Characterization and clinicopathological significance of circulating tumour cells in patients with oral squamous cell carcinoma

Circulating tumour cells (CTCs) are cancer cells released by cancer into the peripheral circulation. Haematogenous tumour spread is a hallmark of metastatic malignancy and a key factor in cancer recurrence and prognosis. CTCs have diagnostic and prognostic significance for a number of adenocarcinomas and melanoma. A review of the published peer-reviewed literature was performed to determine the clinical relevance of CTCs as a biomarker in the management of oral squamous cell carcinoma (OSCC). Fourteen studies met the eligibility criteria. With regard to patients with OSCC, this review found the following: (1) CTCs have been detected using multiple techniques; (2) the presence of CTCs does not appear to be related to tumour differentiation or size; (3) CTCs may be detected without lymph node involvement; (4) the detection of CTCs may be prognostic for both disease-free survival and overall survival; (5) quantification of CTCs may reflect the efficacy of therapy; (6) CTCs may be of value for ongoing patient monitoring. Preliminary evidence suggests that CTCs have diagnostic and prognostic potential as a biomarker for oral cancer management and warrant further investigation to determine their appropriate place in the management of OSCC patients.

Predictors of oropharyngeal cancer survival in Europe

OBJECTIVES

HPV16-positive oropharyngeal cancer (OPC) patients experience better outcomes compared to HPV16-negative patients. Currently, strategies for treatment de-escalation are based on HPV status, smoking history and disease stage. However, the appropriate cut-point for smoking and the role of other non-clinical factors in OPC survival remains uncertain.

MATERIALS AND METHODS

We examined factors associated with OPC outcome in 321 patients recruited in a large European multi-center study. Seropositivity for HPV16 E6 was used as a marker of HPV16 positive cancer. Hazard ratios (HR) and confidence intervals (CI) were estimated using Cox proportional models adjusted for potential confounders.

RESULTS

Overall 5-year survival following OPC diagnosis was 50%. HPV16-positive OPC cases were at significantly lower risk of death (aHR = 0.51, 95% CI: 0.32-0.80). A significant effect on OPC survival was apparent for female sex (aHR 0.50: 95% CI: 0.29-0.85) and being underweight at diagnosis (aHR: 2.41, 95% CI: 1.38-4.21). A 10 pack year smoking history was not associated with overall survival. Higher stage at diagnosis appeared as the only factor significantly associated with OPC recurrence (aHR: 4.88, 95% CI: 2.12-11.21).

CONCLUSION

This study confirms that HPV16 status is an independent prognostic factor for OPC survival while female sex lowers risk of death and being underweight at diagnosis increases the risk of death. Smoking was not an independent predictor of OPC survival.

Perspectives on oral squamous cell carcinoma prevention-proliferation, position, progression and prediction

Squamous cell carcinoma arising from oral mucosal epithelium remains a lethal and deforming disease due to tumour invasion, oro-facial destruction, cervical lymph node metastasis and ultimate blood-borne dissemination. Worldwide, 300 000 new cases are seen each year, with a recent and significant rise in incidence affecting particularly the young. To rationalize perspectives on preventive strategies in oral cancer management, this study addresses a number of fundamental questions regarding carcinogenesis: proliferation-what epithelial cell changes precede tumour development? Position-why are certain oral sites so predisposed to cancer? Progression-why do some precursor lesions progress to invasive carcinoma and others do not? Prediction-how can we predict individual patient and/or lesion behaviour to prevent disease progression? By improving our understanding of oral carcinogenesis, can we thereby facilitate more effective primary, secondary and tertiary preventive strategies and ultimately reduce the global burden of oral squamous cell carcinoma (OSCC)?

Treatment resistance in potentially malignant disorders-'Nature' or 'Nurture'…?

BACKGROUND

Contemporary potentially malignant disorder management is based upon provisional histological diagnosis followed by interventional surgery to excise or ablate 'high-risk' mucosal lesions. Although the majority of patients achieve disease-free status post-treatment, others develop further or persistent disease unresponsive to intervention.

METHODS

A detailed, retrospective clinico-pathological review of treatment resistant potentially malignant lesions, from a 590 patient cohort treated by CO₂ laser surgery and followed for a mean of 7.3 years, was undertaken. Clinical outcome was determined at study census date (31 December 2014).

RESULTS

A total of 87 patients (15%) exhibited PMD disease resistant to treatment: 34 (6%) became disease free following further treatment, whilst 53 (9%) had persistent disease despite intervention. Disease-free patients were younger, changed lesion appearance from erythroleukoplakia to leukoplakia (P = .004), developed further lesions at new sites, demonstrated reduction in dysplasia severity with time and required multiple treatments to achieve disease-free status (P = .0005). In contrast, persistent disease patients were older, male, often presented with proliferative verrucous leukoplakia (PVL) on gingival and alveolar sites, displayed less severe dysplasia initially and underwent laser ablation rather than excision (P = .027).

CONCLUSION

Despite clinico-pathological profiling of treatment resistant patients, the precise inter-relationship between the inherent nature of potentially malignant disease and the external influence of treatment intervention remains obscure.

Profiling cancer risk in oral potentially malignant disorders-A patient cohort study

BACKGROUND

Oral potentially malignant disorders harbour variable and unpredictable risk for squamous carcinoma development. Whilst current management strategies utilise histopathological diagnoses, dysplasia grading and targeted intervention for "high-risk" lesions, clinicians are unable to predict malignant potential.

