The Mechanism of Action and Interaction of Leukotriene B4 and Platelet-Activating Factor as Mediators of Neutrophil Activation

Human neutrophils can be stimulated by a plethora of soluble and particulate stimuli, the majority of which interact with specific recognition sites (receptors) located on the plasma membrane. These agonists evoke a series of cellular responses including chemotaxis, aggregation, degranulation, superoxide generation and the formation of numerous lipid products, for example LTB4 and PAF, which are derived from membrane phospholipids. LTB4 and PAF interact with specific receptors on, and are themselves potent activators of, human neutrophils. Therefore, these lipids have the potential to act as endogenous mediators or amplifiers of neutrophil activation. The mechanisms by which agonist receptor occupancy lead to such cellular activation remain to be fully established. It remains possible that in neutrophils, as in some other cells, reactivity may be regulated by the production of at least two second messenger molecules, 1,2-diacylglycerol (DAG) and [Ca2+]i that are produced as a consequence of phospholipase C catalysed phosphoinositide hydrolysis. The precise nature and role of this receptor mediated sequence of events in the human neutrophil, particularly concerning LTB4 and PAF, still remains to be fully elucidated and is frequently controversial. In this study I attempted to investigate the mechanism of action and interaction of the arachidonic acid metabolite, LTB4, and the ether lipid, PAP, as mediators of neutrophil activation by comparing the responses elicited by these lipids to those evoked by other neutrophil stimuli, namely the chemotactic tripeptide, FMLP, the calcium ionophore, ionomycin and the phorbol eater, PMA. I also examined the possible involvement of G proteins and the role of protein kinase C activation as stimulatory and regulatory mechanisms in the neutrophil. In addition, I explored the role of PAF and LTB4 as endogenous mediators or amplifiers of neutrophil activation induced by other agonists. Neutrophil reactivity was assessed by: a. Examining ultrastructural features using electron microscopy. b. Monitoring aggregation photometrically using a standard platelet aggregometer. c. Determining NAG and lysozyme release using a fluorimetric and a spectrophotometric technique respectively. d. Measuring LTB4 generation by specific radioimmunoassay and the authenticity confirmed using reverse phase HPLC. e. Observing changes in [Ca2+]i using the fluorescent calcium indicator dye, quin2. f. Following inositol phospholipid metabolism in cells prelabelled with [32P]-orthophosphate and monitoring changes in the levels of [32P]-PtdA, [32P]-PtdIns, [32P]-PIP and [32P]-PIP2. Using these in vitro techniques, the major observations and conclusions are listed below: 1. The ultrastructural features associated with neutrophils activated by FMLP, PAF and LTB4 were similar. Control, unstimulated cells were generally rounded with smooth contours and the occasional extension of fine projections. Exposure of cells to agonists caused a marked plasma membrane ruffling followed by cell polarization and the formation of large lamellipodia. Pretreatment of neutrophils with the fungal metabolite, cytochalasin B, caused a marked vacuolation and subsequent additions of agonists resulted in the formation of blebs giving the cells a bizarre appearance. Caution ought to be a priority when using or interpreting data generated by cytochalasin B. 2. LTB4, PAF and EMLP all caused a reversible, concentration-dependent neutrophil aggregation. The aggregatory response produced by ionomycin and PMA was also concentration-dependent but was slower in onset and irreversible. 3. The receptor directed agonists caused a cytochalasin B dependent release of NAG (an azurophil granule marker) and lysozyme (an azurophil and specific granule marker). The calcium ionophore induced the release of both markers independent of pretreatment with cytochalasin B. PMA could release lysozyrae in the absence of the fungal metabolite but the phorbol ester only induced a limited cytochalasin B dependent release of NAG. 4. Ionomycin elicited a concentration-dependent generation and release of LTB4. FMLP and PAP only released barely detectable levels of the arachidonic acid metabolite. 5. All agonists except PMA caused a rapid concentration-dependent elevation of neutrophil [Ca2+]i. Ionomycin induced a greater maximal increase than the receptor directed agonists. (Abstract shortened by ProQuest.)

