Biomedical subjects
K A Eaton
Publications and source records attributed to K A Eaton.
'Schools without walls?' Developments and challenges in dental outreach teaching - report of a recent symposium.
During the 2004 annual meeting of the International Association for Dental Research, the Education Research Group held a symposium on dental outreach teaching. After a brief introduction, which reviews relevant aspects of the relatively sparse literature, this paper summarises the proceedings, the themes and conclusions that emerged and the research issues that were identified. It aims to describe aspects of current practice around the world and to promote future discussion. Presenters gave details of outreach programmes for dental undergraduates in Australia, Finland, Malaysia (and Southeast Asia), the United Kingdom and the United States. From these presentations four themes emerged. They were: reasons for the introduction of outreach teaching, its perceived beneficial effects, organisational issues, educational issues. The reasons included a recognition of the need to educate dental undergraduates as members of 'care teams' in the environments and communities where they were ultimately like to work and the current shortage of both suitable patients and teachers (faculty) in many dental schools. A wide range of potential benefits and some disadvantages were identified. The organisational issues were, in the main, seen to relate to finance and administration. The educational issues included the need to train and monitor the performance of teachers at outreach clinics and to assess the performance of the undergraduates whilst at the outreach locations. It was concluded that new technology made it easier to teach at a distance and it was possible to create a dental 'school without walls'. It was recognised that few evaluations of dental outreach teaching have been carried out and that there were many research questions to be answered, including: whether it should be a voluntary or compulsory part of the undergraduate curriculum, how long it should last and what type of outcomes should be assessed.
Continuing professional development--global perspectives: synopsis of a workshop held during the International Association of Dental Research meeting in Gothenburg, Sweden, 2003. Part 1: access, funding and participation patterns.
There appears to have been little previous research interest in continuing professional development (CPD) of dentists and the oral health team. This paper presents data and information on the following aspects of CPD in 17 countries in Asia, Australasia, Europe and North America: availability of different types of CPD, its providers, data on uptake of CPD courses and activities, and funding of CPD. The results indicate that lectures and hands-on skills courses were held in all 17 countries but the use of the Internet to deliver CPD was by no means universal. CPD was funded from a variety of sources including universities, governments and commercial companies. However, the only universal source of funding for CPD was dentists themselves. Data on participation were available from only three countries. Research issues based on these results will be listed in a second paper.
Continuing professional development--global perspectives: synopsis of a workshop held during the International Association of Dental Research meeting in Gothenburg, Sweden, 2003. Part 2: regulatory and accreditation systems and evidence for improving the performance of the dental team.
This paper is the second in a series of two that report on continuing professional development (CPD). Details of the informants and the methodologies used were reported in the first paper. This paper reports the data and information presented on the topics of regulatory and accreditation systems for CPD and evidence that CPD improves the performance of the oral health team. By June 2003, participation in CPD was mandatory in most of the states of the USA, all Canadian Provinces, the UK and Latvia and was likely to become mandatory in a number of other countries in the near future. A variety of accreditation systems were reported including collecting CPD points, which in some countries were weighted depending on the type of CPD activity, and re-certification examinations. Very few studies for the effectiveness of dental CPD were identified. However, in general it was concluded that there is little evidence for the effectiveness of CPD for the oral health team. The main recommendation from this study is that a systematic review of the effectiveness of CPD in improving the performance of the oral health team and patient based outcomes be undertaken. A range of other research questions was also identified including: how can CPD be best matched to clinicians' needs rather than demands?
Helicobacter pylori with a truncated lipopolysaccharide O chain fails to induce gastritis in SCID mice injected with splenocytes from wild-type C57BL/6J mice.
