83 results on '"Dunn, B. E."'
Search Results
2. COST MINIMIZATION ANALYSIS OF A TELEMEDICINE SERVICE
- Author
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Agha, Z, Weinstein, R S, and Dunn, B E
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- 1998
3. Synthesis and activity of Helicobacter pylori urease and catalase at low pH
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Bauerfeind, P, Garner, R, Dunn, B E, and Mobley, H L T
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- 1997
4. Review Contemporary Theory in Research in Visual Perception
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Dunn, B. E.
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- 1969
5. Review of Eye Movements and Vision
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Dunn, B. E.
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- 1969
6. Review of Foundations of Experimental Research
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Dunn, B. E.
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- 1969
7. Review of The Experimental Psychology of Sensory Behaviour
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Dunn, B. E.
- Published
- 1969
8. Some geometric bases for perceived slant
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Dunn, B. E.
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- 1966
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9. Perceived slant as a function of direction of regard
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Dunn, B. E.
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- 1966
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10. Protein changes occurring during storage of platelet concentrates.
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Snyder, E. L., Dunn, B. E., Giometti, C. S., Napychank, P. A., Tandon, N. N., Ferri, P. M., and Hofmann, J. P.
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- 1987
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11. Cardiovascular response patterns and speech: a study of air traffic controllers.
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Henderson, P R, Bakal, D A, and Dunn, B E
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- 1990
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12. The amnesic and therapeutic effects of bilateral and unilateral ECT.
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Costello, C. G., Belton, G. P., Abra, J. C., and Dunn, B. E.
- Subjects
ELECTROCONVULSIVE therapy ,THERAPEUTICS ,MEMORY ,HOSPITAL wards - Abstract
The article investigates the amnesic and therapeutic effects of unilateral non-dominant, unilateral dominant, and bilateral electroconvulsive therapy (ECT) to verbal memory of patients in Alberta. To determine the effects, 30 in-patients receiving ECT of the Psychiatric Ward at the Foothills Hospital were used as subjects of the study. Some of the apparatuses used in the study are Lafayette Model 2303C memory drum, Marietta Model 15-10 memory drum, and electroshock device. The study revealed that the dominant hemisphere is more closely associated with recall and relearning verbal memory functioning. Furthermore, it showed the different effect between unilateral dominant and unilateral non-dominant ECT in recall.
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- 1970
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13. Two Fatal Cases of Adenovirus-Related Illness in Previously Healthy Young Adults--Illinois, 2000.
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Ryan, M. A. K., Gray, G. C., Malasig, M. D., Binn, L. N., Asher, L. V., Cute, D., Kehl, S. C., Dunn, B. E., and Yund, A. J.
- Subjects
ADENOVIRUS diseases ,VIRAL vaccines ,VACCINES ,YOUNG adults ,DEATH - Abstract
Reports on two fatal cases related to adenovirus infection in two young adults at a military training base in Illinois. Background on adenoviruses; History of adenoviral vaccines given to young adults in military training; Details of the cases; Conclusions.
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- 2001
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14. Acute effects of prostaglandin E1 and E2 on vascular reactivity and blood flow in situ in the chick chorioallantoic membrane.
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Harland DR, Lorenz LD, Fay K, Dunn BE, Gruenloh SK, Narayanan J, Jacobs ER, and Medhora M
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- 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid pharmacology, Alprostadil antagonists & inhibitors, Animals, Biphenyl Compounds pharmacology, Blood Vessels drug effects, Blood Vessels physiology, Bridged Bicyclo Compounds, Heterocyclic, Chick Embryo, Chorioallantoic Membrane blood supply, Chorioallantoic Membrane metabolism, Dibenz(b,f)(1,4)oxazepine-10(11H)-carboxylic acid, 8-chloro-, 2-acetylhydrazide pharmacology, Dinoprostone antagonists & inhibitors, Dose-Response Relationship, Drug, Estradiol pharmacology, Estrogens pharmacology, Fatty Acids, Unsaturated, Hydrazines pharmacology, Microsomes drug effects, Microsomes metabolism, Misoprostol pharmacology, Prostaglandin Antagonists pharmacology, Rats, Receptors, Prostaglandin agonists, Receptors, Prostaglandin antagonists & inhibitors, Receptors, Prostaglandin metabolism, Receptors, Thromboxane agonists, Receptors, Thromboxane antagonists & inhibitors, Receptors, Thromboxane metabolism, Vasoconstriction drug effects, Vasoconstrictor Agents antagonists & inhibitors, Xanthones pharmacology, alpha-Linolenic Acid pharmacology, Alprostadil pharmacology, Chorioallantoic Membrane drug effects, Dinoprostone pharmacology, Vasoconstrictor Agents pharmacology
- Abstract
The chick chorioallantoic membrane (CAM) subserves gas exchange in the developing embryo and shell-less culture affords a unique opportunity for direct observations over time of individual blood vessels to pharmacologic interventions. We tested a number of lipids including prostaglandins PGE(1&2) for vascular effects and signaling in the CAM. Application of PGE(1&2) induced a decrease in the diameter of large blood vessels and a concentration-dependent, localized, reversible loss of blood flow through small vessels. The loss of flow was also mimicked by misoprostol, an agonist for 3 of 4 known PGE receptors, EP(2-4), and by U46619, a thromboxane mimetic. Selective receptor antagonists for EP(3) and thromboxane each partially blocked the response. This is a first report of the effects of prostaglandins on vasoreactivity in the CAM. Our model allows the unique ability to examine simultaneous responses of large and small vessels in real time and in vivo., (Copyright © 2012. Published by Elsevier Ltd.)
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- 2012
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15. Telepathology overview: from concept to implementation.
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Weinstein RS, Descour MR, Liang C, Bhattacharyya AK, Graham AR, Davis JR, Scott KM, Richter L, Krupinski EA, Szymus J, Kayser K, and Dunn BE
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- Diffusion of Innovation, Humans, Models, Theoretical, Remote Consultation methods, Telepathology methods, Remote Consultation organization & administration, Telepathology organization & administration
- Abstract
Telepathology is the practice of pathology at a distance by using video imaging and telecommunications. Significant progress has been made in telepathology. To date, 12 classes of telepathology systems have been engineered. Rapid and ultrarapid virtual slide processors may further expand the range of telepathology applications. Next-generation digital imaging light microscopes, such as miniaturized microscope arrays (MMA), may make virtual slide processing a routine laboratory tool. Diagnostic accuracy of telepathology is comparable with that of conventional light microscopy for most diagnoses. Current telepathology applications include intraoperative frozen sections services, routine surgical pathology services, second opinions, and subspecialty consultations. Three telepathology practice models are discussed: the subspecialty practice (SSP) model; the case triage practice (CTP) model; and the virtual group practice (VGP) model. Human factors influence performance with telepathology. Experience with 500 telepathology cases from multiple organs significantly reduces the video viewing time per case (P < .01). Many technology innovations can be represented as S-curves. After long incubation periods, technology use and/or efficiency may accelerate. Telepathology appears to be following an S-curve for a technical innovation., (Copyright 2001 by W.B. Saunders Company)
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- 2001
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16. Combined robotic and nonrobotic telepathology as an integral service component of a geographically dispersed laboratory network.
