Learning outcomes: Exploring implications of adopting a different level of detail

INTRODUCTION

Outcome-based programmes provide a framework to support educators and learners in understanding content and end points within taught courses. Management of these outcomes in the Dental Degree at Newcastle University has been a challenge in relation to quality assurance and enhancement, having over 1500 detailed student-level outcomes (SLO). This research aimed to explore the implications of adopting a more superficial "course" level of outcome (CLO), when reviewed against a reference set of external LO requirements.

MATERIALS AND METHODS

A purposive sample of five courses within the undergraduate dental programme was selected. The mapping of both SLOs and CLOs was reviewed in relation to their total number and the mapping connections to the reference outcomes.

RESULTS

There was a mean reduction of 79% in outcomes when comparing SLOs to CLOs. The number of mapping connections between CLOs and the reference set reduced in three courses and increased in two, when compared to SLOs.

DISCUSSION

From a purely numerical perspective, changing the detail of learning outcomes has led to a change in mapping connections. As the delivered curriculum has remained unchanged, this demonstrates a potential impact of differing interpretations of learning outcomes. Further review of learning outcomes in relation to the domains categorised within the reference outcome document suggested more mapping links were obtained in clinically focused courses than academic or theoretical courses.

CONCLUSION

A demonstrable impact in mapping connections was observed when the detail within the learning outcomes was changed. This has implications for programme leaders in structuring LOs for a curriculum.

Virtual courses: enhancing a curriculum

INTRODUCTION

Providers of education programmes are required to demonstrate to students, staff and external regulators the content of the programme and how this aligns to key outcomes. Whilst many programme themes are straightforward to illustrate, other integral themes prove challenging to demonstrate independently.

INNOVATION

A virtual course takes elements within the current programme relating to a specific theme, repackages and maps them to provide clear signposting by highlighting each occasion the theme is taught, experienced and assessed. The individual elements remain within their current course, so there is no disruption to the established curriculum, but there is an enhancement in terms of transparently displaying linkages within a theme.

DISCUSSION

Using the concept of virtual courses we have found we can respond to new initiatives and requirements of external regulators, as well as providing improved signposting for staff and students. This can be undertaken without the need to redesign a whole curriculum.

CONCLUSION

In well-designed and currently effective curricula, we would like to recommend that virtual course development can enhance programme transparency, demonstrate external regulatory requirements and promote quality assurance without disruption to current content.

Are implant supported overdentures too complex to be included in the undergraduate curriculum?

To widen the availability of implant supported mandibular overdentures, their inclusion in the undergraduate clinical training curriculum has been encouraged. The aim was to determine whether implant supported mandibular overdentures provided by undergraduates could achieve similar levels of improvement in patient satisfaction and quality of life as previously demonstrated by experienced prosthodontists. Nineteen patients were treated by Stage 3 undergraduate students at Newcastle University, School of Dental Sciences. Changes between pre-treatment and 3 month post-treatment satisfaction and oral health related quality of life suggest dental undergraduates achieve similar levels of improvement as experienced prosthodontists.

Embedding implant dentistry into the undergraduate dental curriculum

This article represents the consensus from a meeting of the British Society of Prosthetic Dentistry's Education Group which met to discuss implant dentistry at the undergraduate student level. The consensus recognises the need to embed the teaching of implant supported prostheses if such a treatment modality is to be widely practised after graduation. This short article makes some recommendations as well as detailing some challenges and barriers that need to be overcome if implant dentistry is to be successfully embedded in an undergraduate dental curriculum.

Facilitation of implant provision in primary care

OBJECTIVE

To investigate primary care practitioner participation in implant-supported mandibular overdenture (ISOD) provision.

DESIGN

Postal questionnaire.

SETTING

Primary dental care, North East England 2007.

SUBJECTS AND METHODS

Two hundred and ninety-five practitioners in North East England were sent questionnaires presenting a case-based scenario of a patient unable to manage a lower denture on an atrophic ridge. The questionnaire led them through the facilitation stages of ISOD provision, asking them to state their anticipated level of participation at each stage. Demographic details were also collected.

RESULTS

Two hundred and seventeen responses were received (74%). Most practitioners would consider the option of provision of ISODs (89%) in this case and all who considered would discuss the option with the patient. Of those offering to facilitate treatment, 66% (122/184) would never deliver themselves, with the majority (60%, 111/184) referring within primary care. Statistical analysis showed associations between demographics and behaviour.

CONCLUSIONS

The majority of practitioners in this study area would facilitate ISOD provision in this case. Practitioners who are male and working in a practice where a framework for the provision of implants already exists are most likely to facilitate provision and/or provide an ISOD within primary care.

Estimating influenza vaccine effectiveness using routinely collected laboratory data

BACKGROUND

Estimation of influenza vaccine effectiveness (V/E) is needed early during influenza outbreaks in order to optimise management of influenza--a need which will be even greater in a pandemic situation.

OBJECTIVE

Examine the potential of routinely collected virological surveillance data to generate estimates of V/E in real-time during winter seasons.

METHODS

Integrated clinical and virological community influenza surveillance data collected over three winters 2004/5-2006/7 were used. We calculated the odds of vaccination in persons that were influenza-virus-positive and the odds in those that were negative and provided a crude estimate of V/E. Logistic regression was used to obtain V/E estimates adjusted for confounding variables such as age.

RESULTS

Multivariable analysis suggested that adjustments to the crude V/E estimate were necessary for patient age and month of sampling. The annual adjusted V/E was 2005/6, 67% (95% CI 41% to 82%); 2006/7 55% (26% to 73%) and 2007/8 67% (41% to 82%). The adjusted V/E in persons <65 years was 70% (57% to 78%) and 65 years and over 46% (-17% to 75%). Estimates differed by small insignificant amounts when calculated separately for influenza A and B; by interval between illness onset and swab sample; by analysis for the period November to January in each year compared with February to April and according to viral load.

CONCLUSION

We have demonstrated the potential of using routine virological and clinical surveillance data to provide estimates of V/E early in season and conclude that it is feasible to introduce this approach to V/E measurement into evaluation of national influenza vaccination programs.