METHODS

Detailed, retrospective clinico-pathological analysis of potentially malignant lesions undergoing malignant transformation, from a 590 patient cohort treated by interventional laser surgery and followed for a mean of 7.3 years, was undertaken. Clinical outcome was documented at study census date (31 December 2014).

RESULTS

A total of 99 patients (16.8%) developed cancer: 71 (12%) seen "unexpectedly" upon excision and 28 (4.8%) progressing to malignancy at a median of 87.3 months post-surgery. Thirty "unexpected" excisions were micro-invasive (42.3%) arising primarily in severely dysplastic precursors (75%) at ventro-lateral tongue and floor of mouth sites (54.5%); 1 patient (1.4%) had a cancer-related death, whilst 58 (81.7%) were disease free. A total of 19 of 28 "progressive" cancers (67.9%) arose at new sites, with erythroleukoplakia a significant predictor of malignancy (P = .0019). Nine (32.1%) developed at the same precursor site, with 6 (77.7%) on the ventro-lateral tongue and floor of mouth. Three (10.7%) were micro-invasive, 9 patients (32.1%) died from metastatic disease and 12 (42.9%) were disease free (P < .001).

CONCLUSION

Squamous carcinoma may arise at the site of a precursor lesion as transformation or new-site development via field cancerisation. Whilst interventional surgery facilitates early diagnosis and treatment of occult disease, thus reducing risk from same-site transformation, new-site cancer is a significant long-term risk for patients with potentially malignant disorder.

Efficacy of oral brush biopsy in potentially malignant disorder management

BACKGROUND

Oral potentially malignant disorders (PMD) harbour unpredictable risk for squamous cell carcinoma development. Current management requires tissue biopsy for histopathology characterisation, dysplasia grading and targeted intervention to "high-risk" lesions, although evidence-based guidelines are limited and diagnoses subjective. This study investigated the use of adjunctive oral brush biopsy techniques during the management of PMD in a UK hospital population.

METHODS

Retrospective review of a 310 PMD patient cohort presenting to Maxillofacial Surgery in Newcastle upon Tyne with new, single-site lesions between December 2009 and May 2014. Patients underwent Orcellex^® brush biopsy and liquid-based cytology examination in addition to conventional biopsy techniques, with management proceeding along established care pathways. Patient demographics, cytology data, most significant histopathology diagnoses and clinical outcome were all documented at the study census date (31.12.15).

RESULTS

A total of 170 male & 140 female patients (age range 18-91 years), exhibiting primarily leukoplakia (86.5%) at floor of mouth and ventrolateral tongue sites (44.9%), were identified. Management comprised: observation (49.7%), laser surgery (44.9%), antifungal treatment (3.5%) and Head & Neck clinic referral following cancer diagnosis (1.9%). Clinical outcomes were as follows: disease free (51.3%), persistent PMD (42.3%) and malignant transformation (6.4%). Histology and cytology diagnoses strongly correlated (r = .305). Treatment modality, lesion site, histology and cytology diagnoses were the best predictors of clinical outcome.

CONCLUSIONS

Orcellex^® brush cytology provides reliable diagnoses consistent with conventional histopathology and offers less invasive, adjunctive assessment appropriate for long-term monitoring of patients in specialist clinics.

Band-limited spectral estimation of autoregressive-moving-average processes

Consider an autoregressive-moving-average process of given order where it is known that a number of moving-average roots are of unit modulus. Such a situation might arise, for example, when a time series has been differenced to induce stationarity by removing a non-stationary polynomial or seasonal trend. A band-limited spectral estimation procedure is proposed for estimating the coefficients of such a process and the asymptotic properties of the estimators investigated. The asymptotic theory is illustrated with reference to simulated and real data. A preliminary investigation of the use of Akaike's AIC criterion and this procedure to determine the number of roots of unit modulus (in the case where this is unknown) is also carried out by means of simulation.

The proposed band-limited spectral estimation procedure can also be used to take account of other possible effects met in practice. These include, for example, the band-limited response of a recording device or trend-contaminated low-frequency components.

Spectral inference over narrow bands

We consider a vector, discrete, time sequence x(n), n = 0, ± 1 ···, of p components Xj(n), j = 1, ··· p. For the most part we shall assume x(n) to be strictly stationary and with finite variances. Thus if μ is the mean vector we shall have

Oral precursor lesions and malignant transformation--who, where, what, and when?

Oral potentially malignant disorders (PMD) are recognisable mucosal conditions that have an unpredictable risk of transformation to squamous cell carcinoma (SCC), a lethal and deforming disease of rising incidence. Contemporary management is based on clinical recognition of suspicious lesions and incisional biopsy to enable histopathological assessment and grading of dysplasia, together with excision of high-risk lesions and long-term surveillance. However, it is impossible to predict clinical outcome or risk of malignant transformation. Our aim was to evaluate the relevance of previously identified oral precursor lesions for the development of SCC and staging of disease. We therefore retrospectively reviewed 1248 cases of SCC diagnosed in oral and maxillofacial surgery units at Newcastle upon Tyne and Sunderland hospitals between 1996 and 2009. Of them, 58 identifiable precursor lesions became malignant but only 25 had been dysplastic on initial biopsy; 19 of 33 non-dysplastic lesions exhibited lichenoid inflammation only. SCC arose most often on the ventrolateral tongue and floor of the mouth, with a mean transformation time of 29.2 months. Transformation time was significantly shorter in men (p=0.018) and those over 70 years of age (p=0.010). Patients who consumed more than 21 units of alcohol/week and those who had had interventional laser surgery to treat precursor lesions, had higher-staged tumours (p=0.048). Although retrospective, this study shows that the results of incisional biopsy and grading of dysplasia have limited use as predictive tools, and supports the view that cancer may arise in the absence of recognisable epithelial dysplasia. Our findings confirm the importance of clinical vigilance and active surveillance in the management of all patients with clinically suspicious oral lesions, irrespective of the histological findings.

