Antenatale Steroidgabe und pulmonales Outcome Frühgeborener

Multiple antenatale Steroidgaben zur Akzeleration der fetalen Lungenreife bei drohender Frühgeburtlichkeit wurde im Universitätsklinikum Münster bis 2000 durchgeführt. Entsprechend der Empfehlungen der ´National Institutes of Health` wurden ab 2001 nur noch eine einmalige antenatale Steroidgabe angestrebt. Ausgangspunkt dieser retrospektiven Arbeit war die Frage, ob diese Umstellung zu einem Anstieg von Häufigkeit und Schweregrad des Atemnotsyndroms bei Frühgeborenen geführt hat. Ferner wurde das Ausmaß der Assoziation zwischen ein- versus mehrmaliger Steroidgabe und dem pulmonalen Outcome untersucht. Erhoben wurden die Daten von 255 Frühgeborenen zwischen 23 und 32 vollendeten Schwangerschaftswochen. Es konnte kein signifikanter Anstieg der Atemnotsyndromhäufigkeit in den Jahren nach der Umstellung im Vergleich zu den Jahren vor der Umstellung nachgewiesen werden. Ein signifikanter Nachteil hinsichtlich des pulmonalen Outcomes nach ein- versus mehrmaliger Steroidgabe ergab sich nicht

INFLUENCE OF HOST CELL DEFENCE DURING INFLUENZA VACCINE PRODUCTION IN MDCK CELLS

For cell culture-based influenza vaccine production virus yield optimisation is of crucial importance. In particular, with the recent threat of the new H1N1 pandemic, not only seasonal vaccines but also pre-/pandemic vaccines have to be supplied in large quantities. In vivo influenza replication is limited by the immune system, but for production cell lines the impact of cellular defence mechanisms on virus yield is unknown. In influenza-infected adherent Madin-Darby canine kidney (MDCK) cells the interferon (IFN) response and subsequent induction of the antiviral state was monitored. Virus yield and host cell signalling intensity were strain-dependent. By over-expression of viral antagonists IFN-signalling could be reduced up to 90%. However, maximum virus titre determined by real-time PCR and HA-assay was not altered significantly. Stimulation of the antiviral state by conditioned medium led to enhanced IFN-signalling, which initially slowed down virus replication but had only minor effects on final virus titres. Interestingly, minireplicon assays revealed that canine Mx proteins are lacking the antiviral activity against influenza of their human or mouse counterparts. In summary, for MDCK cell culture-based influenza virus production host cell defence mechanisms seem to play only a minor role for final virus yields. Antiviral mechanisms of these epithelial cells may slow down influenza replication, which in vivo gains time for the immune system to be activated, but do not reduce maximum virus titres obtained in the bioprocess

Sleep scoring made easy Semi-automated sleep analysis software and manual rescoring tools for basic sleep research in mice

Studying sleep behavior in animal models demands clear separation of vigilance states. Pure manual scoring is time-consuming and commercial scoring software is costly. We present a LabVIEW-based, semi-automated scoring routine using recorded EEG and EMG signals. This scoring routine is • designed to reliably assign the vigilance/sleep states wakefulness (WAKE), non-rapid eye movement sleep (NREMS) and rapid eye movement sleep (REMS) to defined EEG/EMG episodes. • straightforward to use even for beginners in the field of sleep research. • freely available upon request. Chronic recordings from mice were used to design and evaluate the scoring routine consisting of an artifact-removal, a scoring- and a rescoring routine. The scoring routine processes EMG and different EEG frequency bands. Amplitude-based thresholds for EEG and EMG parameters trigger a decision tree assigning each EEG episode to a defined vigilance/sleep state automatically. Using the rescoring routine individual episodes or particular state transitions can be re-evaluated manually. High agreements between auto-scored and manual sleep scoring could be shown for experienced scorers and for beginners quickly and reliably. With small modifications to the software, it can be easily adapted for sleep analysis in other animal models

Short-term elevation of intracranial pressure does neither influence duodenal motility nor frequency of bolus transport events: a porcine model

