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  • 1
    Electronic Resource
    Electronic Resource
    Rapid identification of drug metabolites with tandem mass spectrometry (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 193-204 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method which involves the use of tandem mass spectrometry (MS/MS) for the identification of drug metabolites has been demonstrated with a triple quadrupole mass spectrometer. The method is based on the fact that metabolites usually retain various substructures of the original drug molecule. MS/MS is capable of rapidly identifying molecules with characteristic substructures without prior separation. It is shown that this method makes it possible to postulate possible drug metabolite structures rapidly and systematically without the use of standards. The MS/MS method, as it was applied to the identification of the metabolites of a new antiepileptic drug, zonisamide, is discussed. In this case it was possible to identify isomeric metabolites due to their differences in vaporization times off the probe and their different daughter spectra. The complementary uses of the neutral loss and parent scans for the determination of the site of metabolism is demonstrated. A new figure of merit, the limit of identification, is introduced. The amount of the epoxide metabolite of carbamazepine necessary for its reliable identification in urine was shown to be 0.4 ng/μl. The application of various techniques to confirm preliminary findings with this MS/MS method are described.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200150403
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  • 2
    Electronic Resource
    Electronic Resource
    Size determination of multienzyme complexes using two-dimensional agarose gel electrophoresis (1989)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 5 (1989), S. 224-232 
    Details
    ISSN: 0887-3585
    Keywords: effective pore's radius ; α-ketoglutarate dehydrogenase complex ; branched chain α-keto acid dehydrogenase complex ; electron microscopy ; multienzyme complex ; two-dimensional ; electrophoresis ; multienzyme complex ; aggregation of Pyruvate dehydrogenase complex ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: In the studies of the size and structure of multienzyme complexes, a procedure complementary to electron microscopy for determining the molecular dimensions of hydrated multisubunit complexes is needed. For some applications this procedure must be capable of detecting aggregation of complexes and must be applicable to impure preparations. In the present study, a procedure of two-dimensional agarose gel electrophoresis (2d-AGE) (Serwer, P. et al. Anal. Biochem. 152: 339-345, 1986) was modified and employed to provide accurate sizemeasurements of several classical multienzyme complexes. To improve band clarity and to achieve required gel pore sizes, a hydroxyethylated agarose was used. The effective pore's radius (PE) as a function of gel concentration was determined for this agarose inthe range of PE value needed for multienzyme complexes (effective radius, R = 10-30 nm). Appropriate conditions wereestablished to measure R value ± 1% of the pyruvate (PDC), α-ketoglutarate (α-KGDC), and the branched chain α-keto acid (BCDC) dehydrogenase multienzyme complexes; the accuracy of R was limited by the accuracy of the determinations of the R value for the sizestandards. The PDC from bovine heart was found to have an R = 22.4 ± 0.2 nm following cross-linking with glutaraldehyde that was necessary for stabilization of the complex. Dimers and trimers of PDC, present in the preparations used, were separated from monomeric PDCduring 2d-AGE. All R values for the enzyme complexes studied were agreement with, though more accurate than, R valuesobtained by use of electron microscopy. In contrast to this statement, the internal dihydrolipoyl transacetylase core of PDC (E2) had an R of 18.8 ± 0.2 nm using 2d-AGE, but 10.5 nm by electron microscopy. This observation confirms the proposal that the core of the PDC has externally projecting fibrous domains invisibleto electron microscopy.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prot.340050306
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  • 3
    Electronic Resource
    Electronic Resource
    13C-NMR spectra of cis-polymyrcene and cis-polyfarnesene (1988)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 71-77 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Homopolymers of myrcene and farnesene were prepared anionically in pure cyclohexane. The microstructure, determined from an analysis of the 13C-NMR spectrum and spin-lattice relaxation times, indicates the polymers are at least 85% cis-1,4, 10% cis-3,4, and under 3% trans-1,4.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1988.080260107
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  • 4
    Electronic Resource
    Electronic Resource
    Genetic analysis of the molecular basis for β-adrenergic receptor subtype specificity (1989)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 6 (1989), S. 267-274 
    Details
    ISSN: 0887-3585