To treat...or not to treat? Clinicians' views on the management of oral potentially malignant disorders

Oral potentially malignant disorders (PMD) are recognisable mucosal conditions that have a variable and unpredictable risk of transformation to invasive squamous cell carcinoma (SCC). Modern management relies initially on clinical recognition of suspicious lesions and histopathological assessment and grading after incisional biopsy. However, it then varies from wide excision to observation and review, and depends not only on the severity of dysplasia but also on the clinician's preference as there is no high-level evidence to support best practice. We invited clinicians from oral and maxillofacial surgery, oral medicine, ear, nose, and throat (ENT), and plastic surgery, to complete an online questionnaire on current practice, which included 3 fictitious cases, to ascertain their views on the management of PMD and to find out whether they would be interested in becoming involved in a proposed future randomised controlled trial (RCT). Of the 251 who replied, 178 (71%) were oral and maxillofacial surgeons, and 99 (39%) expressed an interest in participating in a future RCT. Most respondents (n=164 or 99%) would always treat severely dysplastic lesions by excision or laser ablation, whereas only 8% (n=13) would always excise mild dysplasia. The greatest equipoise among those interested in taking part in a RCT was found in the case of moderate dysplasia for which 27% (n=27) favoured observation compared with surgical excision or laser ablation. This study shows that there is support for a multicentre, prospective RCT that compares observation with resection and laser ablation in patients with moderate dysplasia.

Complications following interventional laser surgery for oral cancer and precancerous lesions

Interventional carbon dioxide laser surgery is the preferred method to treat oral precancerous lesions and early invasive squamous cell carcinomas (SCCs). Little is known, however, about the complications that patients experience after such treatment. We retrospectively reviewed the hospital records of 82 patients with new dysplastic oral lesions or early invasive oral SCCs treated by laser surgery in the maxillofacial unit at Newcastle General Hospital. The most common postoperative complications were pain for more than two weeks after operation (n=28), bleeding (n=4), difficulties with speech (n=5), paraesthesia of the lingual nerve (n=17), difficulty swallowing (n=2), obstructive swelling of the submandibular gland (n=22), and tethering of the tongue (n=10). Overall, 78% of patients had one or more complication. In the absence of randomised controlled trials, this study provides the best available evidence for complication rates following interventional surgery. In addition to aiding in the preoperative counselling of patients, the data will help to inform and advise patients particularly during the immediate postoperative period.

Management of oral carcinoma: benefits of early precancerous intervention

Management of oral precancerous lesions remains polarised between interventional surgery and conservative treatment. We have previously shown the efficacy of carbon dioxide laser excision for both diagnosis and treatment of oral precancerous lesions. The aim of this study was to review the clinicopathological details of a group of patients in whom pre-existing but occult invasive carcinoma was diagnosed histopathologically in specimens excised by laser. We retrospectively reviewed 169 patients who attended the Maxillofacial Dysplasia Clinic at Newcastle General Hospital with single, new oral premalignant lesions over a 5-year period (2004-2008). They were all treated by laser excision of lesions that were confirmed to be dysplastic from examination of preoperative incisional biopsy specimens. There was a significant correlation between the results of diagnostic incisional, and laser excision, biopsy specimens (p < 0.01), but 15 patients had signs of occult invasive carcinoma in the excision specimens (9%). In all cases the carcinomas were completely excised by the laser. Carbon dioxide laser excision is not only an effective treatment of precancerous lesions, but also facilitates early diagnosis and management of oral carcinoma at a stage when it is otherwise clinically undetectable.

Factors affecting carbon dioxide laser treatment for oral precancer: a patient cohort study

BACKGROUND

Although the benefits of CO(2) laser surgery in oral precancer management have been evaluated, little consideration has been given to the factors which may influence treatment outcome, especially amongst patients developing recurrence or malignant transformation.

STUDY DESIGN

Seventy eight patients (51 males, 27 females; mean age 57.8 years) undergoing CO(2) laser excision of single, new dysplastic oral precancer lesions (OPLs) were followed up for a minimum of 2 years and the influence of clinico-pathological parameters, socio-demographic factors and the presence or absence of residual dysplasia in excision margins upon clinical outcome were examined.

RESULTS

Seventy three percent of patients were smokers and 78% consumed alcohol regularly. The majority of lesions were leukoplakias arising in the floor of mouth and ventro-lateral tongue and moderate or severe dysplasia accounted for 86% of histopathological diagnoses. Patient follow up ranged from 24 to 119 months (mean 58 months). Sixty four percent of patients were disease free at most recent clinical follow up, whilst 32% developed local recurrent dysplasia or new site dysplasia with 4% developing oral squamous cell carcinoma (but at sites distinct from their initial OPL). Excision margins were clear in 55% of cases, but 19% showed mild, 21% moderate and 5% severe dysplasia on histopathological examination. No statistically significant associations were seen between patients' age, gender, lesion appearance, site of origin, histopathological grading, presence of dysplasia in resection margins, or alcohol consumption and clinical outcome. Smokers, however, were at significantly higher risk of dysplasia recurrence compared to ex-smokers or non-smokers (P = 0.04).

