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  • 1
    Electronic Resource
    Electronic Resource
    Surface immobilization of anchorage-dependent mammalian cells (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 39 (1992), S. 697-706 
    Details
    ISSN: 0006-3592
    Keywords: anchorage-dependent mammalian cells ; immobilization ; fibers ; bioreactor ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Anchorage-dependent HeLa cells were successfully cultured on two fibrous materials (A07 and R100) with porosities of 75-125 and 40 μm, void fractions of 92% and 81%, and fiber diameters of 7.6 and 10.2 μm, respectively, in 100-mL spinner flasks and 2-L stirred tank bioreactors. The matrix was formed into a fixed vertical spiral configuration. All cultures displayed rapid (≤2-3 h) attachment of inoculated cells (≥95%) to the matrix, uniform coverage of the immobilizing area with viable cells, and no significant amount of cell debris in the medium. Spinner flask cultures indicated that the denser material R100 showed better results in terms of final cell density. The growth of HeLa cells on material R100 in both culture systems was similar to that observed in tissue culture dishes (specific growth rate ∼0.03-0.04 h-1, maximum cell density of 8 × 106-9 × 106 cells · mL-1, and yields of 0.4 × 108 cells · mM-1 on glucose and 2 × 108-3 × 108 cells · mM-1 on glutamine). Scale-up of this culture technique in a 2-L bioreactor under perfusion with pH and dissolved oxygen (DO) control yielded cell densities of up to 1.6 × 106 cells · mL-1. Two other anchorage-dependent mammalian cells (ADC) known to be cultured with difficulty in roller bottles or with micro carriers were easily grown on material R100 in spinner flasks. The performance of this culture technique was compared to other ADC culture systems.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260390702
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  • 2
    Electronic Resource
    Electronic Resource
    Improvement of recombinant protein production with the human adenovirus/293S expression system using fed-batch strategies (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 51 (1996), S. 613-623 
    Details
    ISSN: 0006-3592
    Keywords: adenovirus ; 293S cells ; protein production ; lactate ; osmolarity ; fed-batch ; glucose control ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The human adenovirus/293S cell expression system is used for the production of either recombinant protein or adenovirus vectors for use in gene therapy. In this work, the production of protein tyrosine phosphatase (PTP1C) was used as a model for the scale-up of both applications. Maximum specific production of 30 to 45 μg of active protein/106 cells was maintained upon infection with adenovirus vectors at cell densities between 2 × 106 to 3 × 106 cells/mL in a 3.5-L bioreactor. This was achieved by resuspending the culture in fresh medium at infection time. The pH was kept at 7.0 throughout the experiment and, at 24 h postinfection, glucose and essential amino acids were added. Attempts to replace the complete change of medium at the time of infection with nutrient supplementation of the used medium led to lower production levels, suggesting that protein expression was limited not by the absence of a key nutrient but by inhibitory factors. Two potentially inhibitory factors were investigated: lactic acid accumulation and increased osmolarity. Medium acidification such as that which would be brought about by lactic acid accumulation was shown to depress PTP1C production. The lactate molecule itself decreased the cell viability when added in concentrations of 20 mM or more. But the specific productivity was affected at higher lactate concentrations of 40 mM or more. Additions of glucose, amino acids, and NaHCO3 used to control pH, led to increases in osmolarity. Osmolarities above 400 mOsm lowered cell density. However, specific production was not significantly affected below 500 mOsm. But, at 500 mOsm, PTP1C production peak was shifted from 48 to 72 hpi. Because of the cell loss, this per cell yield increase did not translate into higher volumetric production. When glucose concentrations was kept at 5 mM by fed-batch addition, lactate production and increases in osmolarity were reduced. In shake flasks, this method permitted maximum production with cells resuspended either in fresh or spent medium at infection. This fed-batch process was implemented successfully at the 3.5-L scale. Fed-batch with glucose may provide a means to increase infected-cell density beyond 3 × 106 cells/mL.
    Additional Material: 8 Ill.