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Dunn BE, Choi H, Almagro UA, and Recla DL
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- Hospitals, Veterans organization & administration, Humans, Telepathology instrumentation, Telepathology methods, United States, United States Department of Veterans Affairs, Computer Communication Networks organization & administration, Remote Consultation, Robotics, Telepathology organization & administration
- Abstract
To achieve real-time connectivity between its 8 hopital-based laboratories, Veterans Integrated Service Network (VISN) 12, headquartered in Chicago, IL, has implemented a hybrid dynamic store-and-forward (HDSF) telepathology network that extends across portions of 3 states. The majority of diagnostic telepathology functions are provided to the 3 hospitals (Iron Mountain, MI; Tomah, WI; and North Chicago, IL), which lack on-site pathologists and are serviced by the 4 pathologists located in Milwaukee, WI. In surgical pathology, routine primary diagnosis, frozen section diagnosis, and clinical consultation are provided with telepathology. In addition, autopsy and specialty clinical conferences are frequently performed by using telepathology. Telepathology has been applied to a variety of areas within clinical pathology as well, including protein electrophoresis, immunoelectrophoresis, peripheral blood smears, body fluids, microbiology, and distance learning. Implementation of telepathology has allowed VISN 12 to reach the goal of providing a single standard of accurate and timely pathology service, even at small sites that lack an on-site pathologist., (Copyright 2001 by W.B. Saunders Company)
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- 2001
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17. Telepathology networking in VISN-12 of the Veterans Health Administration.
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Dunn BE, Choi H, Almagro UA, Recla DL, and Davis CW
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- Humans, Illinois, United States, United States Department of Veterans Affairs, Wisconsin, Computer Communication Networks organization & administration, Hospitals, Veterans organization & administration, Telepathology organization & administration
- Abstract
The Veterans Integrated Service Network (VISN)-12, headquartered in Chicago, has implemented a telepathology network between the eight VISN-12 hospital laboratories and Loyola University Medical School linked by an economical, high-speed wide-area network (WAN). Implementation of the WAN has reduced monthly telecommunications costs in VISN-12 by approximately 67%. In addition to telepathology, the WAN enables real-time teleradiology (general, computer tomography, and ultrasound), telefluoroscopy, telenuclear medicine imaging, telepsychiatry, and other forms of teleconsultation. Current applications of telepathology in VISN-12 include: primary diagnosis and consultation in surgical pathology, interpretation of serum protein electrophoresis and immunofixation gels, provision of support for consolidated microbiology laboratories, review of problematic peripheral blood smears, and distance learning. We have learned a variety of lessons from telepathology. The enthusiasm and technical skill of providers are essential for success. As well, frequent communication and rapid technical support are necessary. Finally, in a supportive environment, telepathology is a tool that can help bring together clinical laboratories with shared missions and goals.
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- 2000
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18. Routine surgical telepathology in the Department of Veterans Affairs: experience-related improvements in pathologist performance in 2200 cases.
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Dunn BE, Choi H, Almagro UA, Recla DL, Krupinski EA, and Weinstein RS
- Subjects
- Clinical Competence, Gastrointestinal Diseases pathology, Hospitals, Veterans standards, Humans, Male, Pathology Department, Hospital standards, Prostatic Diseases pathology, Reproducibility of Results, Skin Diseases pathology, Telepathology organization & administration, Time and Motion Studies, United States, Wisconsin, Hospitals, Veterans statistics & numerical data, Pathology Department, Hospital statistics & numerical data, Telepathology statistics & numerical data
- Abstract
Objective: To determine whether diagnostic concordance, case deferral rate, and/or time required to review slides changed significantly as telepathologists gained additional experience using a hybrid dynamic/store-and-forward (HDSF) telepathology (TP) system on the 2000 cases following an initial 200 consecutive surgical cases, previously reported., Materials and Methods: Gross surgical pathology specimens were prepared by specially trained personnel in Iron Mountain, Michigan. For TP, glass slides were placed on the stage of a robotic microscope at the Iron Mountain VAMC (remote site); control of the motorized microscope was then transferred to a pathologist located 220 miles away at the Milwaukee, Wisconsin, VAMC (host site). For each case, a telepathologist had the option of either rendering a diagnosis or deferring the case for later analysis by conventional light microscopy (LM). After the slides were read by TP and a surgical pathology report had been generated (for nondeferred cases), the slides were transported to Milwaukee, where they were reexamined by the same pathologist, now using LM. When there was disagreement between the TP and LM diagnosis, a supplemental or revised report was issued, and the referring physician was notified by telephone immediately. All supplemental and revised reports were reviewed by a third pathologist in the group. The slides were then reviewed by the pathology group practice or, when there was no consensus, by the Armed Forces Institute of Pathology to establish a "truth" diagnosis. To determine changes in telepathologist performance with experience after the initial start-up of the service, their performance in handling 10 consecutive sets of 200 surgical pathology cases was analyzed., Results: Concordance rates for clinically significant TP and LM diagnoses were high for all 10 sets, ranging from 99% to 100%. Comparing the first set (Cases 201-400) with the last set (Cases 2001-2200), viewing times per case were reduced from 10.26 min to 3. 58 min. Viewing times per slide were reduced from 3.44 min to 1.13 min per slide, comparing the first and last sets. Case turnaround times (TAT) decreased from 2.46 days to < or =1.5 days., Conclusion: Thes results demonstrate that improvements in TP services occur over time as the result of additional experience using the TP system. The high diagnostic concordance and low rate of case deferral lend additional support to the proposal that a host-site pathologist using HDSF TP can substitute effectively for an on-site pathologist as a service provider.
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- 1999
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19. Cost minimization analysis of telepathology.
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Agha Z, Weinstein RS, and Dunn BE
- Subjects
- Costs and Cost Analysis, Equipment and Supplies economics, Humans, Medical Staff economics, Telepathology economics
- Abstract
Telepathology is gaining acceptance as a mode of providing pathology services to remote sites, but its economic feasibility is unknown. A dynamic robotic telepathology service between the Veterans Affairs Medical Center, Iron Mountain, MI, and the Veterans Affairs Medical Center, Milwaukee, WI, provides diagnostic services for routine and frozen section surgical pathology cases at Iron Mountain. We conducted a cost minimization analysis of this service by building a model to compare telepathology and on-site pathology in Iron Mountain and a courier method of transporting specimens from Iron Mountain to Milwaukee for diagnosis. Base case analysis showed the courier method to be the most economic; telepathology was less costly than on-site pathology. If the costs of telepathology equipment and telecommunication are lowered to reflect current cost, then telepathology becomes the favored option. Telepathology can be an economic mode of providing pathology services to a remote site.
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- 1999
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20. Identification of a novel penicillin-binding protein from Helicobacter pylori.
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Krishnamurthy P, Parlow MH, Schneider J, Burroughs S, Wickland C, Vakil NB, Dunn BE, and Phadnis SH
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- Amino Acid Sequence, Carrier Proteins isolation & purification, Genome, Bacterial, Helicobacter pylori chemistry, Helicobacter pylori metabolism, Isomerism, Molecular Sequence Data, Molecular Weight, Muramoylpentapeptide Carboxypeptidase isolation & purification, Penicillin-Binding Proteins, Penicillins pharmacology, Protein Binding drug effects, Bacterial Proteins, Carrier Proteins chemistry, Carrier Proteins genetics, Helicobacter pylori genetics, Hexosyltransferases, Muramoylpentapeptide Carboxypeptidase chemistry, Muramoylpentapeptide Carboxypeptidase genetics, Penicillins metabolism, Peptidyl Transferases
- Abstract
The Helicobacter pylori genome encodes four penicillin-binding proteins (PBPs). PBPs 1, 2, and 3 exhibit similarities to known PBPs. The sequence of PBP 4 is unique in that it displays a novel combination of two highly conserved PBP motifs and an absence of a third motif. Expression of PBP 4, but not PBP 1, 2, or 3, is significantly increased during mid- to late-log-phase growth.
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- 1999
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21. Unsedated transnasal EGD: an alternative approach to conventional esophagogastroduodenoscopy for documenting Helicobacter pylori eradication.