CONCLUSIONS

In the absence of agreed treatment protocols for OPLs, we recommend CO(2) laser surgery as an effective treatment modality offering precise lesion excision, full histopathological assessment, minimal post-operative morbidity and a 64% disease free clinical outcome. Regular patient follow up is encouraged due to the persistence of field cancerisation effects.

Assessing competency in dentoalveolar surgery: a 3-year study of cumulative experience in the undergraduate curriculum

AIM

To assess and observe the development of competence in oral surgical skills during a 3-year undergraduate programme.

METHOD

Over a 3-year period 75 students were followed through from the beginning of their clinical course to their Bachelor of Dental Surgery graduation and their surgical experience monitored by the use of logbooks. Their development of competence was assessed objectively through structured assessments and subjectively by a single tutor responsible for each year. Assessments were made of their ability in exodontia, pre-surgical assessment and the surgical extraction of teeth/roots.

RESULTS

Seventy-three students completed the course (97%). Successful completion rates for the objective testing were 100% for both exodontia and pre-surgical assessment. The surgical assessment, (surgical extraction of a tooth or root) had a successful completion rate of only 23% and the caseload for students was low with a mean of four teeth removed surgically upon graduation. Relationships were examined between total numbers of teeth extracted, total number of minor oral surgical procedures completed and the successful completion of the surgical competence assessment, but no significant relationships were found.

CONCLUSIONS

This study demonstrates that it is possible to achieve objectively measurable levels of competence in undergraduates undertaking oral surgery procedures. It is however, a labour and time intensive process and appropriate clinical and teaching resources are required. National co-operation towards agreed standardised competencies should be encouraged to allow data to be pooled and more powerful analyses to occur.

Effects of active non-smoking programmes on smoking behaviour in oral precancer patients

Smoking is the commonest risk factor for oral cancer and precancer. The objective of this study was to characterize smoking behaviour and attitude in a cohort of oral precancer patients in Newcastle upon Tyne, UK, and to determine changes in behaviour during diagnosis, treatment and follow-up. Twenty-seven consecutive, smoking patients with dysplastic oral lesions were recruited to the study and a detailed smoking history obtained, quantifying types and numbers of cigarettes smoked, length of smoking history, and changes in smoking behaviour during treatment episodes and long-term follow-up. All patients underwent an interventional management protocol comprising risk-factor education, histopathological diagnosis by incisional biopsy and laser excision of lesions. Patients were followed up for 5 years. Whilst there was a significant decrease in the number of cigarettes smoked at patients' most recent follow-up compared with initial presentation (p<0.001), 74% continued to smoke. Patients received advice from a smoking cessation adviser on support available to them from the local NHS (National Health Service) Stop Smoking services. Six out of 10 patients who set a 'quit date' and attended a programme had quit at the 4-week follow-up but only 5 remained non-smokers. Smoking remains a considerable problem in oral precancer patients even after interventional treatment, with the risk of further precancerous lesions and malignant transformation.

Surgical treatment of chronic parotid sialadenitis

OBJECTIVE

To review the results of surgical management of chronic parotid sialadenitis refractory to medical therapy, with particular respect to long-term symptom resolution and development of post-operative complications.

METHODS

A retrospective review of parotidectomies performed for chronic intractable parotid sialadenitis. Information was collected about presentation, pre-operative investigations, surgical treatment, post-operative complications and outcome.

RESULTS

36 parotidectomies were performed for chronic sialadenitis between 1991 and 2002. Age at presentation was 56+/-9.6 years, with median symptom duration of 2.3 years. For patients with non-specific presentations, magnetic resonance imaging (MRI) was the most useful pre-operative investigation. Superficial parotidectomy with duct preservation was the main treatment with a 94 per cent success rate, and near-total parotidectomy was reserved for patients with extensive deep-lobe involvement. Duct ligation significantly increased the risk of transient facial palsy. There was a 56 per cent and 22 per cent incidence of temporary facial paresis and Frey's syndrome, respectively.

CONCLUSIONS

Controversies exist regarding the optimal pre-operative investigation and surgical treatment of chronic parotid sialadenitis. We advocate magnetic resonance image (MRI) scanning for patients with non-specific symptoms of sialadenitis, and sialography in the presence of reasonable clinical suspicion. We propose superficial parotidectomy without parotid duct ligation as the standard of care, with near-total parotidectomy reserved for extensive deep-lobe disease.

Cyclin A activity predicts clinical outcome in oral precancer and cancer

Accurate, predictive assessment of the behaviour of oral cancers and precancers remains elusive. Increasing dysregulation of cell proliferation is a feature of carcinogenesis, and alterations in cyclin proteins regulating cell cycle progression are involved in enhanced cell proliferation. The authors of the present study have previously demonstrated increased proliferative activity in oral dysplastic lesions and poorly differentiated carcinomas, and hypothesize that cell proliferation can be used as a predictive agent in clinical management. In this preliminary study, immunohistochemical quantification of cyclin A expression was carried out for 33 excised oral lesions (ranging from mild dysplasia to invasive squamous cell carcinoma, SCC). Clinical outcome was determined as: no disease after 2 years follow-up, persistent disease, or further disease presentation. Labelling Indices (LIs) ranged from 5.5 to 32.1%, and whilst a trend to increased labelling in increasingly dysplastic and neoplastic tissue was seen, this was not statistically significant (P=0.06). High LIs were related to poor clinical outcome (P=0.003), suggesting a definite role for cyclin A measurement as a predictive tool in clinical management.