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  • 3
    Electronic Resource
    Electronic Resource
    Serum-free production of recombinant proteins and adenoviral vectors by 293SF-3F6 cells (1998)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 59 (1998), S. 567-575 
    Details
    ISSN: 0006-3592
    Keywords: adenovirus ; adenoviral vectors ; 293 cells ; recombinant proteins ; serum-free medium ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This article describes the step-wise approach undertaken to select a serum-free medium (SFM) for the efficient production of a recombinant adenoviral vectors expressing β-galactosidase (Ad5 CMV-LacZ), in the complementing human embryonic kidney 293S cells. In the first step, a 293S-derived transfectoma, secreting a soluble epidermal growth factor receptor sEGFr (D2-22), was used to estimate the potential of selected serum-free formulations to support the production of a recombinant protein as compared to serum-containing medium. Assays showed that only one among six commercial serum-free formulations could support both sEGFr production and cell growth in static or suspension culture. In commercially available calcium-containing serum-free formulations, the cell aggregates reached up to 3 mm in diameter. In the second step, 293S cells were gradually adapted to a low-calcium version of the selected medium (LC-SFM). Cells were cloned, then screened according to their ability to grow at a rate and an extent comparable to parental cells in serum-containing medium (standard) as single cells or small aggregates. The 293SF-3F6 clone, first adapted to and then cloned in the selected serum-free medium, was selected for further experiments. Bioreactor run performed with the 293SF-3F6 clone showed similar growth curve as in the shake-flask controls. In the final step, the recombinant viral vector productivity of the 293S cells and the 293SF-3F6 clone was tested. The 293SF-3F6 cells infected by Ad5 CMV-LacZ in 3 L-scale bioreactor maintained the specific productivities of both β-galactosidase and adenoviral vector equivalent to the shake-flask controls in suspension culture. Results from this study clearly demonstrate that the 293SF-3F6 cell line thus selected may be used either for establishing stable transfected cell line or for the production of adenoviral vectors required for gene therapy studies. © 1998 John Wiley & Sons, Inc. Biotechnol Bioeng 59: 567-575, 1998.
    Additional Material: 5 Ill.
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  • 4
    Electronic Resource
    Electronic Resource
    Detection of β- 1,3-glucanase activity after native polyacrylamide gel electrophoresis: Application to tobacco pathogenesis-related proteins (1989)
    Weinheim : Wiley-Blackwell
    Electrophoresis 10 (1989), S. 527-529 
    Details
    ISSN: 0173-0835
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: β-1,3-Glucanase (laminarinase) activity was detected after polyacrylamide gel electrophoresis under native conditions by using laminarin as substrate. Following incubation of gels, laminarin was stained with Aniline Blue. Under UV illumination, lysis zones appeared as dark bands against a fluorescent background. As low as 0.001 unit of commercial Penicillium laminarinase could be observed after incubating the polyacrylamide gel for 45 min at pH 5.0. Extracts of commercial Penicillium laminarinase exhibited four bands with lytic activity towards laminarin. Analysis of intercellular fluid extracts of tobacco mosaic virus-infected tobacco leaves revealed four β-1,3-glucanases corresponding to three acidic pathogenesis-related proteins, b4 (2), b5 (N) and b6b (0), and one basic protein. The presence of laminarin in gels retarded the migration of some proteins with β1, 3-glucanase activity. This change in electrophoretic mobility could be used as a complementary affinity test for identifying proteins with β-1,3-glucanase activity.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150100714
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  • 5
    Electronic Resource
    Electronic Resource
    Complexes of starch polysaccharides and poly(ethylene co-acrylic acid): Structural characterization in the solid state (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 42 (1991), S. 2279-2286 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The structural characterization of model complexes of amylose (AM) and amylopectin (AP) with poly(ethylene-co-acrylic acid) (EAA) was undertaken in order to better understand the interactions that occur between the polysaccharides and EAA in starch-EAA-polyethylene films. X-ray diffraction and CP/MAS 13C-NMR studies showed that precipitates from solution mixtures of AM and EAA form crystalline, helical V -type inclusion complexes. The proportion of AM forming the V -type complex in the EAA/AM blends, estimated from shifts in the C1 resonance of AM, increased with increasing EAA/AM ratio, reaching a value of about 80% at EAA/AM = 0.5 (w/w). Similar measurements for EAA/AP complexes showed 〈 10% V structure. Approximately 80% of the AM and 4% of the AP in these blends was resistant to amylase digestion, in good agreement with their V -structure contents as determined above. Resonances at 184 and 181 ppm were observed for the carboxyl carbon of EAA in the EAA/AM and EAA/AP complexes. The resonance at 181 ppm, which was not observed in pure EAA, probably reflects greater shielding of the carboxyl inside the polysaccharide helix as well as changes in hydrogen bonding. The intensity of this peak was 2-3 times larger for the EAA/AM than for the EAA/AP complexes. FTIR experiments suggest that most (〉 50%) of the EAA carboxyl groups were hydrogen bonded to polysaccharide hydroxyl groups in both AM and AP complexes when EAA/polysaccharide 〈 1.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1991.070420819
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  • 6
    Electronic Resource
    Electronic Resource
