Evaluation of the passage of Lactobacillus gasseri K7 and bifidobacteria from the stomach to intestines using a single reactor model

<p>Abstract</p> <p>Background</p> <p>Probiotic bacteria are thought to play an important role in the digestive system and therefore have to survive the passage from stomach to intestines. Recently, a novel approach to simulate the passage from stomach to intestines in a single bioreactor was developed. The advantage of this automated one reactor system was the ability to test the influence of acid, bile salts and pancreatin.</p> <p><it>Lactobacillus gasseri </it>K7 is a strain isolated from infant faeces with properties making the strain interesting for cheese production. In this study, a single reactor system was used to evaluate the survival of <it>L. gasseri </it>K7 and selected bifidobacteria from our collection through the stomach-intestine passage.</p> <p>Results</p> <p>Initial screening for acid resistance in acidified culture media showed a low tolerance of <it>Bifidobacterium dentium </it>for this condition indicating low survival in the passage. Similar results were achieved with <it>B. longum </it>subsp. <it>infantis </it>whereas <it>B. animalis </it>subsp. <it>lactis </it>had a high survival.</p> <p>These initial results were confirmed in the bioreactor model of the stomach-intestine passage. <it>B. animalis </it>subsp. <it>lactis </it>had the highest survival rate (10%) attaining approximately 5 × 10⁶cfu ml^-1compared to the other tested bifidobacteria strains which were reduced by a factor of up to 10⁶. <it>Lactobacillus gasseri </it>K7 was less resistant than <it>B. animalis </it>subsp. <it>lactis </it>but survived at cell concentrations approximately 1000 times higher than other bifidobacteria.</p> <p>Conclusion</p> <p>In this study, we were able to show that <it>L. gasseri </it>K7 had a high survival rate in the stomach-intestine passage. By comparing the results with a previous study in piglets we could confirm the reliability of our simulation. Of the tested bifidobacteria strains, only <it>B. animalis </it>subsp. <it>lactis </it>showed acceptable survival for a successful passage in the simulation system.</p

Patellofemoraler Druck bei Knietotalendoprothesen mit und ohne Retropatellarersatz - eine in vitro Studie

ZUSAMMENFASSUNG: Ziel dieser Studie war es, in einer simulierten dynamischen muskelgesteuerten Knieflexion den Einfluss einer KTP mit und ohne RPE auf den retropatellaren Druck zu messen, um Aussagen über eine veränderte Biomechanik nach Prothesenimplantation und damit über eine mögliche Ursache des persistierenden vorderen Knieschmerzes zu liefern. METHODEN: An einem speziell entwickelten, komplexen Kniekinemator wurde an 7 präparierten Knien eine dynamische Knieflexion zwischen 25° und 90° simuliert. Dabei wurde über die Quadrizepssehnen eine variable Muskelkraft aufgebracht, die dafür sorgte, dass die Gewichtskraft am distalen Ende des Präparats konstant gehalten wurde. Über flexible, in den Retropatellarraum eingebrachte Druckmessfolien (Tekscan®) wurden die retropatellaren Druckverhältnisse während dieser Knieflexion aufgezeichnet. Diese Messung wurde jeweils für native Knie, nach Implantation einer totalen Knieendoprothese Typ Genesis II ( Fa. Smith & Nephew) ohne Retropateelarsatz, als auch nach Implantation des Retropatellarersatzes durchgeführt. ERGEBNISSE: Durch die Implantation einer KTP verdoppelt sich der Maximaldruck retropatellar signifikant (40°-90° p < 0,025) und erreicht nach Implantation des RPE sogar den achtfachen Druckwert (25°-90° p < 0,019). Gleichzeitig wird durch die Implantation der KTP die Druckfläche auf ein Viertel signifikant verkleinert (50°-90° p < 0,001) und wird nach RPE nur noch punktförmig, mit einer signifikanten Verringerung um das achtfache im Vergleich zum nativen Präparat. Ebenfalls konnten signifikante Änderungen der Verlaufs des Druckschwerpunktes nach Implantation der KTP mit und ohne RPE in craniocaudaler Richtung nachgewiesen werden. Veränderte Muskelkraftverteilung der Oberschenkelmuskulatur führt zu keiner signifikanten Veränderung der retropatellaren Druckverteilung. SCHLUSSFOLGERUNG: Die Implantation einer KTP vergrößert den retropatellarer Druck ohne RPE signifikant, nach Implantation eines RPE sogar hochsignifikant. Trotz korrektem Einbau des Retropatellarersatzes kommt es dadurch zu einer deutlichen Veränderung der biomechanischen Verhältnisse im Patellofemoralgelenk und kann als eine mögliche Ursache für persistierende vordere Knieschmerzen nach KTP angesehen werden. Aus biomechanischer Sicht ist daher von einem routinemäßigen Einbau des RPE abzusehen, der Erhalt der nativen Patella voranzustellen und nur in selektiven Fällen mit klinisch bereits bestehender retropatellarer Arthrose und präoperativem vorderen Knieschmerz ein primärer Einbau des RPE durchzuführen