Cancerisation within the oral cavity: the use of 'field mapping biopsies' in clinical management

Field cancerisation within the oral cavity risks multiple primary tumour development. Whilst multi-focal disease may ultimately affect up to 24% of oral cancer patients, a particular management problem is encountered with those patients presenting with pan-oral dysplasia. In an attempt to characterise the extent of dysplasia and to quantify the risk of malignant change, examination under anaesthesia (EUA) and multiple, 'field mapping biopsies' were carried out for 16 consecutive patients presenting with pan-oral disease. Seventy lesions, predominantly homogenous leukoplakias, were biopsied primarily showing hyperkeratosis or mild dysplasia histologically. More significant dysplasia was seen to affect the faucial pillars, floor of mouth and ventral tongue. Interventional CO(2) laser surgery was used to excise 11 severely dysplastic lesions in six patients. Field mapping appears effective in the initial identification and treatment of the most significant areas of dysplasia in patients with multi-focal precancer. Longitudinal, multi-centre trials are now required.

Improved sedation for oral surgery by combining nitrous oxide and intravenous Midazolam: a randomized, controlled trial

The objective is to investigate whether sedation techniques for oral surgery can be improved by combining the use of inhalation of nitrous oxide/oxygen with intravenous Midazolam. Prospective, randomized controlled clinical trial: Patients requiring extractions or surgery were randomly allocated to subgroups receiving either intravenous Midazolam or nitrous oxide/oxygen or a combined technique using nitrous oxide/oxygen and intravenous Midazolam. Safety parameters, amount of sedative agents administered, recovery time and co-operation scores were recorded. Patients receiving the combined sedation technique were initially titrated with 10% nitrous oxide, increasing by increments of 10% up to a maximum of 40% nitrous oxide and 60% oxygen. Midazolam was then titrated (initially 2 mg wait 2 min with increments of 1mg every minute until appropriately sedated) whilst still administering 40% nitrous oxide. When a combined technique of N(2)O/O(2) and Midazolam was used there was a statistically significant reduction in the amount of Midazolam required to achieve effective sedation (P<0.001), an overall significant reduction in recovery time (P<0.001) and a significant improvement in co-operation (P<0.01) and arterial oxygen saturation (P<0.001). This combined technique was found to be safe and reliable, requiring reduced doses of Midazolam and demonstrable improvement in patient recovery and co-operation.

Effect of photoperiod on body mass, food intake and body composition in the field vole, Microtus agrestis

Many small mammals respond to seasonal changes in photoperiod by altering body mass and adiposity. These animals may provide valuable models for understanding the regulation of energy balance. Here, we present data on the field vole (Microtus agrestis) - a previously uncharacterised example of photoperiod-induced changes in body mass. We examined the effect of increased day length on body mass, food intake, apparent digestive efficiency, body composition, de novo lipogenesis and fatty acid composition of adipose tissue in cold-acclimated (8 degrees C) male field voles by transferring them from a short (SD, 8 h:16 h L:D) to long day photoperiod (LD, 16 h:8 h L:D). During the first 4 weeks of exposure to LD, voles underwent a substantial increase in body mass, after which the average difference between body masses of LD and SD voles stabilized at 7.5 g. This 24.8% increase in body mass reflected significant increases in absolute amounts of all body components, including dry fat mass, dry lean mass and body water mass. After correcting body composition and organ morphology data for the differences in body mass, only gonads (testes and seminal vesicles) were enlarged due to photoperiod treatment. To meet energetic demands of deposition and maintenance of extra tissue, voles adjusted their food intake to an increasing body mass and improved their apparent digestive efficiency. Consequently, although mass-corrected food intake did not differ between the photoperiod groups, the LD voles undergoing body mass increase assimilated on average 8.4 kJ day(-1) more than animals maintained in SD. The majority (73-77%) of the fat accumulated as adipose tissue had dietary origin. The rate of de novo lipogenesis and fatty acid composition of adipose tissue were not affected by photoperiod. The most important characteristics of the photoperiodic regulation of energy balance in the field vole are the clear delineation between phases where animals regulate body mass at two different levels and the rate at which animals are able to switch between different levels of energy homeostasis. Our data indicate that the field vole may provide an attractive novel animal model for investigation of the regulation of body mass and energy homeostasis at both organism and molecular levels.

Oral cancer: material deprivation, unemployment and risk factor behaviour--an initial study

Regional variations in the incidence of oral cancer may be related in some cases to material deprivation. The main aim of this study was to identify in cases (and controls matched for age and sex) an index of material deprivation, employment history, smoking and alcohol habits. This prospective study comprised 100 subjects in each group and was questionnaire based. Previous studies in relation to material deprivation in oral cancer have been population based. There was a statistically significant trend for patients to come from the most deprived groups. Sixty-six per cent of the cases had experience of long-term unemployment. Although a high proportion, this was not statistically significant after multi-variable analysis due to the confounding effects of smoking and alcohol use. Such a high proportion of cases with a history of long-term unemployment requires further study to examine in detail if there is a definite link with oral cancer once the confounding effects of smoking and alcohol are removed.

Simulation of cell proliferation in mouse oral epithelium, and the action of epidermal growth factor: evidence for a high degree of synchronization of the stem cells

Computer simulation has been carried out to help to determine the cell-proliferative mechanisms underlying data gathered from a double-labelling experiment on the dorsal tongue of the mouse. Good fits to the data have been obtained by assuming that there is a high degree of synchrony in the stem cells, which have a 24-h cell cycle time, and that daughters of these cells undergo two further divisions, with mean cell cycle times of 48 h, before differentiating. This results in one-seventh of proliferative cells being stem cells, which ties in well with the concept of epidermal proliferative units. There is no need to assume that S-phase duration changes diurnally. The administration of epidermal growth factor seems to increase the degree of synchrony. In such systems, the influx to S-phase and the efflux from it have very sudden short peaks, which it is impossible to observe unless observations are taken very frequently. There are therefore implications for the designs of experiments that attempt to study diurnal rhythms or the effect of factors that disturb the normal proliferative pattern of cells.

