Computed tomographic assessment of lung weights in trauma patients with early posttraumatic lung dysfunction

Introduction: Quantitative computed tomography (qCT)-based assessment of total lung weight (M(lung)) has the potential to differentiate atelectasis from consolidation and could thus provide valuable information for managing trauma patients fulfilling commonly used criteria for acute lung injury (ALI). We hypothesized that qCT would identify atelectasis as a frequent mimic of early posttraumatic ALI. Methods: In this prospective observational study, M(lung) was calculated by qCT in 78 mechanically ventilated trauma patients fulfilling the ALI criteria at admission. A reference interval for M(lung) was derived from 74 trauma patients with morphologically and functionally normal lungs (reference). Results are given as medians with interquartile ranges. Results: The ratio of arterial partial pressure of oxygen to the fraction of inspired oxygen was 560 (506 to 616) mmHg in reference patients and 169 (95 to 240) mmHg in ALI patients. The median reference M(lung) value was 885 (771 to 973) g, and the reference interval for M(lung) was 584 to 1164 g, which matched that of previous reports. Despite the significantly greater median M(lung) value (1088 (862 to 1,342) g) in the ALI group, 46 (59%) ALI patients had M(lung) values within the reference interval and thus most likely had atelectasis. In only 17 patients (22%), Mlung was increased to the range previously reported for ALI patients and compatible with lung consolidation. Statistically significant differences between atelectasis and consolidation patients were found for age, Lung Injury Score, Glasgow Coma Scale score, total lung volume, mass of the nonaerated lung compartment, ventilator-free days and intensive care unit-free days. Conclusions: Atelectasis is a frequent cause of early posttraumatic lung dysfunction. Differentiation between atelectasis and consolidation from other causes of lung damage by using qCT may help to identify patients who could benefit from management strategies such as damage control surgery and lung-protective mechanical ventilation that focus on the prevention of pulmonary complications.Leipzig University Hospita

A collection of bacterial isolates from the pig intestine reveals functional and taxonomic diversity.

Our knowledge about the gut microbiota of pigs is still scarce, despite the importance of these animals for biomedical research and agriculture. Here, we present a collection of cultured bacteria from the pig gut, including 110 species across 40 families and nine phyla. We provide taxonomic descriptions for 22 novel species and 16 genera. Meta-analysis of 16S rRNA amplicon sequence data and metagenome-assembled genomes reveal prevalent and pig-specific species within Lactobacillus, Streptococcus, Clostridium, Desulfovibrio, Enterococcus, Fusobacterium, and several new genera described in this study. Potentially interesting functions discovered in these organisms include a fucosyltransferase encoded in the genome of the novel species Clostridium porci, and prevalent gene clusters for biosynthesis of sactipeptide-like peptides. Many strains deconjugate primary bile acids in in vitro assays, and a Clostridium scindens strain produces secondary bile acids via dehydroxylation. In addition, cells of the novel species Bullifex porci are coccoidal or spherical under the culture conditions tested, in contrast with the usual helical shape of other members of the family Spirochaetaceae. The strain collection, called 'Pig intestinal bacterial collection' (PiBAC), is publicly available at www.dsmz.de/pibac and opens new avenues for functional studies of the pig gut microbiota

Transitions to food democracy through multilevel governance

status: publishe

Clinical and virological characteristics of hospitalised COVID-19 patients in a German tertiary care centre during the first wave of the SARS-CoV-2 pandemic: a prospective observational study

Purpose: Adequate patient allocation is pivotal for optimal resource management in strained healthcare systems, and requires detailed knowledge of clinical and virological disease trajectories. The purpose of this work was to identify risk factors associated with need for invasive mechanical ventilation (IMV), to analyse viral kinetics in patients with and without IMV and to provide a comprehensive description of clinical course. Methods: A cohort of 168 hospitalised adult COVID-19 patients enrolled in a prospective observational study at a large European tertiary care centre was analysed. Results: Forty-four per cent (71/161) of patients required invasive mechanical ventilation (IMV). Shorter duration of symptoms before admission (aOR 1.22 per day less, 95% CI 1.10-1.37, p < 0.01) and history of hypertension (aOR 5.55, 95% CI 2.00-16.82, p < 0.01) were associated with need for IMV. Patients on IMV had higher maximal concentrations, slower decline rates, and longer shedding of SARS-CoV-2 than non-IMV patients (33 days, IQR 26-46.75, vs 18 days, IQR 16-46.75, respectively, p < 0.01). Median duration of hospitalisation was 9 days (IQR 6-15.5) for non-IMV and 49.5 days (IQR 36.8-82.5) for IMV patients. Conclusions: Our results indicate a short duration of symptoms before admission as a risk factor for severe disease that merits further investigation and different viral load kinetics in severely affected patients. Median duration of hospitalisation of IMV patients was longer than described for acute respiratory distress syndrome unrelated to COVID-19