Detection of DNA damage: effect of thymidine glycol residues on the thermodynamic, substrate and interfacial acoustic properties of oligonucleotide duplexes

Thymidine glycol residues in DNA are biologically active oxidative molecular damage sites caused by ionizing radiation and other factors. One or two thymidine glycol residues were incorporated in 19- to 31-mer DNA fragments during automatic oligonucleotide synthesis. These oligonucleotide models were used to estimate the effect of oxidized thymidines on the thermodynamic, substrate and interfacial acoustic properties of DNA. UV-monitoring melting data revealed that modified residues in place of thymidines destabilize the DNA double helix by 8-22 degrees C, depending on the number of lesions, the length of oligonucleotide duplexes and their GC-content. The diminished hybridizing capacity of modified oligonucleotides is presumably due to the loss of aromaticity and elevated hydrophilicity of thymine glycol in comparison to the thymine base. According to circular dichroism (CD) data, the modified DNA duplexes retain B-form geometry, and the thymidine glycol residue introduces only local perturbations limited to the lesion site. The rate of DNA hydrolysis by restriction endonucleases R.MvaI, R.Bst2UI, R.MspR9I and R.Bme1390I is significantly decreased as the thymidine glycol is located in the central position of the double-stranded recognition sequences 5'-CC / WGG-3' (W = A, T) or 5'-CC / NGG-3' (N = A, T, G, C) adjacent to the cleavage site. On the other hand, the catalytic properties of enzymes R.Psp6I and R.BstSCI recognizing the similar sequence are not changed dramatically, since their cleavage site is separated from the point of modification by several base-pairs. Data obtained by gel-electrophoretic analysis of radioactive DNA substrates were confirmed by direct spectrophotometric assay developed by the authors. The effect of thymidine glycol was also observed on DNA hybridization at the surface of a thickness-shear mode acoustic wave device. A 1.9-fold decrease in the rate of duplex formation was noted for oligonucleotides carrying one or two thymidine glycol residues in relation to the unmodified analog.

Change in cardiovascular risk status after dental clearance

There is considerable debate over the relationship between periodontal and cardiovascular disease. It has been postulated that inflammatory mediators prevalent in periodontal disease may impact on atheroma formation and the thrombotic process. In cross-sectional, observational studies, periodontitis is associated with elevated C-reactive protein (CRP), hyperfibrinogenaemia and moderate leukocytosis. CRP levels have also been shown to decrease following periodontal therapy. CRP is a reliable marker of the acute phase reaction to infections and/or inflammation and is a powerful predictor of future coronary events.

Extremely low effective population sizes, genetic structuring and reduced genetic diversity in a threatened bumblebee species, Bombus sylvarum (Hymenoptera: Apidae)

Habitat fragmentation may severely affect survival of social insect populations as the number of nests per population, not the number of individuals, represents population size, hence they may be particularly prone to loss of genetic diversity. Erosion of genetic diversity may be particularly significant among social Hymenoptera such as bumblebees (Bombus spp.), as this group may be susceptible to diploid male production, a suggested direct cost of inbreeding. Here, for the first time, we assess genetic diversity and population structuring of a threatened bumblebee species (Bombus sylvarum) which exists in highly fragmented habitat (rather than oceanic) islands. Effective population sizes, estimated from identified sisterhoods, were very low (range 21-72) suggesting that isolated populations will be vulnerable to loss of genetic variation through drift. Evidence of significant genetic structuring between populations (theta = 0.084) was found, but evidence of a bottleneck was detected in only one population. Comparison across highly fragmented UK populations and a continental population (where this species is more widespread) revealed significant differences in allelic richness attributable to a high degree of genetic diversity in the continental population. While not directly related to population size, this is perhaps explained by the high degree of isolation between UK populations relative to continental populations. We suggest that populations now existing on isolated habitat islands were probably linked by stepping-stone populations prior to recent habitat loss.

Tutor perceptions of the use of a reflective portfolio within a pastoral tutor system to facilitate undergraduate personal development planning

All Higher Education Institutions in the UK are now required to provide transcripts of student activity and outcomes of summative assessments. In addition, the student should be able to reflect on their learning and plan their own development. This article reports on the staff evaluation of the use of a reflective portfolio facilitating the production of highly individualised personal development plans within an existing tutor system. A number of significant issues are highlighted; tutor systems adopting this approach must maintain flexibility for managing student crises when they arise, the difference between appraisal and assessment needs clear definition for both students and tutors, training in basic mentoring skills should be provided for all tutors, tutors should be aware of the difficulties many students experience with reflection and also be alert to the over reflective learner.

The management of drug-induced gingival overgrowth

OBJECTIVES

This review critically evaluates the different therapies that are available to manage drug-induced overgrowth (DIGO).

MATERIAL AND METHODS

This review is based on literature identified using the online databases MEDLINE and PUB MED. It is not a systematic review, but a conventional review of the relevant literature.

RESULTS

Patients benefit from a non-surgical approach if this can be delivered before commencement of medication although in many instances this may not be practicable. Systemic antibiotic usage has been evaluated in the management of ciclosporin-induced gingival overgrowth. Efficacy appears to be equivocal and long-term use is undesirable. Surgical excision remains the main treatment option especially for patients with severe overgrowth. Few studies have compared different techniques with respect to recurrence rate or post-operative sequelae.

CONCLUSION

DIGO is a common clinical problem that often requires intervention. Non-surgical techniques can limit the occurrence of this unwanted affect, reduce the extent of plaque-induced gingival inflammation and reduce the rate of recurrence. Wherever possible this management strategy should be adopted first. Surgical treatment is often the most reliable option and scalpel gingivectomy remains the treatment of choice. Further investigations are required to develop appropriate management strategies to prevent recurrence of DIGO.

The efficacy of three different surgical techniques in the management of drug-induced gingival overgrowth

OBJECTIVES

The aim of the present study was to evaluate the efficacy of three different surgical techniques in both the management and effect upon rate of overgrowth recurrence of drug-induced gingival overgrowth (DIGO).

MATERIALS AND METHODS

Two cohorts of patients who required surgical correction of their DIGO participated in the study. After baseline periodontal measures (plaque index, gingival inflammation and probing pocket depths), the patients underwent surgery. A split-mouth, crossover design was used to compare conventional gingivectomy with flap surgery (n=27), and conventional gingivectomy with laser excision (n=23). The main outcome variable was the rate of recurrence of DIGO following surgery.

