Differential expression of selenoproteins in the human gastrointestinal tract and in gastrointestinal cell lines

Von den bisher entdeckten Selenoproteinen im Organismus von Eu- und Prokaryonten sind nur wenige Proteine hinsichtlich ihrer biologischen Funktion weitgehend analysiert. Mit zunehmenden Erkenntnisgewinn über Funktion und Regulation einzelner Selenoproteine kristallisiert sich eine Gewebsspezifität heraus. Über die Genexpression von Selenoproteinen im Gastrointestinaltrakt des Menschen gibt es nur wenige Daten. Da für die kontinuierliche nutritive Selensupplementation ein eindrucksvoller präventiver Effekt auf die Inzidenz kolorektaler Karzinome nachgewiesen wurde, erscheint der Gastrointestinaltrakt als wichtiges Zielorgan für Selen und Selenoproteine. In der vorliegenden Arbeit wurden molekularbiologische und proteinbiochemische Untersuchungen zur Genexpression und Funktion einzelner Selenoproteine im Gastrointestinaltrakt durchgeführt. Dabei wurden mit Selenoprotein P (SeP), Thioredoxinreduktase (TrxR1) und den beiden Isoformen der Glutathionperoxidase GPx-GI und pGPx erstmals vier verschiedene gastrointestinale Selenoproteine auf mRNA-Ebene identifiziert. Hier zeigte sich ein differenzielles Expressionsmuster in den verschiedenen Kompartimenten des humanen Verdauungstraktes. Dieser Befund bildete die Grundlage für weitere Untersuchungen, in welchen veränderte Expressionsmuster der Selenoproteine in gastrointestinalen Präkanzerosen wie kolorektale Adenome oder Barrett-Ösophagus nachgewiesen werden konnten. Analog hierzu fand sich eine Expression dieser Selenoproteine in den humanen Kolon- und Magenkarzinomzelllinien Caco 2 und ST23132, was diese als geeignetes Zellkultursystem zur Untersuchung der Regulation der Genexpression ausweist. Die Detektion der zu den genannten Proteinen zugehörigen Banden in metabolischen Markierungsversuchen mit 75Se (in Zellkultur und gastrointestinalen Schleimhautbiopsien) ist als Nachweis der Translation dieser Gene zu werten. Von besonderem Interesse ist die Rolle der GPx-GI bei der gastrointestinalen Karzinogenese. Die aus epidemiologischen Daten als Karzinogene einzustufenden Stoffe Ethanol und Tamoxifen bewirken in der Zellkultur eine gesteigerte Genexpression der GPx-GI. Die vermehrte Bildung von GPx-GI wurde auch in kolorektalen Adenomen, einer fakultativen Präkanzerose, gefunden. Der Stellenwert der veränderten Genexpression von gastrointestinalen Selenoproteinen im Rahmen der Karzinogenese bleibt noch weiter zu untersuchen. Eine Wirkung von Östrogen auf die gastrointestinalen Selenoproteine war nicht nachweisbar. Diese Frage war Gegenstand dieser Arbeit, da für Östrogen (wie auch für Selen) epidemiologisch ein Schutzeffekt gegen kolorektale Karzinome bekannt ist. Zu den zukünftig weiter zu klärenden Fragen gehört insbesondere die weitere Aufklärung der biologischen Funktionen von Selenoproteinen.From the so far discovered selenoproteins in the organisms of eukaryotes and prokaryotes only a few proteins are well known for their biological function. With increasing knowledge about function and regulation of selected selenoproteins their tissue specifity becomes clearer. There are only a few data’s about gene expression of selenoproteins in the human gastrointestinal tract. Because a continuous nutritional selenium supplementation showed an impressing preventive effect on the incidence of colorectal cancer, the gastrointestinal tract seems to be an important target for selenium and selenoproteins. In this paper gene expression and function of different selenoproteins in the gastrointestinal tract was investigated with various molecular and biochemical methods. Therefore we first identified selenoprotein P (SeP), thirodoxinreductase (TrxR1) and two glutathionperoxidase isoenzymes (GPx-GI and pGPx) by mRNA-extraction. A differential expression pattern in the different intestinal compartments of the human gastrointestinal tract was found. These data’s built the base for further investigations, in which different patterns of selenoprotein expression in gastrointestinal praecanceroses like colorectal adenoma and Barrett`s oesophagus. Analogous here fore there was an expression of the same proteins in human cell lines of colorectal (Caco 2) and gastric (ST 23132) cancer, which revealed them to be the suitable cell culture system to investigate the regulation of gene expression. The detection of the auto radiographic signals of the above mentioned proteins in the metabolic marker experiment with 75 Se (in cell culture and and gastrointestinal mucosa biopsies) can be interpreted as gene translation. The role of GPx-GI in gastrointestinal carcinogenesis is of special interest. Ethanol and tamoxifen - epidemiological studies identified both as carcinogens - induced a higher expression of GPx-GI. Also in colorectal adenoma GPx-GI showed a higher expression. The biological importance of a modified gene-expression for gastrointestinal selenoproteins in carcinogenesis must be investigated in further experiments. In this study for oestrogen no regulation of selenoprotein expression was found, even though epidemiological data’s show an oestrogen related protection for colorectal carcinoma. The further analysis of the multiple biological functions of the different selenoproteins will be task to future research

