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  • 1
    Electronic Resource
    Electronic Resource
    Dysplasia and cancer complicating strictures in ulcerative colitis (1990)
    Springer
    Digestive diseases and sciences 35 (1990), S. 349-352 
    Details
    ISSN: 1573-2568
    Keywords: ulcerative colitis ; strictures ; dysplasia ; cancer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Previous studies have found a widely variable prevalence of dysplasia and cancer in colonic strictures in patients with ulcerative colitis. Consequently, therapeutic recommendations are conflicting. To better assess the prevalence, we reviewed the clinical and pathological findings in all 27 patients with ulcerative colitis complicated by stricture who were entered into our Inflammatory Bowel Disease Registry. A true stricture was defined as a persistant localized narrowing of the colon found on air-contrast barium enema or on colonoscopy. Upon careful review, 12 of 27 patients were found to have transient colonic spasm, not a stricture, and were excluded. The remaining 15 patients with true strictures represented 3.2% of all ulcerative colitis patients in the registry. Strictures were identified at 13.3± 9.9 years following the diagnosis of ulcerative colitis. Eleven patients had multiple strictures that were principally located in the left colon. Of the 15 patients, 11 had dysplasia and two had cancer found on colonoscopic biopsy. Ultimately, six patients had carcinoma found at colonoscopy or colectomy (three modified Dukes' stage A, one stage B, and two stage D). All cancers were at the site of a stricture. These findings indicate that a true colonic stricture in ulcerative colitis is frequently associated with dysplasia and cancer, which can be diagnosed with colonoscopic biopsy. A stricture should be considered a strong risk factor for cancer, requiring intensive colonscopic surveillance. If dysplasia is discovered, or if the stricture cannot be adequately biopsied, consideration should be given to total colectomy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01537413
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  • 2
    Electronic Resource
    Electronic Resource
    Food group intake and the risk of oral epithelial dysplasia in a United States population (2000)
    Springer
    Cancer causes & control 11 (2000), S. 713-720 
    Details
    ISSN: 1573-7225
    Keywords: diet ; dysplasia ; mouth neoplasms ; precancerous conditions ; risk factors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Objectives: Oral epithelial dysplasia (OED) is a histopathologic diagnosis associated with an increased risk of oral cancer. The paper explores the relationship between OED risk and food group intake. Methods: In this case–control study, incident cases of OED were identified through two oral pathology laboratories. Controls, pair-matched 1:1 to cases on age ( ± 5 years), gender, appointment date ( ± 1 year), and surgeon, were identified through the office in which the respective case was biopsied. Exposure data were obtained via a telephone interview and mailed food-frequency questionnaire. cConditional logistic regression was used to obtain odds ratio point estimates. Results: Based upon 87 matched pairs – and after controlling for smoking, drinking, and other potential covariates–there was an apparent inverse relationship between OED risk and the consumption of fruits and vegetables, with the intake of these foods being associated with a strong attenuating effect among smokers. OED risk decreased with increased poultry consumption, but increased modestly with bread/cereal and dairy food intake. Conclusions: This investigation provides evidence that some aspects of diet may be associated with the risk of OED. It also suggests that in oral carcinogenesis the role of diet is not simply one of a late effect.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008943904085
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  • 3
    Electronic Resource
    Electronic Resource
    Structure of native proteoglycan aggregates from chick limb-bud chondrocytes (1986)
    New York : Wiley-Blackwell
    Biopolymers 25 (1986), S. 931-946 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Laser light-scattering has been used to investigate the size of native proteoglycan aggregates (PGA-aA1) from day-8 chick limb-bud chondrocyte cultures isolated under associative extraction and purification conditions in 0.4M guanidinium chloride (GdnHCl) solution. Dynamic light-scattering measurements yielded a hydrodynamic radius, Rs, of 244 ± 10 nm for PGA-aA1 in 0.4M GdnHCl, and a weight-average molecular weight (Mw) of 150 ± 50 × 106 was obtained from a Zimm plot. Disaggregation in 4.0M GdnHCl aqueous solution yielded proteoglycan subunits (PGS) with Rs = 39 ± 2 nm, Mw = 1.6 ± 0.3 × 106, which reassembled in 0.4M GdnHCl to form “reconstituted native” aggregates (PGA-raA1) with Rs = 121 ± 6 nm, Mw = 17 ± 3 × 106. A second specimen of PGA-aA1 had Rs = 192 ± 10 nm, Mw = 100 ± 10 × 106. The latter value was estimated from an empirical relationship between Mw and Rs. After dissociation, this specimen reassembled to form PGA-raA1 with Rs = 85 ± 5 nm, Mw = 12 ± 1 × 106. These data are compared with those for a specimen of reconstituted aggregate (PGA-A1) that had been extracted under dissociative conditions and then reaggregated by dialysis to 0.4M GdnHCl aqueous solution, for which Rs = 138 ± 9 nm, Mw = 45 ± 8 × 106. From these values, we have calculated the weight-average number of subunits per aggregate Nw: 