The goal of this study was to determine whether Helicobacter pylori lipopolysaccharide (LPS) O-chain polysaccharide contributes to gastritis in a mouse model. C57BL/6J or C57BL/6-Prkdc(scid) (severe combined immunodeficient [SCID]) mice were inoculated with H. pylori strain SS1 or SS1::0826kan, in which a beta-1,4-galactosyltransferase (HP0826), an LPS biosynthetic enzyme, had been disrupted. H. pylori strain SS1::0826kan expresses truncated LPS lacking O chain. Recipient SCID mice were given C57BL/6J splenocytes by intraperitoneal injection. Bacterial colonization, gastric lesions (gastritis, neutrophilic infiltration, and gastric epithelial metaplasia), cellular (delayed-type hypersensitivity) and humoral immune responses to H. pylori sonicate, and gastric gamma interferon (IFN-gamma) mRNA expression were quantified. Recipient SCID mice colonized by H. pylori strain SS1 developed extensive gastritis with loss of normal fundic gland morphology. In contrast, gastric mucosa of recipient SCID mice colonized by H. pylori strain SS1::0826kan was not statistically distinguishable from that of uninfected recipient mice. Delayed-type hypersensitivity and humoral immune responses were detected in infected mice inoculated with wild-type SS1, but not with SS1::0826kan. IFN-gamma transcription was lower in mice infected with SS1::0826kan than in mice infected with SS1. In this model of rapidly progressive gastritis due to H. pylori, the O chain contributed to the extent of gastritis and to the host immune response. These data support a role for H. pylori LPS O chain in direct induction of the host immune response leading to gastritis and gastric damage and are in contrast to protein antigens, such as urease and cag products which do not contribute to gastritis in mice.
A survey of dental hygienist numbers in Canada, the European Economic area, Japan and the United States of America in 1998.
OBJECTIVE: The aims of this study were to establish how many dental hygienists were licensed to practice in Canada, Japan, USA and the 18 member states of the European Economic Area (EEA) and to compare these with the populations and numbers of dentists practising in the countries concerned. METHOD: Data for the overall populations, numbers of 'active' dentists, of dental hygienists and of employed dental hygienists in the member states of the EEA in 1998 were taken from the responses to a Council of European Chief Dental Officers survey carried out in 2000/2001. Data for these variables for Canada, Japan and the USA in 1998 were accessed from published reports. The ratios of population: active dentist; population: dental hygienist; and active dentist: dental hygienist were calculated and compared. RESULTS: The overall populations and total number of active dentists in the 18 EEA member states and Canada plus Japan plus the USA were broadly similar in 1998 (EEA overall population 381 million with 245169 active dentists: Canada/Japan/USA overall population 421 million with 253825 active dentists). However, there were only 13295 dental hygienists in the EEA as opposed to a total of 215435 in Canada, Japan and the USA. In terms of population:dental hygienist and active dentist: dental hygienist ratios the UK was found to have proportionally far fewer dental hygienists than Canada, Japan, USA or the four Nordic members of the EEA. CONCLUSION: The survey revealed that relative to overall populations and numbers of dentists, there are far fewer dental hygienists in the EEA than in Canada, Japan and the USA and that scope for the UK to import dental hygienists from other EEA member states is probably very limited.
Distance learning materials for dentists--a users guide to quality.
In May 2001, an open meeting was held at the BDA headquarters to discuss how the quality of distance learning material for dentists and the dental team could be assured in the future. As a result of the meeting an ad hoc group of users, producers, teachers and researchers was formed. The group have produced this paper which seeks to help dentists and all members of the dental team select quality material relevant to their needs. The President of the General Dental Council has added a foreword to this guide.
Unification of the "burst" and "linear" theories of periodontal disease progression: a multilevel manifestation of the same phenomenon.
Previously, burst and linear theories for periodontal disease progression were proposed based on different but limited statistical methods of analysis. Multilevel modeling provides a new approach, yielding a more comprehensive model. Random coefficient models were used to analyze longitudinal periodontal data consisting of repeated measures (level 1), sites (level 2), teeth (level 3), and subjects (level 4). Large negative and highly significant correlations between random linear and quadratic time coefficients indicated that subjects and teeth with greater-than-average linear change experienced decelerated variation. Conversely, subjects and teeth with less-than-average linear change experienced accelerated variation. Change therefore exhibited a dynamic regression to the mean at the tooth and subject levels. Since no equilibrium was attained throughout the study, changes were cyclical. When considered as a multilevel system, the "linear" and "burst" theories of periodontal disease progression are a manifestation of the same phenomenon: Some sites improve while others progress, in a cyclical manner.
The dental workforce in Europe (or most of it!).
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Helicobacter pylori-specific immunoglobulin synthesis in gnotobiotic piglets: evidence for the induction of mucosal immunity in the stomach.
