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Genetic mutations underlying neurodegenerative disorders impair ribosomal DNA (rDNA) transcription suggesting that nucleolar dysfunction could be a novel pathomechanism in polyglutamine diseases and in certain forms of amyotrophic lateral sclerosis/frontotemporal dementia. Here, we investigated nucleolar activity in pre-symptomatic digenic models of Parkinson's disease (PD) that model the multifactorial aetiology of this disease. To this end, we analysed a novel mouse model mildly overexpressing mutant human α-synuclein (hA53T-SNCA) in a PTEN-induced kinase 1 (PINK1/PARK6) knockout background and mutant mice lacking both DJ-1 (also known as PARK7) and PINK1. We showed that overexpressed hA53T-SNCA localizes to the nucleolus. Moreover, these mutants show a progressive reduction of rDNA transcription linked to a reduced mouse lifespan. By contrast, rDNA transcription is preserved in DJ-1/PINK1 double knockout (DKO) mice. mRNA levels of the nucleolar transcription initiation factor 1A (TIF-IA, also known as RRN3) decrease in the substantia nigra of individuals with PD. Because loss of TIF-IA, as a tool to mimic nucleolar stress, increases oxidative stress and because DJ-1 and PINK1 mutations result in higher vulnerability to oxidative stress, we further explored the synergism between these PD-associated genes and impaired nucleolar function. By the conditional ablation of TIF-IA, we blocked ribosomal RNA (rRNA) synthesis in adult dopaminergic neurons in a DJ-1/PINK1 DKO background. However, the early phenotype of these triple knockout mice was similar to those mice exclusively lacking TIF-IA. These data sustain a model in which loss of DJ-1 and PINK1 does not impair nucleolar activity in a pre-symptomatic stage. This is the first study to analyse nucleolar function in digenic PD models. We can conclude that, at least in these models, the nucleolus is not as severely disrupted as previously shown in DA neurons from PD patients and neurotoxin-based PD mouse models. The results also show that the early increase in rDNA transcription and nucleolar integrity may represent specific homeostatic responses in these digenic pre-symptomatic PD models.
Development of single-port cholecystectomy : results of a case-control study matched to one surgeon
(2012)
Background: Single-port laparoscopic cholecystectomy is an evolving technique which is now widely established. Up until now, the safety of the procedure and a respective learning curve have not been adequately reported in most studies. The aim of this study was to demonstrate that single-port cholecystectomy is a safe procedure, with a positive learning curve from a case-control study matched to one surgeon.
Methods: One hundred single-port cholecystectomies performed by one surgeon (AB) were retrospectively matched to 100 patients who underwent conventional laparoscopic cholecystectomy carried out by the same surgeon. The two groups were matched in respect of surgical indication, gender, age, and body mass index. The groups were compared with respect to operation time, use of additional trocars, analgesics required in the post anesthesia care unit, postoperative complications, and duration of hospital stay.
Results: No significant difference was found between the two groups with respect to postoperative complications and stay in hospital. The operation time increased slightly in the single-port group. Directly after the operation, the analgesic use required in the post anesthesia care unit was higher in the single-port group. Consumption of analgesics on the surgical ward was very similar in each group. In respect to the learning curve, the operation time and use of additional trocars showed a positive trend, starting with the thirtieth operation.
Conclusion: Single-port cholecystectomy is a feasible and safe procedure in a specialist setting. The procedure can be done under the same safety rules as those for conventional laparoscopic cholecystectomy. Considering the learning curve, starting with the thirtieth operation, a positive trend was seen. Long-term studies will be needed to establish the incidence and rate of incisional hernias.
This post hoc analysis of a phase 3 trial explored the effect of pixantrone in patients (50 pixantrone, 47 comparator) with relapsed or refractory aggressive B-cell non-Hodgkin lymphoma (NHL) confirmed by centralized histological review. Patients received 28-d cycles of 85 mg/m2 pixantrone dimaleate (equivalent to 50 mg/m2 in the approved formulation) on days 1, 8 and 15, or comparator. The population was subdivided according to previous rituximab use and whether they received the study treatment as 3rd or 4th line. Median number of cycles was 4 (range, 2–6) with pixantrone and 3 (2–6) with comparator. In 3rd or 4th line, pixantrone was associated with higher complete response (CR) (23·1% vs. 5·1% comparator, P = 0·047) and overall response rate (ORR, 43·6% vs. 12·8%, P = 0·005). In 3rd or 4th line with previous rituximab (20 pixantrone, 18 comparator), pixantrone produced better ORR (45·0% vs. 11·1%, P = 0·033), CR (30·0% vs. 5·6%, P = 0·093) and progression-free survival (median 5·4 vs. 2·8 months, hazard ratio 0·52, 95% confidence interval 0·26–1·04) than the comparator. Similar results were found in patients without previous rituximab. There were no unexpected safety issues. Pixantrone monotherapy is more effective than comparator in relapsed or refractory aggressive B-cell NHL in the 3rd or 4th line setting, independently of previous rituximab.