RESULTS

At 6 months, there was significantly less recurrence (p=0.05) in patients treated with laser excision, compared with those treated by conventional gingivectomy. The differences in rate of recurrence of DIGO were also reflected in changes in several periodontal parameters. Flap surgery offered no advantage over conventional gingivectomy with respect to the rate of recurrence.

CONCLUSIONS

DIGO can be managed by a variety of techniques. Laser excision results in a reduced rate of recurrence.

Population structure and inbreeding in a rare and declining bumblebee, Bombus muscorum (Hymenoptera: Apidae)

Owing to habitat loss populations of many organisms have declined and become fragmented. Vertebrate conservation strategies routinely consider genetic factors, but their importance in invertebrate populations is poorly understood. Bumblebees are important pollinators, and many species have undergone dramatic declines. As monoandrous social hymenopterans they may be particularly susceptible to inbreeding due to low effective population sizes. We study fragmented populations of a bumblebee species, on a model island system, and on mainland Great Britain where it is rare and declining. We use microsatellites to study: population genetic structuring and gene flow; the relationships between genetic diversity, population size and isolation; and frequencies of (sterile) diploid males - an indicator of inbreeding. We find significant genetic structuring (theta = 0.12) and isolation by distance. Populations > 10 km apart are all significantly differentiated, both on oceanic islands and on the mainland. Genetic diversity is reduced relative to closely related common species, and isolated populations exhibit further reductions. Of 16 populations, 10 show recent bottlenecking, and 3 show diploid male production. These results suggest that surviving populations of this rare insect suffer from inbreeding as a result of geographical isolation. Implications for the conservation of social hymenopterans are discussed.

Analysis of changes in gingival contour from three-dimensional co-ordinate data in subjects with drug-induced gingival overgrowth

OBJECTIVES

This aim of this study was to develop and assess a technique that could be used to assess accurately the gingival volume changes seen in drug-induced gingival overgrowth by the analysis of data obtained from an entire gingival surface by means of three-dimensional imaging.

MATERIAL AND METHODS

Stone dental models of patients before and after gingivectomy procedures were digitized with a laser scanner and then regenerated as computer models constructed from the acquired three-dimensional co-ordinate data. A comparison of superposed "before" and "after" surfaces was undertaken to assess and accurately quantify changes in gingival contour.

RESULTS

The mean vertical tissue reduction varied from 1.58 to 2.56 mm in the four study subjects and individual differences are shown. The maximum thickness of removed buccal gingival overgrowth was found to range between 1.20 and 3.40 mm. The volume of tissue removed from each inter-dental papilla ranged from 4.2 to 46.1 mm3 and the mean volume of the papilla removed from each subject+/-SD values was 24.8+/-13.1 mm3.

CONCLUSION

This method will measure changes in gingival tissues to within 60 microm in one plane, making it ideal for the assessment of longitudinal changes in gingival contour as seen in the development of gingival overgrowth, its recurrence after surgery or the changes in volume brought about by surgery.

Plasma TGF-beta1 as a risk factor for gingival overgrowth

BACKGROUND AND AIMS

Induction of the pro-fibrotic growth factor TGF-beta1 has been suggested as a possible mechanism through which immunosuppressant drugs may induce gingival overgrowth. This study aims to investigate plasma levels of TGF-beta1 and relate them to the development and severity of gingival overgrowth in immunosuppressed transplant patients.

MATERIALS AND METHODS

One hundred and thirty-two ciclosporin-treated and 13 tacrolimus-treated transplant patients and 24 drug-free control subjects underwent a full periodontal examination including a determination of the presence and severity of gingival overgrowth.

RESULTS

Plasma TGF-beta1 concentrations were determined by ELISA, and were found to be significantly elevated in samples from the transplant patients (mean=29.1 ng/ml) as compared with controls (mean=6.1 ng/ml, p<0.0001). There was no significant difference between the levels of plasma TGF-beta1 in the ciclosporin- and tacrolimus-treated patient groups.

CONCLUSIONS

Furthermore, concomitant treatment with calcium channel blockers did not influence the levels of plasma TGF-beta1 in the patients group. The relationship between gingival overgrowth, independent periodontal variables and TGF-beta1 plasma concentrations was examined using univariate and multivariate regression analyses; low TGF-beta1 plasma concentrations were found to be a risk factor for gingival overgrowth in immunosuppressed patients concomitantly receiving a calcium channel blocker.

Direct atomic force microscopy observations of monovalent ion induced binding of DNA to mica

Multivalent ions in solution are known to mediate attraction between two like-charged molecules. Such attraction has proved useful in atomic force microscopy (AFM) where DNA may be immobilized to a mica surface facilitating direct imaging in liquid. Theories of DNA immobilization suggest that either 'salt bridging' or fluctuation in the positions of counter ions about both the mica surface and DNA backbone secure DNA to the mica substrate. Whilst both theoretical and experimental evidence suggest that immobilization is possible in the presence of divalent ions, very few studies identify that such immobilization is possible with monovalent ions. Here we present direct AFM evidence of DNA immobilized to mica in the presence of only monovalent ions. Our data depict E. coli plasmid pBR322 adsorbed onto the negatively charged mica both after short (10 min) and long (24 h) incubation periods. These data suggest the need to re-explore current theories of like-charge attraction to include the possibility of monovalent interactions. We suggest that this DNA immobilization strategy may offer the potential to image natural processes with limited immobilization forces and hence enable maximum conformational freedom of the immobilized biomolecule.

Prevalence of gingival overgrowth in transplant patients immunosuppressed with tacrolimus

AIMS

The study aims to determine the prevalence and severity of gingival overgrowth in a group of adult organ transplant recipients immunosuppressed with tacrolimus in comparison with ciclosporin, and to examine various risk factors for the development of gingival overgrowth.

METHODS

Forty patients taking tacrolimus were compared with 197 ciclosporin patients. Demographic, pharmacological and periodontal data were recorded for all patients. Comparison between the groups was made using independent sample t-tests, chi2 statistic or Mann-Whitney test. The effects of risk variables on overgrowth severity were examined using forward and backward stepwise regression analysis.

RESULTS

Those taking tacrolimus had a significantly lower mean gingival overgrowth score (14.1%) compared with ciclosporin (22.4%). Fifteen percent of the tacrolimus group had clinically significant gingival overgrowth compared with 30% in the ciclosporin group (p=0.053).

