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Biomedical subjects

D C Allen

Publications and source records attributed to D C Allen.

53 records · Page 3Linked to original sources
PubMed1986

Misplaced epithelium in ulcerative colitis and Crohn's disease of the colon and its relationship to malignant mucosal changes.

The presence of misplaced mucosal epithelium was studied in the colectomy specimens from 30 patients with Crohn's disease, 30 patients with ulcerative colitis, 15 patients with ulcerative colitis complicated by carcinoma and 30 patients with non-colitic colorectal carcinoma. Misplaced epithelium was present in 21 (70%) of the resection specimens with Crohn's disease, 20 (66.7%) with ulcerative colitis and 12 (80%) with ulcerative colitis complicated by carcinoma. None of the specimens with non-colitic colorectal adenocarcinoma showed misplaced foci of epithelium. Two pathogenetic mechanisms for epithelial misplacement are proposed: (1) the effects of mucosal inflammation and repair; and (2) muscular abnormalities in inflammatory bowel disease. The proposed mechanisms and patterns of epithelial misplacement are discussed and illustrated. The importance of its recognition is emphasized because, when associated with mucosal dysplasia, difficulties in interpretation arise in distinguishing it from 'early' invasive adenocarcinoma. Epithelial misplacement is common in patients with longstanding ulcerative colitis and may be a factor in increasing the significance of pre-existing mucosal dysplasia and promoting the development of adenocarcinoma. This may explain the unusual growth pattern encountered in ulcerative colitis, of submucosal cancer underlying a flat, non-dysplastic mucosa.

Adenocarcinoma↗
PubMed1985

Comparison of epsilon aminocaproic acid and normal saline for postoperative bladder irrigation following transurethral resection of prostate.

A prospective, randomized, double-blind trial of bladder irrigation with a 0.5% solution of epsilon aminocaproic acid (EACA) versus normal saline plus placebo was undertaken in 75 patients undergoing transurethral resection of the prostate for benign or malignant disease. Systemic absorption after irrigation with EACA was not detectable. No significant advantage, however, was demonstrated for the EACA solution over normal saline irrigation in measured postoperative blood loss, irrigant volume, hours of catheterization, or length of hospital stay.

Aminocaproates↗
PubMed1985

An immunoperoxidase study of epithelial marker antigens in ulcerative colitis with dysplasia and carcinoma.

An immunoperoxidase technique was applied to formalin and Helly fixed paraffin wax sections from cases of ulcerative colitis complicated by dysplasia and carcinoma for carcinoembryonic antigen and components of the colonic secretory immunoglobulin system--namely, secretory component, IgA, and J chain. Sections from both resection specimens and mucosal biopsies were available. Intensity of immunostaining was assessed qualitatively. There was appreciable variation in expression of carcinoembryonic antigen and secretory component antigens. Carcinoembryonic antigen stained heavily in dysplasia and carcinoma while these tissues showed only focal light staining for secretory component. Normal tissue stained heavily for secretory component. The variation in staining intensity for both carcinoembryonic antigen and secretory component in inflamed and regenerative mucosa precluded their use as a reliable diagnostic aid in discriminating these tissues from true dysplasia. Loss of secretory component production or transport or both may be incurred during malignant change, but it should not be assessed as an isolated index of epithelial maturity. The relation with mucosal plasma cells warrants further study to determine more fully the factors affecting tissue secretory component expression.

Adenocarcinoma↗
PubMed1985

Large bowel mucosal dysplasia and carcinoma in ulcerative colitis.

The clinicopathological details of eight cases of ulcerative colitis complicated by carcinoma of the colon are described. There was a total of 14 primary colonic cancers, six of which were not detected before pathological examination of the resection specimens. The reason for this may be related to atypical tumour growth patterns. Three occurred in flat mucosa, one in a mucosal plaque lesion, and another in polypoidal mucosa. The occurrence, distribution, and morphology of mucosal dysplasia were noted in both resection specimens and biopsies taken at varying stages before resection. Tumour was associated with normal and adjacent dysplastic mucosa of varying grades. The extent and grade of dysplasia were not reliable indicators of tumour differentiation or subsequent clinical outcome. Only two cancers were poorly differentiated. In five cases a total of 23 mucosal biopsies were taken, all less than 12 months before resection. Three rectal biopsies were graded positive for dysplasia and three colonic biopsies indefinite for dysplasia. The subsequent resection specimens showed both dysplastic and carcinomatous changes. Three rectal and 14 colonic biopsies were graded negative for dysplasia despite positive findings in the subsequent resection specimens. This anomaly is partly attributed to the patchy nature of dysplasia in colitic mucosa. Two cases illustrate the possibility of dysplasia pursuing a rapidly progressive course. The mucosal changes of ulcerative colitis were assessed using a recently introduced and standardised international classification.

