Ammit, AJ & O'Neill, C 1991, 'Comparison of a radioimmunoassay and bioassay for embryo-derived platelet-activating factor', Human Reproduction, vol. 6, no. 6, pp. 872-878.
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Ammit, AJ & O'Neill, C 1991, 'Platelet‐activating factor (PAF) receptor antagonists inhibit arachidonic acid induced platelet aggregation in rabbit whole blood', Lipids, vol. 26, no. 12Part1, pp. 1189-1192.
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AbstractThe potency of several platelet‐activating factor (PAF) receptor antagonists was measured by observing their inhibitory effects against PAF induced platelet aggregation. Their selectivity was assessed by monitoring their effect on platelet aggregation induced by arachidonic acid (AA) and adenosine diphosphate (ADP). The antagonists inhibited platelet aggregation induced at the PAF EC50 (0.023 μM) with the following rank order of potency: WEB 2086> WEB 2170> SRI 64–412> SRI 63–675> BN 52021>kadsurenone> SRI 63–441> alprazolam. While the antagonists had no inhibitory effect at the EC50 for ADP (10 μM), they did inhibit platelet aggregation induced at the EC50 for AA (55 μM). However, there was considerable variability in the slope of the inhibitory response and the relative potency of each antagonist against PAF induced platelet aggregation as compared to AA induced platelet aggregation. The antagonist IC50 (μM) against PAF and AA were as follows, with those that showed significantly different (p<0.01) slopes indicated by an asterisk: SRI 63‐441* (3.8, 15.1); SRI 63‐675 (1.4, 36.2); SRI 64‐412 (0.5, 10.5); BN 52021* (2.4, 58.9); kadsurenone* (2.8, 28.3); alprazolam* (10, 25); WEB 2086 (0.055, 0.220), and WEB 2170 (0.107, 0.534). Therefore, in rabbit whole blood the antagonists were potent, although not completely selective, inhibitors of PAF induced platelet aggregation. These results suggest that the mode of action of PAF and AA induced platelet aggregation may share some common features. However, since the slope of the inhibitory response against PAF and AA for some antagonists differed, mechanistic differences in their action appear to exist.
Anast, M, Wong, A, Bell, JM, Ben-Nissan, B, Cullen, J, Spiccia, L, De Villiers, D, Watkins, I, West, BO & Johnston, G 1991, 'Thin Film Ceramic Coatings via the Sol-Gel Process', Key Engineering Materials, vol. 53-55, pp. 427-432.
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The sol-gel process enables the creation of high quality, thin film ceramic coatings which are adherent and uniform over large areas. The process is controllable and is more cost effective than other currently available techniques. The technique is flexible and can be adapted to form many different ceramic materials. Provided a stable solution of a metal alkoxide or alkanoate can be formed a ceramic coating of that species can be deposited. The main emphasis of the work so far has been on the production of barium titanate films. This system is relatively simple and the problem of differential hydrolysis which can occur in multiple metal alkoxide systems is not found. This paper describes the deposition process for BaTiO3 and results on the crystallization process occuring in the films.
Battye, KM, Ammit, AJ, O'Neill, C & Evans, G 1991, 'Production of platelet-activating factor by the pre-implantation sheep embryo', Reproduction, vol. 93, no. 2, pp. 507-514.
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JAMES, NL, POOLEWARREN, LA, SCHINDHELM, K, MILTHORPE, BK, MITCHELL, RM, MITCHELL, RE & HOWLETT, CR 1991, 'COMPARATIVE-EVALUATION OF TREATED BOVINE PERICARDIUM AS A XENOGRAFT FOR HERNIA REPAIR', BIOMATERIALS, vol. 12, no. 9, pp. 801-809.
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MILTHORPE, BK, SCHINDHELM, K, HOWLETT, CR, HALL, PJ & ROGERS, GJ 1991, 'TREATED XENOGRAFTS AS GLIDING TENDON PROSTHESES IN AN OVINE MODEL', BIOMATERIALS, vol. 12, no. 6, pp. 577-583.
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A model for testing the properties of gliding tendon grafts has been developed that allows anastomoses to be evaluated separately from the mid-portion of the graft. In addition, two different graft materials may be implanted in one sheep foreleg whilst maintaining control (not operated) tendons in both the operated leg and contralateral foreleg. The model has been used to evaluate the response of xenografts made from chemically treated kangaroo tail tendon (KTT) compared with autografts. At 3 month the mid-sections of the glutaraldehyde-fixed xenografts maintained between 57 and 82% of their initial ultimate tensile strength whereas lyophilized KTT dropped to 10% and autografts retained 91% of initial strength. Sterilization by gamma-radiation of wet xenografts did not affect the material and implant properties significantly. Longer term studies are necessary to determine the resorption behaviour of the xenografts. Anastomosis strengths were found to be about the same for all grafts, at about 25% of the strength of the original tendon. Alternatives need to be investigated to improve this strength.
O'Neill, C, Ammit, AJ, Korth, R, Fleming, S & Wells, X 1991, 'The effect of inhibitors of platelet aggregation on the metabolism of platelet‐activating factor (PAF) in washed rabbit platelets', Lipids, vol. 26, no. 12Part1, pp. 1011-1014.
