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Background: Despite a recent statutory ruling stating the binding nature of advance directives (ADs), only a minority of the population has signed one. Yet, a majority deem it of utmost importance to ensure their wishes are followed through in case they are no longer able to decide. The reasons for this discrepancy have not yet been investigated sufficiently.
Patients and methods: This article is based on a survey of patients using a well-established structured questionnaire. First, patients were asked about their attitudes with respect to six therapeutic options at the end of life: intravenous fluids, artificial feeding, antibiotics, analgesia, chemotherapy/dialysis, and artificial ventilation; and second, they were asked about the negative effects related to the idea of ADs surveying their apprehensions: coercion to fulfill an AD, dictatorial reading of what had been laid down, and abuse of ADs.
Results: A total of 1,260 interviewees completed the questionnaires. A significant percentage of interviewees were indecisive with respect to therapeutic options, ranging from 25% (analgesia) to 45% (artificial feeding). There was no connection to health status. Apprehensions about unwanted effects of ADs were widespread, at 51%, 35%, and 43% for coercion, dictatorial reading, and abuse, respectively.
Conclusion: A significant percentage of interviewees were unable to anticipate decisions about treatment options at the end of life. Apprehensions about negative adverse effects of ADs are widespread.
Background: Although the risk of developing colorectal cancer (CRC) is 2-4 times higher in case of a positive family history, risk-adapted screening programs for family members related to CRC- patients do not exist in the German health care system. CRC screening recommendations for persons under 55 years of age that have a family predisposition have been published in several guidelines.
The primary aim of this study is to determine the frequency of positive family history of CRC (1st degree relatives with CRC) among 40–54 year old persons in a general practitioner (GP) setting in Germany. Secondary aims are to detect the frequency of occurrence of colorectal neoplasms (CRC and advanced adenomas) in 1st degree relatives of CRC patients and to identify the variables (e.g. demographic, genetic, epigenetic and proteomic characteristics) that are associated with it. This study also explores whether evidence-based information contributes to informed decisions and how screening participation correlates with anxiety and (anticipated) regret.
Methods/Design: Prior to the beginning of the study, the GP team (GP and one health care assistant) in around 50 practices will be trained, and about 8,750 persons that are registered with them will be asked to complete the “Network against colorectal cancer” questionnaire. The 10 % who are expected to have a positive family history will then be invited to give their informed consent to participate in the study. All individuals with positive family history will be provided with evidence-based information and prevention strategies. We plan to examine each participant’s family history of CRC in detail and to collect information on further variables (e.g. demographics) associated with increased risk. Additional stool and blood samples will be collected from study-participants who decide to undergo a colonoscopy (n ~ 350) and then analyzed at the German Cancer Research Center (DKFZ) Heidelberg to see whether further relevant variables are associated with an increased risk of CRC. One screening list and four questionnaires will be used to collect the data, and a detailed statistical analysis plan will be provided before the database is closed (expected to be June 30, 2015).
Discussion: It is anticipated that when persons with a family history of colorectal cancer have been provided with professional advice by the practice team, there will be an increase in the availability of valid information on the frequency of affected individuals and an increase in the number of persons making informed decisions. We also expect to identify further variables that are associated with colorectal cancer. This study therefore has translational relevance from lab to practice.