    Keywords: β-adrenergic recepor ; chimeric proteins ; receptor subtypes ; ligand binding ; protein structure-function ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Pharmacological analysis of ligand binding to the β-adrenergic receptor (βAR) has revealed the existence of two distinct receptor subtypes (β1 and β2) which are the products of different genes. The predicted amino acid sequence of the β1 and β2 receptors differ by 48%. To identify the regions of the proteins responsible for determining receptor subtype, chimeras were constructed from domains of the human β1 and hamster β2 receptors. Analyses of the ligand-binding characteristics of these hybrid receptors revealed that residues in the middle portion of the βAR sequence, particularly around transmembrane regions 4 and 5, contribute to the subtype specific binding of agonists. Smaller molecular replacement of regions of the hamster β2AR with the analogous regions from the avian β1AR, however, failed to identify any single residue substitution capable of altering the subtype specificity of the receptor. These data indicate that, whereas sequences around transmembrane regions 4 and 5 may contribute to conformations which influence the ligand-binding properties of the receptor, the subtype-specific differences in amine-substituted agonist binding cannot be attributed to a single molecular interaction between the ligand and any amino acid residue which is divergent between the β1 and β2 receptors.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prot.340060309
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  • 5
    Electronic Resource
    Electronic Resource
    Analysis of inositol mono- and polyphosphates by gas chromatography/mass spectrometry and fast atom bombardment (1986)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 13 (1986), S. 333-341 
    Details
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The electron ionization spectra of all of the positional isomers of myo-inositol monophosphate and of myo-inositol 1,2-cyclic phosphate were obtained by gas chromatography/mass spectrometry of the pertrimethylsilyl derivatives. The fragmentation pattern of pertrimethylsilyl myo-inositol-1-phosphate was studied using deuterium labeling. The phosphate moiety was found to direct fragmentation to produce fragment ions of useful intensity with specific carbon retention. The spectrum of pertrimethylsilyl myo-inositol-1,4-bisphosphate is also described. An electron impact gas chromatographic/mass spectrometric method for myo-inositol-1-phosphate has been developed, which has a sensitivity to a level of 0.1 pmol. The positive and negative ion fast atom bombardment spectra of myo-inositol hexakis(disodium phosphate) and myo-inositol hexakis(dihydrogen phosphate) are described. The lesser-phosphorylated inositol polyphosphates were also studied, including inositol pentakis and inositol tetrakis(dihydrogen phosphates) as well as D-myo-inositol-1,4,5-trisphosphate and D-myo-inositol-1,4-bisphosphate from human red blood cells. The sensitivity of fast atom bombardment for the measurement of the latter two substances allows their detection to a level of about 10 nmol. The fast atom bombardment spectrum of synthetic myo-inositol 1,2-cyclic phosphate revealed variable amounts of a dimer produced during its preparation.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200130704
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  • 6
    Electronic Resource
    Electronic Resource
    Alum flocculation and bioflocculation of activated sludge for vacuum filtration (1988)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 31 (1988), S. 71-74 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This study investigated the relationship between sludge loading rate, COD-to-nitrogen ratio of influent waste, and maximum difference in specific resistance as a result of chemical conditioning (ΔZ). It also related ΔZ to sludge carbohydrate content, protein content, and surface charge. This research also explored the necessity of chemical conditioning when an activated sludge exhibits excellent bioflocculation characteristics.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260310111
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  • 7
    Electronic Resource
    Electronic Resource
    Structure of fibrous cellulose acetate: X-ray diffraction, positron annihilation and electron microscopy investigations (1987)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 33 (1987), S. 95-106 
    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: X-ray diffraction, positron annihilation, electron microscopy and bulk density measurements are reported as a function of the degree of acetylation for a linters cotton. Heterogeneous reaction proceeds with a retention of ordered structure in the fibers. Substitution does increase the extent of disorder but is not sufficiently extensive to disrupt completely order at the fiber, fibril, micro fibril, and crystallite levels. The generation of disorder is associated with an increase in the interfibrillar distance, a breakup of the microfibrillar structure without a total disruption of the microcrystalline structure.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1987.070330109
