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Loike J.D.,Columbia University | Plitt A.,Harvard University | Kothari K.,Harvard University | Zumeris J.,NanoVibronix | And 6 more authors.
PLoS ONE | Year: 2013

Biofilms are structured communities of bacteria that play a major role in the pathogenicity of bacteria and are the leading cause of antibiotic resistant bacterial infections on indwelling catheters and medical prosthetic devices. Failure to resolve these biofilm infections may necessitate the surgical removal of the prosthetic device which can be debilitating and costly. Recent studies have shown that application of surface acoustic waves to catheter surfaces can reduce the incidence of infections by a mechanism that has not yet been clarified. We report here the effects of surface acoustic waves (SAW) on the capacity of human neutrophils to eradicate S. epidermidis bacteria in a planktonic state and within biofilms. Utilizing a novel fibrin gel system that mimics a tissue-like environment, we show that SAW, at an intensity of 0.3 mW/cm2, significantly enhances human neutrophil killing of S. epidermidis in a planktonic state and within biofilms by enhancing human neutrophil chemotaxis in response to chemoattractants. In addition, we show that the integrin CD18 plays a significant role in the killing enhancement observed in applying SAW. We propose from out data that this integrin may serve as mechanoreceptor for surface acoustic waves enhancing neutrophil chemotaxis and killing of bacteria. © 2013 Loike et al.

Regeneron Pharmaceutical Inc. | Date: 2014-12-19

Compositions and methods are provided for modifying a genomic locus of interest in a eukaryotic cell, a mammalian cell, a human cell or a non-human mammalian cell using a large targeting vector (LTVEC) comprising various endogenous or exogenous nucleic acid sequences as described herein. Further methods combine the use of the LTVEC with a CRISPR/Cas system. Compositions and methods for generating a genetically modified non-human animal comprising one or more targeted genetic modifications in their germline are also provided.

DeChiara T.M.,Regeneron Pharmaceutical Inc. | Poueymirou W.T.,Regeneron Pharmaceutical Inc. | Auerbach W.,Regeneron Pharmaceutical Inc. | Frendewey D.,Regeneron Pharmaceutical Inc. | And 2 more authors.
Methods in Enzymology | Year: 2010

In conventional methods for the generation of genetically modified mice, gene-targeted embryonic stem (ES) cells are injected into blastocyst-stage embryos or are aggregated with morula-stage embryos, which are then transferred to the uterus of a surrogate mother. F0 generation mice born from the embryos are chimeras composed of genetic contributions from both the modified ES cells and the recipient embryos. Obtaining a mouse strain that carries the gene-targeted mutation requires breeding the chimeras to transmit the ES cell genetic component through the germ line to the next (F1) generation (germ line transmission, GLT). To skip the chimera stage, we developed the VelociMouse® method, in which injection of genetically modified ES cells into eight-cell embryos followed by maturation to the blastocyst stage and transfer to a surrogate mother produces F0 generation mice that are fully derived from the injected ES cells and exhibit a 100% GLT efficiency. The method is simple and flexible. Both male and female ES cells can be introduced into the eight-cell embryo by any method of injection or aggregation and using all ES cell and host embryo combinations from inbred, hybrid, and outbred genetic backgrounds. The VelociMouse® method provides several unique opportunities for shortening project timelines and reducing mouse husbandry costs. First, as VelociMice® exhibit 100% GLT, there is no need to test cross chimeras to establish GLT. Second, because the VelociMouse method permits efficient production of ES cell-derived mice from female ES cells, XO ES cell subclones, identified by screening for spontaneous loss of the Y chromosome, can be used to generate F0 females that can be bred with isogenic F0 males derived from the original targeted ES cell clone to obtain homozygous mutant mice in the F1 generation. Third, as VelociMice are genetically identical to the ES cells from which they were derived, the VelociMouse method opens up myriad possibilities for creating mice with complex genotypes in a defined genetic background directly from engineered ES cells without the need for inefficient and lengthy breeding schemes. Examples include creation of F0 knockout mice from ES cells carrying a homozygous null mutation, and creation of a mouse with a tissue-specific gene inactivation by combining null and floxed conditional alleles for the target gene with a transgenic Cre recombinase allele controlled by a tissue-specific promoter. VelociMice with the combinatorial alleles are ready for immediate phenotypic studies, which greatly accelerates gene function assignment and the creation of valuable models of human disease. © 2010 Elsevier Inc.

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