Trial registration: German Clinical Trials Register DRKS00006277
Recently, the conserved intracellular digestion mechanism ‘autophagy’ has been considered to be involved in early tumorigenesis and its blockade proposed as an alternative treatment approach. However, there is an ongoing debate about whether blocking autophagy has positive or negative effects in tumor cells. Since there is only poor data about the clinico-pathological relevance of autophagy in gliomas in vivo, we first established a cell culture based platform for the in vivo detection of the autophago-lysosomal components. We then investigated key autophagosomal (LC3B, p62, BAG3, Beclin1) and lysosomal (CTSB, LAMP2) molecules in 350 gliomas using immunohistochemistry, immunofluorescence, immunoblotting and qPCR. Autophagy was induced pharmacologically or by altering oxygen and nutrient levels. Our results show that autophagy is enhanced in astrocytomas as compared to normal CNS tissue, but largely independent from the WHO grade and patient survival. A strong upregulation of LC3B, p62, LAMP2 and CTSB was detected in perinecrotic areas in glioblastomas suggesting micro-environmental changes as a driver of autophagy induction in gliomas. Furthermore, glucose restriction induced autophagy in a concentration-dependent manner while hypoxia or amino acid starvation had considerably lesser effects. Apoptosis and autophagy were separately induced in glioma cells both in vitro and in vivo. In conclusion, our findings indicate that autophagy in gliomas is rather driven by micro-environmental changes than by primary glioma-intrinsic features thus challenging the concept of exploitation of the autophago-lysosomal network (ALN) as a treatment approach in gliomas.
kurz und kn@pp news : Nr. 38
(2016)
Mitochondrial complex I (NADH:ubiquinone oxidoreductase) is a key enzyme in cellular energy metabolism and provides approximately 40% of the proton-motive force that is utilized during mitochondrial ATP production. The dysregulation of complex I function--either genetically, pharmacologically, or metabolically induced--has severe pathophysiological consequences that often involve an imbalance in the production of reactive oxygen species (ROS). Slow transition of the active (A) enzyme to the deactive, dormant (D) form takes place during ischemia in metabolically active organs such as the heart and brain. The reactivation of complex I occurs upon reoxygenation of ischemic tissue, a process that is usually accompanied by an increase in cellular ROS production. Complex I in the D-form serves as a protective mechanism preventing the oxidative burst upon reperfusion. Conversely, however, the D-form is more vulnerable to oxidative/nitrosative damage. Understanding the so-called active/deactive (A/D) transition may contribute to the development of new therapeutic interventions for conditions like stroke, cardiac infarction, and other ischemia-associated pathologies. In this review, we summarize current knowledge on the mechanism of A/D transition of mitochondrial complex I considering recently available structural data and site-specific labeling experiments. In addition, this review discusses in detail the impact of the A/D transition on ROS production by complex I and the S-nitrosation of a critical cysteine residue of subunit ND3 as a strategy to prevent oxidative damage and tissue damage during ischemia-reperfusion injury. This article is part of a Special Issue entitled Respiratory complex I, edited by Volker Zickermann and Ulrich Brandt.
Vimentin is currently used to differentiate between malignant renal carcinomas and benign oncocytomas. Recent reports showing Vimentin positive oncocytomas seriously question the validity of this present diagnostic approach. Vimentin 3 is a spliced variant and ends with a unique C-terminal ending after exon 7 which differentiates it from the full length version that has 9 exons. Therefore, the protein size is different; the full length Vimentin version has a protein size of ~57 kDa and the truncated version of ~47 kDa. We designed an antibody, called Vim3, against the unique C-terminal ending of the Vimentin 3 variant. Using immune histology, immune fluorescence, Western blot, and qRT-PCR analysis, a Vim3 overexpression was detectable exclusively in oncocytoma, making the detection of Vim3 a potential specific marker for benign kidney tumors. This antibody is the first to clearly differentiate benign oncocytoma and the mimicking eosinophilic variants of the RCCs. This differentiation between malignant and benign RCCs is essential for operative planning, follow-up therapy, and patients' survival. In the future the usage of Vimentin antibodies in routine pathology has to be applied with care. Consideration must be given to Vimentin specific binding epitopes otherwise a misdiagnosis of the patients' tumor samples may result.
