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Biomedical subjects

C Kroegel

Publications and source records attributed to C Kroegel.

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

[Asthmatic airway inflammation].

Asthma is an inflammatory disease of the airways even in its clinically mildest manifestation. The pathogenesis is based on complex interactions between inflammatory cells, soluble signal molecules (mediators) and structural cells as well as extracellular components of the airways. Bronchial inflammation is closely associated with bronchial hyperreactivity, airways obstruction and asthmatic symptoms. Airways inflammation causes airflow limitation via (1) acute muscular bronchoconstriction, (2) formation of mucous plugs, (3) thickening of the airway wall, and (4) fibrotic remodelling of the airways ("Remodelling"). The insights into bronchial inflammation as the basis of asthma is of principle significance for the diagnosis, prevention, and treatment of the condition.

Asthma↗
PubMed2001

[Asthma therapy for adults].

The goal of asthma management is to achieve control of the condition. This essentially requires environmental control measures (allergen avoidance) and patient training and education. Drug treatment comprises anti-inflammatory (corticosteroids), and bronchodilatory controller therapy (long-acting beta 2-sympathomimetics, leukotriene receptor antagonists, retarded theophylline) as well as bronchodilatory medication as required (short-acting beta 2-sympathomimetics). The number and frequency of pharmacologic therapy relates to the severity of the clinical presentation. The combination of certain controller drugs (corticosteroids with long-acting beta 2-agonists, corticosteroids with leukotriene receptor antagonists, and beta 2-agonists with leukotriene receptor antagonists) yields a synergistic therapeutic effect as well as a compliance advantage.

Adult↗
PubMed2000

[Diagnosis of pulmonary embolism by transthoracic sonography. Sono-morphologic characterization of pulmonary lesions and comparison with spiral computed tomography].

BACKGROUND AND OBJECTIVE: Pulmonary embolism often extends to pleural surfaces, resulting in pleural-based parenchymal lesions. This study was carried out in order to evaluate the clinical value of transthoracic sonography (TS) for the diagnosis of pulmonary embolism. PATIENTS AND METHODS: A prospective study was performed in 45 patients (27 men, 18 women; mean age: 63.4 years; range: 24-88 years) with suspected pulmonary embolism. Transthoracic sonography was performed in all patients. In addition, helical computed tomography (CT) was carried out in 40 patients. Other diagnostic procedures included the estimation of D-dimeres, echocardiography, venous duplex sonography of the legs and ventilation/perfusion scanning. The diagnosis of pulmonary embolism was accepted when an embolus was detected on CT or as a conclusive result of the other investigations. RESULTS: Pulmonary embolism was established in 33 patients. Peripheral parenchymal lesions suspicious of pulmonary embolism were detected by transthoracic sonography in 26 patients (79%). In seven patients with central pulmonary embolism diagnosed by CT, no peripheral lesions could be detected by sonography. One patient with sonographic signs of pulmonary embolism had a diffuse bronchogenic adenocarcinoma which was diagnosed on autopsy. The sensitivity of transthoracic sonography (computed tomography) for pulmonary embolism was 79% (76%) and the specificity 92% (100%). The positive and negative predictive values of transthoracic sonography for the detection of pulmonary embolism were 96% and 61% (100% and 61%), respectively. The accuracy was 82% (82%). CONCLUSIONS: A substantial number of pulmonary emboli involve the peripheral lung areas. Transthoracic sonography is a non-invasive technique for diagnosing such parenchymal alterations and may serve as an alternative method in the diagnosis of pulmonary embolism.

Adenocarcinoma↗
PubMed2000

Putting priming into perspective - from cellular heterogeneity to cellular plasticity.

The concept of priming is widely used in cell biology and has come to mean the functional enhancement of a given cell by cytokines. 'Primed' cells have a number of other cellular alterations, although the relationship between functional and phenotypical diversity has not been established. Here, Claus Kroegel and colleagues discuss the dynamic nature of inflammatory-cell priming, which might be part of a broader means of comprehending cell function in disease.

Cell Adhesion Molecules↗
PubMed2000

[Molecular mechanisms of signal transduction in the framework of CD95 and CD65 receptor-induced apoptosis of human eosinophilic granulocytes. Effect on GM-CSF mediated viability and relationship to intracellular bcl-2 expression].