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AbstractThe rabbit platelet metabolizes platelet‐activating factor (PAF) intracellulary. PAF is deacetylated to produce lysoPAF which, in turn, can be acylated to produce 1‐O‐alkyl‐2‐acyl‐sn‐glycero‐3‐phosphocholine (alkylacyl GPC). Some PAF receptor antagonists have been shown to inhibit this metabolic conversion. In the present study we examined whether the PAF receptor antagonists SRI 63‐441 and WEB 2086 would inhibit the metabolism of PAF by intact rabbit platelets. In addition, we examined whether iloprost, a stable analogue of prostaglandin I2 (PGI2), and a potent inhibitor of platelet activation induced by a range of agonists, would also inhibit PAF metabolism. We found that SRI 63‐441 and WEB 2086 caused an almost complete inhibition of the conversion of PAF to alkylacyl GPC. Iloprost caused up to a 50% inhibition of PAF metabolism compared to antagonist‐free controls. Iloprost (and PGI2) is thought to inhibit platelet response by elevation of cAMP, while receptor antagonists act by blocking PAF binding to its receptor. Since iloprost caused partial inhibition of PAF metabolism, the results of this study suggest that inhibition of PAF metabolism does not occur solely due to competitive inhibition of PAF binding to its receptor.
SCHINDHELM, K, ROGERS, GJ, MILTHORPE, BK, HALL, PJ, HOWLETT, CR, SEKEL, R, GOLDBERG, J & VIGLIONE, W 1991, 'AUTOGRAFT AND LEEDS-KEIO RECONSTRUCTIONS OF THE OVINE ANTERIOR CRUCIATE LIGAMENT', CLINICAL ORTHOPAEDICS AND RELATED RESEARCH, vol. 267, no. 267, pp. 278-293.
Simpson, AM, Tuch, BE & Vincent, PC 1991, 'Characterization of endocrine-rich monolayers of human fetal pancreas that display reduced immunogenicity', Diabetes, vol. 40, no. 7, pp. 800-808.
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Spiccia, L, West, BO, Cullen, J, de Villiers, D, Watkins, I, Bell, JM, Ben-Nissan, B, Anast, M & Johnston, G 1991, 'Sol-gel precursor chemistry', Key Engineering Materials, vol. 53-55, pp. 445-450.
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The application of the 'sol-gel' process in the preparation of mixed metal oxides, both of bulk powders and thin films, has grown dramatically over the last 20 years and is currently attracting much world-wide attention. Recent developments suggest that if careful control of the 'sol-gel' process is to be achieved then a better understanding of the chemistry of precursor solutions is necessary. This paper focuses on recent developments in this area and our work on the deposition of YBa2Cu3 oxide films.
Titchen, DA, Glenn, WK, Nassif, N, Thompson, AR & Thompson, EOP 1991, 'A minor globin gene of the bivalve mollusc Anadara trapezia', Biochimica et Biophysica Acta (BBA) - Gene Structure and Expression, vol. 1089, no. 1, pp. 61-67.
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TUCH, BE, SIMPSON, AM & CAMPBELL, IL 1991, 'Role of Tumor Necrosis Factor-α and Interferon-γ as Growth Factors to the Human Fetal β-Cell*', The Journal of Clinical Endocrinology & Metabolism, vol. 73, no. 5, pp. 1044-1050.
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Watterson, PA 1991, 'A generalization of the Taylor constraint to the advection of axisymmetric poloidal magnetic fields', Journal of Plasma Physics, vol. 46, no. 2, pp. 255-270.
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The range of ▿ ∧ (u ∧ B) is determined for an axisymmetric poloidal incompressible B and incompressible u, by solving ▿ ∧ (u ∧ B) = ▿ ∧ v for u, assumed to be confined to within a surface of revolution. Two constraints on V are shown to be necessary for the existence of solutions, viz that the integral of rç/|B| must vanish on each flux surface, and that the integral of v1 around any dosed field line must vanish. The construction of the general solution proves that the constraints are sufficient conditions, providing also that the second derivative, with respect to the poloidal flux function, of the volume contained by flux surfaces does not vanish. The general solution is stated for the homogeneous case, v = 0. For the particular case of poloidal v1 an integral property of the solution u is established.
Watterson, PA 1991, 'Analytical solutions for the current driven by a rotating magnetic field in a spherical plasma', Journal of Plasma Physics, vol. 46, no. 2, pp. 271-298.
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The steady currents driven in a spherical plasma by a rotating magnetic field via the Hall effect are studied analytically. The total field is shown to be symmetric across the origin. Integral relationships are obtained between Ohmic dissipation, angular momentum and the oscillating axial current density. The topology of the sum of a Hill's vortex field and a rotating field is documented. Analytical solutions for the driven current are obtained by expansion for the limits corresponding to small rotation frequency, to small number density, to large rotating-field magnitude, to small resistivity, and to small rotating-field magnitude combined with very small resistivity. The latter solution, relevant to the reactor limit, indicates that, with control of the vertical field magnitude, an MHD equilibrium can be generated with total current any fraction of the currentcorresponding to synchronous rotation of the electrons. Oscillating currents sufficient to drive the synchronous current are determined.
Yan, H & Braun, M 1991, 'Image reconstruction from Fourier domain data sampled along a zig‐zag trajectory', Magnetic Resonance in Medicine, vol. 18, no. 2, pp. 405-410.
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AbstractWhen the conventional Fourier transform (FT) algorithm is applied to reconstruct a magnetic resonance (MR) image from data sampled along a zig‐zag trajectory in the Fourier space, the nonuniform sampling in the spatial frequency direction may give rise to artifacts. In this paper the nature of the artifacts is analyzed and an alternative reconstruction algorithm is developed to produce artifact‐free images. Methods for reducing noise level in the reconstructed image are discussed. Our approach is compared with another method based on the interlace sampling theorem. © 1991 Academic Press. Inc.
