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  • Biochemistry and Biotechnology  (3)
  • Constipation  (1)
  • Surveillance  (1)
  • 1
    ISSN: 1530-0358
    Keywords: Ulcerative colitis ; Cancer risk ; Surveillance ; Dysplasia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Mucosal dysplasia has been used as a marker for patients with chronic ulcerative colitis considered to be most at risk of developing cancer, and its identification is the basis for colonoscopic surveillance programs. To evaluate the reliability of this premise, colectomy specimens from two groups of patients who had undergone surgery for chronic ulcerative colitis (50 with cancer and 50 without) were retrieved. The groups were matched by age, sex, duration of disease, disease extent, and symptoms at the time of surgery. Using a standard technique of multiple random biopsies, we utilized the standard colonoscopic biopsy forceps to obtain four biopsies from mucosa that was not macroscopically suspicious for dysplasia or cancer in eight defined regions in each of the 100 colon specimens. This technique mimicked exactly the methods used in our clinical surveillance program. All 3,200 biopsies were evaluated blindly by one pathologist for presence and grade of dysplasia. Twenty-six percent of colons with an established cancer harbored no dysplasia in any biopsy from any region in the colon. While an overall association between the presence of cancer and high-grade dysplasia was detected (relative risk = 900; 95 percent CI of 2.73-29.67), the sensitivity and specificity of random colonic biopsies to detect concomitant carcinoma were 0.74 and 0.74, respectively. These findings prompt concern that reliance on random biopsies, obtained during colonoscopic surveillance, may be misplaced.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1530-0358
    Keywords: Biofeedback ; Colectomy ; Pelvic floor disorders ; Constipation ; Colonic inertia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract PURPOSE: Treatment of severe constipation caused by combined colonic inertia and nonrelaxing pelvic floor is controversial. This study is designed to evaluate the outcome of preoperative biofeedback and subtotal colectomy for patients with combined colonic inertia and nonrelaxing pelvic floor. METHODS: One hundred six patients who underwent subtotal colectomy for intractable constipation from 1982 through 1995 answered a detailed questionnaire regarding postoperative bowel function, symptoms of abdominal pain and bloating, and degree of satisfaction after the operation. Sixteen of these patients had a combination of colonic inertia and nonrelaxing pelvic floor diagnosed by transit marker study, electromyography, and defecography. These patients completed preoperative biofeedback training. RESULTS: Electromyographic relaxation of pelvic floor musculature was demonstrated after the biofeedback treatment in all patients, but symptoms of difficult evacuation persisted. Postoperatively, seven patients (43 percent) had complete resolution of symptoms of constipation or difficult evacuation. Six patients still complained of incomplete evacuation that was severe in two and unresponsive to postoperative biofeedback. Three patients (18 percent) complained of diarrhea (〉5 bowel movements per day) and incontinence of liquid stools (at least one episode a week). Nine patients (56 percent) were satisfied despite persistent symptoms. CONCLUSIONS: Subtotal colectomy can improve some symptoms in patients with slow transit constipation and nonrelaxing pelvic floor. However, incomplete evacuation persists in a significant number of patients and almost one-half of patients are dissatisfied with their surgery.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Electrophoresis 4 (1983), S. 36-41 
    ISSN: 0173-0835
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: The progressive increase in circuit resistance observed at times in polyacrylamide gel electrophoresis is attributable in part to the formation of zones of altered salt concentration at the interfaces between gel and solution. Similar changes have been reported for electrophoresis through sucrose gradients. Such zones must develop wherever migrant ions suffer a change in transport number. The paper develops a basic theory for such concentration changes. It is shown that a moving boundary will tend to arise at any interface between two media, leaving behind it a zone of altered concentration. The effect will in general be most noticeable at low ionic strengths and with electrolytes whose ions differ considerably in size, a condition applying to many common buffers. Where both ions are relatively small, diffusion is likely to obscure the boundary movement, but this will not affect the integrated change in concentration. The effect could have various deleterious consequences in gel electrophoresis, particularly in preparative apparatus. There are also implications for techniques such as isoelectric focusing and for the analysis of membrane phenomena.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Electrophoresis 4 (1983), S. 41-45 
    ISSN: 0173-0835
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: The theory developed in the previous paper is extended to cover a system containing three ions. If an “inactive” electrolyte whose ions are equally affected by a retarding medium is added to a “zone-former” for which this is not the case, the main effect is to reduce the integrated concentration changes at the interfaces. Where a buffer contains two ions carrying charges of the same sign, the theory predicts a progressive change of pH within a zone of altered concentration. Other sources of pH change are also considered. Where a buffer includes an uncharged weak acid or base, changes in ionic concentration at an interface will lead to changes in pH. Other changes may arise from the migration of water ions, whose contributions are normally neglected. This is not justified where there are large discontinuities in conductivity. Expressions are derived for the changes in pH under different circumstances. In some cases no steady-state is possible and there are accelerating shifts of pH at the boundaries of a zone. This could have important consequences in practical electrophoresis.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Electrophoresis 4 (1983), S. 46-52 
    ISSN: 0173-0835
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: An assumption used in developing the basic theory, that ionic retardation factors are substantially independent of solute concentration, is tested and found valid. The results of electrophoresis through 15% polyacrylamide gels are found to be in agreement with the theory. Zones of altered concentration appear in the presence of spermine tetrahydrochloride, sodium phosphate buffer (pH 7.2) or Tris-HCl (pH 7.0). The use of ionic retardation factors and transport numbers deduced from conductivity measurements leads to correct prediction of the sign of concentration change in each case. The direction and velocity of migration of a low-concentration boundary can also be predicted, together with associated changes in pH. Further confirmation comes from a detailed analysis of published work on electrophoresis through sucrose gradients. The theoretical treatment is suitable for application to other systems (such as isoelectric focusing and isotachophoresis) where a gel is used as a stabilizing medium, and where effects of the kind discussed may produce unexpected distubances.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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