Synchronous Context-Free Grammars and Optimal Linear Parsing Strategies

Synchronous Context-Free Grammars (SCFGs), also known as syntax-directed translation schemata, are unlike context-free grammars in that they do not have a binary normal form. In general, parsing with SCFGs takes space and time polynomial in the length of the input strings, but with the degree of the polynomial depending on the permutations of the SCFG rules. We consider linear parsing strategies, which add one nonterminal at a time. We show that for a given input permutation, the problems of finding the linear parsing strategy with the minimum space and time complexity are both NP-hard

Extra-virgin olive oil phenols block cell cycle progression and modulate chemotherapeutic toxicity in bladder cancer cells

Epidemiological data indicate that the daily consumption of extra‑virgin olive oil (EVOO), a common dietary habit of the Mediterranean area, lowers the incidence of certain types of cancer, in particular bladder neoplasm. The aim of the present study was to evaluate the antiproliferative activity of polyphenols extracted from EVOO on bladder cancer (BCa), and to clarify the biological mechanisms that trigger cell death. Furthermore, we also evaluated the ability of low doses of extra‑virgin olive oil extract (EVOOE) to modulate the in vitro activity of paclitaxel or mitomycin, two antineoplastic drugs used in the management of different types of cancer. Our results showed that EVOOE significantly inhibited the proliferation and clonogenic ability of T24 and 5637 BCa cells in a dose‑dependent manner. Furthermore, cell cycle analysis after EVOOE treatment showed a marked growth arrest prior to mitosis in the G2/M phase for both cell lines, with the subsequent induction of apoptosis only in the T24 cells. Notably, simultaneous treatment of mitomycin C and EVOOE reduced the drug cytotoxicity due to inhibition of ROS production. Conversely, the co‑treatment of T24 cells with paclitaxel and the polyphenol extract strongly increased the apoptotic cell death at each tested concentration compared to paclitaxel alone. Our results support the epidemiological evidence indicating that olive oil consumption exerts health benefits and may represent a starting point for the development of new anticancer strategies

A joint approach for strategic bidding of a microgrid in energy and spinning reserve markets

n the electricity market, short-term operation is organized in day-ahead and real-time stages. The two stages that are performed in different time intervals have reciprocal effects on each other. The paper shows the strategy of a microgrid that participates to both day-ahead energy and spinning reserve market. It is supposed that microgrid is managed by a prosumer, a decision maker who manages distributed energy sources, storage units, Information and Communication Technologies (ICT) elements, and loads involved in the grid. The strategy is formulated considering that all decisions about the amount of power to sell in both markets and the price links to the offer, must be taken contextually and at the same time, that is through a joint approach. In order to develop an optimal bidding strategy for energy markets, prosumer implements a nonlinear mixed integer optimization model: in this way, by aggregating and coordinating various distributed energy sources, including renewable energy sources, micro-turbines–electricity power plants, combined heat and power plants, heat production plants (boilers), and energy storage systems, prosumer is able to optimally allocate the capacities for energy and spinning reserve market and maximize its revenues from different markets. Moreover, it is considered that both generators and loads can take part in the reserve market. The demand participation happens through both shiftable and curtailable loads. Case studies based on microgrid with various distributed energy sources demonstrate the market behavior of the prosumer using the proposed bidding model

Convergence in Total Variation for nonlinear functionals of random hyperspherical harmonics

Random hyperspherical harmonics are Gaussian Laplace eigenfunctions on the unit $d$-dimensional sphere ($d\ge 2$). We study the convergence in Total Variation distance for their nonlinear statistics in the high energy limit, i.e., for diverging sequences of Laplace eigenvalues. Our approach takes advantage of a recent result by Bally, Caramellino and Poly (2020): combining the Central Limit Theorem in Wasserstein distance obtained by Marinucci and Rossi (2015) for Hermite-rank $2$ functionals with new results on the asymptotic behavior of their Malliavin-Sobolev norms, we are able to establish second order Gaussian fluctuations in this stronger probability metric as soon as the functional is regular enough. Our argument requires some novel estimates on moments of products of Gegenbauer polynomials that may be of independent interest, which we prove via the link between graph theory and diagram formulas