- Author
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Saeian K, Townsend WF, Rochling FA, Bardan E, Dua K, Phadnis S, Dunn BE, Darnell K, and Shaker R
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- Adult, Aged, Breath Tests, Endoscopy, Digestive System economics, Helicobacter Infections drug therapy, Helicobacter Infections pathology, Humans, Male, Middle Aged, Patient Acceptance of Health Care, Pilot Projects, Urea analysis, Urease analysis, Endoscopy, Digestive System methods, Helicobacter Infections diagnosis, Helicobacter pylori
- Abstract
Background: The aim of this study was to assess the yield of antral biopsies performed via unsedated transnasal esophagogastroduodenoscopy, a technique that does not require conscious sedation with its concomitant costs and complications, for documentation of Helicobacter pylori eradication., Methods: Nineteen patients who were previously CLO test positive on conventional esophagogastroduodenoscopy and subsequently treated for H pylori infection were enrolled. The subjects had not received antibiotic therapy in the prior month and had no prior gastric surgery. By using a GIF-N30 fiberoptic endoscope and a tiny cup biopsy forceps (1.8 mm diameter), unsedated transnasal endoscopy was performed and antral biopsy specimens were taken for a CLO test, histologic analysis (Dieterle stain), and tissue culture. On the same day, the subjects underwent a carbon 13-labeled area urea breath test. All subjects completed a visual analog scale, rating the acceptability of the unsedated transnasal examination and the previous sedated conventional esophagogastroduodenoscopy., Results: There was no statistically significant difference between the results of the CLO tests (5/19 positive) versus the 13C-urea breath test (4/19 positive) (p = 0.96), the CLO tests versus histologic findings (5/19 positive) (p = 0.71), or the 13C-urea breath test versus histologic findings (p = 0.96). All tissue culture results were negative. The overall acceptability of unsedated transnasal esophagogastroduodenoscopy was similar to that of sedated conventional esophagogastroduodenoscopy., Conclusion: Unsedated transnasal esophagogastroduodenoscopy, a technique that eliminates the costs and complications associated with conscious sedation, is a feasible and accurate alternative to conventional esophagogastroduodenoscopy when documentation of H pylori eradication and confirmation of gastric ulcer healing are both indicated.
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- 1999
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22. Telemedicine.
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Dunn BE, Schapira RM, and Frahm J
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- Humans, Michigan, Wisconsin, Telemedicine
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- 1999
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23. Helicobacter pylori containing only cytoplasmic urease is susceptible to acid.
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Krishnamurthy P, Parlow M, Zitzer JB, Vakil NB, Mobley HL, Levy M, Phadnis SH, and Dunn BE
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- Benzamides pharmacology, Cytoplasm enzymology, Drug Resistance, Microbial, Enzyme Activation drug effects, Escherichia coli enzymology, Escherichia coli genetics, Escherichia coli ultrastructure, Helicobacter pylori growth & development, Hydroxamic Acids pharmacology, Urea metabolism, Urease antagonists & inhibitors, Citric Acid pharmacology, Helicobacter pylori drug effects, Helicobacter pylori enzymology, Urease metabolism
- Abstract
Helicobacter pylori, an important etiologic agent in a variety of gastroduodenal diseases, produces large amounts of urease as an essential colonization factor. We have demonstrated previously that urease is located within the cytoplasm and on the surface of H. pylori both in vivo and in stationary-phase culture. The purpose of the present study was to assess the relative contributions of cytoplasmic and surface-localized urease to the ability of H. pylori to survive exposure to acid in the presence of urea. Toward this end, we compared the acid resistance in vitro of H. pylori cells which possessed only cytoplasmic urease to that of bacteria which possessed both cytoplasmic and surface-localized or extracellular urease. Bacteria with only cytoplasmic urease activity were generated by using freshly subcultured bacteria or by treating repeatedly subcultured H. pylori with flurofamide (1 microM), a potent, but poorly diffusible urease inhibitor. H. pylori with cytoplasmic and surface-located urease activity survived in an acid environment when 5 mM urea was present. In contrast, H. pylori with only cytoplasmic urease shows significantly reduced survival when exposed to acid in the presence of 5 mM urea. Similarly, Escherichia coli SE5000 expressing H. pylori urease and the Ni2+ transport protein NixA, which expresses cytoplasmic urease activity at levels similar to those in wild-type H. pylori, survived minimally when exposed to acid in the presence of 5 to 50 mM urea. We conclude that cytoplasmic urease activity alone is not sufficient (although cytoplasmic urease activity is likely to be necessary) to allow survival of H. pylori in acid; the activity of surface-localized urease is essential for resistance of H. pylori to acid under the assay conditions used. Therefore, the mechanism whereby urease becomes associated with the surface of H. pylori, which involves release of the enzyme from bacteria due to autolysis followed by adsorption of the enzyme to the surface of intact bacteria ("altruistic autolysis"), is essential for survival of H. pylori in an acid environment. The ability of H. pylori to survive exposure to low pH is likely to depend on a combination of both cytoplasmic and surface-associated urease activities.
- Published
- 1998
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24. Telepathology.
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Almagro UA, Dunn BE, Choi H, and Recla DL
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- Humans, Wisconsin, Telepathology organization & administration, Telepathology standards
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- 1998
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25. Structure, function and localization of Helicobacter pylori urease.
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Dunn BE and Phadnis SH
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- Cell Membrane enzymology, Heat-Shock Proteins metabolism, Helicobacter Infections microbiology, Helicobacter Infections therapy, Helicobacter pylori immunology, Humans, Subcellular Fractions, Urease chemistry, Vaccines, Bacterial Proteins, Helicobacter Infections immunology, Helicobacter pylori metabolism, Helicobacter pylori pathogenicity, Urease physiology
- Abstract
Helicobacter pylori is the causative agent of most cases of gastritis. Once acquired, H. pylori establishes chronic persistent infection; it is this long-term infection that, is a subset of patients, leads to gastric or duodenal ulcer, gastric cancer or gastric MALT lymphoma. All fresh isolates of H. pylori express significant urease activity, which is essential to survival and pathogenesis of the bacterium. A significant fraction of urease is associated with the surface of H. pylori both in vivo and in vitro. Surface-associated urease is essential for H. pylori to resist exposure to acid in the presence of urea. The mechanism whereby urease becomes associated with the surface of H. pylori is unique. This process, which we term "altruistic autolysis," involves release of urease (and other cytoplasmic proteins) by genetically programmed autolysis with subsequent adsorption of the released urease onto the surface of neighboring intact bacteria. To our knowledge, this is the first evidence of essential communal behavior in pathogenic bacteria; such behavior is crucial to understanding the pathogenesis of H. pylori.
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- 1998
26. Telemicrobiology: feasibility study.
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McLaughlin WJ, Schifman RB, Ryan KJ, Manriquez GM, Bhattacharyya AK, Dunn BE, and Weinstein RS
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- Arizona, Feasibility Studies, Female, Humans, Male, Microbiological Techniques, Microscopy, Retrospective Studies, Sensitivity and Specificity, Staining and Labeling, Bacterial Infections diagnosis, Gram-Negative Bacteria isolation & purification, Gram-Positive Bacteria isolation & purification, Remote Consultation methods
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Background: Rural hospitals generally lack staffing with infectious disease specialists or pathologists. Without on-site pathologists, the range of microbiology services offered by clinical laboratories may be limited as well., Objective: To study the feasibility of using static-image telepathology to evaluate Gram stains of microbiologic preparations., Materials and Methods: In this retrospective feasibility study, three pathologists evaluated Gram stains of slides from 50 cases by two viewing modalities: static-image telepathology and conventional light microscopy. Digital video images of slides were captured at two magnifications (using 40x and 100x objective lenses) at 1024 x 768 x 24-bit color and transmitted over standard telephone lines at 14,400 kbps. Pathology reports and culture results served as "truth diagnoses." Categories of interpretations were correct, minor discrepancy, or major discrepancy with regard to the implications for patient care., Results: The diagnostic accuracy of video image readings and conventional light microscopy readings were nearly identical, with no statistically significant differences in the performances of specialty and nonspecialty pathologists (P > 0.05). The mean accuracies of readings of the video images and light microscopy images were 95.3% and 95.4%, respectively. Taking into account the time required by a referring pathologist to capture video digital images, telemicrobiology was somewhat less efficient than conventional light microscopy., Conclusions: Pathologists can accurately evaluate digital video images of preselected fields on Gram-stained slides. In clinical practice, however, a limiting factor may be the availability of local personnel qualified to select the microscopic fields for evaluation by telepathologists. The adequacy of the video images suggests that telepathology may also be used for remote supervision of quality assurance programs in microbiology laboratories, as well as for remote proficiency training of laboratory personnel.
