Zearalenon: Untersuchungen zum in vitro und in vivo Metabolismus

Zearalenon (ZEN) ist ein von Fusarien produziertes Mykotoxin mit estrogener Wirkung. Die Ergebnisse mehrerer Studien weisen darauf hin, dass der Metabolismus von ZEN einen Einfluss auf die Toxizität der Substanz hat. Daher wurden in dieser Arbeit der oxidative Metabolismus und mögliche Konjugationsreaktionen von ZEN, cis-ZEN und der aus ZEN reduktiv gebildeten Derivate a-Zearalenon (ZEL) und b-ZEL mit hepatischen Zellfraktionen und mit Präzisionsgewebeschnitten aus der Rattenleber untersucht

Standardized Loads Acting in Hip Implants

With the increasing success of hip joint replacements, the average age of patients has decreased, patients have become more active and their expectations of the implant durability have risen. Thus, pre-clinical endurance tests on hip implants require defining realistic in vivo loads from younger and more active patients. These loads require simplifications to be applicable for simulator tests and numerical analyses. Here, the contact forces in the joint were measured with instrumented hip implants in ten subjects during nine of the most physically demanding and frequent activities of daily living. Typical levels and directions of average and high joint loads were extracted from the intra- and inter-individually widely varying individual data. These data can also be used to analyse bone remodelling at the implant-bone interface, evaluate tissue straining in finite element studies or validate analytical loading predictions, among other uses. The current ISO standards for endurance tests of implant stems and necks are based on historic analytical data from the 1970s. Comparisons of these test forces with in vivo loads unveiled that their unidirectional orientations deviate from the time-dependent in vivo directions during walking and most other activities. The ISO force for testing the stem is substantially too low while the ISO force for the neck better matches typical in vivo magnitudes. Because the magnitudes and orientations of peak forces substantially vary among the activities, load scenarios that reflect a collection of time-dependent high forces should be applied rather than using unidirectional forces. Based on data from ten patients, proposals for the most demanding activities, the time courses of the contact forces and the required cycle numbers for testing are given here. Friction moments in the joint were measured in addition to the contact forces. The moment data were also standardized and can be applied to wear tests of the implant. It was shown that friction only very slightly influences the stresses in the implant neck and shaft

Factoring Integers above 100 Digits using Hypercube MPQS

In this paper we report on further progress with the factorisation of integers using the MPQS algorithm on hypercubes and a MIMD parallel computer with 1024 T-805 processors. We were able to factorise a 101 digit number from the Cunningham list using only about 65 hours computing time. We give new details about the hypercube sieve initialisation procedure and describe the structure of the factor graph that saves a significant amount of computing time. At March 3rd, we finished the factorisation of a 104 digit composite

Overstretching Expectations May Endanger the Success of the “Millennium Surgery”

Total hip arthroplasty (THA) is an extremely successful treatment strategy. Patient expectations, however, have increased; if not properly guided by surgeons, at present, patients expect next to pain-free restoration of the joint and a fast return to work and sports. While the revision rates after THA also increased in younger patients, knowledge on musculoskeletal loads still remains sparse, and the current recommendations on postoperative rehabilitation are based on expert opinions only. The aim of this study was to unravel biomechanical contact conditions in "working age" (60 years, 67.7 +/- 8.6 years) patients during activities recommended post-THA. We hypothesized that working age patients would show substantially increased hip contact loads compared to older patients. The in vivo joint contact force (F-res) and torsion torque (M-tors), reflecting the main contact load situation, experienced during activities of daily living and sports activities were measured in a unique group of 16 patients with instrumented THA. We summarized patient activities and sports recommendations after THA mentioned within the literature using PubMed (without claim of completeness). The measurements showed that younger working age patients experienced significant (p = 0.050) increased M-tors (21.52 +/- 9.11 Nm) than older retirement age patients (13.99 +/- 7.89 Nm) by walking. Bowling, as a recommended low-impact sport, was associated with F-res of up to 5436 N and M-tors of up to 108 Nm in the working age group, which were higher than the F-res (5276 N) and M-tors (71 Nm) during high-impact soccer. Based on our results, age was proven to be a discriminator in joint loading, with working age patients presenting with increased loads compared to retirement age patients, already during daily activities. The current patient recommendations have led to further increased joint loadings. If THA cannot be delayed in a patient, we propose counselling patients on a carefully considered return to sports, focusing on low-impact activities, as indicated hereby. The findings from this work illustrate the need to provide critical feedback to patient expectations when returning to work and sports activities. Patients returning to more intensive sports activities should be carefully monitored and advised to avoid as much overloading as possible

Influence of Genistein on Hepatic Lipid Metabolism in an In Vitro Model of Hepatic Steatosis

