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  • Polymer and Materials Science  (7)
  • Thalidomide  (3)
  • 1
    ISSN: 1432-0533
    Keywords: Thalidomide ; Wallerian degeneration ; Schwann cell proliferation ; Immune inhibition ; Endoneurial edema
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In addition to the well-known teratogenic effect of thalidomide, previous studies have revealed mild immunosuppressive properties and, more recently, and antiangiogenic activity. To find out more about the specificity of these effects we studied the influence of orally administered thalidomide on Wallerian degeneration in rats. Wallerian degeneration is a potent experimental model for studying reproducible cell proliferation in vivo. Examination of distal nerve segments of transected sciatic nerves from rats that had been treated with thalidomide (2×250 mg/kg per day) revealed a significant reduction of endoneurial cell counts at 10–15 days after surgery compared to that seen in controls. This effect was not statistically significant, at a very early stage of Wallerian degeneration, i.e., at 5 days after transection of the nerve. Subperineurial edema and phagocytosis was also reduced, although this was not statistically significant. This apparently nonspecific inhibitory effect of thalidomide during early Wallerian degeneration shown in the present study should be investigated further for its possible relationship to other previously established inhibitory activities of thalidomide, especially its immunosuppressive effect in man.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-0533
    Keywords: Unmyelinated axons ; Sensory neuropathy ; Thalidomide ; Aging ; Senile peripheral nerves
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Sural nerve biopsies of four patients, aged 54–76 years, with a predominantly sensory type of neuropathy following high dosages of thalidomide were examined by light and electron microscopy. The present study includes a qualitative and quantitative evaluation of unmyelinated nerve fibers. Despite severe neuropathy, increased numbers of small unmyelinated axons per endoncurial area were noted in all patients. This numerical increase appeared to be independent of aging, since it was not seen in two senile controls, studied at the age of 83 and 88 years. The increase in the endoneurial density of unmyelinated axons, especially of small sized fibers, is likely to be related to regeneration following degeneration of unmyelinated axons although endoneurial shrinkage secondary to loss of large myelinated fibers could have caused an additional increase in the number of axons per endoneurial area. Axonal sprouting, despite degeneration of large numbers of myelinated and unmyelinated fibers, appears to be consistent with some of the characteristic clinical features of thalidomide neuropathy such as paresthesias, hyperesthesia for pain and temperature, and disturbances of autonomic functions. On the other hand, a variable number of empty Schwann cells (bands of Büngner) and pockets at the surface of many Schwann cells noted in the four patients with neuropathy were also seen in both senile controls with no signs of neuropathy. Thus, it is obvious that pockets and empty Schwann cells may be related to aging or other causes of slow axonal wasting with Schwann cell proliferation and are not necessarily associated with clinically manifest neuropathy.
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 65 (1985), S. 285-292 
    ISSN: 1432-0533
    Keywords: Thalidomide ; Neuropathy ; Conduction velocity ; Myelin sheath
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Morphological studies of experimental thalidomide neuropathy have thus far failed to show any significant structural changes. The present investigation was performed on sural nerves of female New Zealand white rabbits showing a reduction of sensory conduction velocity after oral treatment with thalidomide (100 mg/kg b.wt. per day) for a period of 33 weeks. Rabbits of the same strain and equal sex, weight, and number served as controls. Very few nerve fibers were undergoing Wallerian degeneration in both groups, experimental animals and controls. Morphometry, however, revealed a statistically significant reduction of the mean myelin thickness of sural nerve fibers in the thalidomide group of rabbits as compared to controls. The mean myelin thickness of the largest nerve fibers was also significantly smaller than in the control group. On the other hand, axonal diameters were not significantly altered. The association between the decrease of the sensory conduction velocity, the reduction of the myelin sheath thickness, and the chronic thalidomide application is discussed.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 29 (1991), S. 1607-1612 
    ISSN: 0887-6266
    Keywords: neutron scattering (SANS) from hot stretched polystyrene ; polystyrene, hot stretched, SANS study of ; chain deformation in hot stretched polystyrene, SANS study of ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Small-angle neutron scattering (SANS) has been used to investigate macromolecular orientation of uniaxially hot-stretched partially deuterated polystyrene. Principle radii of gyration and degree of eccentricity were measured over a range of hot-stretch temperatures, strain rates, and external draw ratios (EDR). Results show affine deformation for EDR 〈4 and an increase in the degree of local molecular orientation with increasing rate of strain and decreasing stretching temperature. It also is found that although the macromolecules follow the external stretching affinely on average, they do not deform uniformly.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Chemie Ingenieur Technik - CIT 60 (1988), S. 152-153 