Objective: Loss of function mutations in PINK1 typically lead to early onset Parkinson disease (PD). Zebrafish (Danio rerio) are emerging as a powerful new vertebrate model to study neurodegenerative diseases. We used a pink1 mutant (pink−/−) zebrafish line with a premature stop mutation (Y431*) in the PINK1 kinase domain to identify molecular mechanisms leading to mitochondrial dysfunction and loss of dopaminergic neurons in PINK1 deficiency.
Methods: The effect of PINK1 deficiency on the number of dopaminergic neurons, mitochondrial function, and morphology was assessed in both zebrafish embryos and adults. Genome-wide gene expression studies were undertaken to identify novel pathogenic mechanisms. Functional experiments were carried out to further investigate the effect of PINK1 deficiency on early neurodevelopmental mechanisms and microglial activation.
Results: PINK1 deficiency results in loss of dopaminergic neurons as well as early impairment of mitochondrial function and morphology in Danio rerio. Expression of TigarB, the zebrafish orthologue of the human, TP53-induced glycolysis and apoptosis regulator TIGAR, was markedly increased in pink−/− larvae. Antisense-mediated inactivation of TigarB gave rise to complete normalization of mitochondrial function, with resulting rescue of dopaminergic neurons in pink−/− larvae. There was also marked microglial activation in pink−/− larvae, but depletion of microglia failed to rescue the dopaminergic neuron loss, arguing against microglial activation being a key factor in the pathogenesis.
Interpretation: Pink1−/− zebrafish are the first vertebrate model of PINK1 deficiency with loss of dopaminergic neurons. Our study also identifies TIGAR as a promising novel target for disease-modifying therapy in PINK1-related PD. Ann Neurol 2013;74:837–847
Stroke is a major public health issue worldwide. The prevalence of stroke in 2010 was 33 million, with 16.9 million people having a first stroke.1 Stroke was the second‐leading cause of death behind heart disease globally, accounting for over 10% of total deaths worldwide.
Stroke is a heterogeneous condition that can be due to rupture of a blood vessel (hemorrhagic) or to blockage of a vessel (ischemic). About 85% of strokes are ischemic in origin and these are often classified by mechanism. This should be distinguished from risk factors such as hypertension, diabetes, smoking, etc. Risk factors increase the risk of stroke but do not necessarily explain the mechanism of a particular stroke. About 25% of ischemic strokes have a radiographic appearance similar to that seen in patients with cardioembolic sources (such as atrial fibrillation [AF], prosthetic valves, valvular prolapse, or mitral valve regurgitation), but no embolic source is found. These "cryptogenic strokes" (CS; also called embolic strokes of undetermined source) pose a particular clinical challenge in that the optimal antithrombotic therapy to reduce recurrence is uncertain. Since there are currently no data to support long‐term oral anticoagulation (OAC) in CS, but also no specific trials that have addressed this question, guidelines recommend antiplatelet therapy. Identification of AF in these patients changes the most likely mechanism to cardioembolism, and thus changes the recommended antithrombotic therapy to OAC, which is extremely effective in preventing stroke in patients with AF.
This report is based on discussions held at The Diagnostics and Monitoring Stroke Focus Group, a meeting held on January 15 to 17, 2015. The meeting focused on CS as a healthcare issue, and the utility of extended cardiac monitoring for AF in patients with strokes of unknown origin. The objectives of the meeting were to review existing information on the subject, define areas where knowledge was lacking or limited, and discuss study designs by which information gaps might be filled.
Aims: The purpose of this study was to analyze the prevalence of depression, anxiety, adjustment disorders, and somatoform disorders in patients diagnosed with age-related macular degeneration (AMD) in Germany.
Methods: This study included 7,580 patients between the ages of 40 and 90 diagnosed with AMD between January 2011 and December 2014 in 1,072 primary care practices (index date). The last follow-up was in July 2016. We also included 7,580 controls without AMD, which were matched (1:1) to the AMD cases by age, sex, type of health insurance (private or statutory), physician, and Charlson comorbidity score as a generic marker of comorbidity. The outcome of the study was the prevalence of depression, anxiety, adjustment disorders, and somatoform disorders recorded in the database between the index date and the end of follow-up.