Overview of Global Monitoring of Terrestrial Chlorophyll Fluorescence from Space

Despite the critical importance of photosynthesis for the Earth system, understanding how it is influenced by factors such as climate variability, disturbance history, and water or nutrient availability remains a challenge because of the complex interactions and the lack of GPP measurements at various temporal and spatial scales. Space observations of the sun-induced chlorophyll fluorescence (SIF) electromagnetic signal emitted by plants in the 650-850nm spectral range hold the promise of providing a new view of vegetation photosynthesis on a global basis. Global retrievals of SIF from space have recently been achieved from a number of spaceborne spectrometers originally intended for atmospheric research. Despite not having been designed for land applications, such instruments have turned out to provide the necessary spectral and radiometric sensitivity for SIF retrieval from space. The first global measurements of SIF were achieved in 2011 from spectra acquired by the Japanese GOSAT mission launched in 2009. The retrieval takes advantage of the high spectral resolution provided by GOSATs Fourier Transform Spectrometer (FTS) which allows the evaluation of the in-filling of solar Fraunhofer lines by SIF. Unfortunately, GOSAT only provides a sparse spatial sampling with individual soundings separated by several hundred kilometers. Complementary, the Global Ozone Monitoring Experiment-2 (GOME-2) instruments onboard MetOp-A and MetOp-B enable SIF retrievals since 2007 with a continuous and global spatial coverage. GOME-2 measures in the red and near-infrared (NIR) spectral regions with a spectral resolution of 0.5 nm and a pixel size of up to 40x40 km2. Most recently, another global and spatially continuous data set of SIF retrievals at 740 nm spanning the 2003-2012 time frame has been produced from ENVISATSCIAMACHY. This observational scenario has been completed by the first fluorescence data from the NASA-JPL OCO-2 mission (launched in July 2014) and the upcoming Copernicus' Sentinel 5-Precursor to be launched in early 2016. OCO-2 and TROPOMI offer the possibility of monitoring SIF globally with a 100-fold improvement in spatial and temporal resolution with respect to the current measurements from the GOSAT, GOME-2 and SCIAMACHY missions. In this contribution, we will provide an overview of existing global SIF data sets derived from space-based atmospheric spectrometers and will demonstrate the potential of such data to improve our knowledge of vegetation photosynthesis and gross primary production at the synoptic scale. We will show examples of ongoing research exploiting SIF data for an improved monitoring of photosynthetic activity in different ecosystems, including large crop belts worldwide, the Amazon rainforest and boreal evergreen forests

How the Direction of Screws Affects the Primary Stability of a Posterior Malleolus Osteosynthesis under Torsional Loading: A Biomechanical Study

Insufficient fixation of a posterior malleolus fracture (PM) can lead to posttraumatic complications such as osteoarthritis and chronic pain. The purpose of this biomechanical study was to test the hypothesis of whether the direction of PM screw fixation has an impact on the primary stability of osteosynthesis of a PM under torsional loading. PM fractures of 7 pairs human cadaveric lower leg specimens were stabilized with posterior to anterior (p.a.) or anterior to posterior (a.p.) screw fixation. Stability of the osteosynthesis was biomechanically tested using cyclic external torsional loading levels, in 2 Nm steps from 2 Nm up to 12 Nm, under constant monitoring with 3D ultrasonic marker (Zebris). The primary stability does not differ between both stabilizations ( p = 0.378) with a medium effect size (η 2 p = 0.065). The movement of the PM tends to be marginally greater for the osteosynthesis with a.p. screws than with p.a. screws. Whether a.p. screws or the alternative p.a. screw fixation is performed does not seem to have an influence on the primary stability of the osteosynthesis of the PM fixation under torsional loading. Although osteosynthesis from posterior seems to be more stable, the biomechanical results in the torsional test show quite equivalent stabilities. If there is no significant dislocation of the PM, a.p. screw fixation could be a minimally invasive but stable surgical strategy

Safety Evaluation of a Medical Congress Held During the COVID-19 Pandemic-A Prospective Cohort

Objectives: During the COVID-19 pandemic, few scientific congresses have been held on-site. We prospectively evaluated the safety concept of the congress of the Swiss Societies of Infectious Diseases and Hospital Hygiene. Methods: The congress was held in Geneva (Switzerland) while local COVID-19 incidence (with SARS-CoV-2 wild type circulating) was 65/100,000 population (September 2020). A rigorous safety concept was implemented. Congress attendees filled out a questionnaire to assess risk perception, exposures, symptoms and diagnoses of SARS-CoV-2 before, during and after the congress. Dried blood spots were taken on-site and 4 weeks later to detect SARS-CoV-2 seroconversions. Results: Of 365 congress attendees, 196 (54%) either answered the questionnaire (N = 150) or provided baseline and follow-up blood samples (N = 168). None of the participants reported a positive PCR in the 2 weeks after the congress. Five of 168 (3%) participants were seropositive at follow-up, all of which had already been positive at baseline. Conclusion: Findings indicate that congresses with a rigorous safety concept may take place, even in areas with moderately-high COVID-19 activity. Whether this holds true in vaccinated populations and with more transmissible viral variants circulating remains unclear