BACKGROUND: Patients with traumatic brain injuries and raised intracranial pressure (ICP) display biphasic response with faster gastric emptying during the early stage followed by a prolonged gastric transit time later. While duodenal contractile activity plays a pivotal role in transpyloric transit we investigated the effects of raised intracranial pressure on duodenal motility during the early phase. In order to exclude significant deterioration of mucosal blood supply which might also influence duodenal motility, luminal microdialysis was used in conjunction. METHODS: During general anaesthesia, 11 pigs (32–37 kg, German Landrace) were instrumented with both a luminal catheter for impedancometry and a luminal catheter for microdialysis into the proximal duodenum. Additionally, a catheter was inserted into the left ventricle to increase the intracranial pressure from baseline up to 50 mmHg in steps of 10 mmHg each hour by injection of artificial cerebrospinal fluid. At the same time, duodenal motility was recorded continuously. Duodenal luminal lactate, pyruvate, and glucose concentrations were measured during physiological state and during elevated intracranial pressure of 10, 20, 30, 40, and 50 mmHg in six pigs. Five pigs served as controls. RESULTS: Although there was a trend towards shortened migrating motor cycle (MMC) length in pigs with raised ICP, the interdigestive phase I–III and the MMC cycle length were comparable in the groups. Spontaneous MMC cycles were not disrupted during intracranial hypertension. The mean concentration of lactate and glucose was comparable in the groups, while the concentration of pyruvate was partially higher in the study group than in the controls (p < 0.05). This was associated with a decrease in lactate to pyruvate ratio (p < 0.05). CONCLUSION: The present study suggests that a stepwise and hourly increase of the intracranial pressure of up to 50 mmHg, does not influence duodenal motility activity in a significant manner. A considerable deterioration of the duodenal mucosal blood flow was excluded by determining the lactate to pyruvate ratio

1011-116 Myocardial Rb Extraction Fraction: Determination in Humans

Ouantitation of myocardial blood flow (MBF) with diffusion-limited radiotracers as 82Rb and positron emission tomography (PET) requires knowledge of flow dependence of myocardial 82Rb extraction fraction. To determine this dependence we evaluated 7 patients (mean age (61.0±9.7) years, 4 males, 3 females) who had undergone coronary angiography with exclusion of relevant coronary stenoses and normal left ventricular function. 82Rb-PET clearance was simultaneously assessed with global MBF by the argon (Ar) inert gas method. 82Rb clearance was dynamically measured by a CTI-Siemens ECAT 931-08-12 scanner after i.v. injection of 1–1.2 GBq 82Rb. Ar gas desaturation was obtained by simultaneous arterial and coronary sinus blood sampling. Measurements were performed at rest and during vasodilatation induced by i.v. dipyridamole (0.7mg/kg/4min). Mean 82Rb clearance and Ar flow values were (0.39±0,03)ml/g/min and (0.69±0.14)ml/g/min at rest, respectively, and (0.47±0.09)ml/g/min and (1.48±0.49)ml/g/min during hyperemia. A fit with a two compartment model yielded E=PS/(PS+MBF) with PS=(0.82±0.09)ml/g/min (PS: permeability surface area product). These data (figure) provide for the best of our knowledge the first measured 82Rb extraction fraction in humans and may form the basis for more accurate quantitation of myocardial blood flow with 82Rb-PET

Влияние термомеханической обработки на структуру, механические и трибологические свойства композитов Al-Si-Sn

Исследование влияния режима спекания порошковых прессовок, а также последующей их деформационной обработки методом горячего доуплотнения и равноканального углового прессования (РКУП) на результирующую структуру, механические и трибологические свойства композитов (Al-Si)-40Sn.Investigation of the effect of sintering regimes of powder compacts, as well as their deformation treatment by hot doping and equal-channel angular pressing (ECAP) on the resulting structure, mechanical and tribological properties of composites (Al-Si)-40Sn

A transient homotypic interaction model for the influenza A virus NS1 protein effector domain

