Humoral and cellular immunopathology of hepatic and cardiac hamster-into-rat xenograft rejection: Marked stimulation of IgM^++bright/IgD^+dull splenic B cells

Normal Lewis rat serum contains antibodies (IgM > IgG) that bind to hamster leukocytes and endothelial cells. Transplantation of either the heart or liver from hamster rat results in release of hamster hematolymphoid cells from the graft, which lodge in the recipient spleen (cell migration), where recipient T- and B-cell populations initiate DNA synthesis within one day. There is marked stimulation of splenic IgM++(bright)/IgD+(dull) B cells in the marginal zone and red pulp, which account for 48% of the total splenic blast cell population by 4 days after liver transplantation. CD4+ predominant T-cell proliferation in the splenic periarterial lymphatic sheath and paracortex of peripheral lymph nodes occurs almost simultaneously. The effector phase of rejection in cardiac recipients is dominated by complement-fixing IgM antibodies, which increase daily and result in graft destruction in 3 to 4 days, even in animals treated with FK506. In liver recipients, combined antibody and cellular rejection, associated with graft infiltration by OX8+ natural killer, and fewer W3/25+ (CD4) lymphocytes, are responsible for graft failure in untreated recipients at 6 to 7 days. FK506 inhibits the T-cell response in liver recipients and significantly prolongs graft survival, but does not prevent the rise or deposition of IgM antibodies in the graft. However, a single injection of cyclophosphamide 10 days before transplantation effectively depletes the splenic IgM++(bright)/IgD+(dull) cells and in combination with FK506, results in 100% survival of both cardiac and hepatic xenografts for more than 60 days. Although extrapolation of morphological findings to functional significance is fraught with potential problems, we propose the following mechanisms of xenograft rejection. The reaction initially appears to involve primitive host defense mechanisms, including an IgM-producing subpopulation of splenic B cells and natural killer cells. Based on the reaction and distribution of OX8+ and W3/25+ cells, antibody dependent cell cytotoxicity and delayed-type hypersensitivity responses seem worthy of further investigation as possible effector mechanisms. Effective control of xenograft rejection is likely to require a dual pharmaceutical approach, one to contain T-cell immunity and another to blunt the primitive B-cell response

Team-maxmin equilibrium: Efficiency bounds and algorithms

The Team-maxmin equilibrium prescribes the optimal strategies for a team of rational players sharing the same goal and without the capability of correlating their strategies in strategic games against an adversary. This solution concept can capture situations in which an agent controls multiple resources-corresponding to the team members-that cannot communicate. It is known that such equilibrium always exists and it is unique (except degenerate cases) and these properties make it a credible solution concept to be used in real-world applications, especially in security scenarios. Nevertheless, to the best of our knowledge, the Team-maxmin equilibrium is almost completely unexplored in the literature. In this paper, we investigate bounds of (in) efficiency of the Team-maxmin equilibrium w.r.t. the Nash equilibria and w.r.t. the Maxmin equilibrium when the team members can play correlated strategies. Furthermore, we study a number of algorithms to find and/or approximate an equilibrium, discussing their theoretical guarantees and evaluating their performance by using a standard testbed of game instances

Long-term survival of heart and liver xenografts with splenectomy and FK 506.

We have reported that while hamster-to-rat liver xenograft survival is prolonged by FK 506, hamster hearts undergo humoral rejection under this immunosuppressant.1 Because the spleen has been shown to be one of the main sources of xenoantibodies,2,3 and in vivo experiments have demonstrated that splenectomy (Spx) is able to increase the efficacy of various immunosuppressive agents after xenotransplantation,4–6 we combined Spx with FK 506 to test whether survival of the intractable cardiac xenografts is prolonged, and of liver xenografts improved

Stability analysis of dual viscous flows saturating a vertical porous pipe

The linear stability analysis of a mixed convection viscous flow in a vertical porous pipe is here investigated. The contribution of viscous heating is assumed to be non negligible. A fully developed flow regime is assumed for the basic state. The local balance equations for this state display dual stationary solutions. The dual branches of stationary solutions are determined numerically. Since the pipe is characterised by an isothermal lateral surface, the viscous heating is the sole cause of the buoyancy force. In order to investigate the stability of the basic dual solutions, small amplitude disturbances with the form of normal modes are superposed to the basic state. The solution of the eigenvalue problem obtained allows one to determine the growth rate associated to both the basic solution branches. The sign of the growth rate determines whether the particular basic solution is stable or unstable

Olive Mill Wastewater Valorization in Multifunctional Biopolymer Composites for Antibacterial Packaging Application

Olive mill wastewater (OMW) is the aqueous waste derived from the production of virgin olive oil. OMW typically contains a wide range of phenol-type molecules, which are natural antioxidants and/or antibacterials. In order to exploit the bioactive molecules and simultaneously decrease the environmental impact of such a food waste stream, OMW has been intercalated into the host structure of ZnAl layered double hydroxide (LDH) and employed as an integrative filler for the preparation of poly(butylene succinate) (PBS) composites by in situ polymerization. From the view point of the polymer continuous phase as well as from the side of the hybrid filler, an investigation was performed in terms of molecular and morphological characteristics by gel permeation chromatography (GPC) and X-ray diffraction (XRD); also, the thermal and mechanical properties were evaluated by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and dynamic thermomechanical analysis (DMTA). Antibacterial properties have been assessed against a Gram-positive and a Gram-negative bacterium, Staphylococcus aureus and Escherichia coli, respectively, as representatives of potential agents of foodborne illnesses

