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591.
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Grunstein M. M.; Springer C.; Godfrey S.; Bar-Yishay E.; Vilozni D.; Inscore S. C.; Schramm C. M. 《Journal of applied physiology》1987,62(5):2107-2114
During breathing under sedation via a two-way valve, airflow (V), volume (delta V), and airway pressure (P) were recorded in eight normal (N) infants, seven with reversible obstructive airway disease (ROAD), and seven with chronic lung disease (CLD). Intermittently, expiratory volume clamping (EVC) was applied, involving selective occlusion of the expiratory valve for three to five breaths. The latter produced cumulative increases in delta V that, due to progressive recruitment of the Hering-Breuer reflex, were accompanied by increasing expiratory plateaus in P (i.e., apneas). The resultant passive inflation delta V-P relationships were closely approximated by the expression: delta V = aP2 + bP + c, wherein a represented the pressure-related changes in chord compliance (Crs), b the Crs at P = 0, and c the difference between the dynamic end-expiratory and relaxation volumes of the respiratory system. Relative to N, the ROAD and CLD infants had significantly reduced weight-specific values of a/kg, their b/kg values were increased, whereas the c/kg measurements did not significantly vary. Moreover, for each subject we determined the net Crs/kg obtaining at P = 20 cmH2O (i.e., Crs20/kg), an estimate of the net deflation compliance; the passive respiratory time constant (tau rs) based on the slope of the expired delta V/V relationship; and the respiratory system conductance (Grs/kg). Relative to N, the mean Crs20/kg was significantly reduced only in the infants with CLD and, due to increases in tau rs, both patient groups depicted significantly diminished values of Grs/kg, suggesting the presence of airways obstruction.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
594.
H Fehlhammer M Schiffer O Epp P M Colman E E Lattman P Schwager W Steigemann H J Schramm 《Biophysics of structure and mechanism》1975,1(2):139-146
The structure of a pi-type Bence-Jones protein variable fragment Au has been determined by molecular replacement methods using the known structure of an other Bence-Jones variable fragment Rei (Epp et al., Eur J. Biochem. 45, 513 (1974). The crystallographic R factor is 0.31 for about 4000 significantly measured reflections between 6.8 to 2.5 A. The Au protein forms a dimer across a crystallographic two fold axis. The spatial relationship of the two monomers, the conformation of the backbones and of the internal residues is extremely similar to that found in Rei. 相似文献
595.
Kevin K. Takaki Francisco J. Roca Gabriele Schramm Ruud H. P. Wilbers Wannaporn Ittiprasert Paul J. Brindley Gabriel Rinaldi Matthew Berriman Lalita Ramakrishnan Antonio J. Pagn 《PLoS neglected tropical diseases》2021,15(1)
Infections by schistosomes result in granulomatous lesions around parasite eggs entrapped within the host tissues. The host and parasite determinants of the Schistosoma mansoni egg-induced granulomatous response are areas of active investigation. Some studies in mice implicate Tumor Necrosis Factor (TNF) produced in response to the infection whereas others fail to find a role for it. In addition, in the mouse model, the S. mansoni secreted egg antigen omega-1 is found to induce granulomas but the underlying mechanism remains unknown. We have recently developed the zebrafish larva as a model to study macrophage recruitment and granuloma formation in response to Schistosoma mansoni eggs. Here we use this model to investigate the mechanisms by which TNF and omega-1 shape the early granulomatous response. We find that TNF, specifically signaling through TNF receptor 1, is not required for macrophage recruitment to the egg and granuloma initiation but does mediate granuloma enlargement. In contrast, omega-1 mediates initial macrophage recruitment, with this chemotactic activity being dependent on its RNase activity. Our findings further the understanding of the role of these host- and parasite-derived factors and show that they impact distinct facets of the granulomatous response to the schistosome egg. 相似文献
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597.
A complete overview on all possible hydrogen bonding patterns of double helices with antiparallel and parallel strand orientation in α‐peptide sequences is provided on the basis of ab initio molecular orbital theory. The most stable representatives belong to the group of antiparallel helices. The study on side chain influence shows that these double helices can only be realized if the strands are composed of L ‐ and D ‐amino acids in alternate order. The stability of the double helices is compared with that of competing single‐stranded helices. The data contribute to an understanding of secondary structure formation in peptides and provide a basis for a rational design of membrane channels. Copyright © 2010 European Peptide Society and John Wiley & Sons, Ltd. 相似文献
598.
Linda Hink Anja Holzinger Tobias Sandfeld Alfons R. Weig Andreas Schramm Heike Feldhaar Marcus A. Horn 《Environmental microbiology》2023,25(12):2776-2791
Microplastic (MP) is an environmental burden and enters food webs via ingestion by macrofauna, including isopods (Porcellio scaber) in terrestrial ecosystems. Isopods represent ubiquitously abundant, ecologically important detritivores. However, MP-polymer specific effects on the host and its gut microbiota are unknown. We tested the hypothesis that biodegradable (polylactic acid [PLA]) and non-biodegradable (polyethylene terephthalate [PET]; polystyrene [PS]) MPs have contrasting effects on P. scaber mediated by changes of the gut microbiota. The isopod fitness after an 8-week MP-exposure was generally unaffected, although the isopods showed avoidance behaviour to PS-food. MP-polymer specific effects on gut microbes were detected, including a stimulation of microbial activity by PLA compared with MP-free controls. PLA stimulated hydrogen emission from isopod guts, while PET and PS were inhibitory. We roughly estimated 107 kg year−1 hydrogen emitted from the isopods globally and identified their guts as anoxic, significant mobile sources of reductant for soil microbes despite the absence of classical obligate anaerobes, likely due to Enterobacteriaceae-related fermentation activities that were stimulated by lactate generated during PLA-degradation. The findings suggest negative effects of PET and PS on gut fermentation, modulation of important isopod hydrogen emissions by MP pollution and the potential of MP to affect terrestrial food webs. 相似文献
599.
The in vitro experiments show that the anticoagulant affect of a new AT III-Heparin-complex preparation in plasma is similar to heparin. The in vivo experiments indicate that the thrombin inhibition is even improved by using the complex preparation, because the aPTT values after complex treatment remained stable for more than one hour in the desired range. Bleeding complications are less likely after complex treatment, because much smaller maximum aPTT values are reached. The prolonged half life of the complex preparation possibly allows a reduced and more accurate dosage. 相似文献
600.
H Daube A Billich K Mann H J Schramm 《Biochemical and biophysical research communications》1991,178(3):892-898
Phosphorylase kinase and calcium-free calmodulin are digested by human immunodeficiency virus-1 protease. In phosphorylase kinase, the alpha subunit is preferentially hydrolyzed at arg748-val749. The beta subunit is cleaved only slowly at leu678-pro679, and calmodulin, the integral delta subunit of phosphorylase kinase, is not cleaved at all. However, free calmodulin in the calcium-depleted form showed to be a good substrate for the protease. Here the cleavage occurs at phe65-pro66 and met71-met72. This fast hydrolysis of free calmodulin can be blocked by micromolar concentrations of Ca2+ or millimolar concentrations of Mg2+. 相似文献