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  • 1985-1989  (10)
  • 1989  (3)
  • 1988  (7)
  • Polymer and Materials Science  (6)
  • Genetics  (2)
  • serum polymorphism  (2)
Materialart
Erscheinungszeitraum
  • 1985-1989  (10)
Jahr
  • 1
    ISSN: 1573-4927
    Schlagwort(e): α-l-fucosidase ; lymphoid cells ; fucosidosis ; serum polymorphism
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract In humans, the quantity of α-l-fucosidase in serum is determined by heredity. The mechanism controlling levels of the enzyme in serum is unknown. Lymphoid cell lines derived from individuals with either low, intermediate, or high α-l-fucosidase in serum were established. Steady-state levels of intracellular and extracellular α-l-fucosidase as well as rates of synthesis and secretion of enzyme overlapped among the cell lines. Thus,vivo} serum phenotypes were not expressed in this system. No appreciable differences in the qualitative processing of newly made α-l-fucosidase were observed among these lymphoid cell lines. Cells pulse-labeled with35S-methionine from 0.25 to 2 hr had an intracellular form of enzyme with aM r=58,000. Cells pulsed for 1.5 hr and chased for 21 hr with unlabeled methionine had an intracellular form ofM r=60,000 and an extracellular form ofM r=62,000. All three enzyme forms were glycoproteins with a common polypeptide chain ofM r=52,000 but with different carbohydrate moieties. No evidence for a high molecular mass precursor form of α-l-fucosidase was found. Fucosidosis is a rare, inherited disease in which α-l-fucosidase activity in tissues and body fluids is low or absent. The mutations for fucosidosis and the serum polymorphism map separately. Lymphoid cells from two siblings with fucosidosis had 8-fold to 341-fold less intracellular α-l-fucosidase protein with 11-fold to 56-fold lower specific activities than control cells. Residual mutant enzyme was a glycoprotein with a polypeptide chain virtually the same size (M r=52,000) as control enzyme. However, residual mutant enzyme was hypoglycosylated and hypersecreted as compared to control enzyme.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    ISSN: 1573-4927
    Schlagwort(e): α-l-fucosidase ; lymphoid cells ; fucosidosis ; serum polymorphism
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract In humans, the quantity of α-l-fucosidase in serum is determined by heredity. The mechanism controlling levels of the enzyme in serum is unknown. Lymphoid cell lines derived from individuals with either low, intermediate, or high α-l-fucosidase in serum were established. Steady-state levels of intracellular and extracellular α-l-fucosidase as well as rates of synthesis and secretion of enzyme overlapped among the cell lines. Thus,vivo} serum phenotypes were not expressed in this system. No appreciable differences in the qualitative processing of newly made α-l-fucosidase were observed among these lymphoid cell lines. Cells pulse-labeled with35S-methionine from 0.25 to 2 hr had an intracellular form of enzyme with aM r=58,000. Cells pulsed for 1.5 hr and chased for 21 hr with unlabeled methionine had an intracellular form ofM r=60,000 and an extracellular form ofM r=62,000. All three enzyme forms were glycoproteins with a common polypeptide chain ofM r=52,000 but with different carbohydrate moieties. No evidence for a high molecular mass precursor form of α-l-fucosidase was found. Fucosidosis is a rare, inherited disease in which α-l-fucosidase activity in tissues and body fluids is low or absent. The mutations for fucosidosis and the serum polymorphism map separately. Lymphoid cells from two siblings with fucosidosis had 8-fold to 341-fold less intracellular α-l-fucosidase protein with 11-fold to 56-fold lower specific activities than control cells. Residual mutant enzyme was a glycoprotein with a polypeptide chain virtually the same size (M r=52,000) as control enzyme. However, residual mutant enzyme was hypoglycosylated and hypersecreted as compared to control enzyme.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    New York : Wiley-Blackwell
    Biopolymers 28 (1989), S. 1475-1484 
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: By use of agarose gel electrophoresis, the sieving of spherical particles in agarose gels has been quantitated and modeled for spheres with a radius (R) between 13.3 and 149 mm. For quantitation, the electrophoretic mobility has been determined as a function of agarose percentage (A). Because a previously used model of sieving [D. Rodbard and A. Chrambach (1970) Proc. Natl. Acad. Sci. USA 65, 970-977] was found incompatible with some of these data, alternative models have been tested. By use of an underivatized agarose, two models, both based on the assumption of a single effective pore radius (PE) for each A, were found to yield PE values that were independent of R and that were in agreement with values of PE obtained independently (PE = 118 nm × A-0.74): sieving by altered hydrodynamics in a cylindrical tube of radius, PE, and sieving by steric exclusion from a circular hole of radius, PE. The same analysis applied to a 6.5% hydroxyethylated commercial agarose yileded a steeper PE vs A plot and also agreement of the above tow models with the data. The PE vs A plot was significantly altered by both further hydroxyethylation and factors that cause variation in the electro-osmosis found in commercial agarose.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 71-77 
    ISSN: 0887-624X
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: 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.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 5
    ISSN: 1040-0397
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Five crown ethers with four ring oxygen atoms and different types of pendant groups were used to prepare ion-selective electrodes by coating a membrane containing the crown ether on the tip of a silver wire incorporated in a flow cell. A flow injection analysis study was conducted to determine the potentiometric selectivities of the crown ethers for lithium, sodium, potassium, magnesium, and calcium ions. It was found that crown ethers with neutral side arms show selectivities for lithium over other ions, while those of acidic side arms show selectivities for potassium over the other ions. The effect of the addition of trioctylphosphine oxide to the electrode matrix was also investigated. A comparison is made between the potentiometric selectivities of the crown ethers for certain metal ions and their selectivities in extracting the ions into an organic phase.