    ISSN: 0009-286X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 39 (1998), S. 539-548 
    ISSN: 0021-9304
    Keywords: cytokine delivery via covalent binding ; tissue repair ; biomaterials ; collagen ; transforming growth factor β ; polyethylene glycol ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: To overcome rapid diffusion and clearance from the implant site and to increase stability, recombinant transforming growth factor β2 (TGF-β2) was covalently bound to injectable bovine dermal fibrillar collagen (FC) and its activity compared to admixed TGF-β2. Covalent binding was achieved in a two-step procedure: First, TGF-β2 was reacted with the difunctional polyethylene glycol (PEG) linker, and then the PEG-attached TGF-β2 (PEG-TGF-β2) was bound to the fibrillar collagen (FC-PEG-TGF-β2). Initial binding of TGF-β2 to difunctional succinimidyl glutarate (D-SG-PEG) or succinimidyl propionate polyethylene glycol (D-SE-PEG) linkers was completed after reacting for 8 or 10 min as monitored by reverse-phase high-performance liquid chromatography. After reaction with injectable fibrillar collagen, extraction of unbound PEG-TGF-β2 and Western blot analysis, using a TGF-β specific antibody, demonstrated that at least 85% of the TGF-β2 was bound to the fibrillar collagen. The activity of PEG-TGF-β2 was fully stable in phosphate-buffered saline at 4°C and 37°C for at least up to 4 weeks. Unmodified TGF-β2 mixed with fibrillar collagen was completely inactivated after 1 week of incubation, as measured by the mink lung epithelial cell (Mv1Lu) growth inhibition assay. Formulations of FC-PEG-TGF-β2 containing 40 μg/mL TGF-β2 were implanted subcutaneously into rats and analyzed after days 7, 21, and 42. All TGF-β2-containing formulations showed the TGF-β typical fibroblastic response at the day 7 time point. Covalent binding of TGF-β2 to collagen with both difunctional PEG crosslinkers resulted in a significantly stronger and longer-lasting TGF-β2 response than that observed with admixed formulations of collagen and TGF-β. The TGF-β response with FC-PEG-TGF-β2 lasted up to day 42 but was not seen after day 7 for TGF-β2 admixed to FC. These findings clearly demonstrate that TGF-β2 remains fully active after being covalently bound to collagen via difunctional PEG. In addition, covalent binding potentiates and prolongs in vivo TGF-β responses and stabilizes the TGF-β in vitro. Results suggest that this method of formulation could be useful to stabilize and deliver similar peptide growth factors or biologically active agents. © 1998 John Wiley & Sons, Inc. J Biomed Mater Res, 39, 539-548, 1998.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 47 (1960), S. 417-433 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Phosphorus trichloride and oxygen react readily with polyethylene to introduce phosphonic dichloride ( - POCl2) groups into the polymer (chlorophosphonation). Treatment of the resulting intermediate with water, alcohols, and amines yields polymeric alkylphosphonic acids, esters and amides, respectively. Derivatives containing as much as 16% phosphorus have been prepared. With increasing degree of phosphonation, polyethylene crystallinity is reduced, the acid and amide derivatives become stiffer, less extensible, and less soluble in nonpolar solvents, and internal plasticization is observed in the ester derivatives. No significant decrease in flammability is effected by phosphonation unless chlorine is introduced also. The ester and amide derivatives crosslink under mild conditions by an unknown mechanism, the acid derivative will crosslink on heating with litharge. The chlorophosphonation reaction is sensitive to inhibitors and no highly active catalyst was found. The rate appears to be governed by the rate at which oxygen dissolves in the mixture. Substitution of air or chlorine for oxygen, phenyldichlorophosphine or diphenylchlorophosphine for phosphorus trichloride results in introduction of phosphorus-containing groups into polyethylene, also, but at reduced rates. In sharp contrast to polyethylene's apparent stability toward the phosphonation conditions, polystyrene, poly(methyl methacrylate), and polyisobutylene undergo a rapid decrease in molecular weight on treatment with phosphorus trichloride and oxygen. The fact that these four polymers exhibit the same relative behavior, i.e., polyethylene is stable whereas the other three polymers are unstable, in various free radical processes argues for a free radical mechanism in the chlorophosphonation reaction.
    Additional Material: 8 Tab.
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  • 8
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 46 (1960), S. 547-550 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Letters Edition 13 (1975), S. 215-219 
    ISSN: 0360-6384
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-1: Polymer Chemistry 10 (1972), S. 2189-2195 
    ISSN: 0449-296X
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
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