CIP2A regulates MYC translation (via its 5'UTR) in colorectal cancer.

BACKGROUND: Deregulated expression of MYC is a driver of colorectal carcinogenesis, suggesting that decreasing MYC expression may have significant therapeutic value. CIP2A is an oncogenic factor that regulates MYC expression. CIP2A is overexpressed in colorectal cancer (CRC), and its expression levels are an independent marker for long-term outcome of CRC. Previous studies suggested that CIP2A controls MYC protein expression on a post-transcriptional level. METHODS: To determine the mechanism by which CIP2A regulates MYC in CRC, we dissected MYC translation and stability dependent on CIP2A in CRC cell lines. RESULTS: Knockdown of CIP2A reduced MYC protein levels without influencing MYC stability in CRC cell lines. Interfering with proteasomal degradation of MYC by usage of FBXW7-deficient cells or treatment with the proteasome inhibitor MG132 did not rescue the effect of CIP2A depletion on MYC protein levels. Whereas CIP2A knockdown had marginal influence on global protein synthesis, we could demonstrate that, by using different reporter constructs and cells expressing MYC mRNA with or without flanking UTR, CIP2A regulates MYC translation. This interaction is mainly conducted by the MYC 5'UTR. CONCLUSIONS: Thus, instead of targeting MYC protein stability as reported for other tissue types before, CIP2A specifically regulates MYC mRNA translation in CRC but has only slight effects on global mRNA translation. In conclusion, we propose as novel mechanism that CIP2A regulates MYC on a translational level rather than affecting MYC protein stability in CRC.

Complement C5a-Induced Changes in Neutrophil Morphology During Inflammation.

The complement and neutrophil defence systems, as major components of innate immunity, are activated during inflammation and infection. For neutrophil migration to the inflamed region, we hypothesized that the complement activation product C5a induces significant changes in cellular morphology before chemotaxis. Exposure of human neutrophils to C5a dose- and time-dependently resulted in a rapid C5a receptor-1 (C5aR1)-dependent shape change, indicated by enhanced flow cytometric forward-scatter area values. Similar changes were observed after incubation with zymosan-activated serum and in blood neutrophils during murine sepsis, but not in mice lacking the C5aR1. In human neutrophils, Amnis high-resolution digital imaging revealed a C5a-induced decrease in circularity and increase in the cellular length/width ratio. Biomechanically, microfluidic optical stretching experiments indicated significantly increased neutrophil deformability early after C5a stimulation. The C5a-induced shape changes were inhibited by pharmacological blockade of either the Cl-/HCO3--exchanger or the Cl- -channel. Furthermore, actin polymerization assays revealed that C5a exposure resulted in a significant polarization of the neutrophils. The functional polarization process triggered by ATP-P2X/Y-purinoceptor interaction was also involved in the C5a-induced shape changes, because pretreatment with suramin blocked not only the shape changes but also the subsequent C5a-dependent chemotactic activity. In conclusion, the data suggest that the anaphylatoxin C5a regulates basic neutrophil cell processes by increasing the membrane elasticity and cell size as a consequence of actin-cytoskeleton polymerization and reorganization, transforming the neutrophil into a migratory cell able to invade the inflammatory site and subsequently clear pathogens and molecular debris.

Field-Line Localized Destabilization of Ballooning Modes in Three-Dimensional Tokamaks.

Field-line localized ballooning modes have been observed at the edge of high confinement mode plasmas in ASDEX Upgrade with rotating 3D perturbations induced by an externally applied n=2 error field and during a moderate level of edge localized mode mitigation. The observed ballooning modes are localized to the field lines which experience one of the two zero crossings of the radial flux surface displacement during one rotation period. The localization of the ballooning modes agrees very well with the localization of the largest growth rates from infinite-n ideal ballooning stability calculations using a realistic 3D ideal magnetohydrodynamic equilibrium. This analysis predicts a lower stability with respect to the axisymmetric case. The primary mechanism for the local lower stability is the 3D distortion of the local magnetic shear.

Damage- and pathogen-associated molecular patterns and alarmins: keys to sepsis?.

The concept that sepsis is the result of an uncontrolled inflammatory response of the host's innate immune system towards invading pathogens has recently been challenged. Evidence is accumulating that, in addition, host-derived alarm molecules are released during sepsis- and trauma-associated cell death, thus triggering the host's immune response. The identification and characterization of exogenous as well as endogenous danger molecules allowed significant advances in our understanding of the pathophysiology of sepsis and may provide potential targets for therapeutic interventions.

Targeting bromodomain-containing protein 4 (BRD4) inhibits MYC expression in colorectal cancer cells.