Infiltration of eosinophils into the airways plays a central role in the pathophysiology of asthma. Human blood eosinophils express apoptosis-inducing receptors (e.g. CD95R and CD69R) regulating both viability and survival and, thus, the extent of eosinophil infiltration into the airways. Signal transduction processes induced by occupation of the CD69 receptor expressed by eosinophils are insufficiently known. Purified human peripheral blood eosinophils (MACS, purity > 99%) were pre-incubated with a GM-CSF for 18 h and stimulated with alpha-CD69mAb (clon TP1/55), alpha-CD95mAb (clon CH-11), and as a control alpha-CD11bmAb (clon Bear-1). The specificity of receptor ligation was assessed using a blocking mAb (Klon ZB4). Phenotype, viability, apoptosis and bcl-2-expression were measured employing flow cytometry. alpha-CD95mAb (1 microgram/ml) induced apoptosis both in control and GM-CSF (10 ng/ml) treated eosinophils. Similarly, alpha-CD69mAb (10 micrograms/ml) induced apoptosis of GM-CSF-stimulated CD69+ cells after an incubation period of 114 h which was not affected by a CD95 blocking mAb. Naive eosinophils showed a basale, bcl-2-expression, which decreased to 30% after 66 h. In the presence of GM-CSF, intracellular bcl-2-concentration remained unchanged. Following stimulation with alpha-CD69mAb or alpha-CD95mAb, a dose-dependent decline of the bcl-2-expression was detected, whereas alpha-CD11bmAb (10 micrograms/ml) had no effect. The data suggest that both CD95R- and CD69R-induced apoptosis of human eosinophils involves a bcl-2-dependent signal transduction mechanism.

Antibodies, Monoclonal↗
PubMed2000

Bilateral symmetrical upper-lobe opacities: an unusual presentation of bronchiolitis obliterans organizing pneumonia.

A 45-year-old man was admitted with nonresolving fever, cough, and dyspnea 2 months after a common cold. His chest radiograph demonstrated bilateral symmetrical upper-lobe opacities reminiscent of tuberculosis. Transbronchial biopsy revealed inflammatory nonspecific alveolar lesions suggestive of bronchiolitis obliterans organizing pneumonia, which responded well clinically and radiologically to oral corticosteroids. Here, the case of a previously unreported radiographic manifestation of bronchiolitis obliterans organizing pneumonia is presented.

Administration, Oral↗
PubMed1999

Modulation of cytokine release from mononuclear cells by prostacyclin, IL-4 and IL-13.

In a previous study, we reported that cicaprost, a stable prostacyclin analogue can inhibit the release of granulocyte-macrophage colony-stimulating factor (GM-CSF) from activated human peripheral mononuclear blood cells (PBMCs). Since interleukin (IL-4) and IL-13 have been shown to inhibit the release of cytokines from PBMCs we tested the hypothesis that prostacyclin in combination with IL-4 or IL-13 can act synergistically to modulate the release of IL-10, generally associated with anti-inflammatory properties, and the pro-inflammatory cytokine tumour necrosis factor alpha (TNF-alpha). For this purpose, PBMCs were isolated over Ficoll, stimulated with lipopolysaccharide (LPS) and incubated in the presence of cicaprost, IL-4 or IL-13. There was a significant reduction in TNF-alpha as well as IL-10 secretion from LPS-stimulated PBMCs following incubation with IL-4 or IL-13. In contrast, cicaprost reduced the secretion of TNF-alpha but led to a slight enhancement of IL-10 release from PBMCs. When LPS-activated PBMCs were incubated in the presence of cicaprost and IL-4 or IL-13 there was a selective, synergistic inhibition of the TNF-alpha release which was not observed for IL-10. Thus, our data suggest that prostacyclin can synergize with cytokines to selectively inhibit the release of pro-inflammatory cytokines from PBMCs.

Cell Survival↗
PubMed1999

CD69 surface expression on human lung eosinophils after segmental allergen provocation.

CD69 expression on eosinophils is observed in asthma and has been proposed as a marker of eosinophil activation. The role of allergens in the in vivo regulation of CD69 expression on eosinophils, however, remains incompletely understood. It was therefore investigated whether CD69 expression on eosinophils can be induced by allergen provocation in vivo. Ten allergic asthmatics were studied by segmental allergen provocation. Two segments of the right and left lung were challenged with allergen or saline. CD69 expression was determined by flow cytometry and concentrations of interleukins were analysed by enzyme-linked immunosorbent assay in bronchoalveolar lavage (BAL) fluid. Expression of CD69 on BAL eosinophils in the segments lavaged 10 min following saline instillation (28.3+/-8.8 specific mean fluorescence (SMF)) was not significantly different to segments lavaged 10 min after allergen (80.2+/-21.8 SMF) and segments lavaged 18 h after saline challenge (87.2+/-23.3 SMF). However, CD69 expression on eosinophils increased significantly 18 h after allergen challenge (128.6+/-21.9 SMF, p<0.03) which was accompanied by elevated granulocyte-macrophage colony-stimulating factor (GM-CSF) concentrations (114.9+/-42.9 pg x mL(-1), p<0.05). CD69 expression on eosinophils and GM-CSF concentrations correlated 18 h following allergen provocation (r = 0.7, p<0.025). These results suggest that in allergic asthma there is an allergen dependent, endobronchial upregulation of eosinophil activation as assessed by CD69 expression on eosinophils.

Adult↗
PubMed1999

Leukocyte infiltration and secretion of cytokines in pleural drainage fluid after thoracic surgery: impaired cytokine response in malignancy and postoperative complications.

