Claus Kroegel

Current role of emergency ultrasound of the chest.

Objective:Chest sonography has gained clinical significance in the diagnosis of various pulmonary, pleural, cardiac, and mediastinal emergency conditions. Therefore, the current role of emergency ultrasound are assessed. Data Source:A systematic literature search of MEDLINE database was performed to identify all studies dealing with transthoracic sonography/chest ultrasound in combination with pulmonary embolism, pneumothorax, pneumonia, pleural effusion, pulmonary edema, and lung contusion. The relevant sonographic studies between 1988 and 2010 were evaluated. Conclusions:The noninvasive ultrasound-based diagnosis is relatively portable permitting the technique to be performed at any time, in any place, and on any patient, an ideal method for emergency conditions. Sonography allows immediate diagnosis of pulmonary embolism, pneumothorax, pneumonia, pleural effusion as well as rib fracture, and it provides a basis for further diagnostic- and treatment-related decisions. The key sonographic features associated with these most common emergency chest diseases are illustrated herein.

Inflammatory determinants of asthma severity: Mediator and cellular changes in bronchoalveolar lavage fluid of patients with severe asthma

Cellular and mediator profiles in bronchoalveolar lavage have not been compared systematically between patients with asthma of different severities, mainly because the patients with more severe asthma have an increased need for antiinflammatory medication. Information is limited to comparisons of allergic and intrinsic asthma, which can be distinguished clinically. When patients from these two groups with similar degrees of bronchial hyperresponsiveness were compared, both groups showed increased numbers of activated T-helper lymphocytes; those in the allergic group expressed the IL-2 receptor (CD25+), whereas in patients with intrinsic asthma there was also an increased number of T-suppressor cells with the activation markers CD25, class II histocompatibility antigen, and very late activation antigen-I, as well as T-helper cells class II histocompatibility antigen and very late activation antigen-I. This pattern is compatible with a more chronic T-cell activation in patients with intrinsic asthma. In patients with allergic asthma the cytokine pattern is compatible with a pure TH2 response (elevated IL-4 and IL-5); however, intrinsic asthma is characterized by elevated IL-5 and IL-2 but not IL-4. Our own findings show similar concentrations of IL-1, IL-8, and granulocyte-macrophage colony-stimulating factor in bronchoalveolar lavage fluid of patients with allergic and intrinsic asthma, whereas IL-6 and interferon-gamma tended to be higher in patients with intrinsic asthma. There are probably fundamental differences in the pathogenesis of allergic and intrinsic asthma. These findings suggest that asthma does not depend on the presence of IgE or IL-4, although both may contribute to the pathogenesis of atopic asthma. The only common pathway in the different presentations of asthma that has been related to clinical symptoms appears to be IL-5-mediated activation of eosinophils; therapies aimed at this mechanism may be promising.

Evidence for two platelet activating factor receptors on eosinophils: Dissociation between PAF-induced intracellular calcium mobilization degranulation and superoxides anion generation in eosinophils

We have compared platelet activating factor (PAF)-induced eosinophil peroxidase (EPO) release and intracellular calcium mobilization with superoxide anion (.O2-) generation from guinea pig eosinophils. EPO release and Ca2+ mobilization occurred at lower concentrations of PAF (EC50 values of 1.3 nM and 11.5 nM, respectively) while .O2- production was observed at higher concentrations (EC50 of 31.7 microM). Receptor characterization with the competitive PAF antagonist, WEB 2086, gave pA2 values of 8.5 and 8.3 for EPO enzyme release and rise in [Ca2+]i, respectively, and 5.8 for the .O2- production. In addition, PAF-induced degranulation and elevation of [Ca2+]i were dependent on extracellular Ca2+ whereas PAF-stimulated .O2- generation was dependent on the presence of extracellular Mg2+ ions. These results suggest the existence either of two subtypes of the PAF receptor or a single receptor that can exist in one of two affinity states on guinea pig eosinophils.

