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Institute
Acute myeloid leukemia (AML) is characterized by an aberrant self-renewal of hematopoietic stem cells (HSC) and a block in differentiation. The major therapeutic challenge is the characterization of the leukemic stem cell as a target for the eradication of the disease. Until now the biology of AML-associated fusion proteins (AAFPs), such as the t(15;17)-PML/RARα, t(8;21)-RUNX1/RUNX1T1 and t(6;9)-DEK/NUP214, all able to induce AML in mice, was investigated in different models and genetic backgrounds, not directly comparable to each other. To avoid the bias of different techniques and models we expressed these three AML-inducing oncogenes in an identical genetic background and compared their influence on the HSC compartment in vitro and in vivo.
These AAFPs exerted differential effects on HSCs and PML/RARα, similar to DEK/NUP214, induced a leukemic phenotype from a small subpopulation of HSCs with a surface marker pattern of long-term HSC and characterized by activated STAT3 and 5. In contrast the established AML occurred from mature populations in the bone marrow. The activation of STAT5 by PML/RARα and DEK/NUP214 was confirmed in t(15;17)(PML/RARα) and t(6;9)(DEK/NUP214)-positive patients as compared to normal CD34+ cells. The activation of STAT5 was reduced upon the exposure to Arsenic which was accompanied by apoptosis in both PML/RARα- and DEK/NUP214-positive leukemic cells. These findings indicate that in AML the activation of STATs plays a decisive role in the biology of the leukemic stem cell. Furthermore we establish exposure to arsenic as a novel concept for the treatment of this high risk t(6;9)-positive AML.
Programele computerizate au un rol indiscutabil în atingerea unor standarde ridicate în procesul educațional. Pe de altă parte acestea sunt instrumente eficiente în identificarea particularităților cazurilor clinice, evaluarea acestora în conformitate cu indicii clinico-biologici specifici. În timpul procesului didactic, simularea are un rol esenţial, ca o prefaţă la procedurile practice care formează abilităţile practice pe fiecare entitate clinică în medicina dentară.
A potential clinical and etiological overlap between schizophrenia (SZ) and bipolar disorder (BD) has long been a subject of discussion. Imaging studies imply functional and structural alterations of the hippocampus in both diseases. Thus, imaging this core memory region could provide insight into the pathophysiology of these disorders and the associated cognitive deficits. To examine possible shared alterations in the hippocampus, we conducted a multi-modal assessment, including functional and structural imaging as well as neurobehavioral measures of memory performance in BD and SZ patients compared with healthy controls. We assessed episodic memory performance, using tests of verbal and visual learning (HVLT, BVMT) in three groups of participants: BD patients (n = 21), SZ patients (n = 21) and matched (age, gender, education) healthy control subjects (n = 21). In addition, we examined hippocampal resting state functional connectivity, hippocampal volume using voxel-based morphometry (VBM) and fibre integrity of hippocampal connections using diffusion tensor imaging (DTI). We found memory deficits, changes in functional connectivity within the hippocampal network as well as volumetric reductions and altered white matter fibre integrity across patient groups in comparison with controls. However, SZ patients when directly compared with BD patients were more severely affected in several of the assessed parameters (verbal learning, left hippocampal volumes, mean diffusivity of bilateral cingulum and right uncinated fasciculus). The results of our study suggest a graded expression of verbal learning deficits accompanied by structural alterations within the hippocampus in BD patients and SZ patients, with SZ patients being more strongly affected. Our findings imply that these two disorders may share some common pathophysiological mechanisms. The results could thus help to further advance and integrate current pathophysiological models of SZ and BD.
Highly promising preclinical data obtained in cultured cells and in nude mice bearing xenografts contrast with the rather modest clinical efficacy of Polo-like kinase 1 (Plk1) inhibitors. In the present study, we investigated if Plk1 might be a suitable target in hepatocellular carcinoma (HCC) and if a genetically engineered mouse tumor model that well reflects the tumor cell and micro-environmental features of naturally occurring cancers might be suitable to study anti-Plk1 therapy. Analysis of Plk1 expression in human HCC samples confirmed that HCC express much higher Plk1 levels than the adjacent normal liver tissue. Inhibition of Plk1 by an adenovirus encoding for a short hairpin RNA against Plk1 or by the small-molecule inhibitor BI 2536 reduced the viability of HCC cell lines and inhibited HCC xenograft progression in nude mice. Treatment of transforming growth factor (TGF) α/c-myc bitransgenic mice with BI 2536 during hepatocarcinogenesis reduced the number of dysplastic foci and of Ki-67-positive cells within the foci, indicating diminished tumorigenesis. In contrast, BI 2536 had no significant effect on HCC progression in the transgenic mouse HCC model as revealed by magnetic resonance imaging. Measurement of BI 2536 by mass spectrometry revealed considerably lower BI 2536 levels in HCC compared with the adjacent normal liver tissue. In conclusion, low intratumoral levels are a novel mechanism of resistance to the Plk1 inhibitor BI 2536. Plk1 inhibitors achieving sufficient intratumoral levels are highly promising in HCC treatment.
