M. Macluskey

Apoptosis, proliferation, and angiogenesis in oral tissues. Possible relevance to tumour progression

Experimental animal models have demonstrated that angiogenesis is essential for tumour progression, whilst sustained tumour growth requires a positive balance between tumour cell proliferation and cell death (apoptosis). The aim of this study was to determine the relative contribution of apoptosis, proliferation, and angiogenesis to disease progression in the oral mucosa. Histological sections of 47 archival specimens were examined; these included four groups of oral tissues: normal mucosa (n=12), moderate dysplasia (n=11) severe dysplasia (n=6), and squamous cell carcinoma (n=18). Apoptotic cells were visualized by in‐situ end‐labelling of DNA, proliferative cells by staining with Ki‐67 antibody, and blood vessels with von Willebrand factor (vWF) antibody. One‐way analysis of variance showed that indices of apoptosis (AI), proliferation (PI), and angiogenesis (vascularity) increased significantly with disease progression from normal oral mucosa, through dysplasia, to carcinoma (p<0.0001 for every index). The increase from normal mucosa to moderate dysplasia was significant for PI and vascularity, but not for AI. In contrast, the increase from dysplasia to carcinoma was significant for AI and vascularity, but not for PI. These data suggest that disease progression in the oral mucosa is accompanied by angiogenesis and increases in both epithelial proliferation and apoptosis. Net epithelial growth results from proliferation starting earlier and proceeding at a higher rate than apoptosis. Copyright

UK national curriculum for undergraduate oral surgery subgroup for teaching of the Association of British Academic Oral and Maxillofacial Surgeons

This article describes a curriculum in oral surgery for undergraduate dental education in the United Kingdom prepared by the Education Subgroup of The British Academic Oral and Maxillofacial Surgeons. This group is made up of representatives from each of the 13 UK Dental Schools, one Irish Dental School and one Post-graduate Institute. The document represents a group consensus of an undergraduate UK oral surgery curriculum that is founded on the frameworks outlined by the General Dental Council, the Quality Assurance Agency for Higher Education and the Association for Dental Education in Europe. Our curriculum document is more prescriptive than the information available in the aforementioned documents. It is based on UK undergraduate oral surgery experience and thus attempts to set achievable core competencies and, in a few areas, challenges the available curriculum and related documentation.

The association between epithelial proliferation and disease progression in the oral mucosa

The purpose of this study was to examine the possible association between epithelial proliferation and disease progression in the oral mucosa. Archival specimens of normal oral mucosa (n = 12), dysplasia (n = 17) and squamous cell carcinoma (n = 18) were sectioned and proliferating cells visualised by staining with Ki-67 antibody. The proliferative index of the epithelium (PI) was determined by total cell counts and point counting. Similar results were obtained using either method. Comparison of the three groups of tissues by one-way analysis of variance showed a significant increase in PI with increasing lesion severity (p < 0.001). The PI of both dysplasia and carcinoma groups was significantly higher than that of normal oral mucosa (p < 0.001). However, the difference between dysplasia and carcinoma groups was not significant. PI was not associated with tobacco or alcohol consumption. We therefore conclude that Ki-67 expression is an early marker of disease progression in the oral mucosa but, on its own, is not a good indicator of neoplastic transformation.

Oral surgery undergraduate teaching and experience in the United Kingdom: a national survey

The aim of this work was to determine the structure, mode of delivery, mode of assessment and staffing of the oral surgery undergraduate curriculum within UK dental schools. A questionnaire was distributed by e-mail in January 2006 to each of the 15 dental schools with undergraduate dental degree programmes in Ireland and the UK. Those providing feedback then met to clarify any areas as required. Thirteen completed questionnaires were returned. There were a total of 55 academics involved in the teaching of oral surgery at these 13 institutions. Over the three clinical years the mean number of clinical sessions was 51. The mean staff student ratio for supervision of forceps exodontia was 1:5. On average 51 teeth were extracted by each student in the clinical years. The mean staff student ratio for surgical extractions was 1:2. The mean number of surgical extractions for each student was 6. All schools formatively assessed competency in forceps exodontia and 9 of 13 assessed surgical extractions. Summative assessment of exodontia was done in six schools and surgical extractions in 4 of 13 schools. All 13 schools deliver teaching programmes designed to meet the requirements of the frameworks governing the central curriculum. There were, however, variations between individual schools in the content and delivery of the oral surgery clinical teaching programmes. There were dramatic variations in the numbers of academic staff involved and some institutions relied on their NHS colleagues to deliver the clinical teaching.

