15-HETE is the main eicosanoid present in mucus of ulcerative protocolitis

Abstract Prostaglandins, leukotrienes and mono-hydroxy acid products of arachidonic acid were measured in mucus of freshly recovered morning stools of a patient with an exacerbation of ulcerative proctocolitis. Eicosanoids in ether extracts were separated by high performance liquid chromatography and amounts determined by radioimmunoassay. Four hydroxy-eicosatetraenoic acids were detected, of which the most important one was identified as 15-hydroxy eicosatetraenoic acid (530 ng/g mucus). Leukotriene B4 was also present (21 ng/g mucus) and small amounts of immunoreactive leukotriene C4 (< 0.8 ng/g mucus). The prostaglandins 6-keto-PGF1α and PGE2 and thromboxane B2 were found in amounts of 3.7, 2.0 and 9.2 ng/g mucus, respectively

Theory of Kondo lattices and its application to high-temperature superconductivity and pseudo-gaps in cuprate oxides

A theory of Kondo lattices is developed for the t-J model on a square lattice. The spin susceptibility is described in a form consistent with a physical picture of Kondo lattices: Local spin fluctuations at different sites interact with each other by a bare intersite exchange interaction, which is mainly composed of two terms such as the superexchange interaction, which arises from the virtual exchange of spin-channel pair excitations of electrons across the Mott-Hubbard gap, and an exchange interaction arising from that of Gutzwiller's quasi-particles. The bare exchange interaction is enhanced by intersite spin fluctuations developed because of itself. The enhanced exchange interaction is responsible for the development of superconducting fluctuations as well as the Cooper pairing between Gutzwiller's quasi-particles. On the basis of the microscopic theory, we develop a phenomenological theory of low-temperature superconductivity and pseudo-gaps in the under-doped region as well as high-temperature superconductivity in the optimal-doped region. Anisotropic pseudo-gaps open mainly because of d\gamma-wave superconducting low-energy fluctuations: Quasi-particle spectra around (\pm\pi/a,0) and (0,\pm\pi/a), with a the lattice constant, or X points at the chemical potential are swept away by strong inelastic scatterings, and quasi-particles are well defined only around (\pm\pi/2a,\pm\pi/2a) on the Fermi surface or line. As temperatures decrease in the vicinity of superconducting critical temperatures, pseudo-gaps become smaller and the well-defined region is extending toward X points. The condensation of d\gamma-wave Cooper pairs eventually occurs at low enough temperatures when the pair breaking by inelastic scatterings becomes small enough.Comment: 15 pages, 14 figure

Magnetic and charge structures in itinerant-electron magnets: Coexistence of multiple SDW and CDW

A theory of Kondo lattices is applied to studying possible magnetic and charge structures of itinerant-electron antiferromagnets. Even helical spin structures can be stabilized when the nesting of the Fermi surface is not sharp and the superexchange interaction, which arises from the virtual exchange of pair excitations across the Mott-Hubbard gap, is mainly responsible for magnetic instability. Sinusoidal spin structures or spin density waves (SDW) are only stabilized when the nesting of the Fermi surface is sharp enough and a novel exchange interaction arising from that of pair excitations of quasi-particles is mainly responsible for magnetic instability. In particular, multiple SDW are stabilized when their incommensurate ordering wave-numbers $\pm{\bf Q}$ are multiple; magnetizations of different $\pm{\bf Q}$ components are orthogonal to each other in double and triple SDW when magnetic anisotropy is weak enough. Unless $\pm 2{\bf Q}$ are commensurate, charge density waves (CDW) with $\pm 2{\bf Q}$ coexist with SDW with $\pm{\bf Q}$. Because the quenching of magnetic moments by the Kondo effect depends on local numbers of electrons, the phase of CDW or electron densities is such that magnetic moments are large where the quenching is weak. It is proposed that the so called stipe order in cuprate-oxide high-temperature superconductors must be the coexisting state of double incommensurate SDW and CDW.Comment: 10 pages, no figure

Monte Carlo and Renormalization Group Effective Potentials in Scalar Field Theories

We study constraint effective potentials for various strongly interacting $\phi^4$ theories. Renormalization group (RG) equations for these quantities are discussed and a heuristic development of a commonly used RG approximation is presented which stresses the relationships among the loop expansion, the Schwinger-Dyson method and the renormalization group approach. We extend the standard RG treatment to account explicitly for finite lattice effects. Constraint effective potentials are then evaluated using Monte Carlo (MC) techniques and careful comparisons are made with RG calculations. Explicit treatment of finite lattice effects is found to be essential in achieving quantitative agreement with the MC effective potentials. Excellent agreement is demonstrated for $d=3$ and $d=4$, O(1) and O(2) cases in both symmetric and broken phases.Comment: 16 pages, 4 figures appended to end of this fil