The transcriptional regulator BRD4 has been shown to be important for the expression of several oncogenes including MYC. Inhibiting of BRD4 has broad antiproliferative activity in different cancer cell types. The small molecule JQ1 blocks the interaction of BRD4 with acetylated histones leading to transcriptional modulation. Depleting BRD4 via engineered bifunctional small molecules named PROTACs (proteolysis targeting chimeras) represents the next-generation approach to JQ1-mediated BRD4 inhibition. PROTACs trigger BRD4 for proteasomale degradation by recruiting E3 ligases. The aim of this study was therefore to validate the importance of BRD4 as a relevant target in colorectal cancer (CRC) cells and to compare the efficacy of BRD4 inhibition with BRD4 degradation on downregulating MYC expression. JQ1 induced a downregulation of both MYC mRNA and MYC protein associated with an antiproliferative phenotype in CRC cells. dBET1 and MZ1 induced degradation of BRD4 followed by a reduction in MYC expression and CRC cell proliferation. In SW480 cells, where dBET1 failed, we found significantly lower levels of the E3 ligase cereblon, which is essential for dBET1-induced BRD4 degradation. To gain mechanistic insight into the unresponsiveness to dBET1, we generated dBET1-resistant LS174t cells and found a strong downregulation of cereblon protein. These findings suggest that inhibition of BRD4 by JQ1 and degradation of BRD4 by dBET1 and MZ1 are powerful tools for reducing MYC expression and CRC cell proliferation. In addition, downregulation of cereblon may be an important mechanism for developing dBET1 resistance, which can be evaded by incubating dBET1-resistant cells with JQ1 or MZ1.

The exercise renogram and its interpretation.

UNLABELLED: The exercise renogram is a rarely used diagnostic procedure, but it may visualize an exercise-induced change in renal function related to the pathophysiology of essential hypertension, which could greatly increase interest in this examination. The aim of this study was to demonstrate the interpretative approach and the terminology which is used to describe results of exercise renography, using a population of hypertensives with renovascular disease. METHODS: We reviewed the examinations of 70 hypertensives who had supine renography as well as exercise renography with a 60-80 W work load. Forty-eight patients were examined with 99mTc-MAG3 and 22 with 131I hippurate. The renographic and angiography results were recorded as well as the antihypertensive drugs used and the site of vascular lesions. RESULTS: Thirty-three hypertensives developed a bilateral-abnormal exercise renogram, which appears to be associated with primary hypertension. Eight individuals responded to exercise with a unilateral-abnormal exercise renogram, in a kidney behind a stenosis. Only 19 patients had a normal exercise renogram, and 10 had only one functioning kidney. Pathology recognized but unrelated to the intervention included nonfunctioning and small kidneys and pelvic retention. CONCLUSION: Exercise renography's only indication is for recognition of pathology unique to hypertension, since other function disturbances were recognized in resting renograms.

Exercise activates renal dysfunction in hypertension.

A bilateral, exercise-mediated renal functional abnormality was first described more than a decade ago. The disturbance is specific for hypertension, is seen in different forms of hypertension, and has been studied most extensively in hypertensives with renovascular disease. The bilateral-abnormal exercise renogram identifies the disturbance. Hypertensives with unilateral renovascular disease were studied in the continuing evaluation of the bilateral function disturbance. We examined 31 hypertensives with documented unilateral renovascular disease, all of whom had renography at rest and during 60 to 80 W ergometric exercise. An additional seven normotensives and 17 essential hypertensives served as controls, and had the same sequence of studies. All patients reported upon continued on to an infusion clearance with 131I-hippurate and 111In-diethylenetriamine pentaacetic acid to determine glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) at rest, and during 25 W ergometric exercise. Eighteen of 31 hypertensives with unilateral renovascular disease were found to have a bilateral-abnormal exercise renogram. Clearance examinations in these identified a prominent reduction of the GFR and a lesser decrease in the ERPF during exercise. Hypertensives with normal exercise renograms did not have the exercise mediated abnormal clearance pattern. Similar results were observed in the control population of essential hypertensives, 65% of whom developed the functional disturbance. The seven normotensives controls did not exhibit the exercise mediated function changes. We conclude that an exercise-mediated bilaterally occurring functional disturbance exists in certain hypertensives, who then have a bilateral-abnormal exercise renogram. Associated with this is a distinctly abnormal clearance during exercise which is characterized by a low filtration fraction.

[The role of electron beam CT in the diagnosis of acute pulmonary embolism--presenting a new examination protocol]. / Wertigkeit der EB-CT in der Diagnostik der akuten Lungenembolie--Vorstellung eines neuen Untersuchungsprotokolls.

