992 resultados para 465


Relevância:

10.00% 10.00%

Publicador:

Resumo:

The development of lymph nodes (LNs) and formation of LN stromal cell microenvironments is dependent on lymphotoxin-β receptor (LTβR) signaling. In particular, the LTβR-dependent crosstalk between mesenchymal lymphoid tissue organizer and hematopoietic lymphoid tissue inducer cells has been regarded as critical for these processes. Here, we assessed whether endothelial cell (EC)-restricted LTβR signaling impacts on LN development and the vascular LN microenvironment. Using EC-specific ablation of LTβR in mice, we found that conditionally LTβR-deficient animals failed to develop a significant proportion of their peripheral LNs. However, remnant LNs showed impaired formation of high endothelial venules (HEVs). Venules had lost their cuboidal shape, showed reduced segment length and branching points, and reduced adhesion molecule and constitutive chemokine expression. Due to the altered EC-lymphocyte interaction, homing of lymphocytes to peripheral LNs was significantly impaired. Thus, this study identifies ECs as an important LTβR-dependent lymphoid tissue organizer cell population and indicates that continuous triggering of the LTβR on LN ECs is critical for lymphocyte homeostasis.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The purpose of the internet-based teachware mySCM is that students of economics, informatics and industrial engineering get familiar with quantitative methods for supply chain management. Input-output-relationships of various optimization methods can be detected by sampling input values, parameters, and alternative methods for the same problem. Students can gain extra benefits by passing so-called mini-exams that motivate active learning. mySCM can be used for free, round-the-clock, and any place where access to the Internet is available.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Previous studies from our lab have established that large molecular weight mucin glycoproteins are major apically-disposed components of mouse uterine epithelial cells in vitro (Valdizan et al., (1992) J. Cell. Physiol. 151:451-465). The present studies demonstrate that Muc-1 represents one of the apically-disposed mucin glycoproteins of mouse uterine epithelia, and that Muc-1 protein and mRNA expression are regulated in the peri-implantation stage mouse uterus by ovarian steroids. Muc-1 expression is high in the proestrous and estrous stages, and decreases during diestrous. Both Muc-1 protein and mRNA levels decline to barely detectable levels by day 4 of pregnancy, i.e., prior to the time of blastocyst attachment. In contrast, Muc-1 expression in the cervix and vagina is maintained during this same period. Delayed implantation was established in pregnant mice by ovariectomy and maintained by administration of exogenous progesterone. Initiation of implantation was triggered by coinjection of progesterone maintained mice with a nidatory dose of 17$\beta$-estradiol. Muc-1 levels in the uterine epithelia of progesterone maintained mice declined to similar low levels as observed on day 4 of normal pregnancy. Coinjection of estradiol did not alter Muc-1 expression suggesting that down-regulation of Muc-1 is a progesterone dominated event. This was confirmed in ovariectomized, non-pregnant mice which displayed stimulation of Muc-1 expression following 6 hr of estradiol injection. Estradiol stimulated Muc-1 expression was inhibited by the pure antiestrogen, ICI 164,384. While progesterone alone had no effect on Muc-1 expression, it antagonized estradiol action in this regard. Injection of pregnant mice with the antiprogestin, RU 486, a known implantation inhibitor, on day 3 of pregnancy restored high level expression of Muc-1 mRNA on day 4, indicating that down-regulation of Muc-1 is progesterone receptor-mediated. Muc-1 appears to function as an anti-adhesive molecule at the apical cell surface of mouse uterine epithelial cells. Treatment of polarized cultures of mouse uterine epithelial cells with O-sialoglycoprotein endopeptidase reduced mucin expression in vitro, by about 50%, and converted polarized uterine epithelia to a functionally receptive state. Similarly, ablation of Muc-1 in Muc-1 null mice resulted in polarized uterine epithelia that were functionally receptive as compared to their wild-type counterparts in vitro. Collectively, these data indicate that Muc-1 and other mucins function as anti-adhesive molecules and that reduction or removal of these molecules is a prerequisite for the generation of a receptive uterine state. ^

