80 research outputs found
Diffusion-weighted imaging in oral squamous cell carcinoma using 3 Tesla MRI: is there a chance for preoperative discrimination between benign and malignant lymph nodes in daily clinical routine?
Background Preoperative staging of cervical lymph nodes is important to determine the extent of neck dissection in patients with oral squamous cell carcinoma (OSCC). Purpose To evaluate whether a preoperative discrimination of benign and malignant cervical lymph nodes with diffusion-weighted imaging (DWI) (3T) is feasible for clinical application. Material and Methods Forty-five patients with histological proven OSCC underwent preoperative 3T-MRI. DWI (b=0, 500, and 1000s/mm(2)) was added to the standard magnetic resonance imaging (MRI) protocol. Mean apparent diffusion coefficients (ADC(mean)) were measured for lymph nodes with 3mm or more in short axis by two independent readers. Finally, these results were matched with histology. Results Mean ADC was significantly higher for malignant than for benign nodes (1.1430.188 * 10(-3) mm(2)/s vs. 0.987 +/- 0.215 * 10(-3) mm(2)/s). Using an ADC value of 0.994 * 10(-3) mm(2)/s as threshold results in a sensitivity of 80%, specificity of 65%, positive predictive value of 31%, and negative predictive value of 93%. Conclusion Due to a limited sensitivity and specificity DWI alone is not suitable to reliably discriminate benign from malignant cervical lymph nodes in daily clinical routine. Hence, the preoperative determination of the extent of neck dissection on the basis of ADC measurements is not meaningful
Embedding Social Innovation and Service Learning in Higher Education's Third Sector Policy Developments in Austria
Social innovation in Austrian HEIs is discussed under the headline of their “Third Mission.” The HE sector is pressured to have more and more impact on society. Internationally speaking, many countries benefit from national policies and networks in the Third Sector, but policies in Austria were initiated only recently, in 2017, on a national level. Interestingly, the service learning approach as an innovative and socially responsible teaching methodology stands out in Austrian HE. This article classifies the developments of the Third Sector in Austria in the form of a policy brief. Austria has a growing community of practice in social innovation and service learning. The article gives insight into the strategic developments in Austria and is underpinned with recommendable action to be transferred to others
Generation of Active Protein Phosphatase 2A Is Coupled to Holoenzyme Assembly
Protein phosphatase 2A (PP2A) is a prime example of the multisubunit architecture of protein serine/threonine phosphatases. Until substrate-specific PP2A holoenzymes assemble, a constitutively active, but nonspecific, catalytic C subunit would constitute a risk to the cell. While it has been assumed that the severe proliferation impairment of yeast lacking the structural PP2A subunit, TPD3, is due to the unrestricted activity of the C subunit, we recently obtained evidence for the existence of the C subunit in a low-activity conformation that requires the RRD/PTPA proteins for the switch into the active conformation. To study whether and how maturation of the C subunit is coupled with holoenzyme assembly, we analyzed PP2A biogenesis in yeast. Here we show that the generation of the catalytically active C subunit depends on the physical and functional interaction between RRD2 and the structural subunit, TPD3. The phenotype of the tpd3Δ strain is therefore caused by impaired, rather than increased, PP2A activity. TPD3/RRD2-dependent C subunit maturation is under the surveillance of the PP2A methylesterase, PPE1, which upon malfunction of PP2A biogenesis, prevents premature generation of the active C subunit and holoenzyme assembly by counteracting the untimely methylation of the C subunit. We propose a novel model of PP2A biogenesis in which a tightly controlled activation cascade protects cells from untargeted activity of the free catalytic PP2A subunit
Survey Evidence on Conditional Norm Enforcement
We discuss survey evidence on individuals' willingness to sanction norm violations - such as evading taxes, drunk driving, fare dodging, or skiving o work - by expressing disapproval or social exclusion. Our data suggest that people condition their sanctioning behavior on their belief about the frequency of norm violations. The more commonly a norm violation is believed to occur, the lower the individuals' inclination to punish it. Based on an instrumental variable approach, we demonstrate that this pattern reflects a causal relationship
Hepatobiliary MRI: Signal intensity based assessment of liver function correlated to 13C-Methacetin breath test
Gadoxetic acid (Gd-EOB-DTPA) is a paramagnetic MRI contrast agent with raising popularity and has been used for evaluation of imaging-based liver function in recent years. In order to verify whether liver function as determined by real-time breath analysis using the intravenous administration of C-13-methacetin can be estimated quantitatively from Gd-EOB-DTPA-enhanced MRI using signal intensity (SI) values. 110 patients underwent Gd-EOB-DTPA-enhanced 3-T MRI and, for the evaluation of liver function, a C-13-methacetin breath test (C-13-MBT). SI values from before (SIpre) and 20 min after (SIpost) contrast media injection were acquired by T1-weighted volume-interpolated breath-hold examination (VIBE) sequences with fat suppression. The relative enhancement (RE) between the plain and contrast-enhanced SI values was calculated and evaluated in a correlation analysis of C-13-MBT values to SIpost and RE to obtain a SI-based estimation of C-13-MBT values. The simple regression model showed a log-linear correlation of C-13-MBT values with SIpost and RE (p < 0.001). Stratified by 3 different categories of C-13-MBT readouts, there was a constant significant decrease in both SIpost (p <= 0.002) and RE (p <= 0.033) with increasing liver disease progression as assessed by the C-13-MBT. Liver function as determined using real-time C-13-methacetin breath analysis can be estimated quantitatively from GdEOB- DTPA-enhanced MRI using SI-based indices
