A Kernel Perspective of Skip Connections in Convolutional Networks

Over-parameterized residual networks (ResNets) are amongst the most successful convolutional neural architectures for image processing. Here we study their properties through their Gaussian Process and Neural Tangent kernels. We derive explicit formulas for these kernels, analyze their spectra, and provide bounds on their implied condition numbers. Our results indicate that (1) with ReLU activation, the eigenvalues of these residual kernels decay polynomially at a similar rate compared to the same kernels when skip connections are not used, thus maintaining a similar frequency bias; (2) however, residual kernels are more locally biased. Our analysis further shows that the matrices obtained by these residual kernels yield favorable condition numbers at finite depths than those obtained without the skip connections, enabling therefore faster convergence of training with gradient descent

Galectin-1 is essential for efficient liver regeneration following hepatectomy

Galectin-1 (Gal1) is a known immune/inflammatory regulator which actsboth extracellularly and intracellularly, modulating innate and adaptive immuneresponses. Here, we explored the role of Gal1 in liver regeneration using 70% partial hepatectomy (PHx) of C57BL/6 wild type and Gal1-knockout (Gal1-KO, Lgals1-/-) mice. Gene or protein expression, in liver samples collected at time intervals from 2 to 168 hours post-operation, was tested by either RT-PCR or by immunoblotting and immunohistochemistry, respectively. We demonstrated that Gal1 transcript and protein expression was induced in the liver tissue of wild type mice upon PHx. Liver regeneration following PHx was significantly delayed in the Gal1-KO compared to the control liver. This delay was accompanied by a decreased Akt phosphorylation, and accumulation of the hepatocyte nuclear p21 protein in the Gal1-KO versus control livers at 24 and 48 hours following PHx. Transcripts of several known regulators of inflammation, cell cycle and cell signaling, including some known PHx-induced genes, were aberrantly expressed (mainly down-regulated) in Gal1-KO compared to control livers at 2, 6 and 24 hours post-PHx. Transient steatosis, which is imperative for liver regeneration following PHx, was significantly delayed and decreased in the Gal1- KO compared to the control liver and was accompanied by a significantly decreased expression in the mutant liver of several genes encoding lipid metabolism regulators.Our results demonstrate that Gal1 protein is essential for efficient liver regeneration following PHx through the regulation of liver inflammation, hepatic cell proliferation, and the control of lipid storage in the regenerating liver.Fil: Potikha, Tamara. Hadassah Hebrew University Medical Center; IsraelFil: Ella, Ezra. Hadassah Hebrew University Medical Center; IsraelFil: Cerliani, Juan Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Mizrahi, Lina. Hadassah Hebrew University Medical Center; IsraelFil: Pappo, Orit. Hadassah Hebrew University Medical Center; IsraelFil: Rabinovich, Gabriel Adrián. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Galun, Eithan. Hadassah Hebrew University Medical Center; IsraelFil: Goldenberg, Daniel S.. Hadassah Hebrew University Medical Center; Israe

Testing transgenic regulatory elements through live mouse imaging

AbstractTo overcome positional and methylation effects on transgene expression, we developed a universal cloning cassette for in vivo assessment of regulatory elements using the luciferase reporter gene and the CCCD camera. Monitoring luciferase expression pattern in live mice enables screening of large numbers of transgenic founders quickly and inexpensively. We demonstrate that in the engineered transgenic mice, the chicken β-globin 5′HS4 insulator did not always provide the desirable expression pattern, and the Island Element, responsible for the demethylation of the surrounding DNA region, was not beneficial. Both tested liver-specific and developmentally regulated promoters exhibited the expected expression pattern in most transgenic founders

HCV Tumor Promoting Effect Is Dependent on Host Genetic Background

BACKGROUND: The hepatitis C virus (HCV) is one of the major risk factors for the development of hepatocellular carcinoma (HCC). Nevertheless, transgenic mice which express the whole HCV polyprotein (HCV-Tg) do not develop HCC. Whereas chronic HCV infection causes inflammation in patients, in HCV-Tg mice, the host immune reaction against viral proteins is lacking. We aimed to test the role of HCV proteins in HCC development on the background of chronic inflammation in vivo. METHODOLOGY/PRINCIPAL FINDINGS: We crossed HCV-Tg mice that do not develop HCC with the Mdr2-knockout (Mdr2-KO) mice which develop inflammation-associated HCC, to generate Mdr2-KO/HCV-Tg mice. We studied the effect of the HCV transgene on tumor incidence, hepatocyte mitosis and apoptosis, and investigated the potential contributing factors for the generated phenotype by gene expression and protein analyses. The Mdr2-KO/HCV-Tg females from the N2 generation of this breeding (having 75% of the FVB/N genome and 25% of the C57BL/6 genome) produced significantly larger tumors in comparison with Mdr2-KO mice. In parallel, the Mdr2-KO/HCV-Tg females had an enhanced inflammatory gene expression signature. However, in the N7 generation (having 99.2% of the FVB/N genome and 0.8% of the C57BL/6 genome) there was no difference in tumor development between Mdr2-KO/HCV-Tg and Mdr2-KO animals of both sexes. The HCV transgene was similarly expressed in the livers of Mdr2-KO/HCV-Tg females of both generations, as revealed by detection of the HCV transcript and the core protein. CONCLUSION: These findings suggest that the HCV transgene accelerated inflammation-associated hepatocarcinogenesis in a host genetic background-dependent manner