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The European Commission’s proposals for the Legislative Framework of the Common Agricultural Policy (CAP) in the period 2014-2020 include, inter alia, the introduction of a “strong greening component”. For the first time, all EU farmers in receipt of support are to “go beyond the requirements of cross compliance and deliver environmental and climate benefits as part of their everyday activities crop diversification as a contribution to all EU farmers in receipt of support go beyond the requirements of cross compliance and deliver environmental and climate benefits as part of their everyday activities.” In a legal opinion prepared at the request of APRODEV, the Association of World Council of Churches related Development Organisations in Europe (www.aprodev.eu), Christian Häberli examines the WTO implications of this proposal, as compared with an alternative proposal to rather link direct payments to crop rotation. The conclusions are twofold: 1. Crop rotation is at least as likely to be found Green Box-compatible as crop diversification. Moreover, it will be more difficult to argue that crop diversification is “not more than minimally production-distorting” because it entails for most farmers less cost and work. 2. Even if (either of the two cropping schemes) were to be found “amber”, the EU would not have to relinquish this conditionality. This is because the direct payments involved would in all likelihood not, together with the other price support instruments, exceed the amount available under the presently scheduled maximum.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Complementarity that leads to more efficient resource use is presumed to be a key mechanism explaining positive biodiversity–productivity relationships but has been described solely for experimental set-ups with controlled environmental settings or for very short gradients of abiotic conditions, land-use intensity and biodiversity. Therefore, we analysed plant diversity effects on nitrogen dynamics across a broad range of Central European grasslands. The 15N natural abundance in soil and plant biomass reflects the net effect of processes affecting ecosystem N dynamics. This includes the mechanism of complementary resource utilization that causes a decrease in the 15N isotopic signal. We measured plant species richness, natural abundance of 15N in soil and plants, above-ground biomass of the community and three single species (an herb, grass and legume) and a variety of additional environmental variables in 150 grassland plots in three regions of Germany. To explore the drivers of the nitrogen dynamics, we performed several analyses of covariance treating the 15N isotopic signals as a function of plant diversity and a large set of covariates. Increasing plant diversity was consistently linked to decreased δ15N isotopic signals in soil, above-ground community biomass and the three single species. Even after accounting for multiple covariates, plant diversity remained the strongest predictor of δ15N isotopic signals suggesting that higher plant diversity leads to a more closed nitrogen cycle due to more efficient nitrogen use. Factors linked to increased δ15N values included the amount of nitrogen taken up, soil moisture and land-use intensity (particularly fertilization), all indicators of the openness of the nitrogen cycle due to enhanced N-turnover and subsequent losses. Study region was significantly related to the δ15N isotopic signals indicating that regional peculiarities such as former intensive land use could strongly affect nitrogen dynamics. Synthesis. Our results provide strong evidence that the mechanism of complementary resource utilization operates in real-world grasslands where multiple external factors affect nitrogen dynamics. Although single species may differ in effect size, actively increasing total plant diversity in grasslands could be an option to more effectively use nitrogen resources and to reduce the negative environmental impacts of nitrogen losses.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Stepwise uncertainty reduction (SUR) strategies aim at constructing a sequence of points for evaluating a function  f in such a way that the residual uncertainty about a quantity of interest progressively decreases to zero. Using such strategies in the framework of Gaussian process modeling has been shown to be efficient for estimating the volume of excursion of f above a fixed threshold. However, SUR strategies remain cumbersome to use in practice because of their high computational complexity, and the fact that they deliver a single point at each iteration. In this article we introduce several multipoint sampling criteria, allowing the selection of batches of points at which f can be evaluated in parallel. Such criteria are of particular interest when f is costly to evaluate and several CPUs are simultaneously available. We also manage to drastically reduce the computational cost of these strategies through the use of closed form formulas. We illustrate their performances in various numerical experiments, including a nuclear safety test case. Basic notions about kriging, auxiliary problems, complexity calculations, R code, and data are available online as supplementary materials.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Why does Adrian Leverkühn choose a Shakespeare play for his major first and his first twelve-tone composition? Why in particular a Shakespeare comedy? And why, of all comedies, Love’s Labour’s Lost? Why does he start working on it in Munich? Why does his work there soon come to a halt? Why does it prosper only in Italy? And why does he eventually return to Upper Bavaria so as to complete it? Why is he said to have completed the opera exactly one hundred years ago? And why, finally, is it first performed only after the outbreak of the war and then, surprisingly, in a German adaptation? In order to answer these and similar questions, this paper sets out to re-contextualise Doktor Faustus with regard to discourse history and re-read the novel from a gender-theoretical perspective. The leading hypothesis is that Thomas Mann’s novel belongs to the proto-history of feminist Shakespeare reception, an assumption to be substantiated through an analysis of settings, locations and the constructions of space.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The aim of our study was to evaluate the quality of histo- and cytomorphological features of PAXgene-fixed specimens and their suitability for histomorphological classification in comparison to standard formalin fixation. Fifteen colon cancer tissues were collected, divided into two mirrored samples and either formalin fixed (FFPE) or PAXgene fixed (PFPE) before paraffin embedding. HE- and PAS-stained sections were scanned and evaluated in a blinded, randomised ring trial by 20 pathologists from Europe and the USA using virtual microscopy. The pathologists evaluated histological grading, histological subtype, presence of adenoma, presence of lymphovascular invasion, quality of histomorphology and quality of nuclear features. Statistical analysis revealed that the reproducibility with regard to grading between both fixation methods was rather satisfactory (weighted kappa statistic (k w) = 0.73 (95 % confidence interval (CI), 0.41-0.94)), with a higher agreement between the reference evaluation and the PFPE samples (k w = 0.86 (95 % CI, 0.67-1.00)). Independent from preservation method, inter-observer reproducibility was not completely satisfactory (k w = 0.60). Histomorphological quality parameters were scored equal or better for PFPE than for FFPE samples. For example, overall quality and nuclear features, especially the detection of mitosis, were judged significantly better for PFPE cases. By contrast, significant retraction artefacts were observed more frequently in PFPE samples. In conclusion, our findings suggest that the PAXgene Tissue System leads to excellent preservation of histomorphology and nuclear features of colon cancer tissue and allows routine morphological diagnosis.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Procurement of fresh tissue of prostate cancer is critical for biobanking and generation of xenograft models as an important preclinical step towards new therapeutic strategies in advanced prostate cancer. However, handling of fresh radical prostatectomy specimens has been notoriously challenging given the distinctive physical properties of prostate tissue and the difficulty to identify cancer foci on gross examination. Here, we have developed a novel approach using ceramic foam plates for processing freshly cut whole mount sections from radical prostatectomy specimens without compromising further diagnostic assessment. Forty-nine radical prostatectomy specimens were processed and sectioned from the apex to the base in whole mount slices. Putative carcinoma foci were morphologically verified by frozen section analysis. The fresh whole mount slices were then laid between two ceramic foam plates and fixed overnight. To test tissue preservation after this procedure, formalin-fixed and paraffin-embedded whole mount sections were stained with hematoxylin and eosin (H&E) and analyzed by immunohistochemistry, fluorescence, and silver in situ hybridization (FISH and SISH, respectively). There were no morphological artifacts on H&E stained whole mount sections from slices that had been fixed between two plates of ceramic foam, and the histological architecture was fully retained. The quality of immunohistochemistry, FISH, and SISH was excellent. Fixing whole mount tissue slices between ceramic foam plates after frozen section examination is an excellent method for processing fresh radical prostatectomy specimens, allowing for a precise identification and collection of fresh tumor tissue without compromising further diagnostic analysis.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

