introductionThe pharmaceutical products for parenteral administration must be tested for contamination of bacterial endotoxins (LPSs 1 ) because of their potent biologic activities, which can cause pyrogenic and shock reactions. LPS, a constituent of the cell walls of Gram-negative bacteria, is a potential contaminant of protein solutions originating from biologic products. There are two methods for determining LPS. One is the rabbit pyrogen test; the other is the limulus test using Limulus amebocyte lysate (LAL).The gel-clot, 2 turbidimetric, 3 and chromogenic 4 testing methods, methods previously approved by the USA Pharmacopoeia in 1981, 1985, and 1985, respectively, are typically employed in the LAL test. The advantages of the LAL test over the rabbit pyrogen test are higher sensitivity, lower cost, and higher reproducibility. The LAL test is inhibited or enhanced by antibiotics, hormones, heavy metals, amino acids, alkaloids, plasma proteins, enzymes, and electrolytes in the sample solution.5 Dilution, heating and dialysis have been used to overcome these problems, but the results have been unsatisfactory. Minobe et al. attempted to develop a new specific assay method for LPSs using histidine-immobilized Sepharose as an adsorbent.6,7 LPSs adsorbed by the adsorbent were separated from the compounds (e.g., amino acids, enzymes) in solution by centrifugation, and the adsorbed LPSs can react directly with the LAL. The great disadvantage of this type of adsorbent is the low adsorption activity of the LPSs in physiologic solution (neutral pH and ionic strength (μ) = 0.1 -0.2).In this study, we developed a novel assay of LPSs with a new adsorption method using a turbidimetric time assay system. We previously found that poly(ε-lysine)-immobilized cellulose beads (PL-Cellufine) can selectively adsorb LPSs in bioproducts over a wide range of ionic strengths (μ) from 0.05 -0.8 8-10 at neutral pH. On the other hand, a simple turbidimetric time assay system has been developed for the quantitative assaying of LPS; an automated apparatus is available commercially. 11In this paper, we describe the LPS-adsorbing activities of PL-Cellufine. Then, using the turbidimetric time assay, we describe the optimum conditions for the LPS assay using the PL-Cellufine as adsorbent. We also compare the apparent quantity of LPS provided by the adsorption method with the apparent quantity of LPS provided by a normal method. experimental Reagents and materialsPurified LPS (Escherichia coli UKT-B and O111:B4) and Limulus ES-II test Wako (Limulus amebocyte lysate) were purchased from Wako Pure Chemicals (Osaka, Japan). Poly(ε-lysine)-immobilized cellulose beads (PL-Cellufine) [8][9][10] was obtained from Chisso Co. Ltd. (Tokyo, Japan). PL (Mw, 4500; pKa, 7.6; Chisso) was produced by Streptomyces albulus. 12 DEAE-Sepharose CL-6B was purchased from GE Healthcare Bio-Sciences Corp. (USA). Ovalbumin (from egg), bovine serum albumin (BSA), γ-globulin (from human serum), lysozyme (from horse heart), and vitamin K3 were purchased from Wako. Myoglobi...
Broadband seismic deployments have been carried out in the Lützow-Holm Bay region (LHB), Dronning Maud Land, East Antarctica. The recorded teleseismic and local events are of sufficient quality to image the structure and dynamics of the crust and mantle of the terrain. Passive seismic studies by receiver functions and shear wave splitting suggest a heterogeneous upper mantle. Depth variations in topography for upper mantle discontinuities were derived from long period receiver function, indicating a shallow depth discontinuity at 660 km beneath the continental area of LHB. These results provide evidence of paleo upwelling of the mantle plume associated with Gondwana break-up. SKS splitting analysis anticipated a relationship between “fossil” anisotropy in lithospheric mantle and past tectonics. Moreover, active source surveys (DSSs) imaged lithospheric mantle reflections involving regional tectonic stress during Pan-African and succeeding extension regime at the break-up. By combining the active and passive source studies of the mantle structure, we propose an evolution model of LHB for constructing the present mantle structure.
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