Non-invasive blood pressure and cardiac index measurements using the Finapres Portapres in an emergency department triage setting

Emergency department (ED) patients are triaged to determine the urgency of care. The Finapres Portapres (FP) measures blood pressure (BP) and cardiac output (CO) non-invasively, and may be of added value in early detection of patients at risk for hemodynamic compromise. Objectives Compare non-invasive BP measurements using FP and standard automated sphygmomanometry. Compare FP cardiac index (CI), CO corrected for body surface area, of normotensive patients, to chart-based physician estimate of shock, to discover if there is additional value in CI measurements in triage. Methods ED Patients requiring BP measurement in triage were included. Systolic (SBP) and diastolic (DBP) BP were measured using both devices during a two minutes measurement. Two physicians independently judged probability of shock, defined as estimated CI ≤ 2.5 L min− 1 m− 2, based on chart review, three weeks after ED visit. Results Of a total of 112 patients 97 patients were included. Pearson's correlation coefficient was 0.50 for SBP, 0.53 for DBP, with a Blant-Altman mean bias of 11.3 (upper limit 65.3, lower limit − 42.8) and 7.7 (39.2, − 23.7) for SBP and DBP respectively. In normotensive patients, the group with low FP CI measurements had significantly more cases with physician-estimated shock, compared to the normal to high measurements (P = .036). Conclusions When used as a triage device in the emergency department setting, non-invasive BP measurements using FP do not correlate well with automated sphygmomanometry. However, this study does indicate that use of the FP device in triage may aid physicians to recognize patients in early phases of shoc

Early restrictive fluid strategy impairs the diaphragm force in lambs with acute respiratory distress syndrome