Epithelial cell proliferative activity and oral cancer progression

Accurate, predictive assessment of the behaviour and progression of oral cancers and precancers remains elusive in clinical practice. Archival tissue specimens from 10 previously treated patients with oral lesions of known clinical outcome (3 years post-treatment) were re-examined histopathologically, and proliferative cell labelling indices (LIs) determined for Ki67, cyclin A and histone mRNA cell cycle markers. While histone mRNA labelling ultimately proved unreliable, both Ki67 and cyclin A LIs demonstrated a clear trend for enhanced labelling to occur in increasingly dysplastic and neoplastic tissue, with particular emphasis on suprabasal labelling in abnormal tissue. Perhaps of greatest significance was the observation of increased LIs and suprabasal labelling in lesions with poor clinical outcome, such as patients developing recurrent disease or cervical lymph node metastasis. Measurement of cell proliferative activity in individual oral epithelial dysplastic lesions or invasive squamous cell carcinomas may thus provide unique, predictive information on clinical outcome.

Field change and oral cancer: new evidence for widespread carcinogenesis?

Patients with oral squamous cell carcinoma (OSCC) are at risk of developing second or multiple primary cancers as a result of field cancerization in the upper aerodigestive tract. In order to quantify the incidence of field change observable in oral mucosa, 26 consecutive new (untreated) patients presenting with a unilateral OSCC (18) or a premaligant lesion (eight) underwent 'mirror image' biopsies from clinically normal-looking mucosa at corresponding anatomical sites. A total of 15 patients (58%) demonstrated histologically abnormal tissue upon microscopic examination: six showed reactive change/cellular atypia associated with chronic irritation, seven exhibited frank dysplasia, whilst two displayed carcinoma-in-situ (CIS) or microinvasive SCC. Although not statistically significant, there was an observable trend for the lateral/ventral tongue and floor of mouth to display increased vulnerability to dysplastic change.

Interventional laser surgery: an effective surgical and diagnostic tool in oral precancer management

Invasive oral squamous cell carcinomas (OSCCs) are often preceded by precancerous lesions, the management of which remains controversial, polarized between active surgical excision to try to prevent malignant change or more conservative, medical or observational techniques. In order to determine the efficacy of interventional CO2 laser surgery in oral precancer management, the records of 57 consecutive laser-treated patients presenting over a 4-year period, with histologically confirmed dysplastic lesions, were reviewed. Leukoplakias were the commonest clinical lesions (69%), whilst the floor of the mouth was the most frequent anatomical site (42%). Laser surgery successfully excised 55 precancerous lesions, 11 of which exhibited more severe dysplasia or neoplasia compared with initial biopsy. Postoperative scarring and morbidity were minimal. After surgery, patients were followed for between 1 and 44 months (mean 18 months). Of these patients, 76% remained disease-free, whilst 24% developed new dysplastic lesions at distinct or multiple sites, often exhibiting increased dysplasia. Of the patients experiencing recurrence, 7% developed OSCC, whilst a further 3.5% presented with other aerodigestive tract cancers. Neither initial lesion appearance nor histological diagnosis predicted clinical behaviour. Interventional laser surgery is thus advised, in contradistinction to conservative management of oral precancers, to facilitate efficacious, low-morbidity treatment and to establish definitive histological diagnosis. As a consequence of field change carcinogenesis, regular follow up of treated precancer patients is mandatory for effective tertiary prevention.

In vitro labelling studies and the measurement of epithelial cell proliferative activity in the human oral cavity

Samples (110) of human mandibular gingiva and buccal mucosa, harvested from patients undergoing third-molar surgery, were subjected to in vitro labelling with tritiated thymidine, bromodeoxyuridine, or a sequential double-labelling technique comprising tritiated thymidine followed by bromodeoxyuridine, in order to determine the efficacy of a new incubation labelling technique, and to characterize S-phase labelling indices in human oral mucosa. Whilst, there were no demonstrable differences in labelling indices obtained by single thymidine, single bromodeoxyuridine or double labelling, there was a significant difference between anatomical sites, with higher S phase labelling observed in buccal mucosa (mean LI 11.7) than mandibular gingiva (mean LI 8.5; P<0.01). There was, however, no significant correlation between individual labelling indices and patient age, sex or the time of day when tissue was harvested. The in vitro labelling technique provides a reliable and quantifiable method of characterizing proliferative labelling indices in the human oral cavity. Further investigation is being carried out to profile wider age and anatomical ranges and to utilize the double-labelling technique to calculate S-phase durations and cell-cycle times. These profiles may have a future role in the assessment of oral mucous membrane disease.

The effects of midazolam and flumazenil on psychomotor function and alertness in human volunteers

OBJECTIVE

To investigate the effect of midazolam and flumazenil on psychomotor function and alertness in human volunteers.

DESIGN

Randomised, double-blind, cross over study.

METHODS

Intravenous flumazenil was administered to sedated and non-sedated healthy human volunteers, in doses typical of those used clinically to induce sedation with midazolam and for reversal with flumazenil. Subjective assessment of alertness and objective measures of psychomotor function using light reaction time and the Maddox wing were made over a 1 hour period.