Nonalcoholic fatty liver disease (NAFLD) is among the leading causes of end-stage liver disease. The impaired hepatic lipid metabolism in NAFLD is exhibited by dysregulated PPARα and SREBP-1c signaling pathways, which are central transcription factors associated with lipid degradation and de novo lipogenesis. Despite the growing prevalence of this disease, current pharmacological treatment options are unsatisfactory. Genistein, a soy isoflavone, has beneficial effects on lipid metabolism and may be a candidate for NAFLD treatment. In an in vitro model of hepatic steatosis, primary human hepatocytes (PHHs) were incubated with free fatty acids (FFAs) and different doses of genistein. Lipid accumulation and the cytotoxic effects of FFAs and genistein treatment were evaluated by colorimetric and enzymatic assays. Changes in lipid homeostasis were examined by RT-qPCR and Western blot analyses. PPARα protein expression was induced in steatotic PHHs, accompanied by an increase in CPT1L and ACSL1 mRNA. Genistein treatment increased PPARα protein expression only in control PHHs, while CPTL1 and ACSL1 were unchanged and PPARα mRNA was reduced. In steatotic PHHs, genistein reversed the increase in activated SREBP-1c protein. The model realistically reflected the molecular changes in hepatic steatosis. Genistein suppressed the activation of SREBP-1c in steatotic hepatocytes, but the genistein-mediated effects on PPARα were abolished by high hepatic lipid levels

Surgical cup placement affects the heating up of total joint hip replacements

The long-term success of highly effective total hip arthroplasty (THA) is mainly restricted by aseptic loosening, which is widely associated with friction between the head and cup liner. However, knowledge of the in vivo joint friction and resulting temperature increase is limited. Employing a novel combination of in vivo and in silico technologies, we analyzed the hypothesis that the intraoperatively defined implant orientation defines the individual joint roofing, friction and its associated temperature increase. A total of 38,000 in vivo activity trials from a special group of 10 subjects with instrumented THA implants with an identical material combination were analyzed and showed a significant link between implant orientation, joint kinematics, joint roofing and friction-induced temperature increase but surprisingly not with acting joint contact force magnitude. This combined in vivo and in silico analysis revealed that cup placement in relation to the stem is key to the in vivo joint friction and heating-up of THA. Thus, intraoperative placement, and not only articulating materials, should be the focus of further improvements, especially for young and more active patients

In vivo load measurements with instrumented implants

Aquatic exercises are widely used for rehabilitation or preventive therapies in order to enable mobilization and muscle strengthening while minimizing joint loading of the lower limb. The load reducing effect of water due to buoyancy is a main advantage compared to exercises on land. However, also drag forces have to be considered that act opposite to the relative motion of the body segments and require higher muscle activity. Due to these opposing effects on joint loading, the load-reducing effect during aquatic exercises remains unknown. The aim of this study was to quantify the joint loads during various aquatic exercises and to determine the load reducing effect of water. Instrumented knee and hip implants with telemetric data transfer were used to measure the resultant joint contact forces in 12 elderly subjects (6x hip, 6x knee) in vivo. Different dynamic, weight-bearing and non-weight-bearing activities were performed by the subjects on land and in chest-high water. Non-weight-bearing hip and knee flexion/extension was performed at different velocities and with additional Aquafins. Joint forces during aquatic exercises ranged between 32 and 396% body weight (BW). Highest forces occurred during dynamic activities, followed by weight-bearing and slow non-weight-bearing activities. Compared to the same activities on land, joint forces were reduced by 36–55% in water with absolute reductions being greater than 100%BW during weight-bearing and dynamic activities. During non-weight-bearing activities, high movement velocities and additional Aquafins increased the joint forces by up to 59% and resulted in joint forces of up to 301%BW. This study confirms the load reducing effect of water during weight-bearing and dynamic exercises. Nevertheless, high drag forces result in increased joint contact forces and indicate greater muscle activity. By the choice of activity, movement velocity and additional resistive devices joint forces can be modulated individually in the course of rehabilitation or preventive therapies

Essener Brot - Herstellung und Verwendung von Keimlingen in der Bäckerei

Der Leitfaden wendet sich in erster Linie an Bäcker, die Keimlinge in der Bäckerei, zum Beispiel zur Herstellung von Keimlingsbroten oder Essener Broten, verwenden wollen, und gibt darüber hinaus auch Einblicke, inwiefern Keimlinge als technologische Zutat eingesetzt werden können. Weiterhin kann dieser Leitfaden auch als Instrument für Berater im Bäckereiwesen verwendet werden. Der Leitfaden ist wie eine „Betriebsanleitung“ zu lesen und dient zur Erläuterung praktischer Vorgehensweisen. Reflexionen zu theoretischen Hintergründen finden eingeschränkt und nur soweit statt, wie diese der Erläuterung der praktischen Vorgehensweisen dienen. Ziel eines jeden Bäckers ist es, „gutes Brot“ zu backen. Um dies beim Backen mit Keimlingen zu erreichen, müssen bestimmte Parameter berücksichtigt werden. Der Einsatz von Keimlingen bedeutet letztlich den Einsatz von Auswuchsgetreide, weil durch das Keimen der Getreidekörner auch Stärke abbauende Enzyme aktiviert werden. Für eine gleichbleibende Brotqualität sollten die Keimlinge eine konstante Nährstoffzusammensetzung und eine möglichst niedrige Belastung mit Mikroorganismen aufweisen. Die Qualität der Keimlinge kann durch den Keimprozess beeinflusst werden. Beeinflussende Faktoren sind die Schichthöhe, die Keimdauer, die Feuchtigkeit und die Temperatur der Keime. Dazu gibt der Leitfaden konkrete Hinweise. Er gibt aber nicht nur eine Handlungsanweisung für das optimale Keimen von Getreide, sondern auch für ein bestmögliches Verbacken

