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Used Procedure (used + procedure)
Selected AbstractsHepatic arterial flow becomes the primary supply of sinusoids following partial portal vein ligation in ratsJOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 10 2006Yukihiro Yokoyama Abstract Background and Aim:, Partial portal vein ligation (PPVL) is a commonly used procedure to induce prehepatic portal hypertension in animal models. The aim of this study was to test the hypothesis that the hepatic arterial flow becomes the primary source feeding the sinusoids in the liver after PPVL. Methods:, Sprague,Dawley rats underwent either sham operation or partial portal vein ligation (PPVL). The number of vessels in the liver at 2 weeks postoperatively was determined by factor VIII immunolocalization and the gene expression of angiogenic factors was assessed by RT-PCR. The total hepatic arterial supply to the liver was measured using the fluorescent microsphere injection technique. To further test the hypothesis, two additional groups of rats underwent hepatic artery ligation (HAL) or PPVL plus HAL (PPHAL). The integrity of hepatic microcirculation was then evaluated in all four groups by intravital microscopy. Results:, At 2 weeks after operation, the number of vessels detected by factor VIII staining was significantly higher in PPVL compared to sham. Densitometric analysis of RT-PCR bands revealed a significant increase of vascular endothelial growth factor gene expression in PPVL compared to sham. Arterial flow to the liver measured by fluorescent microspheres was increased by 190% in PPVL compared to sham. When all four groups were compared, no prominent histological abnormality was observed in sham, HAL, and PPVL groups; however, PPHAL livers showed focal necrosis and inflammatory cell infiltration around the portal triads. Additionally, only the PPHAL livers showed a decreased sinusoidal diameter and significantly lower perfusion index (PPHAL 42.9 ± 6.1; sham 85.7 ± 7.0, PPVL 80.2 ± 6.5, HAL 70.9 ± 4.5). Conclusions:, These results suggest that the hepatic artery flow becomes the primary source for the blood supply of sinusoids and the compensatory change in the hepatic arterial system plays a critical role in maintaining microcirculatory perfusion following the restriction of the portal vein flow by PPVL. [source] Outflow reconstruction in recipients of right liver graft from living donorsLIVER TRANSPLANTATION, Issue 2 2002Yasuhiko Sugawara MD Right-lobe transplantation is now a commonly used procedure in living donor liver transplantation (LDLT) to adult recipients. However, the risk for outflow obstruction is still an issue in LDLT. The right hepatic vein (RHV) was anastomosed end to end to the graft hepatic vein without unfavorable tension on the anastomosis. The anterior wall of the recipient hepatic vein was incised longitudinally, and a V-shaped vein graft was patched to form a wide and long orifice. This new hepatic venoplasty was used in 14 adult patients who received right liver grafts and gave good results without stenosis of the hepatic venous anastomosis or other complications. Our new technique may be useful in recipients of a right liver graft when the recipient or graft RHV is not long enough. [source] On the Use of the Nanoindentation Unloading Curve to Measure the Young's Modulus of Polymers on a Nanometer ScaleMACROMOLECULAR RAPID COMMUNICATIONS, Issue 22 2005Davide Tranchida Abstract Summary: The nanoindentation test is a fundamental tool to assess the link between morphology and mechanical properties. The preliminary results of a more exhaustive study about the applicability to polymers of the most used procedure to determine elastic modulus by indentation are reported in this short communication. A departure of the experimental conditions from the theoretical assumptions and results that give rise to the Oliver and Pharr analysis is shown to occur under a wide range of experimental conditions, with applied loads and penetration depths covering several orders of magnitude and using different indenter geometries. Unloading curves with exponents significantly larger than 2 are observed in disagreement with the contact mechanics approach used by Oliver and Pharr. An AFM image obtained in non contact mode of an indentation induced by a sharp AFM tip with a maximum applied load of ca 1.2 µN on amorphous PET. [source] Human immature dental pulp stem cells share key characteristic features with limbal stem cellsCELL PROLIFERATION, Issue 5 2009B. G. Monteiro Objectives:, Limbal stem cells (LSC) are self-renewing, highly proliferative cells in vitro, which express a set of specific markers and in vivo have the capacity to reconstruct the entire corneal epithelium in cases of ocular surface injury. Currently, LSC transplantation is a commonly used procedure in patients with either uni- or bilateral total limbal stem cells deficiency (TLSCD). Although LSC transplantation holds great promise for patients, several problems need to be overcome. In order to find an alternative source of cells that can partially substitute LSC in cornea epithelium reconstruction, we aimed at investigating whether human immature dental pulp stem cells (hIDPSC) would present similar key characteristics as LSC and whether they could be used for corneal surface reconstruction in a rabbit TLSCD model. Materials:, We used hIDPSC, which co-express mesenchymal and embryonic stem cell markers and present the capacity to differentiate into derivative cells of the three germinal layers. TLSCD was induced by chemical burn in one eye of rabbits. After 30 days, the opaque tissue formed was removed by superficial keratectomy. Experimental group received undifferentiated hIDPSC, while control group only received amniotic membrane (AM). Both groups were sacrificed after 3 months. Results and conclusions:, We have demonstrated, using immunohistochemistry and reverse transcription,polymerase chain reaction, that hIDPSCs express markers in common with LSC, such as ABCG2, integrin ,1, vimentin, p63, connexin 43 and cytokeratins 3/12. They were also capable of reconstructing the eye surface after induction of unilateral TLSCD in rabbits, as shown by morphological and immunohistochemical analysis using human-specific antibodies against limbal and corneal epithelium. Our data suggest that hIDPSCs share similar characteristics with LSC and might be used as a potential alternative source of cells for corneal reconstruction. [source] How to determine free Gd and free ligand in solution of Gd chelates.CONTRAST MEDIA & MOLECULAR IMAGING, Issue 5 2006A technical note Abstract Gd(III) chelates are often used as reporting probes in magnetic resonance imaging applications. Their use relies on the assumption that their high stability ensures against the release of free ligand and free Gd3+ ions, which are both highly toxic to living systems. The presence of free Gd3+ ions may have a profound effect on the contrast in the MR image as they may form highly hydrated, macromolecular complexes endowed with very high relaxivity thus providing erroneous information on the extent of the contrast effect induced by the given reporting probe. Although the stability of a given complex may be high enough, the complexation step could not have been completed. Therefore any Gd complex preparation has to be carefully checked for the content of free ligand and free metal ions. Herein the currently used procedures that allow an assessment of the amounts of free metal ions and free ligand in a solution of a given Gd complex are described in detail. Copyright © 2006 John Wiley & Sons Ltd. [source] Properties of scoring auctionsTHE RAND JOURNAL OF ECONOMICS, Issue 1 2008John Asker This article studies scoring auctions, a procedure commonly used to buy differentiated products: suppliers submit offers on all dimensions of the good (price, level of nonmonetary attributes), and these are evaluated using a scoring rule. We provide a systematic analysis of equilibrium behavior in scoring auctions when suppliers' private information is multidimensional (characterization of equilibrium behavior and expected utility equivalence). In addition, we show that scoring auctions dominate several other commonly used procedures for buying differentiated products, including menu auctions, beauty contests, and price-only auctions with minimum quality thresholds. [source] | ||||||||||