RESULTS

Seven males and seven females each attended four experimental sessions. Psychomotor function was impaired by midazolam but there was some individual variation to this response. All sedated subjects receiving flumazenil had significantly improved alertness and psychomotor function when compared with those subjects who received placebo. Mean alertness (P < 0.01) and light reaction time (P < 0.05) showed significant improvement and returned to baseline by 60 minutes. Stability also showed significant improvement (P < 0.05) but did not return to baseline by 60 minutes. There was no significant effect on psychomotor function or alertness when the antagonist flumazenil was administered in the absence of the agonist midazolam.

CONCLUSION

An earlier discharge time based on subjective assessment of alertness is not advocated for patients whose intravenous midazolam sedation is reversed with flumazenil.

Preparation of hydrogen from water by reduction with lithium aluminium hydride for the analysis of delta(2)H by isotope ratio mass spectrometry

An off-line technique is described for the preparation of H(2) from water prior to analysis of delta(2)H by dual-inlet isotope ratio mass spectrometry. H(2) is produced from sample water by reaction with LiAlH(4). This provides a rapid and inexpensive method for the analysis of delta(2)H in small (10 microL) samples of water. Precision was +/- 4.2 to 8.0 (1sigma(n), n = 8) delta(2)H(VSMOW) for samples between 428 and 1500 delta(2)H(VSMOW), +/- 14.5 delta(2)H(VSMOW) for water enriched to 3750 delta(2)H(VSMOW) and +/- 26.0 delta(2)H(VSMOW) for water enriched to 6100 delta(2)H(VSMOW). Accuracy was +/- 1.1 to 4.2 delta(2)H(VSMOW) for water standards from natural abundance to 1000 delta(2)H(VSMOW) (the highest enrichment at which water of accepted delta(2)H is currently available). This method for delta(2)H determination is most appropriate for use with small (<50 microL) samples of high delta(2)H enrichment such as those produced from doubly labelled water studies of small animals. The levels of measurement precision of delta(2)H would contribute 2.6-3.8% to the precision error in estimates of small animal energy expenditure made using the doubly labelled water technique when duplicate analyses are performed.

Characterization of epithelial cell activity in patients with oral cancer

Accurate, predictive assessment of the clinical behaviour and progression of individual oral cancers and premalignant lesions requires reproducible and quantitative analyses of diseased tissue. In this paper we describe the use of in vitro double labelling (sequential tritiated thymidine and bromodeoxyuridine staining of proliferating epithelial cells) to calculate S phase labelling indices (LIs), estimation of S phase duration (tS), and measurement of variables of flux to and from S for excised specimens of oral squamous cell carcinoma, premalignant lesions, and clinically normal mucosa from patients with oral cancer. There was a significant increase in mean LIs in buccal mucosa leukoplakias (14.5%) compared with normal mucosa (10.3%); P = 0.03. LIs were also increased in patients with cancers of the floor of mouth and ventral tongue but neither these changes nor alterations in flux parameters or S Phase durations were significant. Twenty-one kinetic profiles of dysplastic and malignant tissue were compared with conventional histopathological results, however, and these showed a 2.2% increase in LIs with each increase in grade of dysplasia (P = 0.004) and a 12% increase in LIs with each reduction in tumour differentiation (P = 0.02).

Mapping dynamic epithelial cell proliferative activity within the oral cavity of man: a new insight into carcinogenesis?

Our aim was to characterize epithelial cell proliferative activity within the oral cavity and to find out if there were differences between sites with high and low incidence of cancer. A total of 105 samples of clinically normal mucosa were harvested from various intra-oral sites. Excised specimens were incubated in vitro with tritiated thymidine and bromodeoxyuridine to 'double label' cells undergoing DNA synthesis, and enable calculation of the duration of S phase and estimation of variables of cell flux to and from S. Mean labelling indices (percentage of cells within the S phase of the cell cycle) were highest in the floor of mouth (12.3%) and ventral tongue (10.1%), while activity was lowest in the dorsum of tongue (4.3%) and the palate (7.2%), P<0.001. In general, both cell influx and the duration of S increased proportionally to the labelling index. Sites with a high incidence of cancer were characterized by high labelling indices, increased cell influx and a prolonged S phase.

Tritiated thymidine and bromodeoxyuridine double-labelling studies on growth factors and oral epithelial proliferation in the mouse

Mouse tongue epithelium is characterized by a circadian variation in the number of cells undergoing DNA synthesis. Groups of male BDF1 mice were followed over 48 h and a double-labelling method with tritiated thymidine and bromodeoxyuridine used to determine S-phase labelling indices, together with cell influx to and cell efflux from S, at 4-hourly time points. Control animals exhibited diurnal peaks in labelling index at 03:00 with trough activity 12 h later at 15:00. Cell influx peaked at 23:00 with troughs occurring between 11:00 to 15:00. Peak cell efflux occurred at 07:00 with trough activity at 19:00. Animals injected with epidermal growth factor at 05:00 demonstrated a significant fall in both influx and efflux throughout the 48-h period (P < 0.001), but with preservation of labelling indices, suggesting a slower transit of cells through S-phase, whereas epidermal growth factor injected at 15:00 only produced a significant rise in cell-efflux values. Adrenergic stimulation by intravenous phenylephrine/isoprenaline injection at both 05:00 and 15:00 resulted in a significant rise in cell efflux (P < 0.001), although there was also a rise in labelling index in the 15:00 group (P < 0.001). Animals injected with calmodulin at 05:00 demonstrated a significant reduction in labelling index throughout the 48-h period (P < 0.001), but maintained control values for cell influx and efflux, suggesting faster transit of cells through S. Calmodulin injection at 15:00 produced only a significant reduction in cell influx (P < 0.001). Administration of exogenous growth factors significantly alters the normal rhythmical proliferation of oral epithelial cells in a mouse model. These effects appear to be both growth factor- and time-dependent, and may have both physiological and pathological implications.