Gewichte morphologisch und funktional normaler Lungen von maschinell beatmeten Traumapatienten

The assessment of the lung weight in vivo is possible with the quantitative computer tomography (qCT) analysis. Especially in acute lung injury (ALI) the knowledge of the lung weight can help to identify the etiology of lung-dysfunction. The current definition of ALI is orientating on parameters such as impaired oxygenation or radiological opacifications. With this definition a heterogeneous group is captured. There might be dysfunction of the lung due to atelectasis or due to edema, both leading to impaired oxygenation. For the clinician it is important to differentiate between atelectasis and edema. For example, in patients with edematous lungs the clinician is focusing on prevention of secondary lung injury whereas in atelectasis the clinician is targeting a more aggressive treatment. The method of qCT has the potential to differentiate atelectasis from edema and could thus provide valuable information for managing trauma patients fulfilling commonly used criteria for ALI. So far a reference value for normal lung weights in ventilated patients is not available. In recent studies the lung weights of ALI-Patients where compared to healthy spontaneous breathing patients. Effects of a positive end expiratory pressure ventilation (PEEP) or possible influence of intravenous fluid substitution were ignored. The aim of this work was define a reference value of normal lung-weights in ventilated trauma patients. To reveal possible effects of PEEP or intravenous fluid substitution on the lung weight we provided a comparison group of spontaneous breathing trauma patients. In this prospective observational study CTs of trauma patients with normal lungs who underwent emergency CT were selected and two subgroups formed for spontaneous breathing (n = 31) and mechanically ventilated patients (n = 44). The decision whether a lung was normal was based on independent reviewers of the CT images. The arterial partial pressure of oxygen to fraction of inspired oxygen (PaO2/FiO2) had to be greater than 400mmHg. Demographic data, ventilation and clinical parameters of each patient where obtained from the patient data management system. In demographic data mechanically ventilated patients did not differ from the spontaneous breathing patients (only significant variation in sex, with a higher male proportion in the ventilated group). Mechanically ventilated patients were ventilated with PEEP of 10 mmHg at the time of the CT acquisition. The PaO2/FiO2 ratio was 550  74 mmHg. Mechanically ventilated patients received significant more intravenous fluid substitution (p = 0.02). The lung weight in mechanically ventilated patients was 873  124 g Standard deviation (SD), in spontaneous breathing patients 866  169 g SD. The validity of our method was reviewed by placing a water filled plastic bottle next to the thorax. The mass was calculated in two ways: by quantitative computed tomography and by the volumetric mass density of water. A deviation of 2% could be shown Our results suggest that lung weights of mechanically ventilated patients with normal lungs do not differ from those of other with normal lungs (Gattinoni 2006, Puybasset 2000). In conclusion, a moderate PEEP neither a moderate intravenous fluid substitution do not affect the lung weight. The lung weights assessed in this work can be used as reference values, especially, for the group of the trauma-associated ALI. With these results it is possible to identify pathological lung weights. Furthermore it gives a tool in identifying the etiology of ALI and therefore it helps the clinician in making the right therapeutic decisions.:Bibliografische Beschreibung 3 Abkürzungsverzeichnis 4 Einleitung 6 Gewichtsbestimmungen in der Medizin 6 Quantitative Computertomographie (qCT): Volumen- und Massebestimmung 7 Klinische Anwendung von Analysen des Lungengewichtes 9 Zielsetzung 11 Patienten und Methoden 12 Maschinell beatmete Patienten (maschinell B.) 12 Spontan atmende Patienten (spontan A.) 14 CT-Untersuchung 14 Quantitative CT-Analyse: Segmentierung der CT-Bilder 15 Validierung der Methodik 18 Auswertung der ROI 18 Statistische Analyse 19 Ergebnisse 21 Demographische Daten 21 Ergebnisse der Lungengewichtsanalyse 25 Ergebnisse der Validierung 28 Diskussion 30 Ausblick 40 Zusammenfassung / Abstract 41 Literaturverzeichnis 4

