Acute mesenteric venous thrombosis: Case for nonoperative management

AbstractObjective: Initial treatment in the management of acute mesenteric vein thrombosis (MVT) is controversial. Some authors have proposed a surgical approach, whereas others have advocated medical therapy (anticoagulation). In this study, we analyzed and compared the results obtained with surgical and medical treatment to determine the best initial management for this disease. Methods: We retrospectively reviewed the records of patients treated for MVT in a secondary care surgical department from January 1987 to December 1999. Before January 1995, our departmental policy was to perform surgery in patients with suspected MVT. Since January 1995, we have preferred a medical approach when achievable. Each patient in this study was assessed for diagnosis, initial management (laparotomy or anticoagulation), morbidity, mortality, duration of hospitalization, the need for secondary operation, portal hypertension, and survival rates. Results: Twenty-six patients were treated, 14 before January 1995 (group 1) and 12 since January 1995 (group 2). Morbidity, mortality, secondary operation, portal hypertension, and 2-year survival rates were 34.6%, 19.2%, 15.3%, 19.2%, and 76.9%, respectively. No statistical difference was observed between the two groups. The mean duration of hospitalization was 51.6 days in group 1 and 23.2 days in group 2 (P <.05). Among the 12 patients treated by means of laparotomy with bowel resection, 10 patients (83%) had mucosal necrosis without transmural necrosis at pathologic study. Conclusion: Nonoperative management for acute MVT is feasible when the initial diagnosis with a computed tomography scan is certain and when the bowel infarction has not led to transmural necrosis and bowel perforation. The morbidity, mortality, and survival rates are similar in cases of surgical and nonoperative management. The length of hospital stay is shorter when patients are treated with a nonoperative approach. A nonoperative approach, when indicated, avoids the resection of macroscopically infarcted small bowel (without transmural necrosis) in cases that are potentially reversible with anticoagulation alone. (J Vasc Surg 2001;34:673-9.

Decomposition studies of NH₃ and ND₃ in presence of H₂ and D₂ with Pt/Al₂O₃ and Ru/Al₂O₃ catalysts

In the fusion reactor ITER, ammonia will be produced as a result of the interaction between the hydrogen isotopes used as fuel and nitrogen used to spread the power loads of a larger area. As part of the fuel management in ITER, NQ3 (NQ3, Q = H, D, T) will have to be decomposed using a palladium membrane reactor. The decomposition of pure NH3 and ND3 was studied in this work using commercial platinum (Pt) and ruthenium (Ru) catalysts on alumina (0.5 wt% loading), in a conventional reactor configuration (i.e., without a palladium membrane). With Pt/Al2O3, decomposition fractions larger than 90% were achieved with NH3 above 800 K using the lowest flow-to-mass ratio (/g-cat) of 0.015 sccm g−1. However, with the increase of /g-cat to 0.220 sccm g−1, similar decompositions were achieved only at  K. In contrast, with Ru/Al2O3 decomposition fractions above 90% were attained already below 700 K, regardless of /g-cat. With both catalysts the decomposition of NH3 was found to be more efficient than that of ND3 at a wide range of temperatures, thus evidencing the existence of isotopic effect. A strong inhibition of both NH3 and ND3 in presence of, respectively, H2 and D2 with Pt/Al2O3 was observed. This effect was stronger at lower temperatures and larger hydrogen partial pressures. The inhibition effect with Ru/Al2O3 was less pronounced and it was suppressed at 629 K. Isotopic exchange reactions with equimolar mixtures of NH3-D2 and ND3-H2 revealed that the most and least abundant isotopologue are, respectively, NH2D and ND3. At the relevant temperature window in which the PMR will be operated (673–823 K), the Ru-based catalyst exhibits superior performances in terms of decomposition rates, negligible isotopic and inhibition effects. A slight reduction of the performances with this catalyst was observed with 0.200 sccm g−1. This work suggests that 0.5 wt% Ru/Al2O3 is the most suitable catalyst to be used during ITER operation

Hierarchies and compatibility on Courant algebroids

We extend to the context of Courant algebroids several hierarchies that can be constructed on Poisson-Nijenhuis manifolds. More precisely, we introduce several notions (Poisson-Nijenhuis, deformation-Nijenhuis and Nijenhuis pairs) that extend to Courant algebroids the notion of a Poisson-Nijenhuis manifold, by using the idea that both the Poisson and the Nijenhuis structures, although they seem to be different in nature when considered on manifolds, are just $(1,1)$-tensors on the usual Courant algebroid $TM \oplus T^*M$ satisfying several constraints. For each of the generalizations mentioned, we show that there are natural hierarchies obtained by successive deformation by one of the $(1,1)$-tensor

Ion flux-energy distributions across grounded grids in an RF plasma source with DC-grounded electrodes