- Published
- 1998
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27. Helicobacter pylori.
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Dunn BE, Cohen H, and Blaser MJ
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- Anti-Bacterial Agents administration & dosage, Anti-Bacterial Agents therapeutic use, Antibodies, Bacterial analysis, Antibodies, Bacterial immunology, Bacterial Vaccines immunology, Disease Transmission, Infectious, Endoscopy, Gastric Mucosa metabolism, Gastric Mucosa microbiology, Gastritis metabolism, Gastritis microbiology, Genes, Bacterial, Genome, Bacterial, Helicobacter Infections drug therapy, Helicobacter pylori immunology, Helicobacter pylori isolation & purification, Humans, Polymerase Chain Reaction, Vaccination, Gastric Mucosa pathology, Gastritis pathology, Helicobacter Infections diagnosis, Helicobacter Infections epidemiology, Helicobacter pylori pathogenicity
- Abstract
Helicobacter pylori is a gram-negative bacterium which causes chronic gastritis and plays important roles in peptic ulcer disease, gastric carcinoma, and gastric lymphoma. H. pylori has been found in the stomachs of humans in all parts of the world. In developing countries, 70 to 90% of the population carries H. pylori. In developed countries, the prevalence of infection is lower. There appears to be no substantial reservoir of H. pylori aside from the human stomach. Transmission can occur by iatrogenic, fecal-oral, and oral-oral routes. H. pylori is able to colonize and persist in a unique biological niche within the gastric lumen. All fresh isolates of H. pylori express significant urease activity, which appears essential to the survival and pathogenesis of the bacterium. A variety of tests to diagnose H. pylori infection are now available. Histological examination of gastric tissue, culture, rapid urease testing, DNA probes, and PCR analysis, when used to test gastric tissue, all require endoscopy. In contrast, breath tests, serology, gastric juice PCR, and urinary excretion of [15N]ammonia are noninvasive tests that do not require endoscopy. In this review, we highlight advances in the detection of the presence of the organism and methods of differentiating among types of H. pylori, and we provide a background for appropriate chemotherapy of the infection.
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- 1997
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28. Genetic relatedness of Burkholderia (Pseudomonas) cepacia isolates from five cystic fibrosis centers in Michigan.
- Author
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Kumar A, Dietrich S, Schneider W, Jacobson R, Downes FP, Robinson-Dunn BE, Honicky R, Smith J, and Martin R
- Subjects
- Hospital Departments, Humans, Michigan, Restriction Mapping, Burkholderia cepacia genetics, Cross Infection microbiology, Cystic Fibrosis microbiology, DNA, Bacterial analysis
- Abstract
Burkholderia cepacia isolates from patients with cystic fibrosis (CF) attending five CF centers were studied for relatedness by cellular fatty acid methyl esters (FAME) and by chromosomal DNA restriction analysis. Twenty-eight of 32 (87.5%) isolates tested were grouped in cluster group 1 based on their FAME profiles. DNA analysis revealed that 29 of 32 (90.6%) B. cepacia isolates from five CF centers had one closely related DNA pattern. To examine strain variation over a time period, FAME profiles and DNA patterns of isolates from serial cultures on seven patients from center D were studied. For four patients, all serial B. cepacia isolates belonged to a single FAME cluster group; for the remaining three patients, all serial isolates belonged to any two of the four cluster groups. On serial culture isolates, a single DNA pattern (pattern A) was found in 31 of 32 isolates demonstrating a close genetic relatedness. These data corroborate the observations that the majority of patients colonised with B. cepacia in a CF center harbor strains genetically closely related as determined by FAME profiles and DNA patterns.
- Published
- 1997
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29. Localization of Helicobacter pylori urease and heat shock protein in human gastric biopsies.
- Author
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Dunn BE, Vakil NB, Schneider BG, Miller MM, Zitzer JB, Peutz T, and Phadnis SH
- Subjects
- Biopsy, Humans, Microscopy, Immunoelectron, Stomach microbiology, Stomach pathology, Stomach ultrastructure, Bacterial Proteins analysis, Gastric Mucosa metabolism, Heat-Shock Proteins analysis, Helicobacter pylori enzymology, Urease analysis
- Abstract
Helicobacter pylori is a spiral, gram-negative bacterium which causes chronic gastritis and plays a critical role in peptic ulcer disease, gastric carcinoma, and gastric lymphoma. H. pylori expresses significant urease activity which is an essential virulence factor. Since a significant fraction of urease activity is located on the surface of the bacterium, the urease molecule is a logical choice as an antigen for a vaccine; currently recombinant urease apoenzyme is being tested as a vaccine in phase II clinical trials. We have recently demonstrated that urease and HspB (a homolog of the GroEL heat shock protein) become associated with the surface of H. pylori in vitro in a novel manner: these cytoplasmic proteins are released by bacterial autolysis and become adsorbed to the surface of intact bacteria, reflecting the unique characteristics of the outer membrane. To determine if similar mechanisms are operative in vivo, we determined the ultrastructural locations of urease and HspB within bacteria present in human gastric biopsies. Our results demonstrate that both urease and HspB are located within the cytoplasm of all bacteria examined in human gastric biopsies. Interestingly, a significant proportion of the bacteria examined also possessed variable amounts of surface-associated urease and HspB antigen (from 5 to 50% of the total antigenic material), indicating that in vivo, H. pylori has surface characteristics which enable it to adsorb cytoplasmic proteins. This is consistent with our altruistic autolysis model in which H. pylori uses genetically programmed bacterial autolysis to release urease and other cytoplasmic proteins which are subsequently adsorbed onto the surface of neighboring viable bacteria. These observations have important implications regarding pathogenesis and development of vaccines for H. pylori.
- Published
- 1997
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30. Use of telepathology for routine surgical pathology review in a test bed in the Department of Veterans Affairs.
- Author
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Dunn BE, Almagro UA, Choi H, Recla DL, and Weinstein RS
- Subjects
- Humans, Observer Variation, Surgical Procedures, Operative, Biopsy, Remote Consultation, Telepathology
- Abstract
Background: Routine surgical pathology review by telepathology could be an important service component of multi-institutional pathology laboratory systems. Such service networks would increase access for rural hospitals without on-site pathologists to a broader range of pathology services on a daily basis., Methods: In this clinical trial, we analyzed the diagnostic accuracy, deferral rates, and viewing times of two generalist pathologists using a hybrid dynamic/store-and-forward (HDSF) telepathology (TP) system to render diagnoses in real time on 200 consecutive surgical cases. The objective was to assess the efficacy of TP in providing diagnostic surgical pathology services to a remote hospital without an onsite pathologist. Surgical pathology specimens underwent gross preparation by specially trained personnel. When appropriate, this was done under the video supervision of a telepathologist. For TP, glass slides were placed on the stage of a robotic microscope at the Iron Mountain (MI) Department of Veterans Affairs Medical Center (VAMC) (remote site); control of the motorized microscope was then transferred to a pathologist located 220 miles away at the Milwaukee VAMC (host site). For each case, the telepathologist had the option of rendering a diagnosis or deferring the case for later analysis by conventional light microscopy (LM). After the slides were read by TP and a surgical pathology report had been generated, the slides were transported to Milwaukee, where they were reexamined by the telepathologist using LM and then by the pathology group practice or, when there was no consensus, by an outside consultant to establish a "truth" diagnosis., Results: Compared with the consensus ("truth") diagnosis, clinically important and overall concordance were 99.0% and 97.4%, respectively, by TP, and clinically important and overall concordance were 100.0% and 98.5%, respectively, by LM. The deferral rate was 2.5%. Examining glass slides by HDSF telepathology took an average of 4.43 minutes per slide and 12.09 minutes per case., Conclusion: The high diagnostic accuracy and low rate of case deferral support the proposal that an offsite pathologist using HDSF telepathology can substitute effectively for an onsite pathologist as a service provider.