The degradation of cytosol-invading pathogens by autophagy, a process known as xenophagy, is an important mechanism of the innate immune system. Inside the host, Salmonella Typhimurium invades epithelial cells and resides within a specialized intracellular compartment, the Salmonella-containing vacuole. A fraction of these bacteria does not persist inside the vacuole and enters the host cytosol. Salmonella Typhimurium that invades the host cytosol becomes a target of the autophagy machinery for degradation. The xenophagy pathway has recently been discovered, and the exact molecular processes are not entirely characterized. Complete kinetic data for each molecular process is not available, so far. We developed a mathematical model of the xenophagy pathway to investigate this key defense mechanism. In this paper, we present a Petri net model of Salmonella xenophagy in epithelial cells. The model is based on functional information derived from literature data. It comprises the molecular mechanism of galectin-8-dependent and ubiquitin-dependent autophagy, including regulatory processes, like nutrient-dependent regulation of autophagy and TBK1-dependent activation of the autophagy receptor, OPTN. To model the activation of TBK1, we proposed a new mechanism of TBK1 activation, suggesting a spatial and temporal regulation of this process. Using standard Petri net analysis techniques, we found basic functional modules, which describe different pathways of the autophagic capture of Salmonella and reflect the basic dynamics of the system. To verify the model, we performed in silico knockout experiments. We introduced a new concept of knockout analysis to systematically compute and visualize the results, using an in silico knockout matrix. The results of the in silico knockout analyses were consistent with published experimental results and provide a basis for future investigations of the Salmonella xenophagy pathway.
Author Summary
Salmonellae are Gram-negative bacteria, which cause the majority of foodborne diseases worldwide. Serovars of Salmonella cause a broad range of diseases, ranging from diarrhea to typhoid fever in a variety of hosts. In the year 2010, Salmonella Typhi caused 7.6 million foodborne diseases and 52 000 deaths, and Salmonella enterica was responsible for 78.7 million diseases and 59 000 deaths. After invasion of Salmonella into host epithelial cells, a small fraction of Salmonella escapes from a specialized intracellular compartment and replicates inside the host cytosol. Xenophagy is a host defense mechanism to protect the host cell from cytosolic pathogens. Understanding how Salmonella is recognized and targeted for xenophagy is an important subject of current research. To the best of our knowledge, no mathematical model has been presented so far, describing the process of Salmonella Typhimurium xenophagy. Here, we present a manually curated and mathematically verified theoretical model of Salmonella Typhimurium xenophagy in epithelial cells, which is consistent with the current state of knowledge. Our model reproduces literature data and postulates new hypotheses for future investigations.
In light of increasing division of labour in healthcare, the training and acquisition of both profession-specific and interprofessional competencies have been attributed growing significance, creating the need to test and establish specific teaching formats. Despite ever more complex and interconnected healthcare systems, an increase in patients’ active self-responsibility and innumerable pedagogical and technological innovations, educational systems have not reacted adequately to these new demands. Many authors, not lease the German Council of Science and Humanities, have therefore urged a rethinking of traditional medical education. Student-centred learning activities, such as problem-based and research-based learning, are becoming increasingly significant in view of the numbers of students achieving unsatisfactory levels of competence in critical thinking, communication and writing abilities and complex clinical decision making, for example. The Council of Science and Humanities arrived at a positive evaluation of the various model and reformed courses of study attempting to effectuate a comprehensive reorganisation of medical studies in content and structure as well as methods and didactics. The persistent pervasiveness of instructor-centred learning formats is not only to be found in medical education but in all of the health professions. Although alternative teaching and instruction formats have already been designed and their effectiveness deemed positive in empirical evaluation, the lecture remains the most practised means of transmitting knowledge. In its essence, however, learning is not a question of transmitting information but, moreover, a question of processing information. In traditional instruction units, referred to as “chalk and talk classes” by Becker and Watts, the teaching party presents material in the form of a lecture. As appropriate, questions may be permitted or short processing periods for the students may be integrated into the lecture. The knowledge-assimilating and most essential analysis of the lecture’s contents takes place in the subsequent self-instruction phase, in which the student works alone on concrete tasks. It is during the transfer of knowledge conveyed in the lectures, however, that most questions arise. Of further disadvantage in the traditional lecture is the low level of motivation among students to attend lectures as well as their often heterogeneous knowledge. The Inverted Classroom Model seems to be an eligible instrument for greater facilitation of student-centred and interprofessional learning.