Human γδ-T Lymphocytes Express and Synthesize Connective Tissue Growth Factor: Effect of IL-15 and TGF-β1 and Comparison with αβ-T Lymphocytes

T lymphocytes bearing the γδ-TCR accumulate during wound healing and inflammation. However, the role of γδ-T lymphocytes in fibrogenic tissue reactions is not well understood. Therefore, we addressed the question of whether human γδ-T cells express and synthesize connective tissue growth factor (CTGF), a factor known to regulate fibrogenesis and wound healing. In addition, the lymphoblastic leukemia T cell line (Loucy) that possesses characteristics typical of γδ-T cells was used as a model to evaluate the regulation of CTGF gene expression. Blood γδ-T cells isolated from healthy donors were grown in the presence of IL-15/TGF-β1 for 48 h and assessed for the expression and synthesis of CTGF. Nonstimulated human blood γδ-T cells and Loucy γδ-T cells expressed low levels of CTGF mRNA. Costimulation of the cells with IL-15 and TGF-β1 resulted in a substantially increased level of CTGF mRNA expression within 4–8 h, and it remained elevated for at least 48 h. In contrast, no CTGF mRNA was detected when nonstimulated and stimulated human CD4+ αβ-T cells were analyzed. In addition, Western blot analysis of human γδ-T cell lysates prepared 4 days following stimulation with IL-15 and TGF-β1 revealed a 38-kDa CTGF protein in cell lysates of human γδ-T cells. Detection was confirmed using Colo 849 fibroblasts, which can constitutively express high levels of CTGF. In conclusion, we herein present novel evidence that in contrast to CD4+ αβ-T cells human γδ-T cells are capable of expressing CTGF mRNA and synthesizing its corresponding protein, which supports the concept that γδ-T cells may contribute to wound healing or tissue fibrotic processes.

Characterization of platelet-activating factor-induced elevation of cytosolic free calcium concentration in eosinophils

In order to evaluate the role of calcium in the activation processes in eosinophils induced by platelet‐activating factor (PAF), we investigated the changes in free cytoplasmatic Ca2+ concentration using fura‐2. PAF causes a rapid and transitory rise of the intracellular free calcium ion concentration ([Ca2+]i) in purified guinea pig eosinophils of approx. 1000 nM above a basal level of 120.7 ± 36.5 nM (n = 10). The effect was dose‐related with a maximum rise at 1000 nM PAF and an EC50 of 17.4 nM and specifically inhibited by the PAF antagonist WEB 2086 with an IC50, of 95.5 nM. WEB 2086 did not affect either the leukotriene B4‐ or the fMet‐Leu‐Phe‐induced elevation of [C2+]i. The response to PAF was dependent on external Ca2+ as it was significantly inhibited by EGTA (85.6 ± 5.4%) and Ni2+ (95.8 ± 2.1 %) but not by the dihydropyridine antagonist nimodipine. We conclude that Ca2+ entry via receptor‐operated Ca2+ channels may be involved in PAF‐induced degranulation of eosinophils.

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‐γ as well as TNF‐α, 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‐γ and TNF‐α had synergistic effects on the CD95 surface expression on eosinophils. Addition of IL‐3, IL‐5 or GM‐CSF to IFN‐γ‐ and TNF‐α‐stimulated eosinophils caused in a reduction of CD95 expression. Functional activity for CD95 following incubation with IFN‐γ and TNF‐α was demonstrated by increased apoptosis in response to cross‐linking with FasL. From these data, we conclude that IFN‐γ and TNF‐α 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.

Platelet-activating factor stimulates a rapid accumulation of inositol (1,4,5)trisphosphate in guinea pig eosinophils: Relationship to calcium mobilization and degranulation

