The Cytoscan (TM) model E-II, a new reflectance microscope for intravital microscopy: Comparison with the standard fluorescence method

The Cytoscan(TM) Model E-II (Cytometrics Inc., Philadelphia, Pa., USA) is a newly developed instrument which functions as an intravital microscope and is small and easily portable. Through the use of orthogonal polarization spectral (OPS) imaging, the Cytoscan Model E-II delivers images of the microcirculation which are comparable to those achieved with intravital fluorescence videomicroscopy (IFM), but without the use of fluorescent dyes. The purpose of this study was to validate the Cytoscan Model E-II instrument against IFM. The experiments were carried out on striated muscle in the dorsal skinfold chamber of the awake Syrian hamster. The following parameters were measured in identical regions of interest in the same animal under baseline conditions and 0.5 and 2 h after a 4-hour period of pressure-induced ischemia: arteriolar diameter, venular diameter and venular red blood cell velocity. Bland-Altman plots showed good agreement between the two techniques for venular red blood cell velocity. As expected, arteriolar and venular diameters as measured by the Cytoscan were on average 5 mum smaller than the values from IFM, since the Cytoscan measures the red blood cell column width and IFM measures luminal diameter. Thus, OPS imaging can be used to make valid measurements of microvascular diameter and red blood cell velocity in tissues. Copyright (C) 2000 S. Karger AG, Basel

Wildlife and Pesticides - A practical guide to reducing the risk

Pesticides are widely used in agriculture today. Producers use pesticides because they are effective and generally reasonably priced. The benefits include reduced yield losses and time savings to the producer, and lower food and fiber costs for consumer

Comparison of regional blood flow values measured by radioactive and fluorescent microspheres

Fluorescent microspheres (FM) have become an attractive alternative to radioactive microspheres (RM) for the measurement of regional blood flow (RBF). The aim of the present study was to investigate the comparability of both methods by measuring RBF with FM and RM. Eight anaesthetised pigs received simultaneous, left atrial injections of FM and RM with a diameter of 15 mum at six different time points. Blood reference samples were collected from the descending aorta. RBF was determined in tissue samples of the myocardium, spleen and kidneys of all 8 animals. After radioactivity of the tissue samples was determined, the samples were processed automatically for measuring fluorescence using a recently developed filter device (SPU). RBF was calculated with both the isotope and spectrometric data of both methods for each sample resulting in a total of 10,512 blood flow values. The comparison of the RBF values yielded high linear correlation (mean r(2) = 0.95 +/- 0.03 to 0.97 +/- 0.02) and excellent agreement (bias 5.4-6.7%, precision 9.9-16.5%) of both methods. Our results indicate the validity of MS and of the automated tissue processing technique by means of the SPU. Copyright (C) 2002 S. Karger AG, Basel

Islets of Langerhans Are Protected from Inflammatory Cell Recruitment during Reperfusion of Rat Pancreas Grafts

Background: Ischemia/reperfusion (I/R) injury plays a pivotal role in the development of graft pancreatitis, with ischemia time representing one of its crucial factors. However, it is unclear, whether exocrine and endocrine tissue experience similar inflammatory responses during pancreas transplantation (PTx). This study evaluated inflammatory susceptibilities of islets of Langerhans (ILH) and exocrine tissue after different preservation periods during early reperfusion. Methods: PTx was performed in rats following 2 h (2h-I) or 18 h (18h-I) preservation. Leukocyte-endothelial cell interactions (LEI) were analyzed in venules of acinar tissue and ILH in vivo over 2 h reperfusion. Nontransplanted animals served as controls. Tissue samples were analyzed by histomorphometry. Results: In exocrine venules leukocyte rolling predominated in the 2h-I group. In the 18h-I group, additionally, high numbers of adherent leukocytes were found. Histology revealed significant edema formation and leukocyte extravasation in the 18h-I group. Notably, LEI in postcapillary venules of ILH were significantly lower. Leukocyte rolling was only moderately enhanced and few leukocytes were found adherent. Histology revealed minor leukocyte extravasation. Conclusion: Ischemia time contributes decisively to the extent of the I/R-injury in PTx. However, ILH have a significantly lower susceptibility towards I/R, even when inflammatory reactions in adjacent exocrine tissue are evident. Copyright (C) 2010 S. Karger AG, Base

A portable platform for accelerated PIC codes and its application to GPUs using OpenACC

We present a portable platform, called PIC_ENGINE, for accelerating Particle-In-Cell (PIC) codes on heterogeneous many-core architectures such as Graphic Processing Units (GPUs). The aim of this development is efficient simulations on future exascale systems by allowing different parallelization strategies depending on the application problem and the specific architecture. To this end, this platform contains the basic steps of the PIC algorithm and has been designed as a test bed for different algorithmic options and data structures. Among the architectures that this engine can explore, particular attention is given here to systems equipped with GPUs. The study demonstrates that our portable PIC implementation based on the OpenACC programming model can achieve performance closely matching theoretical predictions. Using the Cray XC30 system, Piz Daint, at the Swiss National Supercomputing Centre (CSCS), we show that PIC_ENGINE running on an NVIDIA Kepler K20X GPU can outperform the one on an Intel Sandybridge 8-core CPU by a factor of 3.4

Clusters of polymersomes and Janus nanoparticles hierarchically self-organized and controlled by DNA hybridization

The combination of "hard", structurally well-defined particles with "soft", functional compartments bears great potential to produce structurally intricate hybrid nanomaterials that promote a multitude of applications that require multimodal agents and that permit the production of molecular factories. However, the co-assembly of "hard" and "soft" components in a programmable and directional manner is challenging due to the strongly differing mechanical properties of such disparate entities. Here, a versatile strategy to generate clusters by the directional and controlled self-organization of "hard" Janus nanoparticles (JNPs) with "soft" polymersomes is described. The hybridization of complementary ssDNA strands bound to the components drives cluster formation, while the asymmetry of the JNPs governs the directionality of the self-organization. Various factors have been explored to simultaneously preserve the integrity of the polymersomes and program the cluster formation. Differently loaded polymersomes on each lobe of the JNPs preserved their architecture in the clusters which, were shown to be non-toxic when interacting with cell lines. The architecture of the clusters, as a molecular factory where each component can be separately controlled bears great promise for use in advanced medical applications, including theranostics and correlative imaging