Expression of Vascular Endothelial Growth Factor in Normal and Tumour Oral Tissues Assessed with Different Antibodies

Expression of vascular endothelial growth factor (VEGF) in oral tissues was assessed using different antibodies. Quantitative and topographical differences were observed between paraffin and cryostat sections. Two polyclonal antibodies (PC36, PC37) differing in their cross-reactivity with VEGF121 (not recognized by PC36), were used to stain serial cryostat sections of normal oral mucosa (n=8) and squamous cell carcinoma (n=7). The expression of VEGF in the epithelium was overall higher with PC37 than with PC36, the difference being significant in normal oral mucosa (p=0.001) but not in squamous cell carcinoma samples (p=0.094). With PC36, VEGF expression was significantly higher in squamous cell carcinoma than in normal oral mucosa specimens, whereas the opposite was true with PC37. Our results suggest that the relative levels of isoform 121 to that of 165 (and possibly others) may be different in the tissues examined, with VEGF121 preferentially expressed in normal oral mucosa. Previously published conflicting results may, therefore, be due to the presence of variable ratios of VEGF isoforms in the tissues examined, combined with differences in the cross-reactivity of the antibodies used. VEGF isoforms 121, 165 and (for the first time) 189 were detected in two frozen oral tissues by polymerase chain reaction amplification. Quantification of specific VEGF isoforms will be required in future studies concerned with the clinical value of VEGF expression.

Is there a pAkt between VEGF and oral cancer cell migration

The PI3K-Akt signalling pathway is a well-established driver of cancer progression. One key process promoted by Akt phosphorylation is tumour cell motility; however the mechanism of VEGF-induced Akt phosphorylation leading to motility remains poorly understood. Previously, we have shown that Akt phosphorylation induced by different factors causes both stimulation and inhibition of motility in different cell types. However, differential phosphorylation of Akt at T308 and S473 residues by VEGF and its role in head and neck cancer cell motility and progression is unknown. The cell lines investigated in this study exhibited a change in phosphorylation of Akt in response to VEGF. However, in terms of motility, VEGF stimulated oral cancer and its associated cell lines, but not normal keratinocytes or oral mucosal fibroblasts. The addition of a PI3 kinase and mTOR inhibitor, inhibited the phosphorylation of Akt and also effectively blocked VEGF-induced oral cancer cell motility, whereas only the PI3 kinase inhibitor blocked oral cancer associated fibroblast cell motility. This study therefore discloses that two different mechanisms of Akt phosphorylation control the motility potential of different cell lines. Akt phosphorylated at both residues controls oral cancer cell motility. Furthermore, immunohistochemical analysis of VEGF positive human head and neck tumour tissues showed a significant increase in Akt phosphorylation at the T308 residue, suggesting that pAkt T308 may be associated with tumour progression in vivo.

The retention of suturing skills in dental undergraduates.

BACKGROUND The ability to place sutures is an essential skill in dentistry. In our institution, the introduction of a video teaching aid and a checklist-based assessment has improved the standardisation of teaching as well as the transparency and objectivity of the assessment of suture skills. The aim of this study was to determine whether this skill once acquired is retained in the short term. MATERIALS AND METHODS The same cohort of 67 fourth-year students performed the same assessment at two different time points 2 months apart. The first was a formative assessment and the second was a summative assessment. Feedback was collected on both occasions. RESULTS On the first sitting of the assessment, 93% of the students were successful compared with 79% on the second occasion. Student feedback was similar on both occasions with 77% and 75% reporting that they thought it was an easy exam. On the first occasion, 27% thought that it was a stressful examination compared with 43% on the second occasion, which may have affected their performance. CONCLUSIONS These findings suggest that regular reinforcement is required to avoid deterioration of suturing skills even in the short term. This might involve exposing the students to surgery earlier in the course and introducing regular formative assessments which the students appear to associate with less stress.