The effect of vortex generators on the flow around a circular cylinder

The effect of circular low-profile vortex generators for rotorcraft application has been investigated on a circular cylinder at a high Reynolds number. These so called Leading Edge Vortex Generators (LEVoGs) have shown significant reductions on the impact of dynamic stall on a pitching helicopter airfoil. However, the principle of operation of such devices remained unclear. In order to understand the aerodynamic phenomena, a wide range of experimental techniques such as oil flow visualization, infrared thermography, surface pressure measurements and stereo particle image velocimetry were employed. In addition, several post-processing approaches such as the proper orthogonal decomposition method were selected. The passive devices were found to significantly alter the flow around the cylinder. Depending on the azimuth angle of the vortex generators, the flow conditions could be classified into three categories, each with characteristic features. Similar to previous experiments on a helicopter rotor blade section, bundling of vortex generator wakes could be found under certain conditions. The vortex generators reduced the periodic Reynolds stress components v'v'/U∞2 and u'v'/U∞2 for all cases. For the cases where bundling was present, the size and peak values of the periodic u'u'/U∞2 component was increased significantly compared to the clean case. This means that the vortex generators almost only influence the periodic motion of the flow under these conditions. Even though the principle of operation couldn't be entirely cleared, the present study sheds some light onto the various mechanisms in the flow around such devices

Loss of CNFY toxin-induced inflammation drives Yersinia pseudotuberculosis into persistency.

Gastrointestinal infections caused by enteric yersiniae can become persistent and complicated by relapsing enteritis and severe autoimmune disorders. To establish a persistent infection, the bacteria have to cope with hostile surroundings when they transmigrate through the intestinal epithelium and colonize underlying gut-associated lymphatic tissues. How the bacteria gain a foothold in the face of host immune responses is poorly understood. Here, we show that the CNFY toxin, which enhances translocation of the antiphagocytic Yop effectors, induces inflammatory responses. This results in extensive tissue destruction, alteration of the intestinal microbiota and bacterial clearance. Suppression of CNFY function, however, increases interferon-γ-mediated responses, comprising non-inflammatory antimicrobial activities and tolerogenesis. This process is accompanied by a preterm reprogramming of the pathogen's transcriptional response towards persistence, which gives the bacteria a fitness edge against host responses and facilitates establishment of a commensal-type life style

Metabolic cost of unloading pedalling in different groups of patients with pulmonary hypertension and volunteers

Abstract Recently, the parameter internal work (IW) has been introduced as change in oxygen uptake (VO2) between resting and unloading workload in cardiopulmonary exercise testing (CPET). The proportional IW (PIW) was defined as IW divided by VO2 at peak exercise. A second option is to calculate the PIW based on the workload [PIW (Watt)] by considering the aerobic efficiency. The aim of our study was to investigate whether IW and PIW differ between patients with and without pulmonary hypertension and healthy controls. Our study population consisted of 580 patients and 354 healthy controls derived from the Study of Health in Pomerania. The PIW was slightly lower in patients (14.2%) than in healthy controls (14.9%; p = 0.030), but the PIW (Watt) was higher in patients (18.0%) than in the healthy controls (15.9%; p = 0.001). Such a difference was also observed, when considering only the submaximal workload up to the VAT (19.8% in patients and 15.1% in healthy controls; p < 0.001). Since the PIW (Watt) values were higher in patients with pulmonary hypertension, this marker may serve as a useful CPET parameter in clinical practice. In contrast to most of the currently used CPET parameters, the PIW does not require a maximal workload for the patient. Further studies are needed to validate the prognostic significance of the PIW

Model of CNF_Y influence on the development of <i>Yersinia</i> persistence.

<p>Schematic overview of induced inflammatory and acute phase responses, which are triggered by the <i>Y</i>. <i>pseudotuberculosis</i> strain YPIII and the isogenic CNF_Y-negative variant based on the transcriptome analysis of <i>Yersinia</i>-infected cecal tissue 5 dpi. Host responses that are expected to result from altered inflammatory responses and other defense reactions, are indicated by dashed arrows. Transcript-based adaptations of <i>Y</i>. <i>pseudotuberculosis</i> and the host during colonization of the cecum during acute and persistent infection and their influence on the outcome of the infection are illustrated.</p

Cytokine responses in wildtype- and Δ<i>cnfY</i> mutant-infected cecal tissue.

<p>BALB/c mice were orally infected with 10⁶ CFU of YPIII or YP147(Δ<i>cnfY</i>). At indicated time points post infection, the cytokines in the cecal tissue were determined. The bars represent the geometric mean of three independent experiments using n = 3–9 mice/group and the dotted line illustrates the detection limits. The cytokine level at any given time point between wildtype- and Δ<i>cnfY</i> mutant-infected mice was analyzed with the Kruskal-Wallis test and Dunn's correction, P-values: * <0.05, ** <0.01, *** <0.001.</p