EWS-FLI1 perturbs MRTFB/YAP-1/TEAD target gene regulation inhibiting cytoskeletal autoregulatory feedback in Ewing sarcoma.

Ewing sarcoma (EWS) is a paediatric bone cancer with high metastatic potential. Cellular plasticity resulting from dynamic cytoskeletal reorganization, typically regulated via the Rho pathway, is a prerequisite for metastasis initiation. Here, we interrogated the role of the Ewing sarcoma driver oncogene EWS-FLI1 in cytoskeletal reprogramming. We report that EWS-FLI1 strongly represses the activity of the Rho-F-actin signal pathway transcriptional effector MRTFB, affecting the expression of a large number of EWS-FLI1-anticorrelated genes including structural and regulatory cytoskeletal genes. Consistent with this finding, chromatin immunoprecipitation sequencing (ChIP-seq) revealed strong overlaps in myocardin-related transcription factor B (MRTFB) and EWS-FLI1 chromatin occupation, especially for EWS-FLI1-anticorrelated genes. Binding of the transcriptional co-activator Yes-associated protein (YAP)-1, enrichment of TEAD-binding motifs in these shared genomic binding regions and overlapping transcriptional footprints of MRTFB and TEAD factors led us to propose synergy between MRTFB and the YAP/TEAD complex in the regulation of EWS-FLI1-anticorrelated genes. We propose that EWS-FLI1 suppresses the Rho-actin pathway by perturbation of a MRTFB/YAP-1/TEAD transcriptional module, which directly affects the actin-autoregulatory feedback loop. As spontaneous fluctuations in EWS-FLI1 levels of Ewing sarcoma cells in vitro and in vivo, associated with a switch between a proliferative, non-migratory EWS-FLI1-high and a non-proliferative highly migratory EWS-FLI1-low state, were recently described, our data provide a mechanistic basis for the underlying EWS-FLI1-dependent reversible cytoskeletal reprogramming of Ewing sarcoma cells.

[Use of 2 % hyperbaric prilocaine for spinal anesthesia : sensitivity analysis in outpatient surgery]. / Einsatz von 2 %igem hyperbarem Prilocain zur Spinalanästhesie : Sensitivitätsanalyse in der ambulanten Chirurgie.

BACKGROUND: Hyperbaric prilocaine 2 % has been available for spinal anesthesia in Germany for 2 years and is characterized by a short duration of action, a lack of postspinal urine retention and a reduction of transient neurological syndromes. However, desirable pharmacological properties are contrasted by higher pharmacological costs compared to hyperbaric bupivacaine 0.5 %. MATERIALS AND METHODS: This paper deals with a sensitivity analysis for the use of hyperbaric prilocaine 2 % versus hyperbaric bupivacaine 0.5 % in Germany and investigates the financial break-even point up to which time a shorter patient stay in the recovery area compensates for the higher costs for the use of prilocaine 2 % for ambulatory spinal aaesthesia. A sensitivity analysis is an instrument of investment appraisal. It is a model to reduce a complex system with numerous variables to a straightforward calculation by assuming a framework requirement and systematically changing only one or two variables. In this paper additional costs for spinal anesthesia have been neglected, only the time a nurse spends with the patient in the recovery area and the costs for each vial of drug have been taken into account. RESULTS: For the assumption of 75 min time until leaving the recovery area and being discharged after spinal anesthesia with hyperbaric prilocaine 2 % versus 150 min (recovery of motor competence) or 405 min (voiding) with hyperbaric bupivacaine 0.5 % the calculation shows a cost benefit for hyperbaric prilocaine 2 % of EUR 11.64 or EUR 64.76 compared to hyperbaric bupivacaine 0.5 % and EUR 13.32 or EUR 66.44 compared to isobaric bupivacaine 0.5 %. Under the assumption that all patients who have received spinal anesthesia with hyperbaric bupivacaine 0.5 % can be discharged from the recovery area after 150 min, the use of hyperbaric prilocaine 2 % remains more economical as long as the patient is discharged from the recovery area within 130 min. If 405 min recovery time is assumed for hyperbaric bupivacaine 0.5 % the costs compared with hyperbaric prilocaine 2 % will be compensated after 300 min. To be more economical compared to patients with hyperbaric prilocaine 2 % those who received hyperbaric bupivacaine 0.5 % must be discharged from the recovery area within at least 100 min. However, a time of less than 160 min for discharge from the recovery area is not published anywhere in the literature. In summary, the use of hyperbaric prilocaine 2 % for 60 min operation time is cheaper than the use of bupivacaine 0.5 % as long as patients do not stay in the recovery area for longer than 120 min and are discharged from the recovery area. CONCLUSIONS: For German framework conditions the use of hyperbaric prilocaine 2 % can provide an economical advantage compared to the use of hyperbaric bupivacaine 0.5 % if staff assignment can be flexible.