A generic consensus assessment of undergraduate competence in forceps exodontia in the United Kingdom

UNLABELLED The assessment of competence in clinical skills has become more frequent in published healthcare curricula and syllabuses recently. There are agreed mechanisms for the assessment of competence in the post-graduate environment, but no consensus within the undergraduate curriculum. This paper seeks to develop an agreed generic checklist for the assessment of competence in forceps exodontia. MATERIALS AND METHODS A modified Delphi process was undertaken with representatives from all UK dental schools (n = 13) to develop a generic checklist for the assessment of competence in forceps exodontia. A content analysis of the assessments employed by each school was used to help discussion and inform the Delphi process. RESULTS Seven schools currently employ a summative assessment of competence in forceps exodontia, with the majority employing a structured clinical objective test (n = 6). From the seven assessments, there were a total of 29 putative items and 10 putative domains identified for a generic checklist. These were reduced to five domains and 19 items through the content analysis and Delphi process, and a generic overarching checklist was created. CONCLUSION Using this generic checklist, it may now be possible to pool data inter-institution to perform more powerful analyses on how our students obtain, or fail to obtain competence in forceps exodontia.

Dental student suturing skills: a multicentre trial of a checklist-based assessment

BACKGROUND The assessment of clinical skills is essential to determine whether an undergraduate is competent to perform the tasks outlined in the curriculum. Such assessments in dentistry have historically not been subjected to large scale validity and reliability testing due the relatively small student numbers at each institute. The aims of this study were to test the validity and reliability of a standardised, checklist-based, suturing objective structured clinical examination (OSCE) and then to perform a multicentre trial to determine its performance over a large cohort of students. MATERIALS AND METHODS A total of seven UK schools agreed to take part in the trial. To test the validity and reliability of the checklist, the examiner at each institution reviewed and scored video footage of 10 students performing the assessment. Each institution then carried out the assessment providing a checklist score and a global score for each of their own students. RESULTS The assessment was well received by the staff, with acceptable inter-examiner variability. In total, 496 students completed the suturing OSCE with a success rate of 81% with a variation between schools of between 66% and 96%. A significant correlation was found between the checklist score and the global score (r = 0.361, P = 0.000). No one item on the checklist was found to be a determinant factor in the outcome of the OSCE. CONCLUSIONS This checklist-based assessment of suturing skills was found to have face and content validity. Its reliability was promising, but merits further investigation. There may be an argument for the standardisation of the assessment of this core surgical skill throughout several UK-based dental schools.

Activation of Akt at T308 and S473 in alcohol, tobacco and HPV-induced HNSCC: is there evidence to support a prognostic or diagnostic role?

BackgroundTobacco, alcohol and HPV infection are associated with increased risk of HNSCC. However, little is known about the underlying signaling events influencing risk. We aimed to investigate the relationship between these risk factors and Akt phosphorylation, to determine prognostic value.MethodVEGF-positive HNSCC biopsies, with known HPV status, were analyzed by immunohistochemistry (IHC) for Akt, phosphorylated at residues S473 and T308. Comparisons between the tissues were carried out using a Mann–Whitney U test. Associations between the variables and continuous immunohistochemical parameters were evaluated with general linear models. Patient characteristics and pAkt IHC score were analyzed for possible association with overall survival by Cox proportional hazard models.ResultsImmunohistochemistry revealed that cancer patients had significantly higher levels of pAkt T308 than S473 (P < 0.001). Smoking and alcohol were found to be independent risk factors for Akt phosphorylation at T308 (P = 0.022 and 0.027, respectively). Patients with tumors positive for HPV or pAkt S473 had a poorer prognosis (P = 0.005, and 0.004, respectively). Patients who were heavy drinkers were 49 times more likely to die than non-drinkers (P = 0.003). Patients with low pAkt T308 were more likely to be HPV positive (P = 0.028). Non-drinkers were also found to have lower levels of pAkt T308 and were more likely to have tumors positive for HPV than heavy drinkers (P = 0.044 and 0.007, respectively).ConclusionThis study suggests different mechanisms of carcinogenesis are initiated by smoking, alcohol and HPV. Our data propose higher phosphorylation of Akt at T308 as a reliable biomarker for smoking and alcohol induced HNSCC progression and higher phosphorylation of Akt at S473 as a prognostic factor for HNSCC.