Adolescent↗
PubMed1985

Presumptive diagnosis of subclinical infections utilizing computer-assisted analysis of sequential enzyme-linked immunosorbent assays against multiple antigens.

One-hundred-seventy-two serum samples, collected sequentially from four flocks of egg- and meat-type chickens, were evaluated for antibodies to multiple infectious agents by enzyme-linked immunosorbent assay (MELISA). The MELISA system used provided simultaneous measurement of antibody titers against avian infectious bronchitis (IB), infectious bursal disease (BD), Newcastle disease, avian encephalomyelitis and reovirus infections, and Mycoplasma gallisepticum. The use of computer-generated graphic print outs of relative MELISA titers provided immediate visulization of over 740 data points and convenient detection of any temporal changes in median titer class (MTC). The temporally changing MTC, or flock profiles obtained, indicated that negligible or waning IB immunity may be a common occurrence in previously vaccinated commercial chickens. These profiles further suggested that, despite no IB revaccination, these same flocks experienced episodes of reexposure to IB which otherwise may have been difficult to detect by conventional clinical or diagnostic laboratory protocols. MELISA profiles and sequential histologic examinations of bursas of Fabricius also provided evidence of a possible BD vaccination problem in young chickens that also experienced excessive losses from coccidiosis, ulcerative enteritis, and Marek's disease. Short sampling intervals were found to foster the detection and definition of fluctuations in MTC which otherwise may have been missed.

Animals↗
PubMed1984

The efficacy of patient-controlled analgesia in patients recovering from flank incisions.

We report on 13 patients undergoing flank incisions in whom the postoperative pain was managed with a patient-controlled analgesia device. An initial group of 7 patients was used to determine the optimal injection dose for each patient and to examine variability in narcotic requirement during the postoperative course. A progressive decrease in narcotic need was noted during the postoperative course with patient-controlled analgesia, resulting in excellent patient acceptance, no postoperative complications and no drug-seeking behavior. A second group of 10 patients was randomized prospectively to receive either patient-controlled analgesia or a standard regimen of intramuscular morphine sulfate. Based on nursing observations, an analgesia and sedation scale was developed that compared the 2 groups. Analysis of a questionnaire evaluating subjective perception of postoperative pain revealed significantly less pain, less sedation and greater activity among patients randomized to patient-controlled analgesia (95 per cent confidence limit).

Adolescent↗
PubMed1984

Pathology of the heart and the cardiac conduction system in Wegener's granulomatosis.

Two cases of Wegener's granulomatosis occurred in two women aged 53 and 67 years. The clinical course in both was of rapid deterioration resulting from renal failure and leading to death. At necropsy both cases showed severe and disseminated necrotising granulomatosis in the lungs, kidneys, and spleen but with variable degrees of cardiac and systemic vasculitis. One patient, with appreciable cardiac damage, developed a P wave abnormality due to atrial disease. In patients with Wegener's granulomatosis damage to the heart should be suspected and signs of conduction system abnormalities looked for on the electrocardiogram.

Aged↗
PubMed1983

Granulomatous disease in the vermiform appendix.

In a twenty-year period 19 appendicectomy specimens were diagnosed as primary Crohn's disease. This represents 4.9% of the total number of both resection specimens and mucosal biopsies diagnosed as Crohn's disease during that time. This is a review of the main histopathological features found in these appendices and their subsequent clinical outcome. The predominant feature is transmural inflammation characterised by fibrosis and giant cell epithelioid granulomata. An accompanying spectrum of acute inflammatory changes is also seen. One patient progressed to more widespread ileal and caecal disease 17 months later. One patient developed perianal fistulae and chronic non-specific proctitis 24 months later. This represents a proven recurrence of one case in a study population of 19. The conclusion is that primary Crohn's disease of the appendix is usually an isolated phenomenon but rarely it may forewarn of more widespread bowel disease in the future. A discussion regarding the differential diagnosis of granulomatous appendiceal lesions is included.

Adolescent↗
PubMed1982

An evaluation of the monocular estimate method of dynamic retinoscopy.

Monocular Estimate Method (MEM) dynamic retinoscopy is an objective clinical method for determining the accommodative response to a fixed accommodative stimulus. Although MEM has been used in many clinical investigations, it has never been compared with the measurement of accommodative response by the haploscope. This report compares the accommodative responses obtained by MEM and by a haploscopic instrument, the phoroaccommodometer. Linear regression analysis indicates that MEM consistently provides a close approximation to the phoroaccommodometer finding (r = 0.975, p less than 0.001). A conversion table has been generated so MEM findings may be adjusted to correspond with the phoroaccommodometer at higher stimulus values.

Accommodation, Ocular↗
PubMed1981

Goldmann applanation tonometry without fluorescein.