We report on posttransplant relapsed pediatric patients with B-precursor acute lymphoblastic leukemia with no further standard of care therapy who were treated with the T-cell engaging CD19/CD3-bispecific single-chain antibody construct blinatumomab on a compassionate use basis. Blast load was assessed prior to, during and after blinatumomab cycle using flow cytometry to detect minimal residual disease, quantitative polymerase chain reaction for rearrangements of the immunoglobulin or T-cell receptor genes, and bcr/abl mutation detection in one patient with Philadelphia chromosome-positive acute lymphoblastic leukemia. Blinatumomab was administered as a 4-week continuous intravenous infusion at a dosage of 5 or 15 μg/m2/day. Nine patients received a total of 18 cycles. Four patients achieved complete remission after the first cycle of treatment; 2 patients showed a complete remission from the second cycle after previous reduction of blast load by chemotherapy. Three patients did not respond, of whom one patient proceeded to a second cycle without additional chemotherapy and again did not respond. Four patients were successfully retransplanted in molecular remission from haploidentical donors. After a median follow up of 398 days, the probability of hematologic event-free survival is 30%. Major toxicities were grade 3 seizures in one patient and grade 3 cytokine release syndrome in 2 patients. Blinatumomab can induce molecular remission in pediatric patients with posttransplant relapsed B-precursor acute lymphoblastic leukemia and facilitate subsequent allogeneic hematopoietic stem cell transplantation from haploidentical donor with subsequent long-term leukemia-free survival.
• Endomicroscopy is a new imaging tool for gastrointestinal endoscopy.
• Panchromoendoscopy with targeted biopsies has become the method of choice for surveillance of patients with inflammatory bowel disease.
• Endomicroscopy can be added after chromoendoscopy to clarify whether standard biopsies are still needed.
• This smart biopsy concept can increase the diagnostic yield of intraepithelial neoplasia and substantially reduce the need for biopsies.
• Endomicroscopy is still mainly used for research but clinical acceptance is increasing because of a multitude of positive studies about the diagnostic value of endomicroscopy.
Hintergrund: Es ist unbekannt bzw. umstritten, ob die in Deutschland eingeführten Umweltzonen (UWZ) die Feinstaubbelastung nachweisbar reduzieren.
Methode: PM10-Konzentrationen von den Messstationen innerhalb und außerhalb der UWZ in 19 deutschen Städten wurden analysiert (Augsburg, Berlin, Dortmund, Duisburg, Düsseldorf, Essen, Frankfurt a. M., Hannover, Herrenberg, Ilsfeld, Karlsruhe, Köln, Ludwigsburg, Mannheim, München, Reutlingen, Stuttgart, Tübingen, Wuppertal), um die Wirksamkeit der Fahrverbote (Stufe 1) für Fahrzeuge der Schadstoffgruppe 1 (ohne Plakette) auf die Schadstoffkonzentration zu untersuchen. Kontinuierliche Halbstundenmesswerte und gravimetrische Tagesmittelwerte wurden für den Zeitraum von ca. 2005 bis Ende 2009 übernommen. Die Analyse beruht auf vier einander paarweise zugeordneten Messwerten als gematchte Quadrupel aus zwei Index- und zwei Referenzwerten (Indexstationen liegen innerhalb, Referenzstationen messen außerhalb der UWZ). Ein Indexwert und der simultan gemessene Referenzwert wurden während der aktiven Phase der UWZ gemessen, das andere Wertepaar wurde vor Einführung der UWZ erhoben. Die Wertepaare haben eine Zeitdifferenz von 364 Tagen oder von einem Vielfachen von 364 Tagen, wodurch die Jahreszeit, der Wochentag und die Tageszeit im Quadrupel konstant gehalten werden. Differenzen der Indexwerte wurden regressionstechnisch mit den Differenzen der Referenzwerte korrigiert, wobei meteorologische Parameter (Mischungsschichthöhe, Niederschlagsmenge, Windgeschwindigkeit), Schulferienzeiten, Phase der Umweltprämie, LKW-Fahrverbotszeiten und Ausgangswerte an den Index- und Referenzstationen als Kovariablen in sog. „fixed effects“ Regressionsanalysen der Quadrupel berücksichtigt wurden (Differenzwertmethode im Zwei-Perioden-Fall). Dieser statistische Ansatz wurde vor der eigentlichen Datenanalyse an simulierten Messdaten der FU Berlin erfolgreich erprobt.