Short term tissue biopsy cultures and paired, sera, bile and gastric and intestinal contents from Helicobacter pylori-infected gnotobiotic piglets were tested for the synthesis of H. pylori-specific immunoglobulin (Ig) isotype production by antigen-specific ELISA from post-infection days (PIDs) 2-28. Serum antibody levels in all three Ig isotypes were elevated from baseline values by PID 14, serum IgM levels reached peak levels on PID 14 and by PID 28 bile was strongly positive for IgA and IgG.Intestinal, but not gastric contents from infected piglets, contained IgA-specific antibody from PID 14 onward. Gastric mucosal epithelia adjacent to areas of inflammation in infected but not uninfected control piglets produced readily detectable amounts of porcine secretory component (SC); IgA-positive plasma cells were identified in gastric submucosa and lamina propria in these areas. Culture fluid supernatants, collected from explanted gastric cardia and antra and intestinal ilea of H. pylori-infected piglets had trace amounts of IgA as early as PID 2 in some animals, and strong IgA reactivity in all by PID 28. Supernatants also contained H. pylori-specific IgG by PID 14. A strong gastric lymph node IgA response contrasted with moderate IgA production in mesenteric lymph nodes and spleen. Mucosal biopsy production of H. pylori-specific IgG was more evenly distributed throughout the lymphoid system. These data support the contention that the Ig response to H. pylori is initiated within the gastric compartment and matures over time to a generalized IgA-dominated mucosal and IgG-dominated nonmucosal humoral immune response.
Participating dentists' assessment of the pilot regional online videoconferencing in dentistry (PROVIDENT) project.
OBJECTIVE: To assess the educational effectiveness of delivering continuing professional education (CPE) from dental schools to small groups of dentists at distant sites via videoconferenced links using relatively inexpensive equipment and ISDN2 links. DESIGN: 41 videoconferences between the four campuses of London Dental Schools and postgraduate centres in South East England were assessed using a pre-piloted questionnaire which contained open and specific questions. The questionnaire was given to all participants at the end of each videoconference. Answers to the specific questions were graded using the Likert scale. RESULTS: 40 of the 41 videoconferences were completed satisfactorily and were attended by 257 participants, all of whom completed questionnaires. However, no individual question was answered by all the participants. Of the responses 90% were positive on the topics of appropriateness of the teaching material for delivery by videoconference and of its educational level. 90% of responses also indicated a wish to attend further videoconferences and satisfaction at avoiding the need to travel to London for similar educational activity. 87% rated the lecturers as good or excellent in their use of the medium. 85% of responses indicated that the question and answer sessions within the videoconferences were useful and 82% that the visual aids enhanced the sessions. The technical aspects of the videoconferences were rated positively but to a lesser extent than the educational aspects with 69% of positive responses for visibility of visual aids, 54% for sound quality and 76% for the lecturers use of the technology. The technical aspects of the videoconferences improved during the pilot study. In response to the open questions, participants stated that they found the most useful aspects of the videoconferences were not having to travel, access to first rate lecturers, the discussions and the opportunity to interact with experts. CONCLUSIONS: The participants in this pilot study were positive about the use of videoconferencing to deliver educational material from dental schools to small groups. Once the technology has improved, this medium has the potential to provide CPE for dentists at work or at home in response to their specific needs.
The role of T cell subsets and cytokines in the pathogenesis of Helicobacter pylori gastritis in mice.
Gastritis due to Helicobacter pylori in mice and humans is considered a Th1-mediated disease, but the specific cell subsets and cytokines involved are still not well understood. The goal of this study was to investigate the immunopathogenesis of H. pylori-induced gastritis and delayed-type hypersensitivity (DTH) in mice. C57BL/6-Prkdc(scid) mice were infected with H. pylori and reconstituted with CD4+, CD4-depleted, CD4+CD45RB(high), or CD4+CD45RB(low) splenocytes from wild-type C57BL/6 mice or with splenocytes from C57BL/6(IFN-gamma-/-) or C57BL/6(IL-10-/-) mice. Four or eight weeks after transfer, DTH to H. pylori Ags was determined by footpad injection; gastritis and bacterial colonization were quantified; and IFN-gamma secretion by splenocytes in response to H. pylori Ag was determined. Gastritis and DTH were present in recipients of unfractionated splenocytes, CD4+ splenocytes, and CD4+CD45RB(high) splenocytes, but absent in the other groups. IFN-gamma secretion in response to H. pylori Ags was correlated with gastritis, although splenocytes from all groups of mice secreted some IFN-gamma. Gastritis was most severe in recipients of splenocytes from IL-10-deficient mice, and least severe in those given IFN-gamma-deficient splenocytes. Bacterial colonization in all groups was inversely correlated with gastritis. These data indicate that 1) CD4+ T cells are both necessary and sufficient for gastritis and DTH due to H. pylori in mice; 2) high expression of CD45RB is a marker for gastritis-inducing CD4+ cells; and 3) IFN-gamma contributes to gastritis and IL-10 suppresses it, but IFN-gamma secretion alone is not sufficient to induce gastritis. The results support the assertion that H. pylori is mediated by a Th1-biased cellular immune response.