PURPOSE: To evaluate electron beam tomography in the detection of acute pulmonary embolism using a new acquisition protocol. MATERIALS AND METHODS: 65 patients underwent electron beam tomography (EBT) and v./p. scintigraphy. According to the inclusion criteria 46 patients participated in the study. Contrast enhancement and detectability of pulmonary arteries were scored on a 4 step scale for image quality. The results of prospective detection of pulmonary embolism were compared for both modalities (blinded reading). "Embolism", "questionable embolism" and "no embolism" were used as categories. RESULTS: 22/46 patients (48%) showed acute pulmonary embolism. EBT and scintigraphy were discordant in 24% of patients. In EBT 1 false positive and 1 false negative case occurred, scintigraphy demonstrated 2 false negative and 3 false positive cases. 6/9 patients with questionable findings in scintigraphy were correctly classified by EBT to a category "embolism" or "no embolism" as "suspected embolism", EBT displayed a sensitivity of 96.3% and a specificity of 94.7%. Scintigraphy evidenced a sensitivity of 93.7% and a specificity of 84.4%. CONCLUSIONS: EBT shows better results than scintigraphy for the detection of acute pulmonary emboli. The evaluated new acquisition protocol for EBT seems to be well suited. High vessel contrast and thin slices allow a reliable detection of segmental and subsegmental pulmonary arteries.

[Electron-beam CT-angiography in abdominal aortic aneurysms. Initial results]. / Elektronenstrahl-CT-Angiographie beim abdominellen Aortenaneurysma. Erste Ergebnisse.

PURPOSE: To evaluate the suitability of ultrafast electron-beam tomography (EBT) for the investigation of abdominal aortic aneurysms using CTA. METHODS: Thirty-one patients with suspected abdominal aortic aneurysm were investigated with EBT using an Evolution XP scanner (Siemens, Erlangen) with the newest software version 12.34 with continuous volume scanning of 140 images in 17 s. Collimation was 3 mm, table increment 4 mm with overlapping image reconstruction every 2 mm, exposure time 200 ms (124 mAs), resulting in a scan-range of 28 cm. A quantity of 80 ml contrast material was administered (flow 4 ml/s). Visualization of the abdominal aorta and its branches was performed with MIPs and shaded surface display. Evaluation of image quality was based on a four-step classification scale (1 = good, 4 = insufficient) for the demonstration of the abdominal aorta and the visceral, renal and iliac arteries. RESULTS: All EBT examinations demonstrated high and homogeneous density values along the whole vessel course with a mean density value of 258.7 +/- 47.3 HU for the abdominal aorta and the iliac arteries. Quality evaluation for the vessel demonstration showed mean values between 1.22 and 1.57 for the abdominal aorta and the visceral, renal and iliac arteries. CONCLUSIONS: EBT with 140 slices and slice reconstruction every 2 mm offers a high z-axis resolution resulting in high-quality CT angiographies of the whole abdominal aorta and its branches.

Combined use of retrograde myocardial and distal coronary protection for last vessel intervention in an aortocoronary vein graft.

Feasibility, safety, and clinical efficacy of the combined application of the PercuSurge system and the Myoprotect SSR device was demonstrated in a patient with high-risk anatomy undergoing saphenous vein graft intervention. This combined approach of coronary and myocardial protection may be considered in high-risk aortocoronary vein graft interventions.

First results of computerised tomographic angiography using electron beam tomography.

The aim of this study was to evaluate the suitability of electron beam tomography (EBT) with fast continuous volume scanning for CT angiography (CTA) in chest and abdomen. An Evolution XP EBT scanner with a new software version (12.34) was used. One hundred forty images per study can be acquired in 17 s using 3-mm collimation and overlapping image reconstruction. Study protocols for five different clinical applications of EBT CTA were established and evaluated. The EBT CTA technique was performed in 155 patients. High- and homogeneous density values were achieved along the whole course of the vessels; the mean density in the aorta was > 240 HU. Coeliac axis, superior and inferior mesenteric artery, renal and lumbar arteries were visualised in all cases. Maximum intensity projection and shaded surface display reconstruction demonstrated the relation between aneurysm and aortic branches very well due to an excellent resolution along the z-axis. In large scan volumes overlapping image reconstruction demonstrated better resolution along the z-axis than is available with helical CT. The EBT CTA technique proved to be very well suited excellent suitability for evaluation of pulmonary vessels. Compared with helical CT, EBT CTA offers a shorter scan time, which allows higher contrast enhancement in pulmonary vessels. The identification of intraluminal emboli and mural thrombi has improved. The EBT CTA technique is a very reliable tool for evaluation of aortic disease and pulmonary vessels.