analyzed by gel shift assays. Antisense pretreatment of HPAEC reduced the monocyte chemotactic bioactivity liberated from tumor necrosis factor-alpha (TNF-alpha)-activated endothelial cells (EC) and reduced the TNF-alpha-induced transendothelial monocyte migration. We conclude that nanomolar concentrations of specific antisense oligodeoxynucleotides effectively inhibit human endothelial MCP-1 synthesis and may thus provide a rational approach to modulate monocyte recruitment under inflammatory conditions.

Cell Line↗
PubMed2000

Decreased plasma levels of nitric oxide derivatives in obstructive sleep apnoea: response to CPAP therapy.

BACKGROUND: Reduced endothelium dependent vasodilation has been reported in patients with obstructive sleep apnoea (OSA) but direct measurements of the most potent naturally occurring vasodilator, nitric oxide (NO) or its derivatives (nitrate and nitrite, NO(x)), have not yet been performed in these patients. METHODS: In 21 patients with OSA of mean (SE) age 54 (2) years, body mass index (BMI) 30.9 (1.1) kg/m(2), and apnoea-hypopnoea index (AHI) 37 (4)/h, NO(x) levels were measured in peripheral venous blood samples by chemiluminescence. Blood samples were obtained before and after two nights of continuous positive airway pressure (CPAP) and after 5.5 (1.5) months of follow up. Thirteen age matched, healthy volunteers and 18 patients without OSA but with a similar spectrum of comorbidity served as controls (control groups 1 and 2). RESULTS: Before CPAP NO(x) levels were 21.7 (1.5) microM in patients with OSA compared with 42.6 (2.2) microM and 36.7 (1.7) microM in control groups 1 and 2, respectively (p<0.01 for each comparison). NO(x) concentrations increased to 32.1 (2.7) microM after two nights of CPAP and remained constant at 32.9 (2.3) microM at follow up (p<0.01 compared with levels before CPAP). CONCLUSIONS: Plasma NO(x) levels are reduced in OSA and can be increased by short and long term CPAP therapy. Although the precise mechanism underlying this observation remains to be clarified, it may have important implications for the development of cardiovascular disease in patients with OSA and for the life saving effect of CPAP.

Case-Control Studies↗
PubMed2000

PAF-induced synthesis of tetraenoic and pentaenoic leukotrienes in the isolated rabbit lung.

In an isolated rabbit lung model, we tested the hypothesis that platelet-activating factor (PAF)-induced leukotriene (LT) synthesis is critically dependent on the free precursor fatty acid supply and the possible substitution of arachidonic acid (AA) by eicosapentaenoic acid (EPA). To augment the intravascular polymorphonuclear neutrophils (PMNs) in the isolated lung, human PMNs were infused into the pulmonary artery. LTs and hydroxyeicosatetra(penta)enoic acids were quantified with HPLC techniques. Application of PAF (5 microM) or AA (10 microM) provoked the generation of limited quantities of 4-series LTs and 5-hydroxyeicosatetraenoic acid (total sum of 5-lipoxygenase products approximately 7 and approximately 27 pmol/ml in lungs both with and without infused PMNs, respectively). Combined administration amplified 5-lipoxygenase product formation, with a predominance of cysteinyl-LT synthesis in lungs both without (total sum approximately 67 pmol/ml) and, much more strikingly, with (total sum approximately 308 pmol/ml) an infusion of neutrophils. EPA (10 microM) elicited exclusive generation of 5-series LTs and 5-hydroxyeicosapentaenoic acid (total sum approximately 82 pmol/ml). Dual stimulation with PAF and EPA provoked amplification of EPA-derived 5-lipoxygenase product formation, again with predominance of cysteinyl-LTs in lungs without (total sum approximately 224 pmol/ml) and, in particular, with (total sum approximately 545 pmol/ml) preceding microvascular PMN entrapment. Combined application of PAF, AA, and EPA resulted in the synthesis of LTs derived from both fatty acids, with a predominance of 5-series products. We conclude that the PAF-evoked 5-lipoxygenase product formation in the neutrophil-harboring lung capillary bed is critically dependent on intravascular precursor fatty acid supply, with EPA representing the preferred substrate compared with AA. PMN-related transcellular eicosanoid synthesis is suggested to underlie the predominant generation of cysteinyl-LTs. The supply of n-3 versus n-6 precursor fatty acid may thus have a major impact on inflammatory mediator generation.

Animals↗