Difference between human and guinea pig Hageman factors in activation by bacterial proteinases: cleavage site shift due to local amino acid substitutions may determine the activation efficiency of serine proteinase zymogens

Human and guinea pig Hageman factors have been subjected to the action of pseudomonal elastase and serratial E15 proteinase. The pseudomonal elastase cleaved 22-24% of the human molecule at Arg353-Val354, and the remainder at Gly357-Leu358 resulting in the generation of about 20% of potential activity as activated Hageman factor, compared with trypsin activation, while it hydrolyzed Arg340-Ile341 bond in guinea pig molecule and generated about 75% of activity as activated Hageman factor. The serratial proteinase did not hydrolyze the essential cleavage site (Arg353-Val354) of the human zymogen but Gly356-Gly357 (30%) and Gly357-Leu358 (70%) bonds. Both products showed no activity. The guinea pig zymogen, in contrast, was cleaved mostly at Arg340-Ile341 (70%) and less abundantly at Gly344-Leu345 (30%), generating about 85% of the whole potential activity as activated Hageman factor. From the high correspondence between the proportions of activation and of hydrolysis at the essential cleavage site in activation, it was concluded that hydrolysis of the bonds different from the essential bond did not cause activation, even when the spatial separation was only 3 or 4 residues. Considering the amino acid differences between human and guinea pig Hageman factors, -Met351-Thr-Arg-Val-Val-Gly-Gly-Leu-Val-Ala360- and -Leu338-Ser-Arg-Ile-Val-Gly-Gly-Leu-Val-Ala347-, respectively, it was realized that even the minor amino acid substitutions caused the cleavage site shift which resulted in significant differences in activation efficiency of the proteinase zymogens.     

Monomeric, monovalent derivative of Maackia amurensis leukoagglutinin. Preparation and application to the study of cell surface glycoconjugates by flow cytometry

A stable subunit of Maackia amurensis leukoagglutinin (MMAL) was prepared by the selective reduction of disulfide bridges between the subunits followed by alkylation with 4-vinylpyridine. MMAL failed to precipitate fetuin, whereas it retained its ability to bind to the same glycoprotein coated on a plastic plate, indicating the monovalency of this derivative. This binding to immobilized fetuin was inhibited by a haptenic sugar, Neu5Ac alpha 2-3lactose, with the same inhibitory potency as against the native M. amurensis leukoagglutinin. Microscopic observation as well as flow cytometric analyses showed that Chinese hamster ovary cells were clearly stained with fluorescein isothiocyanate-labeled MMAL without any detectable agglutination. This staining was inhibited by the addition of fetuin or by the sugar chains of fetuin. Differences in the types of sialylated glycoconjugates on the cell surface of several cell lines were detected by the combined use of fluorescein isothiocyanate-labeled MMAL and the monomeric derivative of elderberry bark lectin (specific for the Neu5Ac alpha 2-6Gal/GalNAc sequence) by flow cytometry. These results demonstrate the usefulness of these monovalent derivatives of sialylated oligosaccharide-specific lectins as probes for the analysis of cell surface glycoconjugates containing sialic acid by the technique of flow cytometry.     

An early phase II trial combining cisplatin and carboplatin in advanced non-small cell lung cancer

We conducted an early phase II trial in advanced non-small cell lung cancer (NSCLC) to evaluate response efficacy of a combination of Cisplatin (CDDP) and Carboplatin (CBDCA). The twenty-six patients in the study had had no previous treatment. They received a sequential administration of 300 mg/m2 CBDCA and 80 mg/m2 CDDP with approximately 3,500 ml of hydration on day 1 every 4 weeks. All patients were evaluable for response and toxicity. Ten (38.5%) of all assessable patients achieved a partial response (95% confidence interval, 19.8-57.2%). Response rates for patients with stage III A, III B and IV- disease were 40.0 (2/5), 70.0 (7/10) and 9.1% (1/11), respectively. Response rates for patients with squamous cell carcinoma, adenocarcinoma and large cell carcinoma were 35.7 (5/14), 45.5 (5/11) and 0.0% (0/1), respectively. The median survival time (MST) of all patients was 11 months. The MST for patients with stage III disease was 14 months; for those with stage IV disease it was 7 months. The MST for responding patients was 15 months and for not responding patients 5 months. Major toxicities were hematologic and gastrointestinal, and the dose-limiting factor was thrombocytopenia. This combination chemotherapy was effective against NSCLC with tolerable toxicities. Further trials are warranted to determine the efficacy of the combination chemotherapy.     