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  • 8
    Electronic Resource
    Electronic Resource
    A comparative study of the biologic and immunologic response to medical devices derived from dermal collagen (1986)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 20 (1986), S. 109-120 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: We examined collagen materials for soft tissue augmentation [Zyderm® Collagen Implant (ZCI), glutaraldehyde cross-linked (GAX) collagen, and Koken Atelocollagen (Atelocollagen)]; hemostatic collagens [Gelfoam® Gelatin Powder (Gelfoam), Avitene® Microfibrillar Collagen Hemostat (Avitene), and Collastat® Collagen Hemostat (Collastat)]; and reconstituted, intact fibrillar collagen from bovine skin in a subcutaneous guinea pig model. After 11, 25, and 39 days in situ, explants from animals injected with GAX collagen demonstrated greater wet-weight persistence than all other materials. Conversely, at all time points, the explants of Atelocollagen were the least persistent. Following 25 days in vivo, explants were examined using differential scanning calorimetry; ZCI and Atelocollagen displayed thermal transition temperatures of 58°C. Avitene and Gelfoam explants displayed transition points of 30°C and 32°C, indicating denatured or cleaved collagen. By contrast, GAX collagen explants had a high (68°C) transition temperature, reflecting its cross-linking. With respect to immunogenicity, day 39 sera from ZCI treated animals showed significantly lower titers in the ELISA to their respective implant collagen than all other groups examined, while antibody activity in the GAX collagen, Gelfoam, Atelocollagen, and intact collagen groups were not significantly different. Collastat elicited antibodies with a greater affinity than observed in these previous groups. Sera from Avitene treated animals demonstrated the highest antibody levels and were the only sera which reacted with bovine serum albumin. Thus, Avitene was the most immunogenic of the collagen materials examined, while GAX collagen demonstrated the greatest persistence and minimal immunogenicity, and ZCI was the least immunogenic.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820200110
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  • 9
    Electronic Resource
    Electronic Resource
    Wound healing using a collagen matrix: Effect of DC electrical stimulation (1988)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 22 (1988), S. 191-206 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Rapid fibroblast ingrowth and collagen deposition occurs in a reconstituted type I collagen matrix that is implanted on fullthickness excised animal dermal wounds. The purpose of this study is to evaluate the effects of direct current stimulation on dermal fibroblast ingrowth using carbon fiber electrodes incorporated into a collagen sponge matrix. Preliminary results suggest that fibroblast ingrowth and collagen fiber alignment are increased in collagen sponges stimulated with direct currents between 20 and 100 μA. Maximum fibroblast ingrowth into the collagen sponge is observed near the cathode at a current of 100 μA. These results suggest that electrical stimulation combined with a collagen matrix may be a method to enhance the healing of chronic dermal wounds.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820221310
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  • 10
    Electronic Resource
    Electronic Resource
    Material properties of living soft tissue composites (1988)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 22 (1988), S. 311-326 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Collagen sponges seeded with fibroblasts have been used as a soft tissue substitute in wound healing applications. This biomaterial is a good in vitro analog of a connective tissue. Therefore, analysis of the properties of this material may be useful for theoretically modeling soft tissues. Stress-strain curves for such cell-seeded collagen sponges were measured to determine composite stiffness and ultimate tensile strength. Theoretical modeling was done by defining a particle-reinforced matrix using the composite sphere model. A system of uniaxially oriented fibers was then introduced to this equivalent homogeneous media and material properties were determined using the composite cylinder model. Geometric averaging was performed to yield the stiffness and Poissons' ratio for a composite with randomly oriented fibers. Inputs to the model were constituent material properties, cell volume fraction, and fiber volume fraction. From theoretical results, material properties of soft tissues and their substitutes depend on fiber mechanical properties and volume fraction and not cellular mechanical properties and volume fraction. Therefore, the increase in experimentally observed composite stiffness with increased cell number was due to deposition of newly synthesized stiffer collagen fibers, and not due to the physical presence of cells themselves.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820221409
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