Association of Machine Learning–Based Predictions of Medial Knee Contact Force With Cartilage Loss Over 2.5 Years in Knee Osteoarthritis

Objective: The relationship between in vivo knee load predictions and longitudinal cartilage changes has not been investigated. We undertook this study to develop an equation to predict the medial tibiofemoral contact force (MCF) peak during walking in persons with instrumented knee implants, and to apply this equation to determine the relationship between the predicted MCF peak and cartilage loss in patients with knee osteoarthritis (OA). Methods: In adults with knee OA (39 women, 8 men; mean ± SD age 61.1 ± 6.8 years), baseline biomechanical gait analyses were performed, and annualized change in medial tibial cartilage volume (mm3 /year) over 2.5 years was determined using magnetic resonance imaging. In a separate sample of patients with force-measuring tibial prostheses (3 women, 6 men; mean ± SD age 70.3 ± 5.2 years), gait data plus in vivo knee loads were used to develop an equation to predict the MCF peak using machine learning. This equation was then applied to the knee OA group, and the relationship between the predicted MCF peak and annualized cartilage volume change was determined. Results: The MCF peak was best predicted using gait speed, the knee adduction moment peak, and the vertical knee reaction force peak (root mean square error 132.88N; R2 = 0.81, P < 0.001). In participants with knee OA, the predicted MCF peak was related to cartilage volume change (R2 = 0.35, β = -0.119, P < 0.001). Conclusion: Machine learning was used to develop a novel equation for predicting the MCF peak from external biomechanical parameters. The predicted MCF peak was positively related to medial tibial cartilage volume loss in patients with knee OA

Keimlinge als neuartige multifunktionelle Zutat in ökologischen Backwaren - Optimierung der Herstellung und Verwendung

Im Rahmen des Projektes „Keimlinge als neuartige multifunktionelle Zutat in ökologischen Backwaren - Optimierung der Herstellung und Verwendung“ wurde die sichere betriebseigene Herstellung von Keimlingen, der Einsatz von Keimlingen in Sprossenbroten und der Einsatz zu technologischen Zwecken entwickelt und optimiert. Diese allgemeinen Handlungsempfehlungen wurden in einem Leitfaden für handwerkliche Bäckereien festgehalten. Um gleichmäßige Backergebnisse zu erhalten, werden Keimlinge mit konstanter Qualität benötigt. Qualitätsbestimmende Faktoren sind die mikrobiologische Belastung, die wertgebenden Inhaltsstoffe und die Enzymatik. Das Keimergebnis lässt sich im Keimprozess durch die Keimtemperatur, die Schichthöhe und die Keimdauer beeinflussen und steuern. Die Einflüsse dieser Faktoren auf die qualitätsbestimmenden Eigenschaften wurden im Projekt untersucht. Aus den Ergebnissen konnte die Faustzahl „15:15:30“ abgeleitet werden. Bei einer Schichthöhe von 15 cm, einer Keimtemperatur von maximal 15 °C und einer Keimdauer von 30 Stunden lassen sich gute Keimlingsergebnisse erzielen. Die Herstellung von Essener Broten stellt besondere Anforderungen an die Teigführung. Durch die Keimung kommt es zu einer deutlichen Vermehrung der Enzymaktivität im Keimgut. Diese Enzymaktivität ist insbesondere für Roggenteige technologisch hoch relevant. Es empfiehlt sich, die Keimlinge möglichst spät und eher grob zerkleinert dem gut gesäuerten Teig hinzu zu geben. Unter Einhaltung der im Leitfaden beschriebenen Bedingungen gelingt es, ein Essener Brot ausschließlich aus Keimlingen herzustellen. Je niedriger die Keimtemperatur, desto fester die Krumenbeschaffenheit und desto weniger klebrig ist die Krume. Die Backergebnisse sind durch die Temperatur bei der Keimung beeinflussbar und die Krumenfestigkeit bzw. die Krumenklebrigkeit kann gesteuert werden. Das so genannte Essener Brot wird typischerweise eher bei niedrigeren Temperaturen über eine verlängerte Backzeit gebacken. Die Keimlinge oder auch das so gewonnene aktive Malz kann zu Steuerung der Enzymatik bei der Teigführung eingesetzt werden. Der Einsatz von Roggenkeimlingen als Zutat bei Weizenbrot kann sehr positive Ergebnisse zeigen. Der Zerkleinerungsgrad der Keimlinge hat entscheidenden Einfluss auf die Qualität der hergestellten Weizengebäcke. Insgesamt konnten das Volumen, die Krumenelastizität und die Krumenfestigkeit verbessert werden