BACKGROUND The impact of prognostic factors in T1G3 non-muscle-invasive bladder cancer (BCa) patients is critical for proper treatment decision making. OBJECTIVE To assess prognostic factors in patients who received bacillus Calmette-Guérin (BCG) as initial intravesical treatment of T1G3 tumors and to identify a subgroup of high-risk patients who should be considered for more aggressive treatment. DESIGN, SETTING, AND PARTICIPANTS Individual patient data were collected for 2451 T1G3 patients from 23 centers who received BCG between 1990 and 2011. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS Using Cox multivariable regression, the prognostic importance of several clinical variables was assessed for time to recurrence, progression, BCa-specific survival, and overall survival (OS). RESULTS AND LIMITATIONS With a median follow-up of 5.2 yr, 465 patients (19%) progressed, 509 (21%) underwent cystectomy, and 221 (9%) died because of BCa. In multivariable analyses, the most important prognostic factors for progression were age, tumor size, and concomitant carcinoma in situ (CIS); the most important prognostic factors for BCa-specific survival and OS were age and tumor size. Patients were divided into four risk groups for progression according to the number of adverse factors among age ≥ 70 yr, size ≥ 3 cm, and presence of CIS. Progression rates at 10 yr ranged from 17% to 52%. BCa-specific death rates at 10 yr were 32% in patients ≥ 70 yr with tumor size ≥ 3 cm and 13% otherwise. CONCLUSIONS T1G3 patients ≥ 70 yr with tumors ≥ 3 cm and concomitant CIS should be treated more aggressively because of the high risk of progression. PATIENT SUMMARY Although the majority of T1G3 patients can be safely treated with intravesical bacillus Calmette-Guérin, there is a subgroup of T1G3 patients with age ≥ 70 yr, tumor size ≥ 3 cm, and concomitant CIS who have a high risk of progression and thus require aggressive treatment.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Recent studies identified unexpected expression and transcriptional complexity of the hemoprotein myoglobin (MB) in human breast cancer but its role in prostate cancer is still unclear. Expression of MB was immunohistochemically analyzed in three independent cohorts of radical prostatectomy specimens (n = 409, n = 625, and n = 237). MB expression data were correlated with clinicopathological parameters and molecular parameters of androgen and hypoxia signaling. Expression levels of novel tumor-associated MB transcript variants and the VEGF gene as a hypoxia marker were analyzed using qRT-PCR. Fifty-three percent of the prostate cancer cases were MB positive and significantly correlated with androgen receptor (AR) expression (p < 0.001). The positive correlation with CAIX (p < 0.001) and FASN (p = 0.008) as well as the paralleled increased expression of the tumor-associated MB transcript variants and VEGF suggest that hypoxia participates in MB expression regulation. Analogous to breast cancer, MB expression in prostate cancer is associated with steroid hormone signaling and markers of hypoxia. Further studies must elucidate the novel functional roles of MB in human carcinomas, which probably extend beyond its classic intramuscular function in oxygen storage.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Researchers have claimed that high quality of supervisor–employee relationships (i.e., leader– member exchange; LMX) fosters creativity at work. Moreover, researchers have acknowledged that this relationship is not clear-cut but rather complex. The present study focused on the moderating role of job autonomy in the LMX-creative work involvement relationship. Longitu-dinal field survey data (N = 144) collected in a high-technology firm revealed a positive asso-ciation between LMX and creative work involvement and confirmed our assumptions on the moderating role of job autonomy. The positive relationship between LMX and creative work involvement was stronger when employees experienced greater job autonomy. Our findings point to the importance of considering the interplay of both, the leader–member relationship and job design issues for increasing employees' creative work involvement.