Role of endogenous endothelin in the development of graft arteriosclerosis in rat cardiac allografts: antiproliferative effects of bosentan, a nonselective endothelin receptor antagonist

BACKGROUND: The purpose of this study was to determine whether endothelin-1 (ET-1) contributes to the development of graft arteriosclerosis and whether the orally active nonpeptide endothelin receptor antagonist bosentan, which blocks both ETA and ETB receptors, can protect against this pathologic damage. METHODS AND RESULTS: Recipient male Lewis rats were divided into three groups; group 1 received heterotopic heart transplantations from Lewis donors and groups 2 and 3 received transplantations from Brown-Norway donors; group 3 recipients also received bosentan orally at the dose of 20 mg/kg per day for 120 days. All recipients were given cyclosporine and were euthanized at examination 120 days after transplantation. Plasma ET-1 levels were significantly higher in group 2 than in group 1 (6.99+/-0.91 and 4.15+/-.83 pg/mL, respectively). Strong ET-1 immunoreactivity was seen in both the thickened neointima and the media of the coronary arteries in group 2 but not in group 1. The mean ratio of the coronary luminal area to the total vascular area in group 2 (19.0+/-11.7%) was significantly lower than that in group 1 (34.2+/-9.9%) and was significantly increased in group 3 (33.2+/-9.2%). CONCLUSIONS: These results show that local upregulation of ET-1, mainly in the thickened neointima and the media of the coronary arteries, may play an important role in the pathogenesis of graft arteriosclerosis by stimulating ETA receptors, ETB receptors, or both. Orally active bosentan might be a useful agent for the clinical prevention of graft arteriosclerosis.     

Translocation breakpoint possibly predisposes to nonrandom X-chromosome inactivation in mouse embryos bearing Searle''s T(X;16)16H translocation

To clarify the sequence of events that ultimately achieves the nonrandom inactivation of the paternally inherited X chromosome in postpartum female mice heterozygous for T(X;16)16H, we set out to examine the expression of Xist alleles and the X-linked HMG-lacZ transgene in embryos recovered at the egg cylinder stage. Lack of expression of the Xist(b) allele on the 16X translocation chromosome in the embryonic region of 7.5 d postcoitum (dpc) X16/X(n)Xist(a);16(X)Xist(b)/16 embryos strongly suggested the occurrence of nonrandom inactivation in favor of the normal X chromosome. The simplest explanation would be biased choice, followed by postinactivation selection against genetically unbalanced cells. However, the frequency and distribution of beta-galactosidase-positive cells in X16/X(n)lacZ;16X/16 embryos at 6.5 and 7.5 dpc, together with earlier cytogenetic data, raised an intriguing possibility that the majority of 16X chromosomes were prevented from completing the inactivation process, when they had been chosen to be silenced. Phenotypes of female mice carrying a spontaneous recombination between Xn and 16X in the segment defined by the T16H breakpoint and the X-linked Ta locus suggested that the nonrandomness was brought about by disruption of an X-chromosomal sequence or structure at the translocation breakpoint.     

Flow Method for Rapidly Producing Barium Hexaferrite Particles in Supercritical Water

We propose a flow method to produce barium hexaferrite (BaO6Fe₂O₃) particles with hydrothermal crystallization in supercritical water. Aqueous iron(III) and barium nitrate solution at room temperature was pressurized to 30 MPa and then mixed with potassium hydroxide solution (OH:NO₃ = 4) at the same conditions to generate metal hydroxides. This mixture was then rapidly heated to 400°C by mixing with supercritical water and then fed into a tubular reactor. Residence time was ~1 min. The reaction was terminated by cooling at the exit of the reactor. The Ba:Fe mole ratio was varied over a range of 0.1-2. When the Ba:Fe ratio was ~1/12, which is the stoichiometric ratio for BaO6Fe₂O₃, the main products were alpha-Fe₂O₃. However, for the case of Ba:Fe > 0.5, fine particles of single-phase BaO6Fe₂O₃ were produced. Batch experiments (380°C, 30 MPa) at Ba:Fe = 0.5 in supercritical water at a reaction time of 10 min produced a mixture of alpha-Fe₂O₃ and BaO6Fe₂O₃. This product transformed to the equilibrium phase, BaO2Fe₂O₃, in 4 h as the reaction time increased, which suggests that the BaO6Fe₂O₃ that formed in supercritical water with our proposed flow method under nonstoichiometric conditions was an intermediate but stable product. Furthermore, the nonstoichiometric and nonequilibrium (dynamic) conditions are important for producing single-phase BaO6Fe₂O₃ particles. The single-phase particles are highly stable and can be produced continuously in a reaction time of <1 min.     

