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Early markers of oxygenator dysfunction during prolonged use of extracorporeal membrane oxygenation (ECMO) are important for timely exchange to avoid sudden loss of function due to clot formation within the system. The measurement of d-dimers (DDs) in plasma might be a marker for early diagnosis of thrombus formation and dysfunction of heparin-coated membrane oxygenators (MOs). This is a retrospective study on prospectively collected data of 24 adult acute respiratory distress syndrome patients requiring long-term veno-venous ECMO with at least 1 MO exchange. Kinetics of coagulation, inflammation, and oxygenator function were analyzed before and after MO exchange. Median (interquartile range) support duration is 20 (15-29) days. Thirty-four MOs had to be replaced. Exchange occurred due to visible thrombus formation in the MO (n = 16), worsening gas exchange (n = 11), increased blood flow resistance (n = 1), and activation of coagulation with diffuse bleeding (n = 6). In 15 cases, DDs were continuously elevated and, therefore, not suitable as marker for MO exchange. In the remaining 19 cases, DDs increased significantly within 3 days before exchange from 15 (9-20) to 30 (21-35) mg/dL (P = .002) and declined significantly within 1 day thereafter to 13 (7-17) mg/dL (P = .003). An increase in plasma DD concentration in absence of other explaining pathology can be helpful in predicting an MO exchange in miniaturized heparin-coated ECMO systems.

The aim of this study was to investigate the basal level as well as the tumor necrosis factor (TNF)-α- and interferon (IFN)-γ-induced expression and release of the neutrophil chemoattractants interleukin (IL)-8 and growth-related oncogene (GRO)-α in primary bronchial epithelial cells (PBECs) from smokers without airflow obstruction and patients with COPD. In addition, the expression of both TNF-α-receptor subtypes—p55 TNF-receptor subtype (TNF-R55) and p75 TNF-receptor subtype (TNF-R75)—was quantified in PBECs. PBECs from eight smokers without airflow limitation and eight patients with COPD were stimulated with 50 ng/mL of TNF and 200 U/mL of IFN-γ for 4 h along with unstimulated time controls. The transcriptional expression and protein release were quantitatively assessed by means of real-time polymerase chain reaction and enzyme-linked immunosorbent assay. Basal level messenger RNA (mRNA) expression and protein release of IL-8 and GRO-α were not significantly different between both groups, although a trend toward higher IL-8 levels was seen in patients with COPD. TNF-α induced significantly higher mRNA amounts of IL-8 (p = 0.005) and GRO-α (p = 0.007) in patients with COPD. This was accompanied by higher protein release data for IL-8 (p = 0.005) and GRO-α (p = 0.007). IFN-γ had no significant effect on the mRNA expression and protein release of IL-8 and GRO-α in either group. TNF-R55 and TNF-R75 were detectable in PBECs. However, no significant differences were found between both groups with respect to steady-state mRNA levels of TNF-α-receptor subtypes. PBECs from patients with COPD show significantly higher TNF-α-induced release of the neutrophil chemoattractant CXC-chemokines IL-8 and GRO-α compared to smokers without airflow limitation. This increased activation of PBECs may contribute to the predominance of neutrophils seen in the airway lumen of patients with COPD.

Background: The 6-min walk distance (6-MWD) is a global marker of functional capacity and prognosis in chronic obstructive pulmonary disease (COPD), but less explored in other chronic respiratory diseases. Objective: To study the role of 6-MWD in chronic hypercapnic respiratory failure (CHRF). Methods: In 424 stable patients with CHRF and non-invasive ventilation (NIV) comprising COPD (n = 197), restrictive diseases (RD; n = 112) and obesity-hypoventilation-syndrome (OHS; n = 115), the prognostic value of 6-MWD for long-term survival was assessed in relation to that of body mass index (BMI), lung function, respiratory muscle function and laboratory parameters. Results: 6-MWD was reduced in patients with COPD (median 280 m; quartiles 204/350 m) and RD (290 m; 204/362 m) compared to OHS (360 m; 275/440 m; p < 0.001 each). Overall mortality during 24.9 (13.1/40.5) months was 22.9%. In the 424 patients with CHRF, 6-MWD independently predicted mortality in addition to BMI, leukocytes and forced expiratory volume in 1 s (p < 0.05 each). In COPD, 6-MWD was strongly associated with mortality using the median [p < 0.001, hazard ratio (HR) = 3.75, 95% confidence interval (CI): 2.24–6.38] or quartiles as cutoff levels. In contrast, 6-MWD was only significantly associated with impaired survival in RD patients when it was reduced to 204 m or less (1st quartile; p = 0.003, HR = 3.31, 95% CI: 1.73–14.10), while in OHS 6-MWD had not any prognostic value. Conclusions: In patients with CHRF and NIV, 6-MWD was predictive for long-term survival particularly in COPD. In RD only severely reduced 6-MWD predicted mortality, while in OHS 6-MWD was relatively high and had no prognostic value. These results support a disease-specific use of 6-MWD in the routine assessment of patients with CHRF.

