Mycophenolate mofetil inhibits lymphocyte binding and the upregulation of adhesion molecules in acute rejection of rat kidney allografts.

Mycophenolate mofetil (MMF) interacts with purine metabolism and possibly with the expression of adhesion molecules. In the present study, we analysed the expression of these molecules in transplanted kidney allografts treated with RS LBNF1 kidneys were orthotopically transplanted into Lewis rats and either treated with RS (20 mg/kg/day) or vehicle. Rats were harvested 3, 5 and 7 days following transplantation. For binding studies, fresh-frozen sections of transplanted kidneys were incubated with lymph node lymphocytes (LNL) derived from transplanted rats. Additionally, immunohistology was performed with various monoclonal antibodies. In general, MMF resulted in better preservation of graft structure by 7 days. Cellular infiltration and tubular atrophy were less pronounced. At day 3, macrophages were diminished in MMF-treated animals to a high extent, while the number of T cells was almost identical to that of controls. In addition, the number of cells positive for MHC class II and LFA-1 was reduced in the MMF-treated animals. These findings correlated with the binding results. Three days following engraftment, LNL bound to MMF-treated kidneys to a lesser extent compared to controls. In conclusion, MMF resulted in a markedly reduced leucocytic infiltrate, presumably based on a reduced expression of lymphocytic adhesion molecules and an interaction with macrophages

Mucosal immune responses following intestinal nematode infection.

In most natural environments, the large majority of mammals harbour parasitic helminths that often live as adults within the intestine for prolonged periods (1-2 years). Although these organisms have been eradicated to a large extent within westernized human populations, those living within rural areas of developing countries continue to suffer from high infection rates. Indeed, recent estimates indicate that approximately 2.5 billion people worldwide, mainly children, currently suffer from infection with intestinal helminths (also known as geohelminths and soil-transmitted helminths) . Paradoxically, the eradication of helminths is thought to contribute to the increased incidence of autoimmune diseases and allergy observed in developed countries. In this review, we will summarize our current understanding of host-helminth interactions at the mucosal surface that result in parasite expulsion or permit the establishment of chronic infections with luminal dwelling adult worms. We will also provide insight into the adaptive immune mechanisms that provide immune protection against re-infection with helminth larvae, a process that is likely to be key to the future development of successful vaccination strategies. Lastly, the contribution of helminths to immune modulation and particularly to the treatment of allergy and inflammatory bowel disease will be discussed

Attitudes Toward the Practical Incorporation of Scenario Based Training (SBT) Into a Pilot Training Syllabus

As aviation moves into its second century, aircraft accidents have become less common, but the rate of decision-based accidents has not decreased in comparison with mechanical-failure based accidents. This is especially true of General Aviation accidents, both in single engine and light twin engine aircraft. While the Federal Aviation Administration has emphasized the use of Scenario Based Training (SBT) in General Aviation flight instruction to address this issue, SBT lessons are not widely utilized and descriptions in associated handbooks of how to incorporate SBT are considered vague by many. This study examines the attitudes of Embry-Riddle Aeronautical University (ERAU) and non ERAU Prescott faculty, staff, and students towards the practical addition of SBT into a typical 14 CFR Part 61 and Part 141 Pilot Training Syllabus, through use of a 12 question survey

A new species of Polemanniopsis (Apiaceae) from Namibia

AbstractA new species of woody Apiaceae, Polemanniopsis namibensis B-E. Van Wyk, A. Burke & C. Mannheimer, is described. The species is allied to Polemanniopsis marlothii but differs in the much smaller habit of (up to 0.6m vs 1.5–4m in Polemanniopsis marlothii), the white or greyish colour of the twigs (brown in Polemanniopsis marlothii), the 3-foliolate leaves (predominantly 5-foliate in Polemanniopsis marlothii), the smaller inflorescences with persistent involucral bracts (caducous in Polemanniopsis marlothii) and anatomical details of the leaves. The species is endemic to Namibia and is known only from a localised area in the southern Namib desert near Lüderitz, where it is relatively common