[Influence of clonidine-induced systemic sympathicolysis on oxygenation and perfusion of the liver. Investigations with healthy pigs under general anesthesia]. / Einfluss der Clonidin-induzierten systemischen Sympathikolyse auf die Oxygenierung und Perfusion der Leber. Untersuchungen am gesunden Hausschwein in Allgemeinanästhesie.

BACKGROUND: Increased sympathetic nervous activity which induces vasoconstriction and decreases perfusion may be an underlying mechanism behind the development of perioperative liver damage. This animal study was designed to assess how clonidine-induced systemic sympathicolysis affects liver oxygenation with respect to induced hypotension and vasodilatation under physiological conditions. METHODS: Following ethical approval 17 anesthetized and acutely instrumented pigs were randomly assigned to 2 groups. Group 1 consisted of 8 animals receiving intravenous clonidine (2 microg x kg(-1) bolus and 2 microg x kg(-1) x h(-1) for induction of sympathicolysis and group 2 consisted of 9 animals serving as controls. After obtaining baseline values, measurements were repeated 90 and 250 min after starting to reduce systemic sympathetic nervous activity. RESULTS: Clonidine-induced systemic sympathicolysis was associated with decreased mean arterial blood pressure, cardiac output and heart rate. Portal venous and hepatic arterial blood flow, oxygen delivery to the liver, oxygen uptake and liver tissue oxygen partial pressure remained unchanged. The plasma indocyanine green disappearance rate increased. CONCLUSION: We concluded that despite decreased mean arterial pressure and cardiac output, clonidine-induced systemic sympathicolysis did not affect liver oxygenation or perfusion.

Effects of systemically applied clonidine on intestinal perfusion and oxygenation in healthy pigs during general anaesthesia and laparotomy.

BACKGROUND AND OBJECTIVE: Clonidine, which is used for induction of sympatholysis and prevention or treatment of alcohol withdrawal in anaesthesia and intensive care medicine, may have deleterious effects on intestinal mucosal perfusion. This study was designed to investigate the effects of clonidine on intestinal perfusion and oxygenation. METHODS: Following ethical approval 17 anaesthetized, and acutely instrumented pigs were randomly assigned to two groups: eight animals received intravenous clonidine (2 microg kg(-1) bolus and 2 microg kg(-1) h(-1)), nine animals served as a control group. Measurement points for systemic and regional haemodynamic and oxygenation parameters were 135 and 315 min after starting the clonidine application. RESULTS: Clonidine elicited systemic haemodynamic changes (median [25-75th interquartile range]): heart rate (106 [91, 126] to 84 [71, 90] beats min(-1)) cardiac output (147 [123, 193] to 90 [87, 107] mL min(-1) kg(-1)) and mean arterial pressure (77 [72, 93] to 69 [61, 78] mmHg) decreased. Despite systemic haemodynamic changes, the superior mesenteric artery blood flow did not change in the clonidine group. The vascular resistance of the superior mesenteric artery decreased. The small intestinal oxygen supply, the mucosal and the serosal tissue oxygen partial pressure did not change. CONCLUSIONS: Systemic sympatholysis induced by intravenously applied clonidine in addition to basic intravenous anaesthesia elicited a decrease in cardiac output and mean arterial pressure. However, regional macrohaemodynamic perfusion was maintained and intestinal oxygenation did not change. Clonidine does not impair intestinal mucosal and serosal oxygenation under physiological conditions.