Gd-EOB-DTPA-enhanced MRI for evaluation of liver function: Comparison betewwn signal-intensity-based indices and T1 relaxometry
Gadolinium ethoxybenzyl-diethylenetriaminepentaacetic acid (Gd-EOB-DTPA) is a paramagnetic hepatobiliary magnetic resonance (MR) contrast agent. Due to its OATP1B1/B3-dependent hepatocyte-specific uptake and paramagnetic properties increasing evidence has emerged to suggest that Gd-EOBDTPA- enhanced MRI can be potentially used for evaluation of liver function. In this paper we compare the diagnostic performance of Gd-EOB-DTPA-enhanced relaxometry-based and commonly used signal-intensity (SI)-based indices, including the hepatocellular uptake index (HUI) and SI-based indices corrected by spleen or muscle, for evaluation of liver function, determined using the Indocyanin green clearance (ICG) test. Simple linear regression model showed a significant correlation of the plasma disappearance rate of ICG (ICG-PDR) with all Gd-EOB-DTPA-enhanced MRI-based liver function indices with a significantly better correlation of relaxometry-based indices on ICG-PDR compared to SI-based indices. Among SI-based indices, HUI achieved best correlation on ICG-PDR and no significant difference of respective correlations on ICG-PDR could be shown. Assessment of liver volume and consecutive evaluation of multiple linear regression model revealed a stronger correlation of ICG-PDR with both (SI)-based and T1 relaxometry-based indices. Thus, liver function can be estimated quantitatively from Gd-EOB-DTPA-enhanced MRI-based indices. Here, indices derived from T1 relaxometry are superior to SI-based indices, and all indices benefit from taking into account respective liver volumes
Diagnostic performance of Gd-EOB-DTPA-enhanced MRI for evaluation of liver dysfunction: a multivariable analysis of 3T MRI sequences
Objective:
The aim of this study was to evaluate the diagnostic performance of a multiparametric gadolinium ethoxybenzyl-diethylenetriaminepentaacetic acid (Gd-EOB-DTPA)-enhanced MRI examination for the estimation of liver dysfunction classified by the Model for End-Stage Liver Disease (MELD) score.
Results:
Liver dysfunction can be assessed by different methods. In a logistic regression analysis, T1- and T2-weighted images were affected by impaired liver function. In the assessment of liver dysfunction, the reduction rate in T1 mapping sequences showed a significant correlation in simple and multiple logistic regression.
Conclusion:
Changes in Gd-EOB-DTPA-enhanced MRI between plain images and images obtained during the hepatobiliary phase allowed good prediction of liver dysfunction, especially when using T1 mapping sequences.
Materials and Methods:
A total of 199 patients underwent contrast-enhanced MRI with a hepatocyte-specific contrast agent at 3T. In the multivariable analysis, the full range of available MRI sequences was used to estimate the liver dysfunction of patients with various MELD scores
Quantification of contrast agent uptake in the hepatobiliary phase helps to differentiate hepatocellular carcinoma grade
This study aimed to assess the degree of differentiation of hepatocellular carcinoma (HCC) using Gd-EOB-DTPA-assisted magnetic resonance imaging (MRI) with T1 relaxometry. Thirty-three solitary HCC lesions were included in this retrospective study. This study's inclusion criteria were preoperative Gd-EOB-DTPA-assisted MRI of the liver and a histopathological evaluation after hepatic tumor resection. T1 maps of the liver were evaluated to determine the T1 relaxation time and reduction rate between the native phase and hepatobiliary phase (HBP) in liver lesions. These findings were correlated with the histopathologically determined degree of HCC differentiation (G1, well-differentiated; G2, moderately differentiated; G3, poorly differentiated). There was no significant difference between well-differentiated (950.2 ± 140.2 ms) and moderately/poorly differentiated (1009.4 ± 202.0 ms) HCCs in the native T1 maps. After contrast medium administration, a significant difference (p ≤ 0.001) in the mean T1 relaxation time in the HBP was found between well-differentiated (555.4 ± 140.2 ms) and moderately/poorly differentiated (750.9 ± 146.4 ms) HCCs. For well-differentiated HCCs, the reduction rate in the T1 time was significantly higher at 0.40 ± 0.15 than for moderately/poorly differentiated HCCs (0.25 ± 0.07; p = 0.006). In conclusion this study suggests that the uptake of Gd-EOB-DTPA in HCCs is correlated with tumor grade. Thus, Gd-EOB-DTPA-assisted T1 relaxometry can help to further differentiation of HCC
Assessment of Physiological Rat Kidney Ageing—Implications for the Evaluation of Allograft Quality Prior to Renal Transplantation
Due to organ shortage and rising life expectancy the age of organ donors and recipients is increasing. Reliable biomarkers of organ quality that predict successful long-term transplantation outcomes are poorly defined. The aim of this study was the identification of age-related markers of kidney function that might accurately reflect donor organ quality. Histomorphometric, biochemical and molecular parameters were measured in young (3-month-old) and old (24-month-old) male Sprague Dawley rats. In addition to conventional methods, we used urine metabolomics by NMR spectroscopy and gene expression analysis by quantitative RT-PCR to identify markers of ageing relevant to allograft survival. Beside known markers of kidney ageing like albuminuria, changes in the concentration of urine metabolites such as trimethylamine-N-oxide, trigonelline, 2-oxoglutarate, citrate, hippurate, glutamine, acetoacetate, valine and 1-methyl-histidine were identified in association with ageing. In addition, expression of several genes of the toll-like receptor (TLR) pathway, known for their implication in inflammaging, were upregulated in the kidneys of old rats. This study led to the identification of age-related markers of biological allograft age potentially relevant for allograft survival in the future. Among those, urine metabolites and markers of immunity and inflammation, which are highly relevant to immunosuppression in transplant recipients, are promising and deserve further investigation in humans
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