CONCLUSIONS

The prevalence and severity of gingival overgrowth is less in adult transplant patients taking tacrolimus compared with ciclosporin. Concomitant use of calcium channel blockers and previous medication with ciclosporin are significant risk factors for the presence and severity of gingival overgrowth. Patients who have alteration of their immunosuppressant from ciclosporin to tacrolimus may persist in demonstrating gingival overgrowth attributable to their ongoing therapy with calcium channel blockers.

Three years of low influenza activity--no reason for complacency

Influenza activity in England and Wales has been unusually low over the last three years. Despite this, substantial morbidity and mortality has occurred in subgroups of the population. Furthermore, the influenza season 2001/02 was characterised by the emergence of a new subtype of the influenza A virus (H1N2), a timely reminder that it is not possible to assess the impact of a change in the virus strains circulating without having a comprehensive surveillance infrastructure in place.

Cardiovascular diseases and periodontology

BACKGROUND

Cardiovascular diseases represent a widespread heterogeneous group of conditions that have significant morbidity and mortality. The various diseases and their treatments can have an impact upon the periodontium and the delivery of periodontal care.

AIM

In this paper we consider three main topics and explore their relationship to the periodontist and the provision of periodontal treatment.

METHOD

The areas reviewed include the effect of cardiovascular drugs on the periodontium and management of patients with periodontal diseases; the risk of infective endocarditis arising from periodontal procedures; the inter-relationship between periodontal disease and coronary artery disease.

RESULTS AND CONCLUSIONS

Calcium-channel blockers and beta-adrenoceptor blockers cause gingival overgrowth and tooth demineralisation, respectively. Evidence suggests that stopping anticoagulant therapy prior to periodontal procedures is putting patients at a greater risk of thromboembolic disorders compared to the risk of prolonged bleeding. The relationship between dentistry and infective endocarditis remains a controversial issue. It would appear that spontaneous bacteraemia arising from a patient's oral hygiene practices is more likely to be the cause of endocarditis than one-off periodontal procedures. The efficacy of antibiotic prophylaxis is uncertain (and unlikely to be proven), and the risk of death from penicillin appears to be greater than the risk of death arising from infective endocarditis. Finally, the association between periodontal disease and coronary artery disease has been explored and there seem to be many issues with respect to data handling interpretation. Many putative mechanisms have been suggested; however, these only further highlight the need for intervention studies.

Combined PCR-heteroduplex mobility assay for detection and differentiation of influenza A viruses from different animal species

Transfer of influenza A viruses from animal hosts to man may lead to the emergence of new human pandemic strains. The early detection and identification of such events are therefore paramount in the surveillance of influenza viruses. To detect and partially characterize influenza A viruses from different animal species, a combined reverse transcription (RT)-PCR heteroduplex mobility assay (HMA) was designed. This M gene RT-PCR was shown to be sensitive and specific for the detection of human, avian, and swine influenza A viruses. PCR amplicons from human, avian, and swine viruses of 15 different subtypes, with between 1.9 and 21.4% nucleotide divergence, were differentiated by HMA. Sequencing of the amplicons showed that the heteroduplex mobility patterns correlated with the sequence divergence between test and reference DNA. The application of the RT-PCR HMA method for rapid screening of samples was assessed with a reference panel of viruses of human, avian, and swine origin. The avian H9N2 virus A/HongKong/1073/99, which crossed the species barrier to humans, was screened against the reference panel. It was found to be most closely related to the avian A/Quail/HongKong/G1/97 H9N2 reference PCR product. Sequence analysis showed a nucleotide divergence of 1.1% between the A/Quail/HongKong/G1/97 and A/HongKong/1073/99 amplicons. From the results of our work, we consider the RT-PCR HMA method described to offer a rapid and sensitive means for screening for novel or unusual influenza viruses.

Photographic scoring of gingival overgrowth

BACKGROUND

A wide range of methods have been employed to determine the severity of gingival overgrowth resulting in uncertainty regarding the prevalence of the side-effect. There is no simple, non-invasive, objective, blind method for assessing gingival overgrowth.

AIM

This article aims to describe a method which is suitable for use in large-scale population studies.

MATERIALS AND METHODS

Photographs were taken of the anterior, buccal gingivae and teeth of 925 patients medicated with calcium channel blockers. In addition, each patient was ascribed a clinical gingival overgrowth score. 100 patients had repeat photographs, and a further 10 patients had alginate impressions taken. The models were scored for severity of gingival overgrowth using a described technique. The slides were scored using a modification of this technique.

RESULTS

When photographic and study model scores were compared, photographic scores were consistently higher, and as a result, a photographic score of 38.6% was considered to represent a significant overgrowth. There was good agreement between clinically determined scores and photographic scores (kappa=0.71).

CONCLUSIONS

The results indicate that this method is suitable for large-scale population studies where it also has the advantage of providing a continuous scale of gingival changes for subsequent statistical analysis.

Risk factors for drug-induced gingival overgrowth

BACKGROUND/AIMS

Drug-induced gingival overgrowth remains a significant problem for the periodontologist. Many patients medicated with the drugs implicated in this unwanted effect experience significant, recurrent gingival problems that require repeated surgical excisions. In this review, we attempt to identify and quantify the various "risk factors" associated with both the development and expression of the drug-induced gingival changes.

METHOD

The risk factors appraised include age, sex, drug variables, concomitant medication, periodontal variables and genetic factors. Elucidation of such factors may help to identify "at risk patients" and then develop appropriate treatment strategies.

RESULTS

Of the factors identified, the only one that can be affected by the periodontologist is the patents' periodontal condition. However, drug variables and concomitant medication do impact upon the expression of gingival overgrowth.

CONCLUSION

The identification of risk factors associated with both the prevalence and severity of drug-induced gingival overgrowth is important for all parties involved with this unwanted effect. Both periodontologist and patient have an important rôle to play in improving oral hygiene and gingival health. Likewise, there is always an opportunity to establish a close liaison between the patient's physician and the periodontologist to try and identify alternative drug regimens that can help reduce the impact of this unwanted effect.

Prevalence of gingival overgrowth induced by calcium channel blockers: a community-based study

BACKGROUND

The prevalence of gingival overgrowth induced by chronic medication with calcium channel blockers is uncertain. Although there have been several studies examining this question, the results are conflicting, with previous estimates ranging from 20% to 83%. There have been only 2 studies examining the prevalence of overgrowth induced by diltiazem and amlodipine, with estimates of 74% and 3.3%, respectively.