Stopping of Charged Particles in a Magnetized Classical Plasma

The analytical and numerical investigations of the energy loss rate of the test particle in a magnetized electron plasma are developed on the basis of the Vlasov-Poisson equations, and the main results are presented. The Larmor rotation of a test particle in a magnetic field is taken into account. The analysis is based on the assumption that the energy variation of the test particle is much less than its kinetic energy. The obtained general expression for stopping power is analyzed for three cases: (i) the particle moves through a collisionless plasma in a strong homogeneous magnetic field; (ii) the fast particle moves through a magnetized collisionless plasma along the magnetic field; and (iii) the particle moves through a magnetized collisional plasma across a magnetic field. Calculations are carried out for the arbitrary test particle velocities in the first case, and for fast particles in the second and third cases. It is shown that the rate at which a fast test particle loses energy while moving across a magnetic field may be much higher than the loss in the case of motion through plasma without magnetic field.Comment: 14 pages, 3 figures, LaTe

First report of Rice stripe necrosis virus infecting rice in Sierra Leone

While Rice stripe necrosis virus (RSNV, Benyvirus, Benyviridae) has been reported on rice plants on two continents, little is known about the diversity of this multipartite virus which is transmitted by the plasmodiophorid protist Polymyxa graminis. First identified in 1983 in the Côte d´Ivoire (Fauquet & Thouvenel, 1983), the disease had previously been observed in Sierra Leone without formal identification of the causal agent (Buddenhagen, pers. comm.). Later, the virus was reported in South and Central America (Colombia, Ecuador, Panama and Brazil) causing up to 40% yield losses (Morales et al., 1999). Recently, RSNV was identified for the first time in several African countries including Burkina Faso (Sérémé et al., 2014), Benin (Oludare et al., 2015) and Mali (Decroës et al., 2017) suggesting a re-emergence of the virus in Africa.In 2019, symptoms of leaf-crinkling and stripe necrosis were observed on a rice plant from the Bo District in Sierra Leone (Fig. 1). Leaf samples were analysed by serological and molecular methods to confirm the presence of RSNV in Sierra Leone. RSNV was detected by plate-trapped antibody (PTA)- ELISA using a polyclonal antiserum against RSNV (Fauquet & Thouvenel, 1983).The presence of the virus was confirmed after total RNA extraction using 0.05 g of leaves and the RNeasy Plant Mini Kit (Qiagen) and RT-PCR amplification (10 U/μl M-MLV-reverse transcriptase, Promega; 10 U/μl Dynazyme, Finnzyme) as described previously (Sérémé et al., 2014, Oludare et al., 2015) with primers RSNV1-2901F 5′-TGAATTTGGTGCTCTCTTG-3′ / RSNV1-3827R 5′-TGTGGCGTTTCCAGACCTAAA-3´ and RSNV2-5´ 5´-TATCACTACTGACGAATTCCACCTAC-3´ / RSNV2-1223R 5´-AATCTGCGGCCTGTTTTGTA-3´. Specific amplicons, 926 and 1241 nt in length, were generated corresponding to sequences in the helicase domain and the coat protein (CP) genes on RSNV RNA 1 and RNA 2, respectively. The amplicons were sequenced directly and the sequences deposited in GenBank (Accession Nos. MN750254 and MN750255, respectively).The helicase sequence obtained from the Sierra Leone RSNV isolate showed 1.8-7.3% genetic distance with those from South America (EU099844.3, MG792544, MG792545, MG792546) and only 1.4-2.2% with those from Africa (KP099623, MF115599, MF115600, MF115601, MF115602, MF115603, MK170452, MK170453). The phylogenetic analysis based on the helicase domain included the sequence obtained from the Sierra Leone within a cluster represented by RSNV from South America and West Africa (Fig. 2a). In contrast, the CP sequence from the Sierra Leone RSNV isolate revealed an unexpected genetic differentiation as compared to all the other sequences from South America (5.6%; NC_038774) or Africa (5.2-6.5%; LK023710, MF115604, MF115605, MF115606, MF115607, MF115608, MK170454, MK170455). Interestingly, the CP sequence from Sierra Leone is located at a basal position in the phylogeny (Fig. 2b).To our knowledge, this is the first confirmed report of RSNV in Sierra Leone. Further studies are needed to assess the molecular and biological diversity of RSNV, the spatial distribution and the incidence of this re-emerging rice disease in Africa.Fil: Tucker, M. J.. Sierra Leone Agricultural Research Institute; Sierra LeonaFil: Giovani Celli, Marcos Giovani. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias. Unidad de Fitopatología y Modelización Agrícola - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Unidad de Fitopatología y Modelización Agrícola; ArgentinaFil: Conteh, A. B.. Sierra Leone Agricultural Research Institute; Sierra LeonaFil: Taylor, D. R.. Sierra Leone Agricultural Research Institute; Sierra LeonaFil: Hebrard, Andrés. Centre National de la Recherche Scientifique. Institut de Recherche pour le Développement; FranciaFil: Poulicard, N.. Centre National de la Recherche Scientifique. Institut de Recherche pour le Développement; Franci