Dieser Artikel beschreibt die Inverted-Classroom-Methode(ICM) im Sinne einer Einführung in die Thematik und soll als Praxisleitleitfaden für diejenigen dienen, die diese Methode in der medizinischen Aus-, Fort- und Weiterbildung einsetzen möchten. Es handelt sich bei der ICM um einen Blended-Learning-Methode, bei dem eine Selbstlernphase (individuelle Phase) vor die Präsenzunterrichtsphase gesetzt wird. In der Online-Phase wird Faktenwissen vermittelt, das als Grundlage für die Präsenzphase dient. Die Präsenzphase soll anschließend dafür genutzt werden, das erlernte Wissen zu vertiefen und anzuwenden. Dem gegenüber stehen die traditionellen Kurskonzepte, in denen das Faktenwissen beispielsweise in Vorlesungen oder in anderen Präsenzunterricht-Formaten vermittelt wird und die Vertiefung dieses Wissens durch die Studierenden im Anschluss daran im Selbststudium stattfinden soll. Das Ziel der ICM ist die Verschiebung des passiven Lernens hin zum aktivierenden Lernen, um das Lernen auf kognitiv anspruchvollen Ebenen wie Analyse, Synthese und Evaluation zu unterstützen. Dabei haben die gestiegene Produktion und Nutzung von Screencasts und Lernvideos, die „Bewegung“ der „Open Educational Resources“ und die verbreitete Nutzung von „Massive Open Online Courses“ (MOOCs) zu einer gestiegenen Verbreitung der Inverted-Classroom-Methode beigetragen. Der Artikel soll als Einführung in die Thematik dienen und dabei eine kurze Übersicht über wichtige Projekte und Forschungsergebnisse in der medizinischen Ausbildung und in weiteren Gesundheitsberufen geben. Außerdem werden die Vor- und Nachteile der Methode und ihr potentieller Nutzen für die zukünftige medizinische Aus- und Weiterbildung dargestellt.
Während des Zellzykluses werden spezifische regulatorische Proteine, die Cycline exprimiert, die mit ihren spezifischen CDK (Cyclin Dependent Kinases) interagieren und sie hierdurch aktivieren. So interagiert in der frühen G1 Phase Cyclin D1 mit CDK4 und CDK6. Die D-Cyclin kontrollieren gemeinsam mit Cyclin E den G1 Restriktionspunkt. Rb wird durch diese D-Cycline und die assoziierten Kinasen CDK4/6 mehrfach phosphoryliert und kann nun Transkriptionsfaktoren wie E2F nicht mehr inhibieren und die nun freie E2F/ DP-Untereinheit ( = DNS-Bindungsprotein) kann Promotoraktivierung vermitteln und Gene aktivieren, die die S-Phase einleiten. Hiermit wird der Zelle der Fortschritt durch den Zellzyklus ermöglicht bis Rb gegen Ende des Zellzyklus durch Phosphatasen dephoshoryliert wird und die aus der Mitose hervorgegangenen Tochterzellen nach Ende der M-Phase erneut in der G1-Phase sind. CDK-Inhibitoren (CDKI) können diese Cyclin/CDK Komplexe in jeder Zellzyklusphase hemmen und Zellzyklusarrest auslösen. In der vorliegenden Arbeit sollte die Expression von Cyclin D1 und Retinoblastomgens immunhistochemisch untersucht werden. Es wurde versucht, mit der Avidin-Biotin-Enzymkomplexmethode die Proteinexpression des Retinoblastomgens mit einem monoklonalem Antikörper in Probeexzisionen von Mammakarzinomen der Jahre 1983 bis 1987 dazustellen, die in Paraffinum