Influenza A virus NS1 protein is a multifunctional virulence factor consisting of an RNA binding domain (RBD), a short linker, an effector domain (ED), and a C-terminal 'tail'. Although poorly understood, NS1 multimerization may autoregulate its actions. While RBD dimerization seems functionally conserved, two possible apo ED dimers have been proposed (helix-helix and strand-strand). Here, we analyze all available RBD, ED, and full-length NS1 structures, including four novel crystal structures obtained using EDs from divergent human and avian viruses, as well as two forms of a monomeric ED mutant. The data reveal the helix-helix interface as the only strictly conserved ED homodimeric contact. Furthermore, a mutant NS1 unable to form the helix-helix dimer is compromised in its ability to bind dsRNA efficiently, implying that ED multimerization influences RBD activity. Our bioinformatical work also suggests that the helix-helix interface is variable and transient, thereby allowing two ED monomers to twist relative to one another and possibly separate. In this regard, we found a mAb that recognizes NS1 via a residue completely buried within the ED helix-helix interface, and which may help highlight potential different conformational populations of NS1 (putatively termed 'helix-closed' and 'helix-open') in virus-infected cells. 'Helix-closed' conformations appear to enhance dsRNA binding, and 'helix-open' conformations allow otherwise inaccessible interactions with host factors. Our data support a new model of NS1 regulation in which the RBD remains dimeric throughout infection, while the ED switches between several quaternary states in order to expand its functional space. Such a concept may be applicable to other small multifunctional proteins

Activation of Type I and III Interferon Signalling Pathways Occurs in Lung Epithelial Cells Infected with Low Pathogenic Avian Influenza Viruses

The host response to the low pathogenic avian influenza (LPAI) H5N2, H5N3 and H9N2 viruses were examined in A549, MDCK, and CEF cells using a systems-based approach. The H5N2 and H5N3 viruses replicated efficiently in A549 and MDCK cells, while the H9N2 virus replicated least efficiently in these cell types. However, all LPAI viruses exhibited similar and higher replication efficiencies in CEF cells. A comparison of the host responses of these viruses and the H1N1/WSN virus and low passage pH1N1 clinical isolates was performed in A549 cells. The H9N2 and H5N2 virus subtypes exhibited a robust induction of Type I and Type III interferon (IFN) expression, sustained STAT1 activation from between 3 and 6 hpi, which correlated with large increases in IFN-stimulated gene (ISG) expression by 10 hpi. In contrast, cells infected with the pH1N1 or H1N1/WSN virus showed only small increases in Type III IFN signalling, low levels of ISG expression, and down-regulated expression of the IFN type I receptor. JNK activation and increased expression of the pro-apoptotic XAF1 protein was observed in A549 cells infected with all viruses except the H1N1/WSN virus, while MAPK p38 activation was only observed in cells infected with the pH1N1 and the H5 virus subtypes. No IFN expression and low ISG expression levels were generally observed in CEF cells infected with either AIV, while increased IFN and ISG expression was observed in response to the H1N1/WSN infection. These data suggest differences in the replication characteristics and antivirus signalling responses both among the different LPAI viruses, and between these viruses and the H1N1 viruses examined. These virus-specific differences in host cell signalling highlight the importance of examining the host response to avian influenza viruses that have not been extensively adapted to mammalian tissue culture

Interferon-β Pretreatment of Conventional and Plasmacytoid Human Dendritic Cells Enhances Their Activation by Influenza Virus

Influenza virus produces a protein, NS1, that inhibits infected cells from releasing type I interferon (IFN) and blocks maturation of conventional dendritic cells (DCs). As a result, influenza virus is a poor activator of both mouse and human DCs in vitro. However, in vivo a strong immune response to virus infection is generated in both species, suggesting that other factors may contribute to the maturation of DCs in vivo. It is likely that the environment in which a DC encounters a virus would contain multiple pro-inflammatory molecules, including type I IFN. Type I IFN is a critical component of the viral immune response that initiates an antiviral state in cells, primarily by triggering a broad transcriptional program that interferes with the ability of virus to establish infection in the cell. In this study, we have examined the activation profiles of both conventional and plasmacytoid dendritic cells (cDCs and pDCs) in response to an influenza virus infection in the context of a type I IFN-containing environment. We found that both cDCs and pDCs demonstrate a greater activation response to influenza virus when pre-exposed to IFN-β (IFN priming); although, the priming kinetics are different in these two cell types. This strongly suggests that type I IFN functions not only to reduce viral replication in these immune cells, but also to promote greater DC activation during influenza virus infections