Convergence in Total Variation for nonlinear functionals of random hyperspherical harmonics

Random hyperspherical harmonics are Gaussian Laplace eigenfunctions on the unit d-dimensional sphere (d >= 2). We study the convergence in Total Variation distance for their nonlinear statistics in the high energy limit, i.e., for diverging sequences of Laplace eigenvalues. Our approach takes advantage of a recent result by Bally, Caramellino and Poly (2020): combining the Central Limit Theorem in Wasserstein distance obtained by Marinucci and Rossi (2015) for Hermite-rank 2 functionals with new results on the asymptotic behavior of their Malliavin-Sobolev norms, we are able to establish second order Gaussian fluctuations in this stronger probability metric as soon as the functional is regular enough. Our argument requires some novel estimates on moments of products of Gegenbauer polynomials that may be of independent interest, which we prove via the link between graph theory and diagram formulas. (c) 2023 The Author(s). Published by Elsevier Inc. This is an open access article under the CC BY license (http:/

Autism and classification systems: a study of 84 children

<p>Abstract</p> <p>Background</p> <p>A number of studies have shown that current classification systems (ICD 10, DSM IV TR) have limitation when applied to autistic children and the category PDD NOS (DSM IV TR) has in particular been criticized. To check the possible usefulness of other classification systems to better describe patient's functioning, we retrospectively studied 84 patients, seen consecutively in our Child Neurology and Psychiatry Department (excluding only those presenting for another disease even if with clinical signs of a PDD).</p> <p>Methods</p> <p>We tried to classify them according to ICD 10, DSM IV TR, CFTMEA-R, "operational classification" (Manzano and Palacio) and de Ajuriaguerra's classification.</p> <p>Results</p> <p>We found a good correspondence between DSM IV TR and ICD 10 and the use of psychodynamic classification systems (in particular CFTMEA-R) was useful to differentiate clinical subtypes collected under the PDD NOS etiquette according to DSM IV TR.</p> <p>Conclusions</p> <p>To rationalize research efforts and find better tailored therapies, we need to improve PDD classification systems, using contributions coming from every field of child psychiatry and neurology: it's possible that 0-3 Classification could help this.</p

Reproduction of Daphnia pulex in a Northern Italy pond

This paper reports on the occurrence of Daphnia pulex in a small fishless water body of Northern Italy (Bodrio del pastore III) and describes its population dynamics. Bodrio is a typical water body originated by erosion from the old Po river-bed surface. During a three year study (2011-2013), D. pulex population showed an increase in density from spring to early summer, it declined in July-August and did not recover, presumably from ephippia, until the following spring. The seasonal dynamics was related to the species thermal tolerance and to invertebrate predation by Chaoborus that resulted in juvenile high mortality and in adaptive predator-avoidance cyclomorphosis. Seasonal variation was observed in the frequency of individuals, most juveniles, showing neckteeth. D. pulex population reproduces by cyclical parthenogenesis and showed a very early investment in sexual reproduction, independent of population density. Males and ephippial females appeared at the beginning of growth season before the density peak according to a typical feature of Daphnia populations from temporary habitats. This suggests a lower influence of the environmental factors on sex determination compared to populations inhabiting more permanent habitats. Lineages that produce males and ephippial females early in the season had lower growth rate than parthenogenetic ones but may preserve from selection pressure by predators a significant percentage of genetic variation linked to sex allocation so that evolution proceeds toward earlier and increased sexual reproduction. Our results suggest further investigation to verify whether the current population is the last remnant of a once much larger metapopulation eventually reduced by anthropogenic disturbances or if it represents the invasion of North American strains