We present an experimental investigation of the ion flux–energy distribution functions (IFEDFs) obtained across grounded grids in an asymmetric capacitively coupled RF source using a helium discharge. The powered electrode in the RF source is DC-grounded via a λ/4 filter, which lifts its DC potential to zero. Grids of different dimensions (hole width, thickness, and geometric transparency) were used to confine the plasma, while the IFEDF of the ion beam departing the grid and reaching the reactor walls was studied using a retarding field energy analyser. The IFEDF obtained was double-peaked, indicating the presence of fast ions arriving from the plasma source, and cold ions generated upon charge exchange collisions between the fast ions and neutrals. The flux, as well as the peak energies of the two ion groups, depended significantly on the process parameters: RF power, He pressure, the distance between grids and walls, and the dimensions of the grids. The results indicate that confining plasma with grids can reduce the ion flux at the walls by over 60%, significantly lowering the wall sputtering rate. This was confirmed with a dedicated long-exposure plasma discharge with a gridded plasma reactor, wherein less than 1 nm of Cu deposition was found on the DC-grounded powered electrode, and the surface reflectivity was preserved to pristine values. In contrast, a similar experiment in a gridless reactor resulted in Cu deposition of 35 nm with a drastic drop in surface reflectivity. These studies are of great importance for the application of similar RF plasma sources with in-situ cleaning of diagnostic mirrors in fusion devices, as well as in a variety of plasma processing applications

Study of Wall Re-Deposition on DC-grounded ITER-relevant Mirrors with RF Plasma in a First Mirror Unit

In ITER, several first mirrors (FMs) are expected to be DC-grounded with the water cooling lines being implemented as a quarter wavelength ($lambda$/4) RF-filter. DC-grounding of the FMs can significantly increase the plasma potential V p, which could trigger an increased wall sputtering and associated re-deposition on the FMs during plasma cleaning. To understand the scope of this impact, helium discharges were excited with DC-grounded FMs in an ITER-sized mock-up of a first mirror unit (FMU) using wall materials with different sputtering energy thresholds (E th). Additionally, a part of the FM was electrically isolated from the RF to study its impact on the erosion/re-deposition properties on the surface. The E th of the wall materials, as well as its native oxide layers, had a significant influence on the re-deposition observed on the FMs. With high E th where walls were unsputtered, both the DC-grounded and electrically isolated parts of the FM were free of deposits. However, with low E th where the walls were sputtered, there was a net wall re-deposition on the DC-grounded parts of the FM, while electrically isolated parts were still relatively clean. Further, to study the impact of floating wall components, Cu walls in the FMU were isolated from the ground. Here the walls developed a floating potential V f and the ion energy at the walls was lowered to e(V p - V f). The floating walls, in this case, were relatively unsputtered and the FMs experienced a net cleaning with total reflectivity of the mirror preserved at pristine mirror levels. This work shows that electrically isolating the FM as well as the wall surface minimizes wall re-deposition in presence of $lambda$/4 filter and therefore are promising techniques for effective FM cleaning in ITER

Experimental and Numerical Characterization of a Radio-Frequency Plasma Source with a DC-grounded Electrode Configuration Using a Quarter-Wavelength Filter

We present a combined experimental and numerical investigation of the plasma properties in an asymmetric capacitively coupled radio frequency plasma source using argon discharge. Besides driving the system in the conventional way, which results in a high negative self-bias voltage due to the asymmetric configuration, we also connect a `quarter-wavelength filter` to the powered electrode, which lifts its DC potential to zero. At the powered side of the plasma, we employ electrodes with conducting and insulating surfaces, as well as electrodes combining both in different proportions (`hybrid electrodes`). Measurements are carried out for the plasma potential, the electron density and temperature in the bulk plasma, as well as for the flux-energy distribution of the ions at the grounded surface of the system. The nature of the surface of the powered electrode as well as the presence of the quarter-wavelength filter are found to highly influence the plasma potential, . For the electrode with a conducting surface 20 V and $sim$150 V are found in the absence and the presence of the filter, respectively. For the electrode with an insulating surface, the self-bias voltage builds up directly at the plasma interface, thus the filter has no effect and a plasma potential of $sim$20 V is found. For the electrodes with different conducting/insulating proportions of their surface, ranges between the above values. Particle-in-Cell/Monte Carlo Collisions calculations for identical conditions with hybrid electrodes predict double-peaked ion energy distribution at the powered electrode with peaks corresponding to and along with a lowering of the plasma potential (whencompared to wholly conducting electrode), a trend that is observed experimentally. These studies are of great importance for the application of similar plasma sources with in-situ cleaning of mirrors in fusion devices and the results can be extended to a variety of plasma processing applications

Identification of gallotannins and ellagitannins in aged wine spirits: a new perspective using alternative ageing technology and high-resolution mass spectrometry

