Homocysteine-lowering treatment with folic acid, cobalamin, and pyridoxine does not reduce blood markers of inflammation, endothelial dysfunction, or hypercoagulability in patients with previous transient ischemic attack or stroke - a randomized substudy

Background and Purpose - Epidemiological and laboratory studies suggest that increasing concentrations of plasma homocysteine ( total homocysteine [tHcy]) accelerate cardiovascular disease by promoting vascular inflammation, endothelial dysfunction, and hypercoagulability. Methods - We conducted a randomized controlled trial in 285 patients with recent transient ischemic attack or stroke to examine the effect of lowering tHcy with folic acid 2 mg, vitamin B-12 0.5 mg, and vitamin B-6 25 mg compared with placebo on laboratory markers of vascular inflammation, endothelial dysfunction, and hypercoagulability. Results - At 6 months after randomization, there was no significant difference in blood concentrations of markers of vascular inflammation (high-sensitivity C-reactive protein [P = 0.32]; soluble CD40L [ P = 0.33]; IL-6 [P = 0.77]), endothelial dysfunction ( vascular cell adhesion molecule-1 [P = 0.27]; intercellular adhesion molecule-1 [P = 0.08]; von Willebrand factor [P = 0.92]), and hypercoagulability (P-selectin [P = 0.33]; prothrombin fragment 1 and 2 [P = 0.81]; D-dimer [P = 0.88]) among patients assigned vitamin therapy compared with placebo despite a 3.7-mumol/L (95% CI, 2.7 to 4.7) reduction in total homocysteine (tHcy). Conclusions - Lowering tHcy by 3.7 mumol/L with folic acid-based multivitamin therapy does not significantly reduce blood concentrations of the biomarkers of inflammation, endothelial dysfunction, or hypercoagulability measured in our study. The possible explanations for our findings are: ( 1) these biomarkers are not sensitive to the effects of lowering tHcy (eg, multiple risk factor interventions may be required); ( 2) elevated tHcy causes cardiovascular disease by mechanisms other than the biomarkers measured; or ( 3) elevated tHcy is a noncausal marker of increased vascular risk.

The role of R&D technology in asymmetric research joint ventures

We characterize asymmetric equilibria in two-stage process innovation games and show that they are prevalent in the different models of R&D technology considered in the literature. Indeed, cooperation in R&D may be accompanied by high concentration in the product market. We show that while such an increase may be profitable, it may be socially inefficient.

Unitary R-matrices for topological quantum computing

The main problem with current approaches to quantum computing is the difficulty of establishing and maintaining entanglement. A Topological Quantum Computer (TQC) aims to overcome this by using different physical processes that are topological in nature and which are less susceptible to disturbance by the environment. In a (2+1)-dimensional system, pseudoparticles called anyons have statistics that fall somewhere between bosons and fermions. The exchange of two anyons, an effect called braiding from knot theory, can occur in two different ways. The quantum states corresponding to the two elementary braids constitute a two-state system allowing the definition of a computational basis. Quantum gates can be built up from patterns of braids and for quantum computing it is essential that the operator describing the braiding-the R-matrix-be described by a unitary operator. The physics of anyonic systems is governed by quantum groups, in particular the quasi-triangular Hopf algebras obtained from finite groups by the application of the Drinfeld quantum double construction. Their representation theory has been described in detail by Gould and Tsohantjis, and in this review article we relate the work of Gould to TQC schemes, particularly that of Kauffman.

Preptetos and Neopreptetos (Digenea: Lepocreadiidae) from Australian marine fishes