The influence of surgical stress on T cells: enhancement of early phase lymphocyte activation

For the control of postoperative infection, it may be important to understand the possible influences of surgical stress on the host immune system. To this end, we examined how the early phase of lymphocyte activation was affected in patients after major surgery (eight patients with esophageal carcinoma and six undergoing cardiac surgery) using a flow cytometric assay based on expression of the early activation antigen, CD69. Freshly isolated T cell in preoperative and postoperative samples did not express CD69. When peripheral blood mononuclear cells were stimulated in vitro, the expression of CD69 was greatly enhanced in both CD4 and CD8 T cells, compared with the preoperative samples. The proportion of de novo CD69-expressing cells in the CD4 subset was approximately 3 times (Postoperative Day 1) and 4 times (Postoperative Days 2, 3, 5, and 7) greater than those preoperatively, whereas the proportion of de novo CD69-expressing cells in the CD8 subset was approximately 1.5 times (Postoperative Days 2 and 5) and 2 times (Postoperative Day 3) greater than those preoperatively. The proportion of CD69+ cells was significantly greater in the CD4+ subset than in the CD8+ subset during the postoperative period. IMPLICATIONS: Our results show that major surgical stress enhances the early phase of lymphocyte activation. The augmentation of activation was greater in CD4 (helper) T cells than in CD8 (cytotoxic) T cells.     

Analysis of cross-flow jet-type singlet oxygen generator

A cross-flow jet-type singlet oxygen generator has been developed, tested and analyzed in order to characterize the dependence of output performance on major input parameters. A thermal-balance model, which can predict O/sub 2/(/sup 1//spl Delta/) yield, gas temperature, and gas residence time, is proposed, and the resultant theoretical results are compared to the experimental data. Combined with computational fluid dynamics-based gas residence-time analysis, the model provides good agreement with the measured value of the O/sub 2/(/sup 1//spl Delta/) yield and the gas temperature. The surface chemistry model was applied to the measured Cl/sub 2/ utilization data, and was found to be inconsistent in the regime of high Cl/sub 2/ loading on the basic hydrogen peroxide jet, indicating that depletion of HO/sub 2//sup -/ is taking place.     

A modern injected steam gas turbine cogeneration system based on exergy concept

Factors such as low capital cost, good match of power and heat requirements and proven reliability can sometimes lead an end user into purchasing gas turbines for use in a modern cogeneration plant. The steam‐injected gas turbine is an attractive electrical generating technology for mitigating the impacts of rising energy prices. According to such mentioned above this paper is to provide results of an optimization study on cogeneration power cycle, which works by gas turbine with recuperator and injection steam added to the combustor of the gas turbine. The performance characteristics of the cycle based on energy and exergy concepts and based upon practical performance constraints were investigated. The effect of the recuperator on the cycle was greatly clarified. Results also show that the output power of a gas turbine increases when steam is injected. When extra steam has to be generated in order to be able to inject steam and at the same time to provide for a given heat demand, power generating efficiency increases but cogeneration efficiency decreases with the increasing of injected steam. Copyright © 2004 John Wiley & Sons, Ltd.     