METHODS

The current study aimed to address the problems associated with these studies by examining a sample of patients taking one of 3 calcium channel blockers, who were drawn from a community-based population in northeastern England. Nine hundred eleven (911) subjects were recruited from general medical practices in the area. Of these, 442 were taking nifedipine, 181 amlodipine, and 186 diltiazem. In addition, 102 control subjects were examined. Drug and demographic data for each subject were recorded. The periodontal condition of all subjects was assessed including plaque index, papillary bleeding index, and a photograph of the anterior gingivae for subsequent analysis of overgrowth severity.

RESULTS

More than six percent (6.3%) of subjects taking nifedipine were seen to have significant overgrowth. This overgrowth was statistically greater than the amount of overgrowth seen in either of the other 2 drug groups or the control population. The prevalence of gingival overgrowth induced by amlodipine or diltiazem was not statistically significant when compared to the control group. The severity of overgrowth within the nifedipine group was found to be related to the amount of gingival inflammation and also to the gender of the subject, with males being 3 times as likely to develop overgrowth than females.

CONCLUSIONS

The prevalence of clinically significant overgrowth related to chronic medication with calcium channel blockers is low, i.e., 6.3% for nifedipine. Males are 3 times as likely as females to develop clinically significant overgrowth. The presence of gingival inflammation is an important cofactor for the expression of this effect.

Multiplex PCR for typing and subtyping influenza and respiratory syncytial viruses

A multiplex reverse transcription (RT)-PCR method that has been developed is capable of detecting and subtyping influenza A (H1N1 and H3N2) and B viruses as well as respiratory syncytial virus (RSV) types A and B in respiratory clinical samples taken as part of a national community-based surveillance program of influenza-like illness in England and Wales. The detection of each different pathogen depended on distinguishing five amplification products of different sizes on agarose gels following RT-PCR with multiple primer sets. The multiplex RT-PCR was tested with 65 nasopharyngeal apirates from which RSV had been isolated and 237 combined nose and throat swabs from which influenza A (H1N1 and H3N2) or B virus had been detected by virus isolation, as well as 40 respiratory samples from which other viruses including cytomegalovirus, herpes simplex virus, enteroviruses, and parainfluenza viruses had been grown. For the typing and subtyping of influenza A and B viruses and RSV types A and B, the multiplex RT-PCR gave an excellent (100%) correlation with the results of conventional typing and subtyping with specific antisera. Multiplex RT-PCR can also be used to accurately detect more than one viral template in the same reaction mixture, allowing viral coinfections to be identified with the same respiratory specimen.

Chronic anemia due to parvovirus B19 infection in a bone marrow transplant patient after platelet transfusion

BACKGROUND

Many reports document the transmission of human parvovirus B19 (B19) infection by clotting factor concentrates manufactured from large plasma pools. Transmission via other blood components originating from a single donor or a small number of donors, however, seems to occur only rarely. The study reported here identifies a B19 infection that was transmitted via a platelet donation.

CASE REPORT

A multiply transfused allogeneic bone marrow transplant patient developed chronic anemia due to persistent B19 infection. The anemia responded to therapy with intravenous immunoglobulin. It was postulated that a transfusion was the source of the B19 infection. Archived sera from 90 implicated blood donors were tested for B19 IgM and DNA by the use of dot-blot hybridization and a nested polymerase chain reaction with primers from the B19 nonstructural gene. B19 DNA from patient and donor sera were sequenced. One of the 90 blood donors (Donor A) was B19 IgM positive and had a high level of B19 DNA. The patient was viremic 3 days after transfusion of platelets from this donor, and the sequence of B19 DNA from the patient exactly matched that of B19 DNA from the donor. A second blood donor (Donor B) had a low level of B19 DNA but was IgM negative. The patient showed no evidence of B19 infection after the transfusion of red cells from Donor B, and the sequence of this donor's B19 DNA was different from that in the patient.

CONCLUSION

Blood Donor A with asymptomatic acute B19 infection was the source of B19 infection in the bone marrow transplant patient. Donor B with a low level of B19 DNA was not the source of infection.

Multiplex reverse transcription-PCR for surveillance of influenza A and B viruses in England and Wales in 1995 and 1996

Multiple-target (multiplex) reverse transcription-PCR (RT-PCR) for detection, typing, and subtyping of the hemagglutinin gene of influenza type A (H3N2 and H1N1) and type B viruses was developed and applied prospectively to virological surveillance of influenza in England in the 1995-1996 winter season. During this season both influenza A H3N2 and H1N1 viruses were circulating, although at different times. Six hundred nineteen combined nose and throat swabs taken by general practitioners in sentinel practices from individuals presenting with "influenzalike illness" were analyzed by culture, multiplex RT-PCR, and immunofluorescence. Of the 619 samples, 246 (39.7%) were positive by multiplex RT-PCR compared with 200 (32.3%) which yielded influenza viruses on culture. There was 100% correlation between multiplex RT-PCR typing and subtyping and the influenza types and subtypes obtained from culture. There was also excellent correlation between the temporal detection of influenza A H3N2 and H1N1 viruses by multiplex RT-PCR and by culture. During the peak weeks of influenza virus activity, a total of 259 specimens were received, of which 101 (38.9%) yielded influenza viruses on culture while 149 (57.5%) were positive in multiplex RT-PCR, providing an increase in detection of influenza viruses of approximately 20%. The increased detection of influenza virus occurred in all the age groups sampled. Samples which were positive by multiplex RT-PCR but negative by culture were not detected significantly earlier or later in the winter of 1995-1996 but were detected during the peak weeks of clinical influenza virus activity. Multiplex RT-PCR was successfully used in surveillance of influenza to provide accurate, sensitive diagnosis directly on clinical specimens sent through the post.