- Published
- 1997
- Full Text
- View/download PDF
31. Dynamic-robotic telepathology: Department of Veterans Affairs feasibility study.
- Author
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Dunn BE, Almagro UA, Choi H, Sheth NK, Arnold JS, Recla DL, Krupinski EA, Graham AR, and Weinstein RS
- Subjects
- Feasibility Studies, Humans, Reproducibility of Results, Retrospective Studies, United States, United States Department of Veterans Affairs, Robotics, Telepathology methods
- Abstract
In this retrospective study, we assess the accuracy, confidence levels, and viewing times of two generalist pathologists using both dynamic-robotic telepathology and conventional light microscopy (LM) to render diagnoses on a test set of 100 consecutive routine surgical pathology cases. The objective is to determine whether telepathology will allow a pathology group practice at a diagnostic hub to provide routine diagnostic services to a remote hospital without an on-site pathologist. For TP, glass slides were placed on the motorized stage of the robotic microscope of a telepathology system by a senior laboratory technologist in Iron Mountain, MI. Real-time control of the motorized microscope was then transferred to a pathologist in Milwaukee, WI, who viewed images of the glass slides on a video monitor. The telepathologists deferred rendering a diagnosis in 1.5% of cases. Clinically important concordance between the individual diagnoses rendered by telepathology and the "truth" diagnoses established by rereview of glass slides was 98.5%. In the telepathology mode, there were five incorrect diagnoses out of a total of 197 diagnoses. In four cases in which the telepathology diagnosis was incorrect, the pathologist's diagnosis by LM was identical to that rendered by telepathology. These represent errors of interpretation and cannot be ascribed to telepathology. The certainty of the pathologists with respect to their diagnoses was evaluated over time. Results for the first 50 cases served as baseline data. For the second 50 cases, confidence in rendering a diagnosis in the telepathology mode was essentially identical to that of making a diagnosis in the LM viewing mode. Viewing times in the telepathology mode also improved with more experience using the telepathology system. These results support the concept that an off-site pathologist using dynamic-robotic telepathology can substitute for an on-site pathologist as a service provider.
- Published
- 1997
- Full Text
- View/download PDF
32. Surface localization of Helicobacter pylori urease and a heat shock protein homolog requires bacterial autolysis.
- Author
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Phadnis SH, Parlow MH, Levy M, Ilver D, Caulkins CM, Connors JB, and Dunn BE
- Subjects
- Antigens, Bacterial analysis, Helicobacter pylori enzymology, Urease antagonists & inhibitors, Bacterial Proteins analysis, Bacteriolysis, Heat-Shock Proteins analysis, Helicobacter pylori chemistry, Urease analysis
- Abstract
Helicobacter pylori is a gram-negative bacterium which causes chronic gastritis and is associated with peptic ulcer disease, gastric carcinoma, and gastric lymphoma. The bacterium is characterized by potent urease activity, thought to be located on the outer membrane, which is essential for survival at low pH. The purpose of the present study was to investigate mechanisms whereby urease and HspB, a GroEL homolog, become surface associated in vitro. Urease, HspB, and catalase were located almost exclusively within the cytoplasm in fresh log-phase cultures assessed by cryo- immunoelectron microscopy. In contrast, significant amounts of surface-associated antigen were observed in older or subcultured preparations concomitantly with the appearance of significant amounts of extracellular antigen, amorphous debris, and membrane fragments. By use of a variety of biochemical methods, a significant fraction of urease and HspB was associated with the outer membrane in subcultured preparations of H. pylori. Taken together, these results strongly suggest that H. pylori cells undergo spontaneous autolysis during culture and that urease and HspB become surface associated only concomitant with bacterial autolysis. By comparing enzyme sensitivity to flurofamide (a potent, poorly diffusible urease inhibitor) in whole cells with that in deliberately lysed cells, we show that both extracellular and intracellular urease molecules are active enzymatically. Autolysis of H. pylori is an important phenomenon to recognize since it likely exerts significant effects on the behavior of H. pylori. Furthermore, the surface properties of H. pylori must be unique in promoting adsorption of cytoplasmic proteins.
- Published
- 1996
- Full Text
- View/download PDF
33. Antimicrobial activity of calprotectin isolated from human empyema fluid supernatants.
- Author
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Santhanagopalan V, Hahn BL, Dunn BE, Weissner JH, and Sohnle PG
- Subjects
- Candida albicans drug effects, Exudates and Transudates chemistry, Humans, Leukocyte L1 Antigen Complex, Neural Cell Adhesion Molecules analysis, Neural Cell Adhesion Molecules drug effects, Neutrophils microbiology, Neutrophils pathology, Zinc pharmacology, Antifungal Agents isolation & purification, Empyema, Pleural metabolism, Neural Cell Adhesion Molecules isolation & purification
- Abstract
Abscess and empyema fluid supernatants have zinc-reversible antimicrobial activity that is thought to be due to calprotectin, a calcium- and zinc-binding protein present within neutrophil cytoplasm. The present studies were undertaken to determine if calprotectin isolated from human empyema fluid supernatants demonstrated similar antimicrobial activity to that of the original specimens. The characteristics of the calprotectin complex on SDS-PAGE and Western blotting with specific antisera were similar in neutrophil lysates and in empyema fluid supernatants. Ion-exchange and size-exclusion chromatography were used to obtain highly purified preparations of calprotectin from empyema fluids, and these preparations demonstrated zinc-reversible anti-Candida albicans activity which was similar to that observed in the original specimens. These findings suggest that calprotectin is responsible for most of the growth-inhibitory activity of empyema fluid supernatants against this organism.
- Published
- 1995
- Full Text
- View/download PDF
34. Correlation between serological and mucosal inflammatory responses to Helicobacter pylori.
- Author
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Pérez-Pérez GI, Brown WR, Cover TL, Dunn BE, Cao P, and Blaser MJ
- Subjects
- Antigens, Bacterial immunology, Bacterial Proteins immunology, Bacterial Toxins immunology, Biomarkers analysis, Chaperonin 60 immunology, Gastritis blood, Gastritis immunology, Gastritis pathology, Helicobacter Infections blood, Helicobacter Infections pathology, Humans, Middle Aged, Antibodies, Bacterial blood, Gastric Mucosa immunology, Gastric Mucosa pathology, Helicobacter Infections immunology, Helicobacter pylori immunology
- Abstract
In 82 patients who underwent gastroduodenoscopy, acute and chronic gastric mucosal inflammation was scored for severity, and systemic humoral immune responses to Helicobacter pylori antigens were assessed by enzyme-linked immunosorbent assays. On the basis of culture, gastric histology, and serologic evaluation, 33 patients were classified as H. pylori infected and 36 were classified as uninfected. Thirteen patients had negative cultures and stains but were seropositive and were analyzed separately from the other two groups. Specific serum immunoglobulin G (IgG) subclass responses to H. pylori whole-cell antigens and specific IgG responses to the 54-kDa heat shock protein homolog (Hp54K) and vacuolating cytotoxin were significantly greater in infected than in uninfected patients as were specific IgA responses to whole-cell antigens and cytotoxin (P < 0.001). Among the H. pylori-infected persons, serum IgG responses to Hp54K and to the vacuolating cytotoxin were correlated with acute mucosal inflammatory scores. In contrast, serum IgA responses to whole-cell sonicate and to vacuolating cytotoxin were inversely related to chronic inflammatory scores. By multivariant regression analysis, only specific serum IgG responses to Hp54K correlated with severity of inflammation (both acute and chronic; P < 0.001); these responses may be markers of inflammation or these antibodies could play a direct role in the pathogenesis of H. pylori-induced inflammation.