    Zusätzliches Material: 2 Tab.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 27 (1989), S. 1911-1925 
    ISSN: 0887-6266
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: Carboxy-terminated polybutadiene neutralized with Cu2+ (CuPBD) and its blend with poly(styrene-co-4-vinylpyridine) (SVP) were examined by differential scanning calorimetry (DSC), transmission electron microscopy (TEM), small-angle x-ray scattering (SAXS), and extended x-ray absorption fine structure (EXAFS) spectroscopy. The DSC results indicate that in the blend substantial mixing occurs in the CuPBD-rich phase, although complete miscibility is not achieved, and the SVP-rich phase remains relatively pure. The TEM micrographs indicate that the morphology, while irregular, is reasonably described as bicontinuous, with a domain size of order 100 nm. The SAXS patterns show that the ionic aggregates present in CuPBD are destroyed upon blending, which is interpreted as being due to steric hindrances between ionic groups coordinated to vinylpyridine nitrogens. The EXAFS radial structure function of the blend exhibits a marked decrease in the Cu-Cu peak in comparison with CuPBD, indicating a change in local structure upon blending. The results indicate that some of the SVP is miscible with CuPBD owing to complexation between the pendant pyridine groups and the Cu2+ ions, which disrupts the ionic aggregates. However, the two materials are not fully miscible, leading to a rather coarse two-phase morphology.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 7
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 22 (1988), S. 191-206 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: 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.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 8
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 22 (1988), S. 311-326 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: 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.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 9
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 9 (1988), S. 337-350 
    ISSN: 0192-253X
    Schlagwort(e): Dictyostelium ; cAMP ; receptor ; gene regulation ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: We have examined the expression of a cAMP pulse-repressed and two cAMP pulse-induced genes in response to cAMP and caffeine under a number of different physiological conditions, and in several classes of developmental mutants altered in cAMP-mediated signal transduction pathways. The data presented help characterize the mutants with regard to early gene expression. Analysis of the data indicates that full induction of the pulse-induced or repression of the pulse-repressed genes requires cycles of activation and adaptation of the cAMP receptor but does not require a rise in intracellular cAMP. Comparison of the results obtained between different mutant classes suggests that repression and activation of the two classes of genes can be uncoupled, implying that different intracellular mechanisms control these processes. In addition, we examined the effects of caffeine and show that it can induce pulse-induced mRNA accumulation in the absence of cAMP.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 10
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 9 (1988), S. 435-454 
    ISSN: 0192-253X
    Schlagwort(e): cis-acting sequences ; trans-acting factors ; gene regulation ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: Expression of the Dictyostelium discoideum pst-cath (CP2) gene is transcriptionally regulated during multicellular development, and the gene is inducible in competent single cells following administration of exogenous cAMP. The 5′ flanking region of pst-cath (CP2) that extends from -313 to the Cap site (+-1) has previously been shown to contain sufficient cis,-acting regulatory elements for proper developmental and cAMP-inducible expression of a foreign gene [Datta and Firtel, 1987, Mol Cell Biol 7:149-159]. The -283 to -201 region includes two exceptional “G-boxes” centered at -233 and -217 respectively, and this ∼ 80 bp region is essential for basal as well as regulated expression of the pst-cath (CP2) gene. Here we summarize results obtained from a detailed analysis of a series of linker-scanner mutants and mutants that carry small internal deletions within the essential 80-bp region. Insertion of a synthetic oligonucleotide that includes the downstream G-box is demonstrated to rescue a low level of cAMP-inducible expression following insertion into cassette mutants. The effect of introducing a change in the relative spacing between regulatory elements has also been investigated.We have analyzed nuclear extracts for the presence of DNA-binding proteins that interact specifically with the pst-cath (CP2) regulatory region and identified two such putative trans-acting factors: (1) the AT-factor that is observed within a few hours following the onset of starvation and that binds tightly to stretches of alternating adenine-thymine residues (poly(dA-dT)); and (2) the AG-factor that is present in nuclear extracts of aggregated cells. Competition studies have demonstrated significant differences in the affinity that characterizes the binding of the two factors to G-box-containing sequences. The binding specificities of these DNA-binding proteins have been analyzed using gel mobility-shift and DNaseI footprinting assays.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
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