Analysis of influenza A H3N2 strains isolated in England during 1995-1996 using polymerase chain reaction restriction

A polymerase chain reaction-restriction (PCR-restriction) endonuclease assay was developed to allow rapid analysis of influenza A H3N2 viruses circulating in England during 1995-1996. Restriction endonuclease digestion with two enzymes of amplicons derived from PCR of the HA1 portion of the influenza haemagglutinin (HA) gene was able to differentiate antigenically similar influenza strains into two groups. Group I variants were similar genetically to the 1995/96 vaccine strain, A/Johannesburg/33/94, whereas the HA sequences of Group II variants were similar genetically to the reference virus A/Thessaloniki/1/95. Of the 700 England A H3N2 strains isolated between February 1995 and the end of April 1996, 384 were analysed by this method. PCR-restriction analysis of sequential influenza isolates revealed a temporal alteration in prevalence of two variants. Groups I and II variants cocirculated with equal frequency during a period of sporadic influenza activity, but following the onset of epidemic influenza activity in 1995, only Group II variants were detected. PCR- restriction analysis was found to be a rapid method for studying genetic variation which could be applied to a large number of samples and provide information about the direction of genetic drift in the HA gene of influenza virus.

Nifedipine pharmacological variables as risk factors for gingival overgrowth in organ-transplant patients

The prevalence and severity of gingival overgrowth in organ-transplant patients medicated with cyclosporin are greater in patients concomitantly medicated with nifedipine; however, no relationship between the gingival overgrowth and any of the nifedipine pharmacological variables has been demonstrated. The study examined the effect of five nifedipine pharmacological variables (nifedipine dosage, plasma concentration and gingival crevicular fluid concentration, M1 metabolite plasma concentration and the nifedipine: M1 ratio). The effect of the nifedipine variables on the gingival overgrowth score were examined using univariate and multivariate regression analysis. Adjustment for the effect of other risk factors was made by adding the distribution of each of the nifedipine variables in turn to a stepwise regression model containing previously identified risk factors for this condition. Despite the high levels of nifedipine sequestered in the GCF, only the plasma concentration of nifedipine was identified as a risk factor for the severity of gingival overgrowth in these patients (P = 0.01) once adjusted for other known risk factors (R2 for the model = 55%).

Molecular analysis of an outbreak of influenza in the United Kingdom

The first outbreak of influenza virus in Europe in 1995/1996 occurred in a school in the south of England. RT-PCR-restriction analysis was performed on the HA1 portion of influenza haemagglutinin gene amplified directly from clinical samples. These were taken at the onset of the outbreak and indicated co-circulation of two distinct genetic variants of influenza virus which were antigenically identical. Investigations of this nature demonstrate the genetic diversity of circulating variants of influenza and have the potential to provide information on molecular evolution of strains within closed populations.

Determinants of gingival overgrowth severity in organ transplant patients. An examination of the rôle of HLA phenotype

The role of HLA phenotype as a risk factor for drug-induced gingival overgrowth was investigated in a cohort of 172 transplant recipients. Clinically significant overgrowth warranting surgical correction was observed in 72 patients (42%). Using stepwise regression modelling, 6 clinical parameters were identified as significant risk factors for the severity of gingival overgrowth. These were; age, sex, creatinine plasma level, duration of therapy, papilla bleeding index and concomitant medication with a calcium channel blocking drug. 3 HLA alleles were also identified as risk factors when adjusted for other clinically significant risk factors (HLA -DR2, A24, B37). However, when the p-values for the HLA variables were corrected to compensate for the use of multiple significance testing, only HLA-B37 remained statistically significant at the 5% level. Organ transplant patients are at risk of developing gingival overgrowth, with approximately 25% medicated with cyclosporin alone requiring corrective gingival surgery. This figure more than doubles in patients concomitantly medicated with a calcium blocking drug. The data at present available would suggest that the severity of gingival overgrowth is also significantly associated with the HLA-B37 phenotype.

Automated gas chromatographic assay for amlodipine in plasma and gingival crevicular fluid

This paper describes an automated capillary gas chromatographic method for the determination of amlodipine in plasma, and in sub-microlitre volumes of gingival crevicular fluid (GCF), in order to assess if amlodipine is present in GCF under conditions of gingival overgrowth, as has been shown for nifedipine, another dihydropyridine drug. Liquid-liquid extraction followed by derivatisation was employed to isolate amlodipine and render it suitable for gas chromatography. Amlodipine was analysed in plasma and GCF of four patients undergoing amlodipine therapy for cardiovascular disorders, three of whom had significant gingival overgrowth. Amlodipine was detected in the plasma of all patients and in massive concentrations in the GCF of those patients with overgrowth, 23- to 290-fold greater than in their plasma. Like nifedipine, amlodipine sequestration into GCF appears to be linked with gingival overgrowth.

The pathogenesis of drug-induced gingival overgrowth

Gingival overgrowth is a well-documented unwanted effect, associated with phenytoin, cyclosporin, and the calcium channel blockers. The pathogenesis of drug-induced gingival overgrowth is uncertain, and there appears to be no unifying hypothesis that links together the 3 commonly implicated drugs. In this review, we consider a multifactorial model which expands on the interaction between drug and/or metabolite, with the gingival fibroblasts. Factors which impact upon this model include age, genetic predisposition, pharmacokinetic variables, plaque-induced inflammatory and immunological changes and activation of growth factors. Of these, genetic factors which give rise to fibroblast heterogeneity, gingival inflammation, and pharmacokinetic variables appear to be significant in the expression of gingival overgrowth. A more thorough understanding of the pathogenesis of this unwanted effect will hopefully elucidate appropriate mechanisms for its control.

Genetic and antigenic variation in the haemagglutinin of recently circulating human influenza A (H3N2) viruses in the United Kingdom

Variation in the haemagglutinin (HA) gene of influenza A (H3N2) viruses isolated in the U.K. and abroad from 1992-1994, was determined by nucleotide sequencing of the HA1 domain of the HA gene. Viruses isolated in the U.K. early in the 1992-93 season were from the A/Beijing/353/89 lineage and were replaced later that season by viruses from the A/Beijing/32/92 lineage. Viruses from the new lineage continued to be isolated during the 1993-94 season, but were heterogeneous. Most of these isolates were more closely related to an A/Beijing/32/92 variant, A Hong Kong/23/92, but could be distinguished into three groups by serology (of which one group was circulating during the previous season) and four groups based on sequence variation in the HA gene. However, phylogenetic analysis of antigenically-distinct isolates showed that the HA gene is evolving along one lineage. Sequence analysis identified mainstream, subgroup and strain specific amino acid substitutions. There was a broad correlation between the observed amino acid changes and the antigenic sites of the HA. The results of this study highlight the value of regular molecular analysis of circulating viruses.