The Force-Velocity Relation for Growing Biopolymers

The process of force generation by the growth of biopolymers is simulated via a Langevin-dynamics approach. The interaction forces are taken to have simple forms that favor the growth of straight fibers from solution. The force-velocity relation is obtained from the simulations for two versions of the monomer-monomer force field. It is found that the growth rate drops off more rapidly with applied force than expected from the simplest theories based on thermal motion of the obstacle. The discrepancies amount to a factor of three or more when the applied force exceeds 2.5kT/a, where a is the step size for the polymer growth. These results are explained on the basis of restricted diffusion of monomers near the fiber tip. It is also found that the mobility of the obstacle has little effect on the growth rate, over a broad range.Comment: Latex source, 9 postscript figures, uses psfig.st

Progress report on familial hypercholesterolaemia in Malta 2018 : the current situation and what needs to be done to improve it

Introduction: FH is an autosomal dominant condition causing premature cardiovascular disease. It is underdiagnosed and undertreated worldwide-yet cost-effective treatment is available which should be started early to prevent disease progression. Expected Maltese prevalence is up to 1,700 individuals. National Premature Years of Life Lost under 65 years (PYLL-65) from cardiovascular disease is high, and FH a likely contributor. Moreover, Schedule V database has only 7 children listed as ‘genetic dyslipidaemia’ (expected number c.300). This represents a public health challenge to cardiologists, physicians, general practitioners and paediatricians. Methods: A Register was established in 2017 as an observational study based on opportunistic testing, with Dutch Lipid Clinic Network phenotypic criteria for inclusion of index cases. Monitoring of progress and quality criteria is ongoing. Cascade testing uses lower LDL cut off points for family member identification. Results: Less than 10% of potentially affected individuals have been identified; 96% of these are on statins, with 60% meeting LDL goals; most ‘Definite cases’ are not achieving target. One patient is on PCSK9 inhibition. Cascade testing has identified five cases to date. Conclusion: Under 10% of affected patients have been identified on the register, with none under 18 years. Measures to raise awareness are ongoing, including presentations to various audiences. Outcomes could be improved through the formulary inclusion of ezetimibe, and PCSK9 inhibitors. Genetic testing would improve identification, facilitating the more accurate identification of children and their early management. Disclosures: No direct funding was provided for this study. Sanofi has funded fees for consulting and lectures, and participation in seminars related to the area.12peer-reviewe

Inner ear tissue preservation by rapid freezing: improving fixation by high-pressure freezing and hybrid methods

In the preservation of tissues in as ‘close to life’ state as possible, rapid freeze fixation has many benefits over conventional chemical fixation. One technique by which rapid freeze-fixation can be achieved, high pressure freezing (HPF), has been shown to enable ice crystal artefact-free freezing and tissue preservation to greater depths (more than 40μm) than other quick-freezing methods. Despite increasingly becoming routine in electron microscopy, the use of HPF for the fixation of inner ear tissue has been limited. Assessment of the quality of preservation showed routine HPF techniques were suitable for preparation of inner ear tissues in a variety of species. Good preservation throughout the depth of sensory epithelia was achievable. Comparison to chemically fixed tissue indicated that fresh frozen preparations exhibited overall superior structural preservation of cells. However, HPF fixation caused characteristic artefacts in stereocilia that suggested poor quality freezing of the actin bundles. The hybrid technique of pre-fixation and high pressure freezing was shown to produce cellular preservation throughout the tissue, similar to that seen in HPF alone. Pre-fixation HPF produced consistent high quality preservation of stereociliary actin bundles. Optimising the preparation of samples with minimal artefact formation allows analysis of the links between ultrastructure and function in inner ear tissues