- Published
- 1994
- Full Text
- View/download PDF
35. Mitral restenosis and mitral regurgitation 1 year after Inoue mitral balloon valvotomy in a population of patients with pliable mitral valve stenosis.
- Author
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Ribeiro PA, Fawzy ME, Mimish L, Awad M, Dunn BE, Arafah MR, and Duran CG
- Subjects
- Adolescent, Adult, Catheterization instrumentation, Female, Follow-Up Studies, Heart Atria pathology, Heart Septum pathology, Humans, Iatrogenic Disease epidemiology, Incidence, Male, Middle Aged, Prospective Studies, Recurrence, Catheterization adverse effects, Mitral Valve Insufficiency etiology, Mitral Valve Stenosis therapy
- Abstract
To determine the rate of mitral restenosis and mitral regurgitation increase 1 year after mitral valvotomy using the Inoue balloon catheter, 66 consecutive patients with severe, pliable mitral stenosis had their mitral valve area (MVA) calculated by two-dimensional echocardiography (2DE) and Doppler before, immediately after balloon valvotomy, and at 1-year follow-up. Color Doppler studies were also done to detect small atrial septal defects (ASDs) and mitral regurgitation. The mean age of the patients was 31 +/- 12 years. Three patients were in New York Heart Association (NYHA) class II and 63 patients were in NYHA class III to IV. Sixty-two of the 66 patients had an echo score (Boston) of < or = 8. After Inoue balloon valvotomy (IBV), the MVA (2DE) increased from 0.8 +/- 0.2 to 1.9 +/- 0.3 cm2 (p < 0.001), and the Doppler MVA increased from 0.8 +/- 0.2 to 1.8 +/- 0.3 cm2 (p < 0.001). We detected 4 of 66 cases (6%) with significant residual mitral stenosis (MVA < 1.5 cm2). Mitral regurgitation increased in 14 of 66 patients (21%), but no patient developed severe mitral regurgitation. Fourteen out of 66 patients (20%) had ASDs that were detected on color Doppler. At 1-year follow-up the mean Doppler MVA was maintained at 1.8 +/- 0.4 cm2, with 6 of 66 patients (9%) exhibiting significant mitral valve restenosis. Residual significant mitral stenosis must be differentiated from mitral restenosis.(ABSTRACT TRUNCATED AT 250 WORDS)
- Published
- 1993
- Full Text
- View/download PDF
36. Pathogenic mechanisms of Helicobacter pylori.
- Author
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Dunn BE
- Subjects
- Bacterial Toxins biosynthesis, Gastrins blood, Gastritis microbiology, Helicobacter Infections blood, Helicobacter Infections immunology, Helicobacter pylori enzymology, Helicobacter pylori metabolism, Humans, Helicobacter Infections microbiology, Helicobacter pylori pathogenicity
- Abstract
There is general agreement that motility, urease activity, and association with gastric mucosal cells are important virulence factors of H. pylori. Urease activity is perhaps the best characterized of these factors. Presumably, urease activity creates a "cloud" of ammonia around the bacterium, thus neutralizing the lethal effects of gastric acid. Motility allows the bacterium to penetrate the mucus layer and promotes specific association of the bacteria with epithelial cells, further allowing evasion of gastric acidity. The association between gastrin levels and H. pylori infection is currently the most thoroughly studied feature relating to pathogenesis in vivo. Prolonged hypergastrinemia associated with H. pylori infection may contribute to increased parietal cell mass and chronically increased secretion of gastric acid; however, long-term studies are needed to validate this hypothesis. The identification of mucosal gamma delta T cells and immunologic cross-reactivity between H. pylori and gastric cells implies that the immune response contributes significantly to the pathogenesis of H. pylori. The role of the immune system in modulating H. pylori infection requires further study. Although many putative pathogenic factors have been identified on the basis of in vitro phenomena alone, their significance in vivo is not known. Ultimately, it will be necessary to evaluate the significance of these factors in animal models by using isogenic strains of H. pylori that differ only in a single genotypic characteristic.
- Published
- 1993
37. Identification of Ehrlichia chaffeensis morulae in cerebrospinal fluid mononuclear cells.
- Author
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Dunn BE, Monson TP, Dumler JS, Morris CC, Westbrook AB, Duncan JL, Dawson JE, Sims KG, and Anderson BE
- Subjects
- Aged, Bacteriological Techniques, DNA, Bacterial genetics, Ehrlichia classification, Ehrlichia genetics, Humans, Male, Polymerase Chain Reaction, Rickettsiaceae Infections cerebrospinal fluid, Rickettsiaceae Infections microbiology, Ehrlichia isolation & purification, Leukocytes, Mononuclear microbiology, Rickettsiaceae Infections diagnosis
- Abstract
We report a case of ehrlichiosis in a 72-year-old man who developed extreme lethargy, acute renal failure requiring hemodialysis, and respiratory insufficiency requiring intubation. Lumbar puncture performed on the second day of hospitalization revealed significant cellular pleocytosis. Ehrlichia morulae were tentatively identified in mononuclear cells in routinely processed Wright-stained cytospin preparations of cerebrospinal fluid (CSF). Identification was confirmed by a specific immunocytochemical staining procedure. Subsequent identification specifically as Ehrlichia chaffeensis morulae was established by polymerase chain reaction analysis, which revealed E. chaffeensis-specific DNA in CSF, bone marrow, and blood samples; by indirect fluorescent-antibody analysis, the patient developed an antibody titer of 32,768 against E. chaffeensis antigen. The patient responded to intravenous therapy with doxycycline and dexamethasone. Subsequently, neurologic, hematologic, renal, and pulmonary status had returned to baseline at follow-up 12 weeks after admission. To our knowledge, this is the first identification of E. chaffeensis morulae in CSF cells in an infected patient.
- Published
- 1992
- Full Text
- View/download PDF
38. Identification and purification of a cpn60 heat shock protein homolog from Helicobacter pylori.
- Author
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Dunn BE, Roop RM 2nd, Sung CC, Sharma SA, Perez-Perez GI, and Blaser MJ
- Subjects
- Amino Acid Sequence, Cross Reactions, Heat-Shock Proteins immunology, Molecular Sequence Data, Heat-Shock Proteins isolation & purification, Helicobacter pylori chemistry
- Abstract
Helicobacter pylori is associated with gastritis and peptic ulcer disease in humans. We have identified a homolog of the chaperonin cpn60 family of heat shock proteins in H. pylori, referred to as Hp54K. Hp54K, purified from water-extractable H. pylori proteins, migrated as a single band at 54 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Its native molecular mass was 740 kDa; thus, Hp54K apparently comprises a 14-mer. The N-terminal 33 residues of Hp54K exhibited 60.6, 57.6, 54.5, 54.5, 51.5, and 51.5% identity with corresponding sequences in the following cpn60 homologs: HtpB (Legionella pneumophila), P1 (human mitochondria), GroEL (Escherichia coli), BA60K (Brucella abortus), HypB (Chlamydia trachomatis), and the 65-kDa immunodominant protein of Mycobacterium bovis BCG, respectively. Hp54K was the only protein recognized in whole-cell preparations of H. pylori by immunoblotting using monospecific antisera against cpn60 homologs from L. pneumophila, E. coli, C. trachomatis, and M. bovis BCG. Antiserum against Hp54K recognized proteins with molecular masses of 50 to 60 kDa in a large number of gram-negative bacteria, consistent with the known highly conserved nature of cpn60 proteins. Hp54K is a major protein and is immunogenic in humans infected with H. pylori. Thus, Hp54K shares many similarities with known cpn60 homologs. On the basis of the proposed role of other cpn60 proteins in induction of chronic inflammation, immune cross-reactivity between Hp54K and gastric tissue may provide an important link between H. pylori infection and gastritis.
- Published
- 1992
- Full Text
- View/download PDF
39. Molecular cloning and nucleotide sequence analysis of the gene encoding the immunoreactive Brucella abortus Hsp60 protein, BA60K.