Recently, there have been several suggestions that Goldmann applanation tonometry can be performed without fluorescein. In order to determine the clinical efficacy of performing Goldmann applanation tonometry without fluorescein, 100 consecutive patients had applanation tonometry performed without fluorescein (Ophthetic only) and with fluorescein (Fluress), according to a predetermined randomization schedule. It was found that the average difference between readings with fluorescein and without fluorescein was 7.01 mm Hg. Tonometry readings without fluorescein were lower than readings with fluorescein. In addition, regression analysis indicated that the differences between the readings with and without fluorescein increased as intraocular pressure increased. By not utilizing fluorescein in Goldmann applanation tonometry, the clinician will record lower readings. In addition, greater errors in measurement occur with increasing intraocular pressures. Because eyes with higher intraocular pressures are at a greater risk to develop glaucomatous optic atrophy and loss of visual field, the merits of Goldmann applanation tonometry without fluorescein are speculative.

Fluoresceins↗
PubMed1976

Statistical and methodological considerations for vision screening.

The statistical measures and definitions currently in use for screening programs are discussed. Sensitivity, specificity, false negative, and false positive rates are defined and illustrated. The positive and negative predictive values and the over- and underrefferal rates are also discussed, and an example of these measures is provided. The relationship of rates to prevalence and expected screening results is shown. A method for calculating the standard error of sensitivity and specificity is also given.

Color Vision Defects↗
PubMed1975

National health and optometry--a survey of public attitudes.

A stratified probability sample of the Houston, Texas population was interviewed to assess public opinion of national health care and public awareness of vision care and its role in a national health care system. Over 80% of the population surveyed are in favor of a national health care bill, with a large percentage of the population favoring inclusion of vision care. Demographic trends are reported as they relate to various questions in the survey, and comparisons are made to a similar questionnaire one year earlier.

Attitude to Health↗
PubMedDate not supplied

Rapid serological profiling by enzyme-linked immunosorbent assay. IV. Association of infectious bursal disease serology with broiler flock performance.

Breeder and broiler flocks were serologically evaluated using a multiple enzyme-linked immunosorbent assay (M-ELISA). The serologic status of two commercial broiler-breeder flocks and their progeny was monitored, and 840 sera were promptly assessed for antibodies against six infectious agents using the M-ELISA. Breeder flocks were sampled at lay, and broiler chicks were hatched from fertile eggs collected on the scheduled lay date of the breeders. The broiler chicks were placed for growout as eight separate flocks (four from each breeder), and the serologic survey of broilers included sequentially sampling each flock five times between 1 day of age and market. Association of broiler vaccination schedules, mortality, and condemnation data with the temporal serologic data obtained indicated that the earlier appearance of active antibody against infectious bursal disease (IBD) in some unvaccinated flocks was associated with subsequent higher growout mortality and with the poorer overall performance that these flocks experienced. The results of this serologic survey also demonstrated that if a constant, well-timed monitoring program had not been used, major serologic differences between flocks would not have been detected. Serologic profiles of selected broiler flocks by virus-neutralization (VN) tests for infectious bronchitis virus (IBV) and reovirus or by hemagglutination-inhibition (HI) tests for Newcastle disease virus (NDV) compared favorably with the serologic profiles obtained by M-ELISA. Comparison of vaccination histories with serologic results derived from M-ELISA, VN or HI tests indicated that response to vaccination for IBV and NDV at 1 day was either blocked or significantly delayed by moderate levels of maternal antibody and/or were suppressed by an apparent field outbreak of IBD that occurred in all eight broiler flocks.

Animals↗
PubMedDate not supplied

Rapid serological profiling by enzyme-linked immunosorbent assay. III. Simultaneous measurements of antibody titers to infectious bronchitis, infectious bursal disease, and Newcastle disease viruses in a single serum dilution.

The present paper describes a method for measuring enzyme-linked immunosorbent assay (ELISA) antibody titers to infectious bronchitis (IB), infectious bursal disease (IBD), and Newcastle disease (ND) viruses from a single serum dilution using the same assay procedures and analyses. A regression line equation generated for predicting NDV ELISA antibody titers at a single serum dilution was successfully used to predict ELISA antibody titers to IB and IBD antigen preparations at the same test sera dilutions. Duplicate samples of 46 field and control sera were transferred simultaneously, with the aid of a replica plating device, from a reservoir plate to three different test plates, which were coated separately with IB, IBD, and ND antigens. After similar indirect ELISA parameters were conducted for each antigen, raw absorbance values from duplicate tests and controls were transmitted directly from an ELISA reader to a microcomputer, which subsequently processed average corrected absorbance values directly into individual ELISA antibody titer for each test antigen. The computer output listed individual field and control sample titers to each antigen, as well as graphing the relative ELISA titer distribution of the entire test group to each antigen. In a comparative study, test sera were evaluated for ELISA antibody titer to NDV, IBV, and IBDV by this method in three separate assays. Consistent titer values were obtained in all assays, as 96% of the 414 replicate titers evaluated varied less than twofold.

Animals↗