Comprehensive Sex Steroid Profiling in Multiple Tissues Reveals Novel Insights in Sex Steroid Distribution in Male Mice

A comprehensive atlas of sex steroid distribution in multiple tissues is currently lacking, and how circulating and tissue sex steroid levels correlate remains unknown. Here, we adapted and validated a gas chromatography tandem mass spectrometry method for simultaneous measurement of testosterone (T), dihydrotestosterone (DHT), androstenedione, progesterone (Prog), estradiol, and estrone in mouse tissues. We then mapped the sex steroid pattern in 10 different endocrine, reproductive, and major body compartment tissues and serum of gonadal intact and orchiectomized (ORX) male mice. In gonadal intact males, high levels of DHT were observed in reproductive tissues, but also in white adipose tissue (WAT). A major part of the total body reservoir of androgens (T and DHT) and Prog was found in WAT. Serum levels of androgens and Prog were strongly correlated with corresponding levels in the brain while only modestly correlated with corresponding levels in WAT. After orchiectomy, the levels of the active androgens T and DHT decreased markedly while Prog levels in male reproductive tissues increased slightly. In ORX mice, Prog was by far the most abundant sex steroid, and, again, WAT constituted the major reservoir of Prog in the body. In conclusion, we present a comprehensive atlas of tissue and serum concentrations of sex hormones in male mice, revealing novel insights in sex steroid distribution. Brain sex steroid levels are well reflected by serum levels and WAT constitutes a large reservoir of sex steroids in male mice. In addition, Prog is the most abundant sex hormone in ORX mice

International Validation of a Nomogram to Predict Recurrence after Resection of Grade 1 and 2 Nonfunctioning Pancreatic Neuroendocrine Tumors

Background: Despite the low recurrence rate of resected nonfunctional pancreatic neuroendocrine tumors (NF-pNETs), nearly all patients undergo long-term surveillance. A prediction model for recurrence may help select patients for less intensive surveillance or identify patients for adjuvant therapy. The objective of this study was to assess the external validity of a recently published model predicting recurrence within 5 years after surgery for NF-pNET in an international cohort. This prediction model includes tumor grade, lymph node status and perineural invasion as predictors. Methods: Retrospectively, data were collected from 7 international referral centers on patients who underwent resection for a grade 1-2 NF-pNET between 1992 and 2018. Model performance was evaluated by calibration statistics, Harrel's C-statistic, and area under the curve (AUC) of the receiver operating characteristic curve for 5-year recurrence-free survival (RFS). A sub-analysis was performed in pNETs >2 cm. The model was improved to stratify patients into 3 risk groups (low, medium, high) for recurrence. Results: Overall, 342 patients were included in the validation cohort with a 5-year RFS of 83% (95% confidence interval [CI]: 78-88%). Fifty-eight patients (17%) developed a recurrence. Calibration showed an intercept of 0 and a slope of 0.74. The C-statistic was 0.77 (95% CI: 0.70-0.83), and the AUC for the prediction of 5-year RFS was 0.74. The prediction model had a better performance in tumors >2 cm (C-statistic 0.80). Conclusions: External validity of this prediction model for recurrence after curative surgery for grade 1-2 NF-pNET showed accurate overall performance using 3 easily accessible parameters. This model is available via www.pancreascalculator.com

Interlaboratory comparison study of the Colony Forming Efficiency assay for assessing cytotoxicity of nanomaterials

Nanotechnology has gained importance in the past years as it provides opportunities for industrial growth and innovation. However, the increasing use of manufactured nanomaterials (NMs) in a number of commercial applications and consumer products raises also safety concerns and questions regarding potential unintended risks to humans and the environment. Since several years the European Commission’s Joint Research Centre (JRC) is putting effort in the development, optimisation and harmonisation of in vitro test methods suitable for screening and hazard assessment of NMs. Work is done in collaboration with international partners, in particular the Organisation for Economic Co-operation and Development (OECD). This report presents the results from an interlaboratory comparison study of the in vitro Colony Forming Efficiency (CFE) cytotoxicity assay performed in the frame of OECD's Working Party of Manufactured Nanomaterials (WPMN). Twelve laboratories from European Commission, France, Italy, Japan, Poland, Republic of Korea, South Africa and Switzerland participated in the study coordinated by JRC. The results show that the CFE assay is a suitable and robust in vitro method to assess cytotoxicity of NMs. The assay protocol is well defined and is easily and reliably transferable to other laboratories. The results obtained show good intra and interlaboratory reproducibility of the assay for both the positive control and the tested nanomaterials. In conclusion the CFE assay can be recommended as a building block of an in vitro testing battery for NMs toxicity assessment. It could be used as a first choice method to define dose-effect relationships for other in vitro assays.JRC.I.4-Nanobioscience

Network Compression as a Quality Measure for Protein Interaction Networks

With the advent of large-scale protein interaction studies, there is much debate about data quality. Can different noise levels in the measurements be assessed by analyzing network structure? Because proteomic regulation is inherently co-operative, modular and redundant, it is inherently compressible when represented as a network. Here we propose that network compression can be used to compare false positive and false negative noise levels in protein interaction networks. We validate this hypothesis by first confirming the detrimental effect of false positives and false negatives. Second, we show that gold standard networks are more compressible. Third, we show that compressibility correlates with co-expression, co-localization, and shared function. Fourth, we also observe correlation with better protein tagging methods, physiological expression in contrast to over-expression of tagged proteins, and smart pooling approaches for yeast two-hybrid screens. Overall, this new measure is a proxy for both sensitivity and specificity and gives complementary information to standard measures such as average degree and clustering coefficients

A Tutorial for Analysing the Cost-effectiveness of Alternative Methods for Assessing Chemical Toxicology: The Case of Acute Oral Toxicity Prediction

Compared with traditional animal methods for toxicity testing, in vitro and in silico methods are widely considered to permit a more cost-effective assessment of chemicals. However, how to assess the cost-effectiveness of alternative methods has remained unclear. This paper offers a user-oriented tutorial for applying cost-effectiveness analysis (CEA) to alternative (non-animal) methods. The purpose is to illustrate how CEA facilitates the identification of the alternative method, or the combination of methods, that offers the highest information gain per unit of cost. We illustrate how information gains and costs of single methods and method combinations can be assessed. By using acute oral toxicity as an example, we apply CEA to a set of four in silico methods (ToxSuite, TOPKAT, TEST, ADMET Predictor), one in vitro method (the 3T3 Neutral Red Uptake cytotoxicity assay), and various combinations of these methods. Our results underline that in silico tools are more cost-effective than the in vitro test. Battery combinations of alternative methods, however, do not necessarily outperform single methods, because additional information gains from the battery are easily outweighed by additional cost