Silica Pigments for Glossy Ink Jet Media

Silica is a versatile pigment for ink jet media. Micronized silica gel is the worldwide standard for high performance matte ink jet media. For glossy ink jet media, several different forms of silica are widely used. Submicron silica gel dispersions, with either anionic or cationic surfaces, can be employed in either absorptive basecoat layers or in the glossy ink receptive top layer. Colloidal silica, with a variety of particle sizes and surface modifications, is utilized extensively in glossy top layers. It will show how various silica pigments can be utilized in glossy ink receptive coatings, both in cast based glossy media and RC based glossy media. Several novel silica pigments will be examined by relating the physical properties of the pigments and the formula variables to the print quality of the ink jet media.     

Precisely Programmed and Robust 2D Streptavidin Nanoarrays by Using Periodical Nanometer‐Scale Wells Embedded in DNA Origami Assembly

A new punched DNA origami assembly with periodic nanometer‐scale wells has been successfully designed and constructed. Through the attachment of two biotins at the two edges of each well, just one streptavidin (SA) tetramer (d=5 nm) was size‐selectively captured in each 6.8×12×2.0 nm well; this allowed formation of a 28 nm‐period SA nanoarray of individual molecules. The position of SA capture can be fully controlled by placement of biotins in the nanoarray well. Moreover, construction of a 2D nanoarray of individual SA tetramers through selective positioning of SA tetramers in any desired wells in a complex of such punched origami motifs is also possible. The stability of the SA captured by this fixation strategy (DNA wells and two biotin linkers) was directly compared on the same molecule with the stability of SA captured with other possible strategies that do not employ wells or two linkers. In this way, the robustness of this means of fixation was clearly established.     

Pullout Behavior of Geogrid by Test and Numerical Analysis

This paper presents a study of geogrid pullout behavior in laboratory pullout tests and finite element modeling of the laboratory pullout tests. The pullout tests and the finite element method (FEM) analyses were carried out on two geogrid types with different stiffness values in dense sand under different overburden pressures. The pullout test results show that the geogrid behavior can be categorized into three types based on the bond stress distributions. The FEM results show reasonable agreement not only with the pullout force against the geogrid displacement, but also with the distributions of geogrid displacements, strains, tensile forces, and bond stresses along the geogrid length during deformation. This research demonstrates that the deformation characteristics of geogrids play an important role in the pullout tests while the interface properties play a significant role in the FEM simulations of geogrid pullout behavior. A method to obtain suitable interface parameters for designing of actual reinforced structures from the laboratory pullout tests is provided.     

Characterization of albumin- and lysozyme–adsorption evaluated on two differently prepared apatites

Ca2+-deficient hydroxyapatite (r-HAp) originated from cattle bones and stoichiometric hydroxyapatite (s-HAp) derived from reagents were prepared by wet syntheses. The adsorption characteristics of albumin (BSA) and lysozyme (LSZ) on the two HAp surfaces were compared by changing the heating temperature of the powders at 273–1073 K in a stream of water vapour. The saturated amount of adsorption (ASA(B) for BSA and ASA(L) for LSZ) on these HAp powders changed little at 273–673 K (Region I), but at 673–1073 K (Region II), clearly increased with crystallite size growth and transformation of crystal morphology. As far as the surface proportions of HAp for P- and C-adsorption sites (the ratios ASA(L)/ASA(B)) are concerned, r-HAp gave no change in Region I and decreased in Region II, whereas those for s-HAp were kept constant through all regions. The heats of LSZ adsorption, QL, for r-HAp and s-HAp, respectively, increased and decreased in Region II. These differences could be a result of the Ca2+-deficient structure of r-HAp with the OH–-vacancy and loosening surface structure due to segregation of impurities in Region II. r-HAp exhibited a 157% higher heat of BSA adsorption, QB, and a 60% lower QL in Region I than s-HAp. Conclusively, r-HAp can be used as an excellent adsorbent, rather than s-HAp, because of its chromatographic characteristics for the separation of acidic and basic proteins. © 1998 Chapman & Hall