Background: The effect of fluid management strategies in critical illness–associated diaphragm weakness are unknown. This study hypothesized that a liberal fluid strategy induces diaphragm muscle fiber edema, leading to reduction in diaphragmatic force generation in the early phase of experimental pediatric acute respiratory distress syndrome in lambs. Methods: Nineteen mechanically ventilated female lambs (2 to 6 weeks old) with experimental pediatric acute respiratory distress syndrome were randomized to either a strict restrictive fluid strategy with norepinephrine or a liberal fluid strategy. The fluid strategies were maintained throughout a 6-h period of mechanical ventilation. Transdiaphragmatic pressure was measured under different levels of positive end-expiratory pressure (between 5 and 20 cm H 2O). Furthermore, diaphragmatic microcirculation, histology, inflammation, and oxidative stress were studied. results: Transdiaphragmatic pressures decreased more in the restrictive group (–9.6 cm H 2O [95% CI, –14.4 to –4.8]) compared to the liberal group (–0.8 cm H 2O [95% CI, –5.8 to 4.3]) during the application of 5 cm H 2O positive end-expiratory pressure (P = 0.016) and during the application of 10 cm H 2O positive end-expiratory pressure (–10.3 cm H 2O [95% CI, –15.2 to –5.4] vs. –2.8 cm H 2O [95% CI, –8.0 to 2.3]; P = 0.041). In addition, diaphragmatic microvessel density was decreased in the restrictive group compared to the liberal group (34.0 crossings [25th to 75th percentile, 22.0 to 42.0] vs. 46.0 [25th to 75th percentile, 43.5 to 54.0]; P = 0.015). The application of positive end-expiratory pressure itself decreased the diaphragmatic force generation in a dose-related way; increasing positive end-expiratory pressure from 5 to 20 cm H 2O reduced transdiaphragmatic pressures with 27.3% (17.3 cm H 2O [95% CI, 14.0 to 20.5] at positive end-expiratory pressure 5 cm H 2O vs. 12.6 cm H 2O [95% CI, 9.2 to 15.9] at positive end-expiratory pressure 20 cm H 2O; P < 0.0001). The diaphragmatic histology, markers for inflammation, and oxidative stress were similar between the groups. Conclusions: Early fluid restriction decreases the force-generating capacity of the diaphragm and diaphragmatic microcirculation in the acute phase of pediatric acute respiratory distress syndrome. In addition, the application of positive end-expiratory pressure decreases the force-generating capacity of the diaphragm in a dose-related way. These observations provide new insights into the mechanisms of critical illness–associated diaphragm weakness

Breast cancer risk assessment in a mammography screening program and participation in the IBIS-II chemoprevention trial

International audienceIt has been shown in several studies that antihormonal compounds can offer effective prophylactic treatment to prevent breast cancer. In view of the low participation rates in chemoprevention trials, the purpose of this study was to identify the characteristics of women taking part in a population-based mammography screening program who wished to obtain information about the risk of breast cancer and then participate in the the International Breast Cancer Intervention Study II (IBIS-II) trial, a randomized double-blind controlled chemoprevention trial comparing anastrozole with placebo. A paper-based survey was conducted in a population-based mammography screening program in Germany between 2007 and 2009. All women who met the criteria for the mammography screening program were invited to complete a questionnaire. A total of 2,524 women completed the questionnaire, and 17.7% ( = 446) met the eligibility criteria for the IBIS-II trial after risk assessment. The women who wished to receive further information about chemoprevention were significantly younger ( < 0.01) and had significantly more children ( = 0.03) and significantly more relatives with breast cancer ( < 0.001). There were no significant differences between the participants with regard to body mass index or hormone replacement therapy. Normal mammographic findings at screening were the main reason (42%) for declining to participate in the IBIS-II trial or attend risk counseling. The ultimate rate of recruitment to the IBIS-II trial was very low (three women). Offering chemoprevention to women within a mammography screening unit as part of a paper-based survey resulted in low participation rates for both, the survey and the final participation in the IBIS-II trial. More individualized approaches and communication of breast cancer risk at the time of the risk assessment might be helpful to increase the participation and the understanding of chemopreventive approaches

Bevacizumab and platinum-based combinations for recurrent ovarian cancer: a randomised, open-label, phase 3 trial

International audienceState-of-the art therapy for recurrent ovarian cancer suitable for platinum-based re-treatment includes bevacizumab-containing combinations (eg, bevacizumab combined with carboplatin-paclitaxel or carboplatin-gemcitabine) or the most active non-bevacizumab regimen: carboplatin-pegylated liposomal doxorubicin. The aim of this head-to-head trial was to compare a standard bevacizumab-containing regimen versus carboplatin-pegylated liposomal doxorubicin combined with bevacizumab