34 research outputs found
The rolling problem: overview and challenges
In the present paper we give a historical account -ranging from classical to
modern results- of the problem of rolling two Riemannian manifolds one on the
other, with the restrictions that they cannot instantaneously slip or spin one
with respect to the other. On the way we show how this problem has profited
from the development of intrinsic Riemannian geometry, from geometric control
theory and sub-Riemannian geometry. We also mention how other areas -such as
robotics and interpolation theory- have employed the rolling model.Comment: 20 page
The phosphorylated prodrug FTY720 is a histone deacetylase inhibitor that reactivates ERα expression and enhances hormonal therapy for breast cancer
Estrogen receptor-α (ERα)-negative breast cancer is clinically aggressive and does not respond to conventional hormonal therapies. Strategies that lead to re-expression of ERα could sensitize ERα-negative breast cancers to selective ER modulators. FTY720 (fingolimod, Gilenya), a sphingosine analog, is the Food and Drug Administration (FDA)-approved prodrug for treatment of multiple sclerosis that also has anticancer actions that are not yet well understood. We found that FTY720 is phosphorylated in breast cancer cells by nuclear sphingosine kinase 2 and accumulates there. Nuclear FTY720-P is a potent inhibitor of class I histone deacetylases (HDACs) that enhances histone acetylations and regulates expression of a restricted set of genes independently of its known effects on canonical signaling through sphingosine-1-phosphate receptors. High-fat diet (HFD) and obesity, which is now endemic, increase breast cancer risk and have been associated with worse prognosis. HFD accelerated the onset of tumors with more advanced lesions and increased triple-negative spontaneous breast tumors and HDAC activity in MMTV-PyMT transgenic mice. Oral administration of clinically relevant doses of FTY720 suppressed development, progression and aggressiveness of spontaneous breast tumors in these mice, reduced HDAC activity and strikingly reversed HFD-induced loss of estrogen and progesterone receptors in advanced carcinoma. In ERα-negative human and murine breast cancer cells, FTY720 reactivated expression of silenced ERα and sensitized them to tamoxifen. Moreover, treatment with FTY720 also re-expressed ERα and increased therapeutic sensitivity of ERα-negative syngeneic breast tumors to tamoxifen in vivo more potently than a known HDAC inhibitor. Our work suggests that a multipronged attack with FTY720 is a novel combination approach for effective treatment of both conventional hormonal therapy-resistant breast cancer and triple-negative breast cancer
Event extraction of bacteria biotopes: a knowledge-intensive NLP-based approach
International audienceBackground: Bacteria biotopes cover a wide range of diverse habitats including animal and plant hosts, natural, medical and industrial environments. The high volume of publications in the microbiology domain provides a rich source of up-to-date information on bacteria biotopes. This information, as found in scientific articles, is expressed in natural language and is rarely available in a structured format, such as a database. This information is of great importance for fundamental research and microbiology applications (e.g., medicine, agronomy, food, bioenergy). The automatic extraction of this information from texts will provide a great benefit to the field
The first small-molecule inhibitors of members of the ribonuclease E family
The Escherichia coli endoribonuclease RNase E is central to the processing and degradation of all types of RNA and as such is a pleotropic regulator of gene expression. It is essential for growth and was one of the first examples of an endonuclease that can recognise the 5′-monophosphorylated ends of RNA thereby increasing the efficiency of many cleavages. Homologues of RNase E can be found in many bacterial families including important pathogens, but no homologues have been identified in humans or animals. RNase E represents a potential target for the development of new antibiotics to combat the growing number of bacteria that are resistant to antibiotics in use currently. Potent small molecule inhibitors that bind the active site of essential enzymes are proving to be a source of potential drug leads and tools to dissect function through chemical genetics. Here we report the use of virtual high-throughput screening to obtain small molecules predicted to bind at sites in the N-terminal catalytic half of RNase E. We show that these compounds are able to bind with specificity and inhibit catalysis of Escherichia coli and Mycobacterium tuberculosis RNase E and also inhibit the activity of RNase G, a paralogue of RNase E
Nuclear Receptor, Coregulator Signaling, and Chromatin Remodeling Pathways Suggest Involvement of the Epigenome in the Steroid Hormone Response of Endometrium and Abnormalities in Endometriosis
Nuclear receptor, coregulator signaling, and chromatin remodeling pathways suggest involvement of the epigenome in the steroid hormone response of endometrium and abnormalities in endometriosis.
Human endometrium, a steroid hormone-dependent tissue, displays complex cellular regulation mediated by nuclear receptors (NRs). The NRs interact with histone-modifying and DNA-methylating/-demethylating enzymes in the transcriptional complex. We investigated NRs, their coregulators, and associated signaling pathways in endometrium across the normal menstrual cycle and in endometriosis, an estrogen-dependent, progesterone-resistant disorder. Endometrial tissue was processed for analysis of 84 genes using NR and coregulator polymerase chain reaction (PCR) arrays. Select genes were validated by immunohistochemistry. Ingenuity pathway analysis identified DNA methylation and transcriptional repression signaling as the most affected pathway in endometrium in women with versus without endometriosis, regardless of cycle phase. Thyroid hormone receptor (THR) and vitamin D receptor (VDR) pathways were also regulated in normal and disease endometrium by activation of TH or vitamin D regulated genes. These data support the involvement of the epigenome in steroid hormone response of normal endometrium throughout the cycle and abnormalities in endometrium in women with endometriosis
Could mobile phone text messages be used for infant feeding education in Ethiopia? A formative qualitative study
A majority of the world’s population now live in areas with a mobile telephone network. This expansion of the network enables people to use more mobile phone functionalities such as short message service, multimedia, and the Internet. Mobile phone–based health (mHealth) interventions have been considered to have benefits in low-income countries. The aim of this study was to explore the feasibility of a short message service for breastfeeding education in Ethiopia. Four focus groups—two with mothers and two with fathers—were conducted with a total of 41 participants. The focus group discussion recordings were transcribed in Tigrigna verbatim, and then translated to English. The data were analyzed using thematic analysis, underpinned by the technology acceptance model. The following four general themes emerged from the focus group discussions: (1) Mobile phones: integrated into everyday life; (2) SMS text messaging: anytime, anywhere, as long as there is a sound; (3) Marketing versus utility: a barrier to SMS; and (4) Scientific messages from credible experts are key to reading SMS-based messages. Parents in Ethiopia showed interest in receiving weekly infant feeding-related short messages. Short message service–based interventions could therefore be an option for improving knowledge and awareness of parents regarding infant feeding. </jats:p