Iatrogenic gingival overgrowth in cardiac transplantation

It is well established that both cyclosporin and nifedipine are associated with gingival overgrowth. Although both drugs are widely used in the management of organ transplant patients, there is little information on the prevalence and severity of this unwanted effect in cardiac transplant patients. This study evaluated the gingival health of 94 dentate cardiac transplant patients, all of whom were medicated with cyclosporin as a component of their immunosuppressive therapy. Sixty-three (63) of the patients were also medicated with nifedipine. Significantly higher gingival overgrowth scores (P < 0.0001) and periodontal probing depths (P = 0.001) were observed in patients medicated with the combination of cyclosporin and nifedipine than those medicated with cyclosporin alone. Likewise, there was a significantly greater need to carry out gingival surgery on patients taking the combination (62%), than those medicated with cyclosporin alone (25.8%) (P = 0.001). Patient's age, sex, duration of therapy, gingival bleeding index, and nifedipine therapy were important determinants for both the expression of gingival overgrowth and the need for surgery. Significant sequestration of nifedipine in the gingival crevicular fluid (GCF) was observed. The concentration of nifedipine in GCF did not relate to either the gingival changes or plasma concentration of the drug. Cardiac transplant patients are at risk of developing gingival overgrowth and approximately 50% require surgical intervention. This risk increases significantly when patients are medicated concomitantly with nifedipine.

Periodontal variables affecting nifedipine sequestration in gingival crevicular fluid

We previously demonstrated the sequestration of nifedipine in gingival crevicular fluid (GCF), especially in patients exhibiting significant gingival overgrowth. The aim of the present study is to determine the role of site specific periodontal factors in this phenomenon. 10 adult patients exhibiting nifedipine induced gingival overgrowth were studied. In each patient GCF was harvested from two sites that demonstrated inflammation and increased probing depth as well as from two clinically healthy sites. The concentration of nifedipine was determined using gas chromatography. Drug concentrations were significantly increased in the presence of inflammation (p = 0.004) and plaque (p = 0.029) whilst increased probing depths and gingival overgrowth were not significantly related to drug sequestration. We can conclude that inflammatory changes in gingival tissues appear to be a significant determinant for the sequestration of nifedipine in the GCF.

Oral and dental problems in the organ transplant patient

The number of people receiving organ transplants has dramatically increased over the last decade. It is now likely that a dental surgeon will come across patients who have undergone transplantation. This paper considers the particular problems that these patients are likely to present their general dental practitioners.

Amlodipine-induced gingival overgrowth

Amlodipine is a calcium channel blocker used in the management of angina and hypertension. We report 3 cases of gingival overgrowth in adult dentate patients associated with chronic usage of this drug. Gingival changes occurred within 3 months of dosage and appeared to be compounded by the patient's existing periodontal condition. In all 3 patients, there was sequestration of amlodipine in their crevicular fluid. The significance of this finding in relation to the pathogenesis of this unwanted effect remains to be elucidated.

Drug-induced gingival overgrowth and its management

Gingival overgrowth is associated with the chronic usage of phenytoin, cyclosporin and the dihydropyridines. The pathogenesis of this unwanted effect is uncertain but appears to be enhanced by plaque-induced gingival inflammation. Certain patients appear to be more susceptible to gingival overgrowth and this may be related to gingival fibroblast phenotypes. In most cases, treatment involves surgical excision, followed by a concentrated oral hygiene programme. Recurrence of gingival overgrowth is a persistent problem particularly in the 'responder' patients. If an alternative, suitable medication is available, it may be worth while considering such a change through consultation with the patient's physician. Since patients are retaining their teeth into old age, the prevalence of this unwanted effect is likely to increase.

Determination of nifedipine in gingival crevicular fluid: a capillary gas chromatographic method for nifedipine in microlitre volumes of biological fluid

This paper describes a sensitive capillary gas chromatographic (GC) method for the determination of nifedipine in sub-microliter samples of gingival crevicular fluid (GCF) in order to assess if nifedipine is present in the GCF and if so, whether the local tissue concentrations of this drug are an important determinant in the development of gingival overgrowth. Liquid-liquid and solid-phase extraction were combined to give adequate sample clean-up and concentration for measurement by automated capillary GC with electron capture detection. Nifedipine and its principal metabolite, M-I, were analysed in both plasma and GCF in 9 adult male patients who had been taking nifedipine for over six months. M-I could not be measured in GCF. Plasma nifedipine and M-I levels were normal, but the nifedipine levels found in the GCF of 7 patients (including all those with overgrowth) were remarkably elevated, 15 to 316-fold greater. This massive concentration of nifedipine into the GCF is therefore linked with gingival overgrowth. This is the first time that a GC method has been developed which permits determination of GCF pharmacokinetics of a drug which causes gingival overgrowth, and further investigation will lead to a better understanding of the tissue mechanisms involved.

Disposition of nifedipine in plasma and gingival crevicular fluid in relation to drug-induced gingival overgrowth

The present study investigates the relationship between the pharmacokinetic variables of nifedipine with the incidence and severity of gingival overgrowth in 9 adult male patients medicated with the drug for at least 6 months. Five of the patients had experienced significant gingival changes and were thus designated "responders". The remaining four patients exhibited no gingival overgrowth, and thus acted as a control. A baseline periodontal examination (plaque scores, bleeding index and gingival overgrowth assessment) was carried out on each patient, and confined to the upper and lower anterior teeth. Serial blood and gingival crevicular fluid samples were collected over an eight-hour investigation period. Samples were analyzed for nifedipine by gas chromatography. No significant difference (p > 0.05) was seen between responders and non-responders with regard to drug therapy, periodontal parameters or plasma pharmacokinetics of nifedipine. Nifedipine was detected in the gingival crevicular fluid of seven subjects (all responders, and two non-responders). The peak concentration of nifedipine in crevicular fluid was 15-90 fold greater than levels observed in plasma.