- Author
-
Roop RM 2nd, Price ML, Dunn BE, Boyle SM, Sriranganathan N, and Schurig GG
- Subjects
- Amino Acid Sequence, Base Sequence, Blotting, Western, Cloning, Molecular, DNA, Bacterial, Escherichia coli genetics, Gene Expression, Genes, Bacterial, Heat-Shock Proteins immunology, Molecular Sequence Data, Restriction Mapping, Sequence Alignment, Brucella abortus genetics, Heat-Shock Proteins genetics
- Abstract
A recombinant 60 kDa Brucella abortus protein expressed in Escherichia coli was recognized in immunoblots by sera from mice experimentally infected with B. abortus and a dog experimentally infected with B. canis. Sera from humans and dogs with naturally acquired brucellosis also recognized this protein, which was designated BA60K. The gene encoding BA60K was localized within an 18 kb B. abortus genomic fragment and its direction of transcription determined by subcloning and maxicell analysis of selected restriction fragments. The nucleotide sequence of 1800 bases encompassing the predicted gene location was determined, revealing an open reading frame encoding a protein of 546 amino acids (predicted relative molecular mass of 57515). Solid phase micro-sequencing of BA60K eluted from two-dimensional polyacrylamide gels confirmed the predicted amino acid sequence. Comparison of the predicted amino acid sequence of BA60K with a protein sequence database revealed that BA60K shares 67.9% identity with the GroEL protein of E. coli, a member of the Hsp60 family of chaperonins. The immunodominant Hsp60 homologs from Legionella pneumophila, Chlamydia trachomatis and Mycobacterium tuberculosis were also found to share greater than 59% amino acid sequence identity with the BA60K protein. The identification of BA60K as a member of the Hsp60 family of chaperonins supports its role in stimulating a prominent host immune response during the course of Brucella infections. It also indicates that BA60K is an important candidate for studies aimed at identifying the antigens responsible for eliciting the protective immune response to brucellosis.
- Published
- 1992
- Full Text
- View/download PDF
40. Purification and characterization of Helicobacter mustelae urease.
- Author
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Dunn BE, Sung CC, Taylor NS, and Fox JG
- Subjects
- Chromatography, Gel, Chromatography, High Pressure Liquid, Electrophoresis, Polyacrylamide Gel, Helicobacter pylori enzymology, Molecular Weight, Urease chemistry, Campylobacter enzymology, Urease isolation & purification
- Abstract
Helicobacter mustelae is a urease-rich bacterium associated with gastritis in ferrets. The ureases of H. mustelae and Helicobacter pylori, a bacterium implicated in human gastritis, share many characteristics. Helicobacter sp. ureases appear to be unique among bacterial enzymes in exhibiting submillimolar Km values and in being composed of two subunits.
- Published
- 1991
- Full Text
- View/download PDF
41. Adherence of Helicobacter pylori to gastric carcinoma cells: analysis by flow cytometry.
- Author
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Dunn BE, Altmann M, and Campbell GP
- Subjects
- Cell Line, Flow Cytometry, Fluorescent Antibody Technique, Helicobacter pylori ultrastructure, Humans, Microscopy, Electron, Microscopy, Fluorescence, Stomach Neoplasms, Tumor Cells, Cultured, Bacterial Adhesion drug effects, Helicobacter pylori metabolism
- Abstract
An in vitro assay using immunofluorescence and flow cytometry for quantitative assessment of the adherence of Helicobacter pylori to cultured human gastric carcinoma (KATO III) cells was developed. Adherence was rapid, saturable, energy dependent, mannose resistant, and significantly inhibited by fetuin, a glycoprotein containing N-acetylneuraminyllactose. Pretreatment of KATO cells with neuraminidase from Clostridium perfringens, however, did not reduce adherence of H. pylori. Ultrastructurally, adherent cells of H. pylori were associated with indentations of KATO cell membranes. KATO cells should prove useful in the investigation of mechanisms of adherence of H. pylori to mammalian cells. Ultimately, this flow cytometric assay may be helpful in assessment of the adherence of laboratory strains of H. pylori directly to surface mucous cells dissociated from biopsied human gastric tissue.
- Published
- 1991
- Full Text
- View/download PDF
42. Lactoferrin and transferrin damage of the gram-negative outer membrane is modulated by Ca2+ and Mg2+.
- Author
-
Ellison RT 3rd, LaForce FM, Giehl TJ, Boose DS, and Dunn BE
- Subjects
- Cell Membrane drug effects, Cell Membrane ultrastructure, Deoxycholic Acid pharmacology, Drug Resistance, Microbial, Escherichia coli drug effects, Gram-Negative Bacteria growth & development, Gram-Negative Bacteria ultrastructure, Hydrogen-Ion Concentration, Kinetics, Lipopolysaccharides metabolism, Microscopy, Electron, Polymyxin B pharmacology, Rifampin pharmacology, Calcium pharmacology, Gram-Negative Bacteria drug effects, Lactoferrin pharmacology, Magnesium pharmacology, Transferrin pharmacology
- Abstract
Lactoferrin and transferrin have antimicrobial activity against selected Gram-negative bacteria, but the mechanism of action has not been defined. We studied the ability of lactoferrin and transferrin to damage the Gram-negative outer membrane. Lipopolysaccharide release by the proteins could be blocked by concurrent addition of Ca2+ and Mg2+. Addition of Ca2+ also blocked the ability of lactoferrin to increase the susceptibility of Escherichia coli to rifampicin. Transferrin, but not lactoferrin, increased susceptibility of Gram-negative bacteria to deoxycholate, with reversal of sensitivity occurring with exposure to Ca2+ or Mg2+. In transmission electron microscopy studies polymyxin B caused finger-like membrane projections, but no morphological alterations were seen in cells exposed to EDTA, lactoferrin or transferrin. These data provide further evidence that lactoferrin and transferrin act as membrane-active agents with the effects modulated by Ca2+ and Mg2+.
- Published
- 1990
- Full Text
- View/download PDF
43. Purification and characterization of urease from Helicobacter pylori.
- Author
-
Dunn BE, Campbell GP, Perez-Perez GI, and Blaser MJ
- Subjects
- Amino Acid Sequence, Blotting, Western, Chromatography, Gel, Chromatography, Ion Exchange, Humans, Isoelectric Point, Kinetics, Klebsiella pneumoniae enzymology, Molecular Sequence Data, Molecular Weight, Proteus mirabilis enzymology, Sequence Homology, Nucleic Acid, Urea metabolism, Urease metabolism, Campylobacter enzymology, Urease isolation & purification
- Abstract
Urease was purified 112-fold to homogeneity from the microaerophilic human gastric bacterium, Helicobacter pylori. The urease isolation procedure included a water extraction step, size exclusion chromatography, and anion exchange chromatography. The purified enzyme exhibited a Km of 0.3 +/- 0.1 mM and a Vmax of 1,100 +/- 200 mumols of urea hydrolyzed/min/mg of protein at 22 degrees C in 31 mM Tris-HCl, pH 8.0. The isoelectric point was 5.99 +/- 0.03. Molecular mass estimated for the native enzyme was 380,000 +/- 30,000 daltons, whereas subunit values of 62,000 +/- 2,000 and 30,000 +/- 1,000 were determined. The partial amino-terminal sequence (17 residues) of the large subunit of H. pylori urease (Mr = 62,000) was 76% homologous with an internal sequence of the homohexameric jack bean urease subunit (Mr = 90,770; Takashima, K., Suga, T., and Mamiya, G. (1988) Eur. J. Biochem. 175, 151-165) and was 65% homologous with amino-terminal sequences of the large subunits of heteropolymeric ureases from Proteus mirabilis (Mr = 73,000) and from Klebsiella aerogenes (Mr = 72,000; Mobley, H. L. T., and Hausinger, R. P. (1989) Microbiol. Rev. 53, 85-108). The amino-terminal sequence (20 residues) of the small subunit of H. pylori urease (Mr = 30,000) was 65 and 60% homologous with the amino-terminal sequences of the subunit of jack bean urease and with the Mr = 11,000 subunit of P. mirabilis urease (Jones, B. D., and Mobley, H. L. T. (1989) J. Bacteriol. 171, 6414-6422), respectively. Thus, the urease of H. pylori shows similarities to ureases found in plants and other bacteria. When used as antigens in an enzyme-linked immunosorbent assay, neither purified urease nor an Mr = 54,000 protein that co-purified with urease by size exclusion chromatography was as effective as crude preparations of H. pylori proteins at distinguishing sera from persons known either to be infected with H. pylori or not.