Lack of galectin-1 exacerbates chronic hepatitis, liver fibrosis, and carcinogenesis in murine hepatocellular carcinoma model

Chronic liver inflammation (CLI) is a risk factor for development of hepatocellular carcinoma (HCC). Galectin-1 (Gal1) is involved in the regulation of inflammation, angiogenesis, and tumorigenesis, exhibiting multiple anti-inflammatory and protumorigenic activities. We aimed to explore its regulatory role in CLI and HCC progression using an established model of CLI-mediated HCC development, Abcb4 [multidrug-resistance 2 (Mdr2)]-knockout (KO) mice, which express high levels of Gal1 in the liver. We generated double-KO (dKO) Gal1- KO/Mdr2-KO mice on C57BL/6 and FVB/N genetic backgrounds and compared HCC development in the generated strains with their parentalMdr2-KO strains. Loss of Gal1 increased liver injury, inflammation, fibrosis, and ductular reaction in dKO mice of both strains starting from an early age. Aged dKO mutants displayed earlier hepatocarcinogenesis and increased tumor size compared with control Mdr2-KO mice. We found that osteopontin, a well-knownmodulator of HCC development, and oncogenic proteins Ntrk2 (TrkB) and S100A4 were overexpressed in dKO compared with Mdr2-KO livers. Our results demonstrate that in Mdr2-KO mice, a model of CLI-mediated HCC, Gal1-mediated protection from hepatitis, liver fibrosis, and HCC initiation dominates over its known procarcinogenic activities at later stages of HCC development. These findings suggest that anti-Gal1 treatmentsmay not be applicable at all stages of CLI-mediated HCC.—Potikha, T., Pappo, O., Mizrahi, L., Olam, D., Maller, S. M., Rabinovich, G. A., Galun, E., Goldenberg, D. S. Lack of galectin-1 exacerbates chronic hepatitis, liver fibrosis, and carcinogenesis in murine hepatocellular carcinoma model.Fil: Potikha, Tamara. Universidad Academica de Hadassa Jerusalem; IsraelFil: Pappo, Orit. Universidad Academica de Hadassa Jerusalem; IsraelFil: Mizrahi, Lina. Universidad Academica de Hadassa Jerusalem; IsraelFil: Olam, Devorah. Universidad Academica de Hadassa Jerusalem; IsraelFil: Maller, Sebastián M.. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Rabinovich, Gabriel Adrián. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Galun, Eithan. Universidad Academica de Hadassa Jerusalem; IsraelFil: Goldenberg, Daniel S.. Universidad Academica de Hadassa Jerusalem; Israe

Iscador Qu inhibits doxorubicin-induced senescence of MCF7 cells (vol 7, 3763, 2017)

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Multiple adaptive mechanisms to chronic liver disease revealed at early stages of liver carcinogenesis in the Mdr2-knockout mice Cancer Res 66

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Efekti ekstrakta bele imele na markere aktivacije i agregacije trombocita

BACKGROUND: Viscum album preparations are extensively used as complementary therapy in cancer and are shown to exert antitumor activities which involve the cytotoxic properties, induction of apoptosis, inhibition of angiogenesis and several other immunomodulatory mechanisms. AIM: The aim of this study was to investigate the eft fects of mistletoe extract on platelet as well as monocyte functions, as an important factors in immunomodulation of cancers metas tatic potencial and angiogenesis in tumors. METHODS: The effect of different concentrations of mistletoe extract on agonist-induced platelet activation markers and their aggregation with leukocytes was examined in the blood of healthy subjects ( n = 6 ) using flow cytometry. Effects on LPS -induced activation markers was det ermined in the blood of healthy subj ects as well as on THP- 1 cell line using an ELISA essays and flow cytometry. RESULTS: Mistletoe extract significantly inhibited agonist induced P selectin expression and platelet-monocytes aggregation. Additionally, mistletoe extract exerts anti-tumor effect through the stimulation of TNF-a production in LPS induced monocytes activation. CONCLUSION: Obtained data demonstrate that mistletoe extract was effective in modulating platelet and monocyte functions, as a part of pleiotropic anticancer effect.UVOD: Preparati biljke Viscum album se intenzivno koriste kao komplementarna terapija u lecenju kancera. Mehanizmi antitumorskog delovanja, potvrđeni in vitro, ukljucuju citotoksicno delovanje, indukciju apoptoze, inhibiciju angiogeneze, imunomodulatorno delovanje. CILJ: Cilj ovog istraživanja je ispitivanje uticaja ekstrakta bele imele na funkciju trombocita i monocita kao važnih faktora u imunomodulaciji kancerskog procesa, metastatskom potencijalu i tumorskoj angiogenezi. METODE: Uticaj razlicitih koncentracija ekstrakta bele imele na markere agonistom indukovane aktivacije trombocita i njihove agregacije sa leukocitima ispitivan je u krvi zdravih ispitanika (n=6) primenom protocne citometrije. Uticaj na markere LPS indukovane aktivacije određivan je u krvi ispitanika i kulturi THP-1 celija korišceenjem ELISA eseja i protocne citometrije. REZULTATI: Ekstrakt imele znacajno inhibira ekspresiju P-selektina i trombocitno-monocitnu agregaciju. Pokazana stimulacija produkcije TNF-a u LPS-om aktiviranim monocitima dodatno doprinosi antitumorskom potencijalu. ZAKLJUČAK: Dobijeni rezultati potvrđuju potenci jal ekstrakta imele da modulira trombocitnu i monocitnu funkciju, kao deo pleotropnog antitumorskog delovanja