eingebettet waren. Trotz vielfacher Versuchswiederholungen gelang es nicht, eine Kernfärbung hervorzubringen, die wissenschaftlichem Standard genügte. Zum damaligen Zeitpunkt stand noch nicht viel know-how bezüglich der Kernfärbung mittels Antikörpern zur Verfügung. Vor allem nicht bei Präparaten, die bis zu 15 Jahre in Paraffinum eingebetet waren. Somit konnte eine verwertbare Kernfärbung der Gewebeschnitte, das Retinoblastomgen betreffend, nicht nachgewiesen werden und damit war es bedauerlicherweise auch nicht möglich, eine Korrelation zwischen Cyclin D1 und Retinoblastomgen im Mammakarzinom nachzuweisen. Bei der nun verbliebenen Analyse des Cyclin D1 wiesen von 198 Tumoren 10,6% (21 Präparate) eine positive Kernfärbung auf. Hierbei wurden die Präparate, die bei der lichtmikroskopischen Beurteilung der immunhistochemisch gefärbten Zellen einen Prozentsatz von 10% oder größer aufwiesen, wurden als positiv gewertet.13 von den 198 Tumoren zeigten eine Färbbarkeit zwischen 1%-10% auf und wurden per definitionem als negativ gewertet. Hieraus folgt, dass bei 164 Tumoren überhaupt keine Zellkernfärbung stattfand. Es zeigte sich, dass aufgrund der niedrigen positiven Fallzahlen nur schwer eine statische Signifikanz erreichbar sein würde. Das spiegelte unter anderem die Korrelation mit dem Menopausenstatus wieder, die einen p-Wert von 0,273 aufwies und sich hiermit einer statistischen Signifikanz entzog. Auch beim Vergleich von Cyclin D1 mit dem Ostrogen/Progesteron- Rezeptorstatus ist ein verwertbares Ergebnis nicht erreichbar (p=0,08) Eine prognostische Signifikanz des TNM-Stagings konnte bei T:p= 0,496; N:p=0,052 und M:p=0,720 nicht bestätigt werden. Zwar zeigte sich bei der Cyclin D1-Expression der Lymphknoten primär ein grenzwertig positiver Wert von p=0,047. Dieser wurde jedoch durch den kontrollierenden Fisher Exact-Test nicht bestätigt (p=0,052). Ebenfalls konnte keine signifikante Beziehung zum histologischen Tumortyp (p=0,553) und zum Differenzierungsgrad (p=0,575) nachgewiesen werden. Bei den Kaplan-Meier-Analysen in Bezug auf das rezidivfreie Intervall
(p=0,934), das metastasenfreie Intervall (p=0,386) sowie das krankheitsfreie Intervall (p=0,709), konnte kein signifikanter Parameter erhoben werden. Der Einfluss von Cyclin D1 auf das Gesamtüberleben spiegelt letztendlich auch keinen signifikanten Zusammenhang wider (p=0,830). Insgesamt zeigte sich bei keinem Parameter ein signifikanter Bezug. Dies ist wohl, wie auch bei der Versuchsreihe mit dem Retinoblastom, bei dem es ja zu überhaupt keiner verwertbaren Kernfärbung kam, auf das Alter der Probeexcisionen und der damals noch in Entwicklung befindlichen Verfahren zu erklären. Wobei hier nur gemutmaßt werden kann. Eine etablierte Methode jedoch, stand noch nicht zur Verfügung. In den letzten Jahren ist zunehmend wenig Augenmerk dem Gebiet der Cycline und des Retinoblastomgens, besonders im Hinblick auf das Mammakarzinom, gelegt worden. Vielleicht lässt sich mit den jetzigen etablierten Methoden eine Renaissance dieser interessanten Forschungsrichtung erwecken.