111 for PGA-aA1 and 12 for raA1 (70 and 7 for the second PGA-aA1 and PGA-raA1 specimen, respectively) as compared to 32 for PGA-A1. The numbers of subunits per aggregate were also determined from electron micrographs of spread specimens. The latter results show the same trends as those obtained by light scattering, but lead in each case to lower numbers of subunits per aggregate. These data demonstrate conclusively that PGA samples exhibit a higher degree of aggregation in solution than visualized in typical electron microscopy (EM) preparations, probably due to disaggregation during EM specimen preparation. Since Nw determined both by light scattering (LS) and by EM are larger for native versus reconstituted aggregate samples, our data point to a more compact aggregation of subunits along the hyaluronic acid (HA) chains in the former.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360250512
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  • 4
    Electronic Resource
    Electronic Resource
    Optical Resolution of [2,2]Paracyclophanes by High-Performance Liquid Chromatography on Tris(3,5-dimethylphenylcarbamates) of Celllulos and Amylose (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 841-845 
    Details
    ISSN: 0009-2940
    Keywords: Resolution, optical / Stationary phase, Chiral / Anylose carbamates / Celluslose carbamates / [3.2]Paracyclophanes, functionalized ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Optical resolution of 22 [2,2]paracyclophane derivatives was examined by high-performance liquid chromatography (HPLC) using tris(3,5-dimethylphenylcarbamates) of cellulose and amylose as chiral stationary phases. Most compounds were completely separated into enantiomers at least on one of the stationary phases. The preparation of hte new cyclophane derivatives 10, 11, 12, 14, 16, and 19 as wel as a new procedure for the synthesis of 4-fluoro-[2,2]paracyclophane (3) are described.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230432
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  • 5
    Electronic Resource
    Electronic Resource
    The polymerisation of ethylene with high activity magnesium reduced titanium trichloride catalysts in the absence of hydrogen (1974)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 175 (1974), S. 3461-3473 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die Polymerisation von Äthylen unter Verwendung eines mit Magnesium reduzierten Titantrichlorid-Katalysators, zusammen mit gewöhnlichen Aluminiumalkyl-Aktivatoren, wird beschrieben. Die bereits berichtete hohe Aktivität dieses Katalysatortyps wird bestätigt. Bei 50°C und 1 Atm. (1,01325 bar) Druck wird ein Wert für die Aktivitätskonstante von 3,4.106 g dm3 (mol TiCl3)-1 h-1 erhalten. Dieser Wert ist ungefähr 102 mal höher als derjenige eines auf übliche Weise mit Aluminium reduzierten Titantrichlorids. Die Viskosotäts-Molekulargewichts-Zeit (oder Umsatz)-Beziehungen sind nicht sehr verschieden von denen, die mit den üblichen Katalysatoren erhalten werden. Die Analyse der Resultate weist darauf hin, daß ein großer Teil (z. B. 50%) der Titan-Atome im Titantrichlorid, das mit Magnesium reduziert wurde, als aktive Zentren fungieren.
    Notes: The polymerisation of ethylene using magnesium reduced titanium trichloride catalysts, together with the usual aluminium alkyl activators is described. The previously reported high activity of this type of catalyst was confirmed. At 50°C and 1 atm. (1,01325 bar) pressure a value of 3,4.106 g dm3 (mol TiCl3)-1h-1 was obtained for the activity constant, a value about 102 times larger than for a conventional aluminium reduced TiCl3. On the other hand the viscosity-molecular weight-time (or conversion) relations are not very different from those given by conventional catalysts. Analysis of the results suggests that a high proportion (e.g. 50%) of the titanium atoms in the magnesium reduced TiCl3 functions as active sites.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1974.021751212
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  • 6
    Electronic Resource
    Electronic Resource
    Ring-opening metathesis polymerization of 7-methylnorbornadiene (1993)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 194 (1993), S. 2907-2922 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Ring-opened metathesis polymers of 7-methylnorbornadiene (1) have been synthesized with cis main-chain double bond contents ranging from 20 to 97% using several initiators; their microstructures have been examined in detail using 13C NMR spectroscopy. The result show that polymerization from the anti-exo orientation is greatly favoured over the syn-exo mode. A nonbonded repulsion energy of 6-8 kJ · mol-1 between the syn-7-methyl group and the double bond is estimated. The microstructural features also resemble those for polymers of the anti- and syn-7-methylnorbornenes, in contrast to poly(norbornadiene) itself and to poly(norbornene), in that the splitting of a given resonance due to tacticity effects is of the same order as splittings due to neighbouring double bonds. Cis double bond contents and tacticities using different catalysts agree well with those expected from previous work with norbornadiene and several methyl-substituted norbornenes, respectively, as monomers. The previous surprising observation that there is significantly less or no discrimination between the syn- and anti-orientations in polymerizing 7-tert-butoxy- and 7-acetoxynorbornadiene is discussed and is attributed to a pseudo [3 + 2] transition state replacing the normal one for [2 + 2] metallacyclobutanation. In the [3 + 2] mode a lone pair of electrons on the oxygen acts in conjunction with the π pairs of the C=C and [Mt]=C moieties. The net effect is to lower the energy barriers for the [2 + 2] cycloaddition and the reverse step. The same explanation, rather than chelation, is also believed to be correct for the beneficial effect on the metathesis polymerization of the 7-oxa group in several substituted 7-oxanorbornenes and 7-oxanorbornadienes when compared to the corresponding 7-methylene monomers.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1993.021941023