STUDY OBJECTIVE: To assess the postoperative course of pleural leukocyte counts and cytokine concentrations in patients with malignant and nonmalignant lung disease who underwent thoracic surgery. PATIENTS AND INTERVENTIONS: A total of 21 patients undergoing thoracic surgery were included in the study. Twelve patients had a malignant disease, and 9 had a nonmalignant disease. Six patients underwent video-assisted thoracoscopy and 15 underwent thoracotomy. Pleural drainage fluid from the chest tubes was collected postoperatively at Oh, 3h, 6h, 12h, 24h, 48h, 72h, and 96 h. The same schedule, as well as one additional preoperative sample, was applied for blood collections. RESULTS: A trend toward lower concentrations of tumor necrosis factor-alpha (TNF-alpha), granulocytemacrophage colony-stimulating factor, and interleukin-10 was observed in patients with malignant disease compared to those without malignancy. These differences achieved significance for TNF-alpha in the drainage fluid of those patients with nonmalignant disease who had undergone formal thoracotomy. Patients with malignant disease showed significantly lower macrophage fractions in drainage fluid and lymphocyte fractions in serum. All patients with complications had malignant disease and showed the lowest cytokine concentrations, as well as the lowest fractions of both macrophages in drainage fluid and lymphocytes in serum. CONCLUSION: The data suggest that malignancy may lead to impairment of the wound-healing process via modification of the inflammatory cell infiltrate and locally released cytokines.

Adult↗
PubMed1998

Differential regulation of CD95 (Fas/APO-1) expression in human blood eosinophils.

CD95 (Fas, APO-1) is a cell surface receptor expressed on many cells including eosinophils which mediates apoptosis when ligated by agonistic antibodies or its natural ligand FasL. Since inhibition of apoptosis may play an important role in controlling tissue eosinophilia, we investigated the expression of CD95 on purified peripheral blood eosinophils from normal donors. Freshly isolated eosinophils expressed CD95 on the cell surface as well as CD95-specific mRNA at low levels which did not change during 24-h culture. Incubation of eosinophils with IL-3, IL-5 and granulocyte-macrophage colony-stimulating factor (GM-CSF) did not modulate the basal expression of CD95. IFN-gamma as well as TNF-alpha, however, induced a significant, dose- and time-dependent increase in CD95 mRNA and cell surface expression as measured by reverse transcription-PCR and flow cytometry. Co-stimulation with IFN-gamma and TNF-alpha had synergistic effects on the CD95 surface expression on eosinophils. Addition of IL-3, IL-5 or GM-CSF to IFN-gamma- and TNF-alpha-stimulated eosinophils caused in a reduction of CD95 expression. Functional activity for CD95 following incubation with IFN-gamma and TNF-alpha was demonstrated by increased apoptosis in response to cross-linking with FasL. From these data, we conclude that IFN-gamma and TNF-alpha can up-regulate cell surface expression of CD95 on eosinophils, which leads to an increased susceptibility of eosinophils to Fas-mediated apoptosis. Thus, our results suggest that receptors involved in eosinophil apoptosis can be regulated by antagonistic cytokines.

Apoptosis↗
PubMed1998

Evidence for eosinophil activation in bronchiectasis unrelated to cystic fibrosis and bronchopulmonary aspergillosis: discrepancy between blood eosinophil counts and serum eosinophil cationic protein levels.

BACKGROUND: Increased serum levels of eosinophil cationic protein (ECP) have been detected in adolescent patients with cystic fibrosis. However, ECP concentrations in adult patients with bronchiectasis unrelated to cystic fibrosis have not been studied. METHODS: Eosinophil numbers and serum concentrations of ECP were determined in 14 patients with known or newly diagnosed bronchiectasis and compared with age and sex matched patients with allergic bronchial asthma, chronic obstructive pulmonary disease (COPD), and controls in whom bronchiectasis or obstructive pulmonary disease could be excluded. RESULTS: Serum ECP levels were significantly raised both in patients with bronchiectasis (median (range) 22.5 micrograms/l (7-85)) and allergic asthma (35.0 micrograms/l (7-128)) compared with the sex and age matched subjects suffering from COPD (6.7 micrograms/l (1.5-28); p < 0.006) and non-obstructive normal controls (7.5 micrograms/l (3.5-19); p < 0.003). In contrast, significantly increased peripheral eosinophil numbers were observed in patients with bronchial asthma (305 x 10(6)/l; p < 0.01) but not in those with bronchiectasis (10(2) x 10(6)/l), COPD (117 x 10(6)/l), and healthy controls (101 x 10(6)/l). CONCLUSIONS: The discrepancy between eosinophil counts and eosinophil numbers in patients with bronchiectasis suggests that serum ECP levels may be more relevant in assessing local eosinophil involvement than blood eosinophil numbers.

Adult↗