One Loop Effects of Non-Standard Triple Gauge Boson Vertices

Low energy effects of generic extensions of the Standard Model can be comprehensively parametrized in terms of higher dimensional effective operators. After the success of all the recent precission tests on the Standard Model, we argue that any sensible description of these extensions at the Z-scale must be stable under higher order quantum corrections. The imposition of $SU(2)_L \times U(1)_Y$ gauge invariance seems to be the simplest and most natural way to fulfill this requirement. With this assumption, all the possible deviations from the standard triple gauge boson vertices can be consistently parametrized in terms of a finite set of gauge invariant operators. We deal here with those operators that do not give any tree level effect on present experimental observables and constrain them by computing their effects at the one-loop level. We conclude that for a light Higgs boson, the direct measurement at LEP200 can improve present bounds on these "blind directions", while for a heavy Higgs it is most unlikely to provide any new information.Comment: 17 pags. 2 figures not included, available on request. Latex. CERN-TH 667

Is the mean-field approximation so bad? A simple generalization yelding realistic critical indices for 3D Ising-class systems

Modification of the renormalization-group approach, invoking Stratonovich transformation at each step, is proposed to describe phase transitions in 3D Ising-class systems. The proposed method is closely related to the mean-field approximation. The low-order scheme works well for a wide thermal range, is consistent with a scaling hypothesis and predicts very reasonable values of critical indices.Comment: 4 page

Understanding axial progenitor biology in vivo and in vitro

The generation of the components that make up the embryonic body axis, such as the spinal cord and vertebral column, takes place in an anterior-to-posterior (head-to-tail) direction. This process is driven by the coordinated production of various cell types from a pool of posteriorly-located axial progenitors. Here, we review the key features of this process and the biology of axial progenitors, including neuromesodermal progenitors, the common precursors of the spinal cord and trunk musculature. We discuss recent developments in the in vitro production of axial progenitors and their potential implications in disease modelling and regenerative medicine

Species differences in the pattern of eicosanoids produced by inflamed and non-inflamed tissue

The synthesis of14C labelled arachidonic acid metabolites was measured in colonic tissues obtained from mice, rats, guinea pigs, rabbits, piglets and in colonic biopsies from humans during colonoscopy. The main eicosanoids formed after stimulation with calcium ionophore A23187 were: in humans, 15-hydroxy-eicosatetraenoic acid (15-HETE); in mice, 12-HETE; in rats, 12-HETE, 12-hydroxy-5,8,10-heptadecatrienoic acid (HHT) and 6-keto-prostaglandine F1α (6kPGF1α); in guinea pigs, PGD2; in rabbits, 6kPGF1α, PGE2 and 15-HETE; and in pigs PGE2 and 12-HETE. In inflamed 15-HETE production was increased in man, HHT and 12-HETE production in rats and overall eicosanoid production in mice

Production of inflammatory mediators by human macrophages obtained from ascites

Ascites is a readily available source of human macrophages (Mø), which can be used to study Mø functions in vitro. We characterized the mediators of inflammation produced by human peritoneal Mø (hp-Mø) obtained from patients with portal hypertension and ascites. The production of the cytokines interleukin-1β (IL-1β), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) was found to be lipopolysaccharide (LPS) concentration dependent (0–10 μg/ml) with a maximal production at 10 μg/ml and also dependent on the time of exposure to the stimulus (0–36 h). IL-1β, IL-6 and TNF-α production after LPS administration reached a plateau at 24 h. In vitro stimulation for 24 h with LPS does not influence the eicosanoid production from endogenous arachidonate. 13 min of exposure of the cells to the calcium ionophore A23187 gives a significant increase in eicosanoid production from both exogenous and endogenous arachidonate. The main eicosanoids produced are the 5-lipoxgenase products LTB4 and 5-hydroxyeicosatetraenoic acid (HETE). The increase in production of the other eicosanoids is not significant. The eicosanoid production depends on the stimulus concentration. The optimal A23187 concentration is 1 μM. Oxygen radical production was measured in the Mø by a flowcytometric method. The fluorescence intensity of phorbol 12-myristate 13-acetate stimulated and dihydro-rhodamine 123 loaded. hp-Mø increases significantly after 15 min. We conclude that LPS stimulation of hp-Mø from liver disease results in similar production of IL-1β, IL-6 and TNF-α, but that the profile of the eicosanoid production of these Mø stimulated with LPS and A23187 differs from Mø of other origin and species