Sensitization of allo-specific T lymphocytes in vivo: role of antigen-presenting cells

The migratory behavior of antigen-presenting cells was investigated in vivo. Purified murine splenic dendritic cells and splenic and peritoneal macrophages were labelled and injected subcutaneously in the hind foot-pads of mice and monitored for seven days. In the first 24 h, a small quantity of label was recovered from popliteal but not inguinal lymph nodes with radioactive (111In-oxine and 3H-uridine) but not fluorescent (1,1'-dioctadecyl 3,3,3'3'-tetramethylindocarbocyanine perchlorate and fluorescein isothiocyanate) labelling of the antigen-presenting cells. Chemical fixation of the injected antigen-presenting cells had no effect on the detection of label in the popliteal lymph nodes, suggesting that it was unlikely to be due to active cellular migration. Label recovery from hind feet declined with time over the seven day period and was independent of the label type. Essentially the same observations were made whether the antigen-presenting cells were syngeneic or allogeneic to the injected mice and irrespective of the type of antigen-presenting cell used. However, allogeneic antigen-presenting cells, which did not migrate to the draining lymph nodes, successfully primed T lymphocytes in these lymph nodes as shown by a secondary in vitro mixed leukocyte reaction. Again, chemical fixation of the injected antigen-presenting cells had no effect on their ability to prime allogeneic T lymphocytes in the draining lymph nodes. These experiments suggest that, during experimental allo-sensitization via the subcutaneous route, indirect priming of allogeneic T lymphocytes may be a dominant pathway.

Adjuvant composition determines the induction of type II collagen-induced arthritis

In this study we have investigated the influence of adjuvant composition on the development of collagen-induced arthritis and of anti-collagen type II specific B- and T-cell responses following immunization with type II collagen. DBA/l mice immunized with bovine collagen type II emulsified in complete Freund's adjuvant (CFA) containing Mycobacterium tuberculosis strain H37Ra developed footpad swelling indicative of arthritis. Animals immunized with collagen type II plus CFA containing Mycobacterium butyricum, or incomplete Freund's adjuvant showed no significant increase in footpad width. Induction of anti-CII specific T-cell proliferation was also dependent upon immunization with CII plus CFA containing M. tb H37RA. In contrast, ovalbumin-reactive T-cell proliferation was unaffected by the species of mycobacteria, indicating that the difference in adjuvant activity of the mycobacterial species is specific for anti-collagen type II T-cell responses. Antibody response to collagen type II, unlike T-cell responses, was not significantly different using the two adjuvants. This study therefore demonstrates that murine collagen-induced arthritis requires immunization with collagen type II together with complete Freund's adjuvant containing Mycobacterium tuberculosis H37RA. Since only this combination of antigen and adjuvant induces detectable arthritis and T-cell responses against collagen type II, while antibody synthesis does not have such stringent adjuvant requirements, this suggests that the development of the full pattern of the collagen-induced arthritis disease requires synergistic activation of both humoral and cell-mediated responses.

Gingival sequestration of nifedipine in nifedipine-induced gingival overgrowth

The mechanism of gingival overgrowth associated with long-term use of nifedipine and of other drugs that affect calcium homoeostasis, such as cyclosporin and phenytoin, is unknown. With an ultrasensitive assay, we measured the pharmacokinetics of nifedipine in plasma and gingival crevicular fluid (GCF) of nine patients receiving this drug for angina and hypertension. In seven patients, the maximum nifedipine concentration was in the range 15-316 (mean 84 [SD 105]) times greater in GCF than in plasma. The two patients with low (undetectable) GCF nifedipine did not have overgrowth. We propose that gingival tissues sequester nifedipine and that the very high nifedipine concentrations predispose the tissues to overgrowth.

Antigen processing for presentation by class II major histocompatibility complex requires cleavage by cathepsin E

Proteolytic degradation (processing) of antigen by antigen-presenting cells is a major regulatory step in the activation of a T lymphocyte immune response. However, the enzymes responsible for antigen processing remain largely undefined. In this study we show that cathepsin E, and not the ubiquitous lysosomal cathepsin D, is the major aspartic proteinase in a murine antigen-presenting cell line, A20. This enzyme is localized to a non-lysosomal compartment of the endosomal system in these cells. Functional studies using a highly specific inhibitor of cathepsin E show that this enzyme is essential for the processing of ovalbumin by this cell line. Thus, cathepsin E, whose function was hitherto unknown, may play a major role in antigen processing.

Chemically modified antigen-presenting cells induce T lymphocyte allospecific hyporesponsiveness

We have investigated the interaction between murine T lymphocytes and allogeneic APC in an in vitro proliferative mixed leukocyte reaction. Our results demonstrate that freshly isolated potentially alloreactive murine splenic T lymphocytes, in primary culture, can be induced to develop a state of allospecific proliferative hyporesponsiveness in vitro by exposure to 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide-modified allogeneic APC, a method similar to that previously used to induce nonresponsiveness in murine Ag-specific self-MHC-restricted T lymphocyte clones. This hyporesponsiveness was: specific for the allohaplotype of inducing APC, maintained for 96 h in vitro, not due to cellular inhibitory mechanisms, and associated with reduced ability to secrete IL-2 but not IL-3. Induction of this hyporesponsiveness was not due to altered expression of class II MHC gene products on the APC but was associated with markedly reduced T lymphocyte-APC adhesive interactions despite the lack of a detectable immunophenotypic change in lymphocyte function-associated Ag 1 (LFA-1) and intercellular adhesion molecule 1 (ICAM-1) expression on the modified APC. Therefore, we propose that TCR occupancy in the absence of normal T lymphocyte-APC adhesive clustering may induce T lymphocyte tolerance.

Chemically modified antigen-presenting cells induce T lymphocyte allospecific hyporesponsiveness

We have investigated the interaction between murine T lymphocytes and allogeneic APC in an in vitro proliferative mixed leukocyte reaction. Our results demonstrate that freshly isolated potentially alloreactive murine splenic T lymphocytes, in primary culture, can be induced to develop a state of allospecific proliferative hyporesponsiveness in vitro by exposure to 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide-modified allogeneic APC, a method similar to that previously used to induce nonresponsiveness in murine Ag-specific self-MHC-restricted T lymphocyte clones. This hyporesponsiveness was: specific for the allohaplotype of inducing APC, maintained for 96 h in vitro, not due to cellular inhibitory mechanisms, and associated with reduced ability to secrete IL-2 but not IL-3. Induction of this hyporesponsiveness was not due to altered expression of class II MHC gene products on the APC but was associated with markedly reduced T lymphocyte-APC adhesive interactions despite the lack of a detectable immunophenotypic change in lymphocyte function-associated Ag 1 (LFA-1) and intercellular adhesion molecule 1 (ICAM-1) expression on the modified APC. Therefore, we propose that TCR occupancy in the absence of normal T lymphocyte-APC adhesive clustering may induce T lymphocyte tolerance.