Wille, Glück und Napoleon

Die Herkunftserzählungen der heutigen Schweiz sind vielfältig, woher aber rühren sie? Was kommt heraus, wenn man sie in den zeitgenössischen politischen Diskurs übersetzt? Und: leidet die Eidgenossenschaft an einer Depression

Large-scale morphometry of the subarachnoid space of the optic nerve.

BACKGROUND The meninges, formed by dura, arachnoid and pia mater, cover the central nervous system and provide important barrier functions. Located between arachnoid and pia mater, the cerebrospinal fluid (CSF)-filled subarachnoid space (SAS) features a variety of trabeculae, septae and pillars. Like the arachnoid and the pia mater, these structures are covered with leptomeningeal or meningothelial cells (MECs) that form a barrier between CSF and the parenchyma of the optic nerve (ON). MECs contribute to the CSF proteome through extensive protein secretion. In vitro, they were shown to phagocytose potentially toxic proteins, such as α-synuclein and amyloid beta, as well as apoptotic cell bodies. They therefore may contribute to CSF homeostasis in the SAS as a functional exchange surface. Determining the total area of the SAS covered by these cells that are in direct contact with CSF is thus important for estimating their potential contribution to CSF homeostasis. METHODS Using synchrotron radiation-based micro-computed tomography (SRµCT), two 0.75 mm-thick sections of a human optic nerve were acquired at a resolution of 0.325 µm/pixel, producing images of multiple terabytes capturing the geometrical details of the CSF space. Special-purpose supercomputing techniques were employed to obtain a pixel-accurate morphometric description of the trabeculae and estimate internal volume and surface area of the ON SAS. RESULTS In the bulbar segment, the ON SAS microstructure is shown to amplify the MECs surface area up to 4.85-fold compared to an "empty" ON SAS, while just occupying 35% of the volume. In the intraorbital segment, the microstructure occupies 35% of the volume and amplifies the ON SAS area 3.24-fold. CONCLUSIONS We provided for the first time an estimation of the interface area between CSF and MECs. This area is of importance for estimating a potential contribution of MECs on CSF homeostasis

Disentangling Changes in the Spectral Shape of Chlorophyll Fluorescence : Implications for Remote Sensing of Photosynthesis

Novel satellite measurements of solar-induced chlorophyll fluorescence (SIF) can improve our understanding of global photosynthesis; however, little is known about how to interpret the controls on its spectral variability. To address this, we disentangle simultaneous drivers of fluorescence spectra by coupling active and passive fluorescence measurements with photosynthesis. We show empirical and mechanistic evidence for where, why, and to what extent leaf fluorescence spectra change. Three distinct components explain more than 95% of the variance in leaf fluorescence spectra under both steady-state and changing illumination conditions. A single spectral shape of fluorescence explains 84% of the variance across a wide range of species. The magnitude of this shape responds to absorbed light and photosynthetic up/down regulation; meanwhile, chlorophyll concentration and nonphotochemical quenching control 9% and 3% of the remaining spectral variance, respectively. The spectral shape of fluorescence is remarkably stable where most current satellite retrievals occur (far-red, >740nm), and dynamic downregulation of photosynthesis reduces fluorescence magnitude similarly across the 670- to 850-nm range. We conduct an exploratory analysis of hourly red and far-red canopy SIF in soybean, which shows a subtle change in red:far-red fluorescence coincident with photosynthetic downregulation but is overshadowed by longer-term changes in canopy chlorophyll and structure. Based on our leaf and canopy analysis, caution should be taken when attributing large changes in the spectral shape of remotely sensed SIF to plant stress, particularly if data acquisition is temporally sparse. Ultimately, changes in SIF magnitude at wavelengths greater than 740 nm alone may prove sufficient for tracking photosynthetic dynamics. Plain Language Summary Satellite remote sensing provides a global picture of photosynthetic activity-allowing us to see when, where, and how much CO2 plants are assimilating. To do this, satellites measure a small emission of energy from the plants called chlorophyll fluorescence. However, this measurement is typically made across a narrow wavelength range, while the emission spectrum (650-850 nm) is quite dynamic. We show where, why, and to what extent leaf fluorescence spectra change across a diverse range of species and conditions, ultimately informing canopy remote sensing measurements. Results suggest that wavelengths currently used by satellites are stable enough to track the downregulation of photosynthesis resulting from stress, while spectral shape changes respond more strongly to dynamics in canopy structure and chlorophyll concentration.Peer reviewe