The genera Preptetos Pritchard, 1960 and Neopreptetos Machida, 1982 are redefined. The following species are described and/or recorded from marine fishes. From the Great Barrier Reef: Preptetos caballeroi Pritchard, 1960 in Naso annulatus, N. brevirostris and N. vlamingii; P. xesuri (Yamaguti, 1940) in Zebrasoma veliferum and Z.scopas; Preptetos cannoni Barker, Bray et Cribb, 1993 in Siganus doliatus and S. fuscescens; Preptetas luguncula sp. n. in Naso unicoris (type-host); P. impar sp. n. in Lutjanus erythropterus (type-host) and L. malabaricus; Neopreptetos arursettae Machida, 1982 in Pomacanthus semicirculatus; and N. kurochkini (Toman, 1989) in Chaetodontoplus meredithi. From southwestern Australia: Preptetos rotto sp. n. in Nelusetta ayraudi (type-host), Neosebastes pandus, Oplegnathus woodwardi and Pagrus auratus. The new combination Preptetos trulla (Linton, 1907) (originally Distormum then Lepocreadium) is made and the species Lepocreadium areolatum (Linton, 1900) is considered likely to belong in Preptetos.

Twisted quantum affine superalgebra U-q[sl(2/2)((2))], U-q[osp(2/2)] invariant R-matrices and a new integrable electronic model

We describe the twisted affine superalgebra sl(2\2)((2)) and its quantized version U-q[sl(2\2)((2))]. We investigate the tensor product representation of the four-dimensional grade star representation for the fixed-point sub superalgebra U-q[osp(2\2)]. We work out the tensor product decomposition explicitly and find that the decomposition is not completely reducible. Associated with this four-dimensional grade star representation we derive two U-q[osp(2\2)] invariant R-matrices: one of them corresponds to U-q [sl(2\2)(2)] and the other to U-q [osp(2\2)((1))]. Using the R-matrix for U-q[sl(2\2)((2))], we construct a new U-q[osp(2\2)] invariant strongly correlated electronic model, which is integrable in one dimension. Interestingly this model reduces in the q = 1 limit, to the one proposed by Essler et al which has a larger sl(2\2) symmetry.

Molecular Lego (R): non-centrosymmetric alignment within interdigitating layers

(E)-N-Hexadecyl-4-[2-(4-octadecyloxynaphthyl) ethenyl] quinolinium bromide, which has a wide-bodied chromophore and terminal n-alkyl groups, adopts a U-shape when spread at the air-water interface but a stretched conformation when compressed to ca. 35 mN m(-1). The high-pressure phase has a narrow stability range prior to collapse but may be extended from 40 to 60 mN m(-1) by co-spreading the dye in a 1 : 1 ratio with docosanoic acid. The mixed Langmuir-Blodgett (LB) film has a monolayer thickness of 4.6 +/- 0.2 nm which decreases to 2.5 +/- 0.1 nm layer(-1) in the bulk, the reduction arising from an interdigitating layer arrangement, both top and bottom. It is the first example of LB-Lego(R) and, in addition, represents the only fully interdigitating structure with non-centrosymmetrically aligned chromophores. They are tilted 38 degrees from the substrate normal. The second-harmonic intensity increases quadratically with the number of layers, i.e. as I-(N)(2 omega) = (I(1)N2)-N-2 omega, with a second-order susceptibility of chi ((2))(zzz) = 30 pm V-1 at 1064 nm for refractive indices of n(omega) = 1.55 and n(2 omega) = 1.73, d = 2.5 nm layer(-1) and phi = 38 degrees. Angle resolved X-ray photoelectron spectra (XPS) of these films provide no evidence of the bromide counterion, which suggests that it is replaced by OH 2 or HCO3-, which occur naturally in the aqueous subphase, or C21H43COO- from the co-deposited fatty acid. This probably applies to all cationic dyes deposited by the LB technique.

Immune responses to ISCOM (R) formulations in animal and primate models

ISCOMs(R) are typically 40 nm cage-like structures comprising antigen, saponin, cholesterol and phospholipid. ISCOMs(R) have been shown to induce antibody responses and activate T helper cells and cyrolytic T lymphocytes in a number of animal species, including non-human primates. Recent clinical studies have demonstrated that ISCOMs(R) are also able to induce antibody and cellular immune responses in humans. This review describes the current understanding of the ability of ISCOMs(R) to induce immune responses and the mechanisms underlying this property. Recent progress in the characterisation and manufacture of ISCOMs(R) will also be discussed. (C) 2001 Elsevier Science Ltd. All rights reserved.