The effect of platelet-activating factor (PAF) on inositol (1,4,5)trisphosphate (Ins[1,4,5]P3) mass, calcium mobilization, and the release of granule enzymes was studied on guinea pig peritoneal eosinophils (EOSs). PAF evoked a concentration-dependent accumulation of Ins(1,4,5)P3 with a drug concentration that elicits 50% of the maximum attainable response (EC50) of 10 nmol/L; the production of this second messenger was maximal at 1 mumol/L of PAF. Kinetic analysis of PAF (1 mumol/L)-induced Ins(1,4,5)P3 accumulation demonstrated it to be transient with a 3.8-fold increase over resting levels observed at 5 seconds. Thereafter, the level of Ins(1,4,5)P3 declined, returning to vehicle-treated levels 60 seconds after PAF challenge. Lyso-PAF, the inactive precursor and metabolite of PAF, was inactive at all concentrations examined. PAF also induced a rapid, concentration-dependent (EC50, 12 nmol/L) rise in the cytosolic-free calcium concentration ([Ca++]i) in fura 2-AM-loaded EOSs that was transient, peaking after the maximum increase in Ins(1,4,5)P3 mass was observed. A highly significant positive correlation was found between the peak increase in Ins(1,4,5)P3 and the peak rise in [Ca++]i. Functionally, PAF evoked a concentration-dependent release of granule constituents from both the small (arylsulfatase B; EC50, 3 nmol/L) and specific (EOS peroxidase; EC50, 2.7 nmol/L) granules that lagged, temporally, behind both Ins(1,4,5)P3 accumulation and the rise in [Ca++]i. Both the biochemical and functional effects of PAF examined in this study were antagonized by WEB 2086 (300 nmol/L), a selective PAF receptor-blocking drug. It is concluded that stimulus (PAF)-response coupling in guinea pig peritoneal EOSs may involve the receptor-mediated formation of Ins(1,4,5)P3 and subsequent release of intracellularly stored Ca++. This sequence of events may link PAF receptor activation to Ca(++)-dependent cellular responses, such as degranulation.

Expression and synthesis of fibroblast growth factor-9 in human γδ T-lymphocytes. Response to isopentenyl pyrophosphate and TGF-β1/IL-15

γδ T‐lymphocytes are believed to play a role in maintaining the normal configuration of epithelial tissue. As little is known about the factors mediating this function, we addressed the question of whether γδ T‐lymphocytes produce fibroblast growth factor (FGF)‐9 as well as two other growth factors associated with epithelial tissue reconstitution. Blood γδ T cells isolated from healthy donors were grown in the presence of isopentenyl pyrophosphate (IPP) or transforming growth factor‐β1 (TGF‐β1)/interleukin‐15 (IL‐15) for 24 h and were assessed for the expression and synthesis of FGF‐9, keratinocyte growth factor (KGF), and epidermal growth factor (EGF). Resting human γδ T cells constitutively expressed KGF and FGF‐9 mRNA but no EGF mRNA. In the presence of IPP, FGF‐9 mRNA expression significantly increased in a dose‐dependent manner, expression of KGF remained unaltered, and EGF mRNA could not be detected. In contrast to IPP, stimulation of the cells with TGF‐β1/IL‐15 did not alter FGF‐9 expression. Moreover, stimulation with anti‐CD3 does not induce FGF‐9 expression but triggers a high signal of interferon‐γ mRNA. Western blot analysis of γδ T cell lysates, prepared 4 days following stimulation with IPP, showed an increase of FGF‐9 protein as compared with control cells. In conclusion, the results demonstrate for the first time that human blood and bronchoalveolar lavage γδ T‐lymphocytes are capable of expressing FGF‐9. The data also provide novel evidence that immunoregulatory cells can synthesize FGF‐9.

Asthmatherapie bei Kindern und Erwachsenen

Zie le 9 Vermeidung von Asthmaanf~llen, 9 Wiederherstellung und Erhaltung einer normalen oder bestm6glichen Lungenfunktion, o Verhinderung einer krankheitsbedingten BeeintrSchtigung der k6rperlichen Aktivit~iten und der physischen und geistigen Entwicklung. ~1 Meidung von Anfallsausl6sem 9 Rauchen aktiv und passiv, 9 Umweltallergene sowie Allergene und inhalative Noxen am Arbeitsplatz, 9 Betarezeptorenblocker in jeder Darreichungsform, bei bekannter • empfindlichkeit: 0 Acetylsalicyls2iure, 0 weitere nichtsteroidale Antiphlogistika.

The role of eosinophils in asthma

During recent years it has become apparent that the eosinophil may represent a powerful effector cell in the pathogenesis of asthma, particularly in the late asthmatic response. It can be stimulated by a number of stimuli among which PAF appears to be one of the most effective. The eosinophil is a source for a variety of proinflammatory and toxic products with profound effects in the lungs and airways. These eosinophil products mimic some of the features of asthma and the strong association of the eosinophil with asthma has led to the suggestion that asthma would be better classified as “chronic desquamating eosinophilic bronchitis.” Although the evidence known to date is persuasive many questions still remain unanswered and await further investigation. Future therapeutic approaches in asthma may aim at interrupting the mechanisms leading to eosinophil bronchial accumulation and activation.