Robustness of diffuse reflectance spectra analysis by inverse adding doubling algorithm

Analysing diffuse reflectance spectra to extract properties of biological tissue requires modelling of light transport within the tissue, considering its absorption, scattering, and geometrical properties. Due to the layered skin structure, skin tissue models are often divided into multiple layers with their associated optical properties. Typically, in the analysis, some model parameters defining these properties are fixed to values reported in the literature to speed up the fitting process and improve its performance. In the absence of consensus, various studies use different approaches in fixing the model parameters. This study aims to assess the effect of fixing various model parameters in the skin spectra fitting process on the accuracy and robustness of a GPU-accelerated two-layer inverse adding-doubling (IAD) algorithm. Specifically, the performance of the IAD method is determined for noiseless simulated skin spectra, simulated spectra with different levels of noise applied, and in-vivo measured reflectance spectra from hyperspectral images of human hands recorded before, during, and after the arterial occlusion. Our results suggest that fixing multiple parameters to a priori known values generally improves the robustness and accuracy of the IAD algorithm for simulated spectra. However, for in-vivo measured spectra, these values are unknown in advance and fixing optical parameters to incorrect values significantly deteriorates the overall performance. Therefore, we propose a method to improve the fitting performance by pre-estimating model parameters. Our findings could be considered in all future research involving the analysis of diffuse reflectance spectra to extract optical properties of skin tissue.     

External iliac artery endofibrosis in an amateur runner: hemodynamic, angiographic, histopathological evaluation and percutaneous revascularization

We describe a case of external iliac artery endofibrosis in an amateur competitive runner. The diagnosis was made by a combination of hemodynamic, angiographic and histopathological assessment and percutaneous revascularization was performed using a balloon expandable stent.     

Expressions of Topoisomerase IIα and BCRP in Metastatic Cells are Associated with Overall Survival in Small Cell Lung Cancer Patients

The aim of this study was to investigate the mRNA expression levels of multidrug resistance-associated proteins in chemo-na?ve metastatic lung cancer cells and to determine the correlation with response to chemotherapy and overall survival. Metastatic cells were obtained by transbronchial fine needle aspiration biopsy of enlarged mediastinal lymph nodes in 14 patients with small cell lung cancer (SCLC) and 7 patients with non-small cell lung cancer (NSCLC). After cytological confirmation of lung cancer type, total RNA was extracted from biopsy samples and reverse transcribed to cDNA, and real-time PCR for the genes of interest [P-glycoprotein (P-gp), multidrug resistance protein 1 (MRP1), breast cancer resistance protein (BCRP), lung resistance protein (LRP) and topoisomerase IIα (TOPIIα)], was performed. We observed significantly decreased expression of BCRP and significantly increased expression of TOPIIα in metastatic SCLC cells compared to NSCLC. Furthermore, in SCLC high topoisomerase IIα and low BCRP expression levels positively correlated with longer overall survival. Our results showed higher expression levels of BCRP as well as lower levels of topoisomerase IIα in chemo-na?ve metastatic cells in NSCLC than in SCLC. These results correlate with previous observations that metastatic SCLC cells at the beginning of chemotherapy are potentially more sensitive to chemotherapeutic agents while in metastatic NSCLC cells resistance is usually inherent. We also showed that altered levels of topoisomerase IIα and BCRP in SCLC are important factors that contribute to resistance to chemotherapeutics that interfere with the enzyme and/or DNA and are highly associated with overall survival.     

Malignant cells facilitate lung metastasis by bringing their own soil

Metastatic cancer cells (seeds) preferentially grow in the secondary sites with a permissive microenvironment (soil). We show that the metastatic cells can bring their own soil--stromal components including activated fibroblasts--from the primary site to the lungs. By analyzing the efferent blood from tumors, we found that viability of circulating metastatic cancer cells is higher if they are incorporated in heterotypic tumor-stroma cell fragments. Moreover, we show that these cotraveling stromal cells provide an early growth advantage to the accompanying metastatic cancer cells in the lungs. Consistent with this hypothesis, we demonstrate that partial depletion of the carcinoma-associated fibroblasts, which spontaneously spread to the lung tissue along with metastatic cancer cells, significantly decreases the number of metastases and extends survival after primary tumor resection. Finally, we show that the brain metastases from lung carcinoma and other carcinomas in patients contain carcinoma-associated fibroblasts, in contrast to primary brain tumors or normal brain tissue. Demonstration of the direct involvement of primary tumor stroma in metastasis has important conceptual and clinical implications for the colonization step in tumor progression.     

