Developmental effect of antenatal exposure to betamethasone on renal angiotensin II activity in the young adult sheep

Antenatal corticosteroids may have long-term effects on renal development which have not been clearly defined. Our objective was to compare the responses to intrarenal infusions of ANG II in two groups of year-old, male sheep: one group exposed to a clinically relevant dose of betamethasone before birth and one not exposed. We wished to test the hypothesis that antenatal steroid exposure would enhance renal responses to ANG II in adult life. Six pairs of male sheep underwent unilateral nephrectomy and renal artery catheter placement. The sheep were infused for 24 h with ANG II or with ANG II accompanied by blockade of the angiotensin type 1 (AT1) or type 2 (AT2) receptor. Baseline mean arterial blood pressure among betamethasone-exposed sheep was higher than in control animals (85.8 ± 2.2 and 78.3 ± 1.0 mmHg, respectively, P = 0.003). Intrarenal infusion of ANG II did not increase systemic blood pressure (P ≥ 0.05) but significantly decreased effective renal plasma flow and increased renal artery resistance (P < 0.05). The decrease in flow and increase in resistance were significantly greater in betamethasone- compared with vehicle-exposed sheep (betamethasone P < 0.05, vehicle P ≥ 0.05). This effect appeared to be mediated by a heightened sensitivity to the AT1 receptor among betamethasone-exposed sheep. Sodium excretion initially decreased in both groups during ANG II infusion; however, a rebound was observed after 24 h. AT1 blockade was followed by a significant rebound after 24 h in both groups. AT2 blockade blunted the 24-h rebound effect among the vehicle-exposed sheep compared with the betamethasone-exposed sheep. In conclusion, antenatal corticosteroid exposure appears to modify renal responsiveness to ANG II by increasing AT1- and decreasing AT2 receptor-mediated actions particularly as related to renal blood flow and sodium excretion

Real-time in vivo imaging of stem cells following transgenesis by transposition

Previous studies have identified Sleeping Beauty transposons as efficient vectors for nonviral gene delivery in mammalian cells. However, studies demonstrating the usefulness of transposons as gene delivery vehicles into adult stem cells are lacking. Multipotent adult progenitor cells (MAPC) are nonhematopoietic stem cells with the capacity to form most, if not all, cell types of the body and as such hold great therapeutic potential. The whole-body biodistribution and persistence of MAPC are unknown, and such data would help direct clinical applications. We have nucleofected murine MAPC with two plasmid-based Sleeping Beauty transposons encoding the red fluorescent protein (DsRed2) and firefly luciferase. Transgenic euploid MAPC clones maintained their characteristic multilineage differentiation potential in vitro. DsRed2 and luciferase expression allowed for MAPC detection in vivo and in tissue sections. To confirm that transgenesis occurred by transposition into the genome of MAPC, we mapped Sleeping Beauty transposon integration sites in two MAPC clones using splinkerette PCR. This novel dual-reporter imaging approach based on the transgenesis of MAPC with Sleeping Beauty transposons sheds light on the homing patterns of MAPC and paves the way for quantification of MAPC engraftment in real time in vivo.status: publishe

A Real-Time Clinical Endoscopic System for Intraluminal, Multiplexed Imaging of Surface-Enhanced Raman Scattering Nanoparticles

<div><p>The detection of biomarker-targeting surface-enhanced Raman scattering (SERS) nanoparticles (NPs) in the human gastrointestinal tract has the potential to improve early cancer detection; however, a clinically relevant device with rapid Raman-imaging capability has not been described. Here we report the design and <i>in vivo</i> demonstration of a miniature, non-contact, opto-electro-mechanical Raman device as an accessory to clinical endoscopes that can provide multiplexed molecular data via a panel of SERS NPs. This device enables rapid circumferential scanning of topologically complex luminal surfaces of hollow organs (e.g., colon and esophagus) and produces quantitative images of the relative concentrations of SERS NPs that are present. Human and swine studies have demonstrated the speed and simplicity of this technique. This approach also offers unparalleled multiplexing capabilities by simultaneously detecting the unique spectral fingerprints of multiple SERS NPs. Therefore, this new screening strategy has the potential to improve diagnosis and to guide therapy by enabling sensitive quantitative molecular detection of small and otherwise hard-to-detect lesions in the context of white-light endoscopy.</p></div

Imaging device and system.

<p>(a) Photographs of the components of the distal end of the device adjacent to a quarter (diameter = 24 mm) for scale. All the components shown, less the motor, were custom designed and fabricated for this device. (b) Close-up photograph of the distal end of the fully functional device. The fiber bundle was enclosed and sealed within a flexible extrusion sheath. The window was placed between the scan mirror and the tissue in order to seal the inner mechanisms of the device from fluids in the surrounding environment. The use of a toroidal mirror compensates for beam distortion from the curvature of the glass window in order to maintain a collimated beam. Utilization of a 50-degree inclination angle of the toroidal mirror effectively eliminates back reflections from the window into the fiber bundle detector. (c) System overview. A continuous wave (CW) laser at 785 nm was used and the Raman-scattered light is collected through the multi-mode fibers of the fiber bundle. At the proximal end of the fiber bundle, the multimode fibers are arranged into a vertical array for efficient coupling to the spectrometer. A long-pass filter at the entrance of the spectrometer filters out the illumination light. A function generator signal controls a motor control board to finely tune the rotational speed of the motor to the desired speed of 1 rev/s. (d) Photograph of the completed fully functional system.</p

Real-time, multiplexed imaging overlaid onto 3D lumen topography in a colon phantom.

<p>(a) Top view of the colon phantom. Location of some the SERS samples are shown, some of which were placed directly in front of a fold (S482 and S481). (b) Bottom view of the colon phantom. Location of some the SERS samples are shown, some of which were placed directly in behind a fold (S493, S420, and the Equimolar sample). The Equimolar sample consists of an equal mixture of all 6 flavors. (c) The phantom measured roughly 8cm tall. The laser can be seen sweeping along the lumen of the surface. (d) Both the topography and Raman signal overlay is being generated simultaneously and in real-time. A total of 6,500 pixels (65 rev x 100 pix/rev) were acquired in a period 65 seconds (1 rev/s). See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0123185#pone.0123185.s003" target="_blank">S3 Video</a> for real-time reconstruction and Raman signal overlay.</p