Results: The mean age among subjects was 75.7 years (SD=10.1 years), 34.0% were men, and 7.8% had private health insurance coverage. The Charlson comorbidity index was 2.0 (SD=1.8). Depression was the most frequent disease (33.7% in AMD patients versus 27.3% in controls), followed by somatoform disorders (19.6% and 16.7%), adjustment disorders (14.8% and 10.5%), and anxiety disorders (11.7% and 8.2%). Depression (OR=1.37, 95% CI: 1.27–1.47), anxiety (OR=1.50, 95% CI: 1.35–1.67), adjustment disorders (OR=1.50, 95% CI: 1.36–1.65), and somatoform disorders (OR=1.22, 95% CI: 1.12–1.32) were all positively associated with AMD.
Conclusion: Overall, a significant association was found between AMD and depression, anxiety, adjustment disorders, and somatoform disorders.
Green tea (GT) and green tea extracts (GTE) have been postulated to decrease cancer incidence. In vitro results indicate a possible effect; however, epidemiological data do not support cancer chemoprevention. We have performed a PubMED literature search for green tea consumption and the correlation to the common tumor types lung, colorectal, breast, prostate, esophageal and gastric cancer, with cohorts from both Western and Asian countries. We additionally included selected mechanistical studies for a possible mode of action. The comparability between studies was limited due to major differences in study outlines; a meta analysis was thus not possible and studies were evaluated individually. Only for breast cancer could a possible small protective effect be seen in Asian and Western cohorts, whereas for esophagus and stomach cancer, green tea increased the cancer incidence, possibly due to heat stress. No effect was found for colonic/colorectal and prostatic cancer in any country, for lung cancer Chinese studies found a protective effect, but not studies from outside China. Epidemiological studies thus do not support a cancer protective effect. GT as an indicator of as yet undefined parameters in lifestyle, environment and/or ethnicity may explain some of the observed differences between China and other countries.
Das Buch "Qualitative Evaluation" zeigt Schritt für Schritt die Vorgehensweise und stellt damit in sehr anwendungsorientierter Form das Handwerkszeug für eine qualitative Evaluation zur Verfügung. So werden Lesende in die Lage versetzt, eine solche Evaluation auch bei geringen Vorkenntnissen durchzuführen, wobei damit das Risiko verbunden sein kann, dass bei der Interpretation der Befunde wichtige Voraussetzungen für das Gelingen einer qualitativen Studie wie Verwurzelung der Interpretation im tatsächlich aufgezeichneten Text vernachlässigt werden.
Osteoid osteoma is a benign bone tumor of undetermined etiology, composed of a central zone named nidus which is an atypical bone completely enclosed within a wellvascularized stroma and a peripheral sclerotic reaction zone. There are three types of radiographic features: cortical, medullary and subperiosteal. Forty-four patients with osteoid osteoma were studied retrospectively. In plain films, 35 patients presented as the cortical type, six cases were located in the medullary zone and three had subperiosteal osteoid osteoma. In all the cases, the nidus was visualized on computed tomography (CT) scan. The nidus was visible in four out of five patients who had also undergone magnetic resonance imaging (MRI). Double-density sign, seen on radionuclide bone scans was positive in all patients. MRI is more sensitive in the diagnosis of bone marrow and soft tissue abnormalities adjacent to the lesion, and in the nidus that is located closer to the medullary zone. On the other hand, CT is more specific when it comes to detecting the lesion’s nidus.
Die Entwicklungen in der Medizinischen Ausbildung der letzten Jahre konfrontieren Lehrende zunehmend mit neuen didaktischen Herausforderungen. An zahlreichen Standorten im deutschsprachigen Raum werden bereits Qualifizierungsangebote für Lehrende angeboten, jedoch fehlt bisher ein Orientierungsrahmen für medizindidaktische Kompetenzen, der ein Qualifikationsprofil für Lehrende darstellt.
Vor dem Hintergrund der Diskussion um die Kompetenzorientierung des Medizinstudiums und auf Grundlage aktueller internationaler Literatur wurde durch den GMA Ausschuss für Personal- und Organisationsentwicklung in der Lehre ein Kernkompetenzmodell für Lehrende in der Medizin entwickelt. Das Modell soll nicht nur den Lehrenden Orientierung zu ihrem Qualifikationsprofil geben, sondern auch die inhaltliche Ausrichtung hochschuldidaktischer (Aus-) Weiter- und Fortbildungen sowie die Evaluation von Fakultätsentwicklungsprozessen erleichtern und nicht zuletzt einheitliche Kriterien für die Beurteilung der Lehrqualifikation in deutschsprachigen Raum definieren.
Das Modell besteht aus sechs Kompetenzfeldern, für die jeweils Teilkompetenzen definiert und Lernziele beschrieben wurden. Anwendungsbeispiele sollen die jeweiligen Kompetenzen verdeutlichen.
Das Modell ist für die praktische Anwendung konzipiert und soll in einem nächsten Schritt durch spezifische Kompetenzen für Lehrende mit besonderen Aufgaben ergänzt werden.