Ergebnisse: 2 110 803 Quadrupel kontinuierlicher PM10-Messungen und 15 735 gravimetrische Quadrupel wurden aus den verfügbaren Daten der Messstationen identifiziert, aus denen 61 169 Quadrupel zu Tagesmittelwerten aufgebaut wurden. Die Analysen für die erste Stufe ergaben als beste Effektschätzer (an allen Indexstationen) eine Feinstaubreduktion von ≤ 0,2 μg/m3 (bzw. relative PM10-Reduktionen ≤ 1 %). Der beste Effektschätzer an allen Verkehrsstationen (also ohne städtische Hintergrund- und Industrieindexstationen) lag unterhalb von 1 μg/m3 (bzw. weniger als 5 %).
Schlussfolgerungen: Alle Analysewerte liegen damit unter den vor Einführung von UWZ prognostizierten Feinstaubreduktionen. Diese Studie untersuchte als erste übergreifend die Wirksamkeit von UWZ der Stufe 1 in Deutschland auf die Feinstaubkonzentrationen von PM10 nach einem einheitlichen Datensammlungs- und Analyseplan und unter Berücksichtigung möglichst vieler Störeinflüsse.
The highly conserved eukaryotic process of macroautophagy (autophagy) is a non-specific bulk-degradation program critical for maintaining proper cellular homeostasis, and for clearing aged and damaged organelles. This decision is inextricably dependent upon prevailing metabolic demands and energy requirements of the cell. Soluble monomeric decorin functions as a natural tumor repressor that antagonizes a variety of receptor tyrosine kinases. Recently, we discovered that decorin induces endothelial cell autophagy, downstream of VEGFR2. This process was wholly dependent upon Peg3, a decorin-inducible genomically imprinted tumor suppressor gene. However, the signaling cascades responsible have remained elusive. In this report we discovered that Vps34, a class III phosphoinositide kinase, is an upstream kinase required for Peg3 induction. Moreover, decorin triggered differential formation of Vps34/Beclin 1 complexes with concomitant dissolution of inhibitive Bcl-2/Beclin 1 complexes. Further, decorin inhibited anti-autophagic signaling via suppression of Akt/mTOR/p70S6K activity with the concurrent activation of pro-autophagic AMPK-mediated signaling cascades. Mechanistically, AMPK is downstream of VEGFR2 and inhibition of AMPK signaling abrogated decorin-evoked autophagy. Collectively, these findings hint at the complexity of the underlying molecular relays necessary for decorin-evoked endothelial cell autophagy and reveal important therapeutic targets for augmenting autophagy and combatting tumor angiogenesis.
The highly conserved eukaryotic process of macroautophagy (autophagy) is a non-specific bulk-degradation program critical for maintaining proper cellular homeostasis, and for clearing aged and damaged organelles. This decision is inextricably dependent upon prevailing metabolic demands and energy requirements of the cell. Soluble monomeric decorin functions as a natural tumor repressor that antagonizes a variety of receptor tyrosine kinases. Recently, we discovered that decorin induces endothelial cell autophagy, downstream of VEGFR2. This process was wholly dependent upon Peg3, a decorin-inducible genomically imprinted tumor suppressor gene. However, the signaling cascades responsible have remained elusive. In this report we discovered that Vps34, a class III phosphoinositide kinase, is an upstream kinase required for Peg3 induction. Moreover, decorin triggered differential formation of Vps34/Beclin 1 complexes with concomitant dissolution of inhibitive Bcl-2/Beclin 1 complexes. Further, decorin inhibited anti-autophagic signaling via suppression of Akt/mTOR/p70S6K activity with the concurrent activation of pro-autophagic AMPK-mediated signaling cascades. Mechanistically, AMPK is downstream of VEGFR2 and inhibition of AMPK signaling abrogated decorin-evoked autophagy. Collectively, these findings hint at the complexity of the underlying molecular relays necessary for decorin-evoked endothelial cell autophagy and reveal important therapeutic targets for augmenting autophagy and combatting tumor angiogenesis.