Characteristics of a continuous Si-Ti-C-O fibre with low oxygen content using an organometallic polymer precursor

A continuous Si-Ti-C-O fibre with 12 wt% oxygen content, which is lower than the usual 18 wt% found in the normal fibres, was synthesized by using polytitanocarbosilane which has fewer Si-Si bonds than the usual precursor polymer. The density, tensile strength, tensile modulus and thermal conductivity were found to be 2.37 g cm^–3, 3.4±0.3 GPa, 190±10 GPa and 1.40 W m^–1 K^–1, respectively. Amongst these properties, the tensile modulus was improved by 20 GPa and the thermal conductivity had a higher value in comparison with that of the ordinary Si-Ti-C-O fibre with 18 wt% oxygen content. The Si-Ti-C-O fibre with a 12 wt% oxygen content has a better heat resistance above 1400 °C in an argon atmosphere and 1300 °C in air, than the usual fibre. About 60 and 40% of its tensile strength at room temperature were retained in air at respectively, 1500 and 1600 °C. This improved ceramic fibre is considered to be useful as a reinforcing material for advanced composites such as high-temperature ceramic matrix composites and metal matrix composites.     

A monocyte chemotactic factor, S19 ribosomal protein dimer, in phagocytic clearance of apoptotic cells

HL-60 cells derived from a human promyelocytic leukemia underwent apoptosis by heat treatment. When the heat-treated HL-60 cells were injected into guinea pig skin, monocyte/macrophage infiltration was observed 24 or 36 hours later, and the apoptotic cells were phagocytically cleared by 48 hours after their injection. The infiltration and clearance patterns were quite different from those observed in injection of necrotic or boil-fixed HL-60 cells. The apoptotic cells released a monocyte chemotactic factor in vitro 24 hours after the heat treatment. The chemotactic factor generated was identified as the cross-linked homodimer of S19 ribosomal protein by its immunologic and physicochemical properties. A serine protease that inactivates the monocyte chemotactic factor was also released from the apoptotic cells 30 hours after the heat treatment. A super infusion of this protease into the skin where the apoptotic cells had been injected diminished the number of infiltrated monocytes. The present results indicate an important role of the S19 ribosomal protein dimer in the phagocytic clearance of apoptotic cells.     

Fractal characteristics of gas-solids flow in a circulating fluidized bed

A fractal approach is adopted to describe the dynamic behavior of a circulating fluidized bed. Two times series, differential pressure fluctuations along the riser height and solids momentum fluctuations along the radial direction, are measured and analyzed in terms of fractal dimensions. The influences of operating conditions and axial/radial positions on the fractal dimension are discussed. Attempts are also made to interpret the flow structure in the bed in terms of the fractal dimension. It is found that fractal analysis can provide a useful tool for understanding the characteristics of gas-solids flow in circulating fluidized beds.     

Adsorption and desorption properties of cationic polyethylene film gels to organic anions and their regeneration

An investigation was undertaken on the adsorption and desorption properties of 2‐(dimethylamino)ethyl methacrylate grafted polyethylene (PE‐g‐PDMAEMA) films to anionic dye anions with one to three sulfonic groups in response to pH and temperature changes. The amounts of dye anions adsorbed on the PE‐g‐PDMAEMA films passed through the maximum values at about pH 3 because of an increase in the protonation of dimethylamino groups caused by a decrease in the pH value. The amounts of adsorbed dye anions decreased below pH 3 because the ionic strength increased with the addition of HCl to adjust the initial pH values of the aqueous dye solutions. The amounts of adsorbed dye anions decreased with an increase in the number of sulfonic groups in the dye molecules at the same pH value because electrostatic repulsion was generated between free sulfonic groups of the dye anions adsorbed onto the PE‐g‐PDMAEMA films and free dye anions in the medium. A large number of dye anions adsorbed were desorbed from the PE‐g‐PDMAEMA film with initial pH values above 11.0. The cyclic processes of adsorption at pH 3.0 and desorption at pH 11.0 were repeated without considerable fatigue. The PE‐g‐PDMAEMA films showed practically regenerative adsorption and desorption behavior in response to the pH changes. In addition, when the dye‐anion‐adsorbed PE‐g‐PDMAEMA films were alternately immersed in water at two different temperatures, dye anions were desorbed in water at higher temperatures without any chemical agents because of the deprotonation of dimethylamino groups and thermosensitive contraction of grafted PDMAEMA chains. These results indicate that PE‐g‐PDMAEMA films can be applied as regenerative ion‐exchange membranes for adsorption and desorption processes of anionic compounds in response to the pH and temperature. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 381–391, 2006     

Detection of Buckminsterfullerene in Usual Soots and Commercial Charcoals

Abstract

It was confirmed that soot produced by free burning of small hydrocarbons like benzene and cyclohexane generally contains less than 0.1 ppm of C₆₀. Small, but measurable amounts of C₆₀ were found in two samples of charcoal, providing the first indication of fullerene formation in the solid state.