The Human Fungal Pathogen Cryptococcus neoformans Escapes Macrophages by a Phagosome Emptying Mechanism That Is Inhibited by Arp2/3 Complex-Mediated Actin Polymerisation

The lysis of infected cells by disease-causing microorganisms is an efficient but risky strategy for disseminated infection, as it exposes the pathogen to the full repertoire of the host's immune system. Cryptococcus neoformans is a widespread fungal pathogen that causes a fatal meningitis in HIV and other immunocompromised patients. Following intracellular growth, cryptococci are able to escape their host cells by a non-lytic expulsive mechanism that may contribute to the invasion of the central nervous system. Non-lytic escape is also exhibited by some bacterial pathogens and is likely to facilitate long-term avoidance of the host immune system during latency. Here we show that phagosomes containing intracellular cryptococci undergo repeated cycles of actin polymerisation. These actin ‘flashes’ occur in both murine and human macrophages and are dependent on classical WASP-Arp2/3 complex mediated actin filament nucleation. Three dimensional confocal imaging time lapse revealed that such flashes are highly dynamic actin cages that form around the phagosome. Using fluorescent dextran as a phagosome membrane integrity probe, we find that the non-lytic expulsion of Cryptococcus occurs through fusion of the phagosome and plasma membranes and that, prior to expulsion, 95% of phagosomes become permeabilised, an event that is immediately followed by an actin flash. By using pharmacological agents to modulate both actin dynamics and upstream signalling events, we show that flash occurrence is inversely related to cryptococcal expulsion, suggesting that flashes may act to temporarily inhibit expulsion from infected phagocytes. In conclusion, our data reveal the existence of a novel actin-dependent process on phagosomes containing cryptococci that acts as a potential block to expulsion of Cryptococcus and may have significant implications for the dissemination of, and CNS invasion by, this organism.\ud \u

Molecular mechanism for the subversion of the retromer coat by the Legionella effector RidL

Microbial pathogens employ sophisticated virulence strategies to cause infections in humans. The intracellular pathogen Legionella pneumophila encodes RidL to hijack the host scaffold protein VPS29, a component of retromer and retriever complexes critical for endosomal cargo recycling. Here, we determined the crystal structure of L. pneumophila RidL in complex with the human VPS29?VPS35 retromer subcomplex. A hairpin loop protruding from RidL inserts into a conserved pocket on VPS29 that is also used by cellular ligands, such as Tre-2/Bub2/Cdc16 domain family member 5 (TBC1D5) and VPS9-ankyrin repeat protein for VPS29 binding. Consistent with the idea of molecular mimicry in protein interactions, RidL outcompeted TBC1D5 for binding to VPS29. Furthermore, the interaction of RidL with retromer did not interfere with retromer dimerization but was essential for association of RidL with retromer-coated vacuolar and tubular endosomes. Our work thus provides structural and mechanistic evidence into how RidL is targeted to endosomal membranes.ACKNOWLEDGMENTS: We thank Ander Vidaurrazaga (Centro de Investigación Cooperativa en Biociencias) for technical assistance and Devanand Bondage (National Institute of Child Health and Human Development) for proliferation assays of Legionella pneumophila. This study made use of the Diamond Light Source (Oxfordshire, United Kingdom), the European Synchrotron Radiation Facility (Grenoble, France), and the ALBA synchrotron beamline BL13-XALOC, funded in part by the Horizon 2020 programme of the European Union, iNEXT (H2020 Grant 653706). We thank all the staff from these facilities for technical and human support. This work was supported by the Spanish Ministry of Economy and Competitiveness Grant BFU2014-59759-R (to A.H.); the Severo Ochoa Excellence Accreditation SEV-2016-0644; and the Intramural Program of the Eunice Kennedy Shriver National Institute of Child Health and Human development (Projects ZIA HD001607 and ZIA HD008893). M.R.-M. is supported by a pre-doctoral fellowship from the Basque Government (PRE_2016_2_0249)