- Published
- 1990
44. Cognitive correlates of headache intensity and duration.
- Author
-
Demjen S, Bakal DA, and Dunn BE
- Subjects
- Female, Headache etiology, Humans, Male, Sex Factors, Stress, Psychological complications, Surveys and Questionnaires, Time Factors, Cognition, Emotions, Headache psychology, Thinking
- Abstract
Cognitive processes and cognitive styles of persistent headache sufferers were examined in relation to indices of intensity and duration of head pain. One hundred and eight persistent headache patients, referred for cognitive-behavioral management of their disorder, completed questionnaires designed to assess: distressing thoughts and feelings experienced during headache attacks, evaluation of the experienced pain, perceived influence of stress and worry on headaches, and capacity to verbally express emotions. The results showed that the intensity of head pain correlated with measures of headache-related distress and with the proportion of headache-related distress to situation-related distress. Duration of head pain was also associated with the proportion of headache-related distress to situation-related distress, and additionally with a tendency to deny the influence of stress and worry on headaches and with difficulty in expressing emotions. These findings were taken as support of our previously stated hypothesis that head pain of increased severity is associated with a cognitive shift whereby the patient's primary concern moves from situational and interpersonal distress to distress associated with the disorder itself. In addition, these findings point to affective distress and lack of emotional expressiveness as correlating differentially with the headache dimensions of intensity and duration.
- Published
- 1990
- Full Text
- View/download PDF
45. Seroprevalence of Helicobacter pylori infections in Thailand.
- Author
-
Perez-Perez GI, Taylor DN, Bodhidatta L, Wongsrichanalai J, Baze WB, Dunn BE, Echeverria PD, and Blaser MJ
- Subjects
- Child, Child, Preschool, Cross Reactions, Enzyme-Linked Immunosorbent Assay, Humans, Infant, Predictive Value of Tests, Prevalence, Thailand epidemiology, Antibodies, Bacterial analysis, Campylobacter immunology, Campylobacter Infections epidemiology
- Abstract
Serologic studies in developed countries indicate that Helicobacter (formerly Campylobacter) pylori infection is uncommon until the third decade of life and achieves a peak prevalence of 50% in the seventh decade. In developing countries the epidemiology of H. pylori has not well been described. A sensitive and specific serologic assay for H. pylori infection was validated in Thai patients also studied by culture and histologic examination of biopsy specimens. The prevalence of H. pylori antibodies in persons from a rural Thai community began early (17.5% of children 5-9 years old), increased to 55% during the third decade of life, and peaked (75%) in the 30- to 49-year age group. At a Bangkok orphanage where enteric infections are hyperendemic, 74% of children 1-4 years old were seropositive. This study shows that the prevalence of H. pylori infection in Thailand is higher than in industrialized countries. The high infection rate at the orphanage suggests that person-to-person transmission of H. pylori may be occurring.
- Published
- 1990
- Full Text
- View/download PDF
46. Electrocardiographic changes induced by suction curettage for elective termination of pregnancy.
- Author
-
Mabee LM Jr, Dunn BE, and Sherrer CW
- Subjects
- Adolescent, Adult, Electrocardiography, Female, Humans, Middle Aged, Pregnancy, Abortion, Induced adverse effects, Dilatation and Curettage adverse effects, Heart Rate, Vacuum Curettage adverse effects
- Abstract
To determine if significant electrocardiographic changes occur during suction curettage for elective termination of pregnancy, continuous electrocariogram tracings were obtained from 103 patients prior to, during, and after suction curettage. Sixty-eight of 103 patients (66%) demonstrated transient sinus techycardia presumably attributable to pain (P < 0.001). Eleven of 103 patients (10.6%) demonstrated premature atrial contractions or premature ventricular contractions during suction curettage (P < 0.005). When more rigid (8 or 9 mm) curets were used, a threefold increased incidence of extrasystoles was noted. In a comparison of the incidents of electrocardiographic changes in parous versus nulliparous patients, no statistically significant differences could be demonstrated. (Unlike in previous published reports on intrauterine manipulation, bradycardia was not noted.)
- Published
- 1980
- Full Text
- View/download PDF
47. The differential contribution of muscle contraction and migraine symptoms to problem headache in the general population.
- Author
-
Kaganov JA, Bakal DA, and Dunn BE
- Subjects
- Adult, Female, Headache epidemiology, Humans, Male, Middle Aged, Sex Factors, Headache etiology, Muscle Contraction, Muscles physiopathology, Neck Muscles physiopathology
- Published
- 1981
- Full Text
- View/download PDF
48. Abnormal electrocardiograms in highly trained athletes.
- Author
-
Goldman MH and Dunn BE
- Subjects
- Electrocardiography, Humans, Cardiomegaly diagnosis, Sports Medicine
- Published
- 1983
- Full Text
- View/download PDF
49. Vibrio cholerae wound infection acquired in Colorado.
- Author
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Cover TL, Dunn BE, Ellison RT 3rd, and Blaser MJ
- Subjects
- Colorado, Fresh Water, Humans, Vibrio Infections etiology, Vibrio cholerae isolation & purification, Water Microbiology, Wound Infection etiology
- Published
- 1989
- Full Text
- View/download PDF
50. Embryonic chick allantois: functional isolation and development of sodium transport.
- Author
-
Graves JS, Dunn BE, and Brown SC
- Subjects
- Allantois drug effects, Allantois ultrastructure, Amiloride pharmacology, Animals, Biological Transport, Cell Membrane Permeability, Chick Embryo, Electric Conductivity, Epithelium physiology, Microscopy, Electron, Nystatin pharmacology, Time Factors, Allantois physiology, Extraembryonic Membranes physiology, Sodium metabolism
- Abstract
By removing the shell membranes from the chorioallantoic membrane, the chorion is damaged, as visualized by electron microscopy, and rendered permeable, as evidenced by penetration of horseradish peroxidase and increased inhibition of the allantoic Na+-K+ pump by ouabain applied on the chorionic side. The short-circuit current (SCC) of this functionally isolated allantoic epithelium is augmented by nystatin, a channel-forming ionophore, when applied to the mucosal surface. Electrical parameters were determined for three age groups between 12 and 19 days of incubation. The SCC approximately doubled from the youngest (12-13 days) to the oldest (18-19 days) groups, whereas the transepithelial resistance (Re) of 700-900 omega X cm2 remained the same. Amiloride, an inhibitor of apical Na+ uptake, inhibited 98-100% of the SCC at 10(-4) M in both 15-16 and 18-19 day epithelia. In the 12- to 13-day preparation 20-25% of the SCC was insensitive to 10(-3) M amiloride. The Ki's for amiloride were similar in all preparations, at about 5 X 10(-7) M. Determination of the Hill coefficients for inhibition revealed a lower value (0.75 +/- 0.03) for the 12-13 day preparation compared with the two older preparations with coefficients not significantly different from unity. Replacing Na+ in the bathing solutions abolished the SCC of 18-19 day epithelia, whereas about 15% of the SCC remained at 12-13 days. Thus, during development, the SCC of the allantoic epithelium increases in magnitude and becomes increasingly (to 100%) amiloride-sensitive and Na+-dependent.
- Published
- 1986
- Full Text
- View/download PDF
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