Oral healthcare in transition in Eastern Europe.
Big changes have occurred in the oral healthcare delivery systems of most Eastern European countries since the fall of the Berlin wall in 1989 and the demise of communism in the former USSR in 1991. In the new situation it was necessary to reform the political and social systems including healthcare. Reforms were started to improve the economy and, in comparison with Western Europe, the generally lower living standards. It is difficult to obtain comprehensive data on oral healthcare in Eastern European countries but this paper reports data from nine countries and provides a 'macro' view of the current situation in these countries. Many countries seem to have adopted a Bismarckian model for the provision of oral healthcare based on a sickness insurance system.
Prevalence and extent of lifetime cumulative attachment loss (LCAL) at different thresholds and associations with clinical variables: changes in a population of young male military recruits over 3 years.
AIM: The aims of this study were to monitor the prevalence and progression of lifetime cumulative attachment loss (LCAL) in a group of young British male military recruits over a 3-year period, and to determine the relationship between signs of LCAL and selected periodontal variables. METHODS: 100 subjects, aged 16-20 years (mean 17 years) at baseline, were examined at 0 (baseline), 12 and 30 months. LCAL, probing depth, plaque, bleeding on probing, gingival colour and supra- and subgingival calculus were assessed on the mesio-buccal, disto-buccal, mesio-lingual and disto-lingual surfaces of all teeth present, excluding third molars. Data were analysed cross-sectionally at each examination. RESULTS: Over the period of the study, the prevalence of LCAL > or =1 and 2 mm ranged from 95-100%, whereas LCAL > or =3 mm ranged from 40-47%. The extent of LCAL > or =1 mm ranged from 76-86%. However, the extent of LCAL > or =2 mm was dramatically lower (10.5-12.7%), and LCAL > or =3 mm was uncommon (0.5-0.9%). Examining the number of subjects according to the number of sites affected above a threshold, showed that a small number of subjects have a large number of sites above threshold. Using Pearson's rank correlation coefficient a significant correlation (p<0.05) was found between LCAL and the periodontal variables of gingival bleeding and supra- and subgingival calculus. CONCLUSIONS: These data suggest that the onset and progression of chronic periodontitis can be seen in young adults, and in this group gingival bleeding and supra- and subgingival calculus are the variables most strongly associated with early periodontitis.
A study of videoconferencing for postgraduate continuing education in dentistry in the UK--the teachers' view.
Videoconferencing is an established method for providing medical education over long distances. Our aims were to assess the feasibility of videoconferencing in dental postgraduate education, to evaluate its practicability, teacher satisfaction and evaluate equipment. Twenty-seven teachers from the 4 London Dental Schools provided 41 postgraduate dental education sessions on a range of topics to regional postgraduate centres and dental practices as part of the Thames Health Region's programme. Videoconferencing was carried out using a relatively inexpensive personal computer system link using ISDN2 telephone lines and Z350 protocol. Presenter views and assessment were obtained by questionnaire, interview and videotape. Teachers felt that minimal additional preparation time was required for videoconferencing and 21/27 preferred it to in-person teaching, most noting the saving in travel time. Only 3 of the teachers were dissatisfied with their ability to communicate, 4 were equivocal and 20 were either pleased or very pleased. The teachers largely enjoyed the experience and performed well in the new medium. However, sound quality proved inadequate in 5/41 links and most sessions included some periods of suboptimal sound. Only 4 teachers were satisfied with their ability to perform question and answer interaction with the audience. We conclude that experienced teachers adapt readily to videoconferencing and learn to communicate effectively very quickly. Teachers were positive about the medium despite its shortcomings and improvements in sound quality would allow a rapid expansion of postgraduate dental education by videoconference.
Cure of Helicobacter pylori infection and resolution of gastritis by adoptive transfer of splenocytes in mice.