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  • 7
    Electronic Resource
    Electronic Resource
    Structural investigation of C4b-binding protein by molecular modeling: Localization of putative binding sites (1998)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 31 (1998), S. 391-405 
    Details
    ISSN: 0887-3585
    Keywords: complement control protein ; protein modeling ; blood coagulation ; C4b-binding protein ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: C4b-binding protein (C4BP) contributes to the regulation of the classical pathway of the complement system and plays an important role in blood coagulation. The main human C4BP isoform is composed of one β-chain and seven α-chains essentially built from three and eight complement control protein (CCP) modules, respectively, followed by a nonrepeat carboxy-terminal region involved in polymerization of the chains. C4BP is known to interact with heparin, C4b, complement factor I, serum amyloid P component, streptococcal Arp and Sir proteins, and factor VIII/VIIIa via its α-chains and with protein S through its β-chain. The principal aim of the present study was to localize regions of C4BP involved in the interaction with C4b, Arp, and heparin. For this purpose, a computer model of the 8 CCP modules of C4BP α-chain was constructed, taking into account data from previous electron microscopy (EM) studies. This structure was investigated in the context of known and/or new experimental data. Analysis of the α-chain model, together with monoclonal antibody studies and heparin binding experiments, suggests that a patch of positively charged residues, at the interface between the first and second CCP modules, plays an important role in the interaction between C4BP and C4b/Arp/Sir/heparin. Putative binding sites, secondary-structure prediction for the central core, and an overall reevaluation of the size of the C4BP molecule are also presented. An understanding of these intermolecular interactions should contribute to the rational design of potential therapeutic agents aiming at interfering specifically some of these protein-protein interactions. Proteins 31:391-405, 1998. © 1998 Wiley-Liss, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Separation of syn and anti-7-alkylnorbornene isomers by regioselective ring-opening metathesis polymerization (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 993-995 
    Details
    ISSN: 0887-624X
    Keywords: metathesis ; regioselective polymerization ; 7-alkylnorbornenes ; ab initio MO Calculations ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080320522
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  • 9
    Electronic Resource
    Electronic Resource
    Sucrose diacrylate: A unique chemically and biologically degradable crosslinker for polymeric hydrogels (1997)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 35 (1997), S. 2221-2229 
    Details
    ISSN: 0887-624X
    Keywords: biodegradation ; hydrogels ; crosslinking agent ; sucrose diacrylate ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of degradable hydrogels based on different vinyl monomers such as acrylamide, sucrose-1′-acrylate, and acrylic acid were synthesized using sucrose-6,1′-diacrylate (SDA) as a crosslinking agent. SDA was prepared by enzymatic transesterification of vinyl acrylate with sucrose in pyridine. Base catalyzed hydrolysis of SDA in aqueous solution was studied as a function of pH. As expected, hydrolysis of SDA was faster at higher pHs such that poly(acrylamide), poly(sucrose 1′-acrylate), and poly(acrylic acid) hydrogels underwent substantial degradation at and above pH 7, 9, and 13, respectively. The degradation was characterized by changes in the swelling ratios of the hydrogels indicating breakage of the crosslinking agent. Degradation of the hydrogels at their chemically stable pHs was studied in presence of enzymes. Enzymes, including pepsin and a fungal Lipase, were able to degrade the poly(acrylamide) hydrogel at pH 4 and 5, respectively. Poly(acrylic acid) hydrogel was degraded in presence of a fungal protease at pH 7.8. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 2221-2229, 1997
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Crystallization of ADP-ribosyl cyclase from Aplysia californica (1996)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 24 (1996), S. 138-140 
    Details
    ISSN: 0887-3585
    Keywords: ADP-ribosyl cyclase ; crystals ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: ADP-ribosyl cyclase synthesizes the secondary messenger cyclic ADP-ribose from NAD+. Diffraction quality crystals of the enzyme from ovotestes of Aplysia californica have been obtained. Crystallographic analysis of this enzyme will yield insight into the mode of binding of the novel cyclic nucleotide and the mechanism by which NAD+ is cyclized.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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