This research was focused on identifying gallotannins and ellagitannins degradation pathways to better understand their behavior in complex media such as wine spirits (WS). A WS was aged with chestnut wood staves with three levels of micro-oxygenation, nitrogen, and using wooden barrels. Gallotannins and ellagitannins were identified by LC-ESI-HRMS/MS using a Q-TOF in samples collected at 8, 21, 60, 180, 270, and 365 days of ageing, allowed comparing their relative abundances according to the ageing technology. It was established for the first time, the importance of oxygen in gallotannins and ellagitannins formation/degradation pathways in WS and shading light into the explanation for the steady increase of gallic and ellagic acid contents on WS during ageing. The results also highlighted the presence of penta-O-galloyl-β-D-glucose, tetra-O-galloyl-β-D-glucose, tri- O-galloyl-β-D-glucose, di-O-galloyl-β-D-glucose, and mono-O-galloyl-β-D-glucose, 2,3-(S)-hexahydroxydiphenoyl- β-D-glucose, pedunculagin, isomers vescalagin/castalagin and two products stemming from ethanol-promoted oxidation of castalagin/vescalagin and vescalin/castalin, in the composition WS aged with chestnut wood.This paper is a result of the research Project OXYREBRAND, funded by National Funds through FCT - Foundation for Science and Technology under the Project POCI-01-0145-FEDER-027819 (PTDC/OCE-ETA/ 27819/2017). This work was also funded by National Funds through FCT - Foundation for Science and Technology under the Projects UIDB/ 05183/2020 [MED]; UID/AGR/04129/2020, DL 57/2016/CP1382/ CT0025 [LEAF]; UIDB/00239/2020 [CEF]; UIDB/00100/2020, PTDC/ QUI-QAN/32242/2017 and UIDP/00100/2020 [CQE], and contracts CEECIND/02725/2018 (to T.A.F.) and CEECIND/02001/2017 (to A.M. M.A). Joint funding from FCT and the COMPETE Program through grant RNEM-LISBOA-01-0145-FEDER-022125 funding are also gratefully acknowledged.info:eu-repo/semantics/publishedVersio

Hypoxia-induced Autophagy Drives Colorectal Cancer Initiation and Progression by Activating the PRKC/PKC-EZR (Ezrin) Pathway

In solid tumors, cancer stem cells (CSCs) or tumor-initiating cells (TICs) are often found in hypoxic niches. Nevertheless, the influence of hypoxia on TICs is poorly understood. Using previously established, TIC-enriched patient-derived colorectal cancer (CRC) cultures, we show that hypoxia increases the self-renewal capacity of TICs while inducing proliferation arrest in their more differentiated counterpart cultures. Gene expression data revealed macroautophagy/autophagy as one of the major pathways induced by hypoxia in TICs. Interestingly, hypoxia-induced autophagy was found to induce phosphorylation of EZR (ezrin) at Thr567 residue, which could be reversed by knocking down ATG5, BNIP3, BNIP3L, or BECN1. Furthermore, we identified PRKCA/PKCα as a potential kinase involved in hypoxia-induced autophagy-mediated TIC self-renewal. Genetic targeting of autophagy or pharmacological inhibition of PRKC/PKC and EZR resulted in decreased tumor-initiating potential of TICs. In addition, we observed significantly reduced in vivo tumor initiation and growth after a stable knockdown of ATG5. Analysis of human CRC samples showed that p-EZR is often present in TICs located in the hypoxic and autophagic regions of the tumor. Altogether, our results establish the hypoxia-autophagy-PKC-EZR signaling axis as a novel regulatory mechanism of TIC self-renewal and CRC progression. Autophagy inhibition might thus represent a promising therapeutic strategy for cancer patients

Loss of Myosin Vb in colorectal cancer is a strong prognostic factor for disease recurrence

Background: Selecting the most beneficial treatment regimens for colorectal cancer (CRC) patients remains challenging due to a lack of prognostic markers. Members of the Myosin family, proteins recognized to play a major role in trafficking and polarization of cells, have recently been reported to be closely associated with several types of cancer and might thus serve as potential prognostic markers in the context of CRC. Methods: We used a previously established meta-analysis of publicly available gene expression data to analyse the expression of different members of the Myosin V family, namely MYO5A, 5B, and 5C, in CRC. Using laser-microdissected material as well as tissue microarrays from paired human CRC samples, we validated both RNA and protein expression of MYO5B and its known adapter proteins (RAB8A and RAB25) in an independent patient cohort. Finally, we assessed the prognostic value of both MYO5B and its adapter-coupled combinatorial gene expression signatures. Results: The meta-analysis as well as an independent patient cohort study revealed a methylation-independent loss of MYO5B expression in CRC that matched disease progression. Although MYO5B mutations were identified in a small number of patients, these cannot be solely responsible for the common down-regulation observed in CRC patients. Significantly, CRC patients with low MYO5B expression displayed shorter overall, disease- and metastasis-free survival, a trend that was further reinforced when RAB8A expression was also taken into account. Conclusions: Our data identifies MYO5B as a powerful prognostic biomarker in CRC, especially in early stages (stages I and II), which might help stratifying patients with stage II for adjuvant chemotherapy