Vaccination suppresses Helicobacter pylori colonization but does not cure infection. Furthermore, postvaccination gastritis, likely induced by enhanced host response to residual colonization, may exacerbate disease. The goal of this study was to determine if adoptive transfer of C57BL/6 splenocytes to C57BL/6scid/scid (severe combined immunodeficient [SCID]) mice cures infection without exacerbating gastritis. H. pylori-infected and uninfected C57BL/6 mice and SCID recipients of normal splenocytes were killed at intervals between 5 and 51 weeks after infection. Colonization and gastritis were quantified, humoral immune responses were determined by enzyme-linked immunosorbent assay, and cellular immune responses were determined by delayed-type hypersensitivity response and by a proliferative response of cultured splenocytes to H. pylori sonicate. In infected C57BL/6 mice, gastritis developed gradually and bacterial colonization diminished but persisted throughout the experiment. In contrast, gastritis in infected recipient SCID mice developed rapidly and bacterial colonization decreased precipitously. Gastritis in those mice peaked 9 weeks after adoptive transfer, however, and began to resolve. By 45 weeks after transfer, gastritis had returned to background levels and bacteria were no longer detectable. Resolution of gastritis and elimination of infection were associated with a cellular but not humoral immune response to H. pylori antigens. These results demonstrate that although the host response fails to clear bacterial colonization in normal mice, enhanced cellular immune responses in recipient SCID mice are capable of clearing H. pylori infection and allowing resolution of gastritis. Thus, immune mechanisms of cure exist, and effective and safe vaccination protocols may be feasible.
Role of Helicobacter pylori cag region genes in colonization and gastritis in two animal models.
The Helicobacter pylori chromosomal region known as the cytotoxin-gene associated pathogenicity island (cag PAI) is associated with severe disease and encodes proteins that are believed to induce interleukin (IL-8) secretion by cultured epithelial cells. The objective of this study was to evaluate the relationship between the cag PAI, induction of IL-8, and induction of neutrophilic gastric inflammation. Germ-free neonatal piglets and conventional C57BL/6 mice were given wild-type or cag deficient mutant derivatives of H. pylori strain 26695 or SS1. Bacterial colonization was determined by plate count, gastritis and neutrophilic inflammation were quantified, and IL-8 induction in AGS cells was determined by enzyme-linked immunosorbent assay. Deletion of the entire cag region or interruption of the virB10 or virB11 homolog had no effect on bacterial colonization, gastritis, or neutrophilic inflammation. In contrast, these mutations had variable effects on IL-8 induction, depending on the H. pylori strain. In the piglet-adapated strain 26695, which induced IL-8 secretion by AGS cells, deletion of the cag PAI decreased induction. In the mouse-adapted strain SS1, which did not induce IL-8 secretion, deletion of the cagII region or interruption of any of three cag region genes increased IL-8 induction. These results indicate that in mice and piglets (i) neither the cag PAI nor the ability to induce IL-8 in vitro is essential for colonization or neutrophilic inflammation and (ii) there is no direct relationship between the presence of the cag PAI, IL-8 induction, and neutrophilic gastritis.
Differential gene expression from two transcriptional units in the cag pathogenicity island of Helicobacter pylori.
Infection with Helicobacter pylori strains containing the cag Pathogenicity Island (cag PAI) is strongly correlated with the development of severe gastric disease, including gastric and duodenal ulceration, mucosa-associated lymphoid tissue lymphoma, and gastric carcinoma. Although in vitro studies have demonstrated that the expression of genes within the cag PAI leads to the activation of a strong host inflammatory response, the functions of most cag gene products and how they work in concert to promote an immunological response are unknown. We developed a transcriptional reporter that utilizes urease activity and in which nine putative regulatory sequences from the cag PAI were fused to the H. pylori ureB gene. These fusions were introduced in single copies onto the H. pylori chromosome without disruption of the cag PAI. Our analysis indicated that while each regulatory region confers a reproducible amount of promoter activity under laboratory conditions, they differ widely in levels of expression. Transcription initiating upstream of cag15 and upstream of cag21 is induced when the respective fusion strains are cocultured with an epithelial cell monolayer. Results of mouse colonization experiments with an H. pylori strain carrying the cag15-ureB fusion suggested that this putative regulatory region appears to be induced in vivo, demonstrating the importance of the urease reporter as a significant development toward identifying in vivo-induced gene expression in H. pylori.