The E3 ubiquitin ligase RNF186 and RNF186 risk variants regulate innate receptor-induced outcomes

Balancing microbial-induced cytokines and microbial clearance is critical at mucosal sites such as the intestine. How the inflammatory bowel disease (IBD)–associated gene RNF186 regulates this balance is unclear. We found that macrophages from IBD-risk rs6426833 carriers in the RNF186 region showed reduced cytokines to stimulation through multiple pattern recognition receptors (PRRs). Upon stimulation of PRRs, the E3-ubiquitin ligase RNF186 promoted ubiquitination of signaling complex molecules shared across PRRs and those unique to select PRRs. Furthermore, RNF186 was required for PRR-initiated signaling complex assembly and downstream signaling. RNF186, along with its intact E3-ubiquitin ligase activity, was required for optimal PRR-induced antimicrobial reactive oxygen species, reactive nitrogen species, and autophagy pathways and intracellular bacterial clearance in human macrophages and for bacterial clearance in intestinal myeloid cells. Cells transfected with the rare RNF186-A64T IBD-risk variant and macrophages from common rs6426833 RNF186 IBD-risk carriers demonstrated a reduction in these RNF186-dependent outcomes. These studies identify mechanisms through which RNF186 regulates innate immunity and show that RNF186 IBD-risk variants demonstrate a loss of function in PRR-initiated outcomes.

Inflammatory bowel disease (IBD) is characterized by dysregulated host–microbial responses and is composed of two subtypes: Crohn’s disease and ulcerative colitis (UC). Pattern recognition receptors (PRRs) are critical for recognition and responses to microbes. Both loss of function and gain of function in PRR-initiated outcomes can be associated with intestinal inflammation (1), thereby highlighting the importance of the balance in innate immune regulation in intestinal tissues. Despite the tremendous success in genetic studies identifying loci associated with susceptibility to IBD (2), altered functions for most of these loci are not well defined. One such region is on chromosome 1, encompassing the RNF186 gene (2, 3).The UC rs6426833 A risk variant in the RNF186 region is observed at a 0.395 to 0.548 frequency in European ancestry healthy individuals (per the Single Nucleotide Polymorphism Database; accessed July 2019), and this common variant confers a 1.265 increased risk of developing UC (2). Importantly, a rare Ring Finger Protein 186 (RNF186) Ala64Thr mutation confers a 1.49-fold increased risk for developing UC (4). RNF186 is a member of the RING family E3 ubiquitin ligases and has a conserved C₃HC₄ type zinc finger (ZnF) motif in the RING domain consistent with its ability to catalyze ubiquitination of select downstream substrates (5, 6). E3 ubiquitin ligases are key mediators for posttranslational modifications of PRR-initiated signaling intermediates (7). Only a few reports have examined roles for RNF186, and these have focused on its functions in epithelial cells (4–6, 8). In HeLa cells, RNF186 can localize to the endoplasmic reticulum (ER) and enhance ER stress-associated apoptotic signaling (5). RNF186-deficient and rare variant RNF186 A64T knockin mice demonstrated more severe dextran sodium sulfate–induced colitis associated with intestinal epithelial dysregulation (6). RNF186 can regulate nutrient sensing in epithelial cells (8). Therefore, while some functions for RNF186 have been identified in epithelial cells, roles for RNF186 in mediating outcomes in innate immunity, including downstream of PRRs, have not been examined. Moreover, the consequences of UC-associated common genetic variants in the RNF186 region have not been defined.We identify that RNF186 is expressed in human monocyte-derived and intestinal myeloid-derived cells. We establish that RNF186 is required for optimal PRR-induced signaling, cytokine secretion, and induction of a range of antimicrobial pathways. We define mechanisms and structural regions through which RNF186 regulates these PRR-initiated outcomes and identify that the rare and common RNF186 IBD-risk variants lead to a loss of function in these outcomes.