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  • 1
    ISSN: 1432-198X
    Keywords: Key words Angiotensin converting enzyme ; Angiotensin ; Polymorphism ; Uropathy ; Renal failure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  We investigated angiotensin converting enzyme gene (ACE I/D) polymorphism as a risk for progressive renal damage in congenital uropathies. The ACE I/D genotype was determined in 196 Caucasian patients with congenital uropathies and 163 individuals with no clinical or sonographic evidence of any urological malformations. The study group included patients with ureteropelvic junction obstruction (n=49), primary obstructive megaureter (n=19), primary vesicoureteral reflux (VUR) (n=67), and posterior urethral valves (n=27). Thirty-four patients were excluded because of additional diseases or insufficient follow-up. There was no difference in the ACE I/D distribution between children with uropathies and normal controls (II 16%, ID 56%, DD 28% vs. II 26%, ID 50%, DD 24%). Renal lesions were found in 99 of 162 children by ultrasonography, intravenous pyelography, and nuclear scans. In these children there was significant over-representation of the DD genotype (II 11%, ID 53%, DD 36%) compared with normals (P〈0.005, X2=14.9) or with patients with uropathies but no renal lesions (II 23%, ID 62%, DD 15%, P〈0.005, X2=14.9). Because ACE I/D has been linked with progressive deterioration of renal function, we evaluated a subset of patients with initially normal kidneys who developed radiographic renal lesions (n=28). Among these patients there was an even greater over-representation of the DD genotype (II 0%, ID 43%, DD 57%, P〈0.001, X2=22.6) compared with patients with uropathies but no radiographic lesions. Multivariate analysis revealed that the DD genotype is a risk factor for parenchymal destruction, which was independent of time of diagnosis, surgical intervention, or urinary tract infection. This finding was particularly relevant in patients with VUR who constituted the majority with initially normal kidneys who developed radiographic damage (22/28). Indeed, the odds ratio of developing parenchymal damage with VUR was significantly increased if the individual had the DD genotype (4.2, 95% confidence interval 1.4–13.0). In conclusion the ACE I/D gene polymorphism is a risk factor for renal parenchymal damage in patients with congenital urological abnormalities and appears particularly relevant in children with VUR, where it is an independent predisposing factor.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 13 (1969), S. 2689-2697 
    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: High molecular weight linear polyethylene has been irradiated in the solid state by high energy electrons. The irradiated samples were characterized by differential scanning calorimetry, solubility properties, and stress-strain measurements. A failure mechanism is proposed for the observed embrittlement of the polymer.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 14 (1970), S. 2707-2722 
    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: A process for encapsulating cotton fibers in the form of woven clothes at ambient temperatures with polyoxymethylene is described. It involves pretreatment of the cotton with a carbon tetrachloride solution of tributylamine and diphenylamine to deposit the basic catalyst on the surface of the fibers. Subsequent exposure to dry, purified vapors of monomeric formaldehyde at 25°C results in the encapsulation of individual fibers with high molecular weight polyoxymethylene. The process is relatively fast (30% fiber weight gain in approx. 20 min) with the polymer located only at the fiber surfaces. Fiber cementation does not become pronounced for weight increases below approximately 60%-65% based upon the weight of the fibers. Thickness of the polymer sheath increases with the time of the polymerization reaction. Because of the uniformity of the polymer layer deposition, the encapsulated cotton cellulose fibers can be expected to exhibit substantially different physical and chemical surface properties even at low polymer add-on. The tensile and tear strengths of the polyoxymethylene-encapsulated cotton fibers are generally improved, with some gains in abrasion resistance also noted. Differential staining techniques and polarized light microscopy have shown the location and uniformity of the polymer sheaths.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 4 (1970), S. 107-119 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Composite hydrophilic materials (CHM) containing collagen or cellulose as the insoluble fibrous component and potassium salts of proteinpolysaccharide or carboxymethylcellulose as the soluble polyelectrolyte were prepared as simple models of the connective tissue, cartilage. The tensile properties of uncrosslinked and formaldehyde-crosslinked collagenous CHM were measured and compared to those of bovine nasal cartilage (BNC). The compressive properties of uncrosslinked and formaldehyde-crosslinked cellulosic CHM were measured and compared to bovine nasal cartilage. Although elongating to approximately the same extent before breaking (20%), the uncrosslinked collagenous CHM had lower tensile strengths than BNC (330 psi). Formaldehyde crosslinking increased the tensile strength of the collagenous CHM to as much as 3 times that of BNC but reduced the elongation at failure to only 7%. The uncrosslinked cellulosic CHM attained a maximum of only ¼ the compressive strength of BNC (940 psi). Formaldehyde crosslinking extended the compressive strength to as high as ⅓ that of BNC. The results indicate that the simple uncrosslinked and crosslinked models can only partially account for the mechanical properties of BNC.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
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