    Evaluation of steady-state flow curves from model molecular weight distributions (1973)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 17 (1973), S. 1639-1650 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Graessley's theory of entanglement was applied to several model distributions. The distribution functions chosen were such that the differential weight distributions were triangular with respect to a log molecular weight axis. The molecular weight level, breadth of the molecular weight distribution, skewness, and blending of simple distributions were studied in their effect on the steady-state flow curve. The governing factor for the shape of the reduced flow curve was shown to be M̄z+1·M̄z/M̄w2. Other general features of the flow curve predicted by Graessley's theory were discussed.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1973.070170601
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  • 7
    Electronic Resource
    Electronic Resource
    L'action de l'ammoniac sur l'hydroxyde de cobalt(II) et la stabilité des complexes en milieu aqueux (1970)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 53 (1970), S. 1229-1235 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: From the solubility of precipitated Co(OH)2 (s) determined radiometrically as a function of pH and ammonia content of the heterogeneous systems, the formation constants have been obtained for the following mononuclear hydroxo-, ammine- and mixed hydroxo-ammine-complexes: Co(OH)2, Co(OH)3-, Co(NH3)22+, Co(NH3)32+, Co(NH3)42+ and Co(OH)2 (NH3)2. The solubility of cobalt(II) hydroxide has also been calculated. The medium was 1M NaClO4 and the temperature 25° C.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19700530542
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  • 8
    Electronic Resource
    Electronic Resource
    L'action de l'ammoniac sur l'oxyde cuivrique. et les hydroxo-complexes de cuivre (II) (1970)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 53 (1970), S. 186-197 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Using a new mathematical treatment, the nature and stability constants of the simple and mixed complex-species of copper(II) with hydroxyde and ammonia as ligands have been determined. The solubility curves of CuO in heterogeneous equilibrium have been identified in function of pH only and in function of pH and pNH3tot at 25° and unit ionic strength (NaClO4).The predominent species in the relatively dilute system limited by the ionic strength are [Cu2+], [Cu(OH)2], [Cu(OH)3-], [Cu(OH)42-], [Cu(NH3)22+], [Cu(NH3)32+], [Cu(NH3)42+], [Cu(NH3) (OH)+], [Cu(NH3)3(OH)+] and [Cu(NH3)2(OH)2].
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19700530126
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  • 9
    Electronic Resource
    Electronic Resource
    Properties of poly-β-hydroxybutyrate. I. General considerations concerning the naturally occurring polymerPortions of this work were taken from a thesis by R. Alper submitted to the Graduate School, Syracuse University in partial fulfillment of the requirements for the degree of Doctor of Philosophy. Presented before the Polymer Division at the 145th National American Chemical Society Meeting, New York, September 1963. (1963)
    New York : Wiley-Blackwell
    Biopolymers 1 (1963), S. 545-556 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Poly-β-hydroxybutyric acid has been isolated from two bacterial sources by two different procedures. Molecular weight and intrinsic viscosity for the two samples were vastly different. This was blamed on degradation occurring during polymer isolation. An optical rotatory dispersion curve for the high molecular weight sample showed a sharp increase in specific rotation at wavelengths less than 450mμ. From this fact and the reported optical activity of the monomer it is concluded that the polymer is stereo-regular. X-ray examination of the “native” and “regenerated” polymer yielded the same crystalline pattern. Electron diffraction and x-ray data on single crystals of the polymer indicate a fiber repeat of 5.9 A. The value can only be reconciled with some kind of helical conformation in the solid state.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360010605
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  • 10
    Electronic Resource
    Electronic Resource
    Chemical inactivators as sterilization agents for bovine collagen materials (1997)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 37 (1997), S. 212-221 
    Details
    ISSN: 0021-9304
    Keywords: collagen materials ; chemical inactivators ; sterilization ; prion ; nucleic acids ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The use of collagen as a biomedical implant raises safety issues with regard to viruses and prions. Specific chemical agents that inactivate prion infectivity could be applied to collagen implants. The physiochemical changes and the in vitro and in vivo biocompatibility of collagen treated by formic acid (FA), trifluoroacetic acid (TFA), tetrafluoroethanol (TFE), and hexafluoroisopropanol (HFIP) were investigated. In addition, the effects of these treatments on nucleic acids incorporated in collagen were analyzed. The molecules of FA and, more important, of TFA remained within collagen. FA, TFA, and HFIP treatments modify the secondary structure of collagen, as shown by Fourier transform infrared spectroscopy, while TFE does not. Differential scanning calorimetry measurements showed a decrease in the denaturation temperature compared to untreated collagen. However, resistance to collagenase was modified only after HFIP treatment. In vitro, cell growth was not impaired; in vivo, implants induced a temporary inflammatory reaction that was prolonged with TFA and HFIP treatments. TFE and FA-treated collagen were thoroughly infiltrated by fibroblasts. On the other hand, FA and TFA resulted in extensive depurination of nucleic acids while HFIP and TFE did so to a lesser degree. Among the investigated chemical scrapie inactivators, FA treatment could offer a safe and biocompatible collagen-derived material for biomedical use. © 1997 John Wiley & Sons, Inc. J Biomed Mater Res, 37, 212-221, 1997.
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