To the Editor: Schulman et al. (Oct. 30 issue) 1 state that their study of ximelagatran for the secondary prevention of venous thromboembolism was performed “in accordance with the Declaration of Helsinki and Good Clinical Practice.” However, 97 patients assigned to the placebo group had a history of recurrent venous thromboembolism, accounting for 16 percent of patients in this group. The current accepted international recommendation for patients with recurrent venous thromboembolism is 12 months of primary oral anticoagulant therapy. 2 Thus, the assignment of these patients to no therapy is a violation of the Helsinki Declaration. The authors should have studied the . . .

Visible light is an abundant source of energy. While the conversion of light energy into electrical energy (photovoltaics) is highly developed and commercialized, the use of visible light in chemical synthesis is far less explored. Chemical photocatalysts that mimic principles of biological photosynthesis utilize visible light to drive endothermic or kinetically hindered reactions. This work summarizes in 16 chapters the state of the art and the challenges of this emerging future technology.

In this chapter we report on the molecular biology of crystalline surface layers of different bacterial groups. The limited information indicates that there are many variations on a common theme. Sequence variety, antigenic diversity, gene expression, rearrangements, influence of environmental factors and applied aspects are addressed. There is considerable variety in the S-layer composition, which was elucidated by sequence analysis of the corresponding genes. In Corynebacterium glutamicum one major cell wall protein is responsible for the formation of a highly ordered, hexagonal array. In contrast, two abundant surface proteins form the S-layer of Bacillus anthracis. Each protein possesses three S-layer homology motifs and one protein could be a virulence factor. The antigenic diversity and ABC transporters are important features, which have been studied in methanogenic archaea. The expression of the S-layer components is controlled by three genes in the case of Thermus thermophilus. One has repressor activity on the S-layer gene promoter, the second codes for the S-layer protein. The rearrangement by reciprocal recombination was investigated in Campylobacter fetus. 7–8 S-layer proteins with a high degree of homology at the 5′ and 3′ ends were found. Environmental changes influence the surface properties of Bacillus stearothermophilus. Depending on oxygen supply, this species produces different S-layer proteins. Finally, the molecular bases for some applications are discussed. Recombinant S-layer fusion proteins have been designed for biotechnology.

In this chapter we report on the molecular biology of crystalline surface layers of different bacterial groups. The limited information indicates that there are many variations on a common theme. Sequence variety, antigenic diversity, gene expression, rearrangements, influence of environmental factors and applied aspects are addressed. There is considerable variety in the S‐layer composition, which was elucidated by sequence analysis of the corresponding genes. In Corynebacterium glutamicum one major cell wall protein is responsible for the formation of a highly ordered, hexagonal array. In contrast, two abundant surface proteins form the S‐layer of Bacillus anthracis. Each protein possesses three S‐layer homology motifs and one protein could be a virulence factor. The antigenic diversity and ABC transporters are important features, which have been studied in methanogenic archaea. The expression of the S‐layer components is controlled by three genes in the case of Thermus thermophilus. One has repressor activity on the S‐layer gene promoter, the second codes for the S‐layer protein. The rearrangement by reciprocal recombination was investigated in Campylobacter fetus. 7–8 S‐layer proteins with a high degree of homology at the 5′ and 3′ ends were found. Environmental changes influence the surface properties of Bacillus stearothermophilus. Depending on oxygen supply, this species produces different S‐layer proteins. Finally, the molecular bases for some applications are discussed. Recombinant S‐layer fusion proteins have been designed for biotechnology.