Preoperative vascular assessment: an aid to radial forearm surgery

Twenty-three patients undergoing oral reconstructive surgery with radial forearm free flaps had a vascular assessment of the forearm preoperatively. Segmental upper limb pressures were measured and colour flow duplex visualization of forearm vessels and blood flow done. In 18 the blood pressure and flow were within normal limits, but five (22%) showed either unilateral or bilateral arteriopathy or aberrant vascular anatomy. Identification of pre-existing vascular disease helps to rationalize the selection of donor vessels, reduces the risk of ischaemic damage to the hand after disruption of the radial artery and may be of benefit in reducing the incidence of failure of free flaps.

Auditing clinical teaching in oral surgery: the use of a student log book

Objective assessments of clinical teaching are difficult; in oral surgery students must acquire a wide range of clinical and operative skills before qualifying as independent dental practitioners. A student log book system was introduced in Manchester University to monitor student progress and assess the efficacy of clinical instruction in oral and maxillofacial surgery following the introduction of the new 5-year BDS curriculum. Initial appraisal of third- and fourth year students undertaking 10-week clinical attachments revealed generally high levels of attendance (greater than 80%), and reasonable clinical experience (over 80% of students acquiring regular experience of dentoalveolar surgery and extractions). However, individual variation in both attendance and achievement was wide, and a persistent 8% of students did not appear to gain any practical experience. Students achieving less than the average course performance marks were thus easily identified and measures initiated to identify and correct their difficulties. Log book assessment also facilitated effective audit of teaching staff, clinical sessions and overall course delivery. The use of student log books to record clinical performance is recommended as a versatile aid to clinical teaching practice.

Persistent haemorrhage following dental extractions in patients with liver disease: two cautionary tales

Two cases are reported in which patients known to suffer from chronic liver disorders underwent local anaesthetic dental extractions. In both cases the procedure was followed by severe, intractable post-operative haemorrhage, resistant to local haemostatic measures and requiring hospital admission for intravenous fluid replacement and administration of clotting factors. The importance of not only eliciting details of a patient's medical history, but also of acting appropriately upon that information is emphasised and a recommendation is made that patients with active liver disorders, such as cirrhosis, who require oral surgery procedures should be managed in hospital departments, where access to haematological assessment and appropriate surgical and medical care is readily available. Close liaison with liver physicians and haematologists is recommended.

Mental nerve dysfunction: a symptom of diverse mandibular disease

Paraesthesia and anaesthesia of the mental nerve may result from a variety of pathological conditions, and in persistent cases of orofacial sensory disturbance thorough clinical assessment, including CT scanning, is vital to exclude underlying systemic or neoplastic disease. This paper presents three patients with right mental nerve dysfunction, and reviews the aetiology of mental nerve paraesthesia and anaesthesia.

Statistical discriminant analysis of arrhythmias using intracardial electrograms

The problem of classifying ventricular arrhythmias from intracardial electrograms is considered. Standard statistical discrimination procedures are applied using a simple parametric model for the shape of the pulse near its peak. This approach makes simultaneous use of the model parameters, has well known statistical properties, and involves computations that can be carried out efficiently. Preliminary analyses of real data sets, using both linear and quadratic discrimination functions, yield promising results.

Recovery from intravenous sedation with midazolam--the value of flumazenil

A total of 40 patients receiving intravenous midazolam for surgical removal of impacted wisdom teeth were randomly assigned to recover either spontaneously or undergo reversal by the benzodiazepine antagonist flumazenil. Whilst initial postoperative recovery to a 'fully awake' state occurred more rapidly in the reversal group, objective psychomotor testing revealed significantly poorer performance postoperatively compared with spontaneously recovering patients; this emphasises the need to retain patients for at least 1 h prior to discharge home.

A central venous catheter complicating head and neck surgery

A case is reported of a central venous catheter that was placed inadvertently into the internal jugular vein during the anaesthetic preparation for surgery. The catheter tip was sectioned during surgery and was feared to have embolised into the central circulation but it was subsequently identified in the pathological specimen. A summary of the complications associated with central venous catheterisation is reported and a simple protocol is proposed to avoid a similar complication.

Cancelled operations. A current problem in oral and maxillofacial surgery

Public concern has recently focused on the problem of cancelled operations. In order to investigate the extent of oral and maxillofacial surgery cancellations, the University of Manchester initiated a 12-month prospective audit of lost operating time. During 1990, 31% of planned operations were cancelled, while nearly 20% of operating lists were lost completely. With the exception of public holidays and theatre maintenance days, the commonest reasons for cancellation included financial cut-backs, nursing staff shortages and failure of patients to attend.

Changes in oxygen saturation using two different sedation techniques

Pulse oximetry was used to assess the degree of hypoxia observed in patients receiving simple midazolam sedation for removal of lower third molars and compared to that seen in patients receiving a combination sedation technique using nalbuphine and midazolam. Results showed that the degree of hypoxia experienced by patients receiving the combination technique was significantly more profound in both incidence and depth than that seen in the group receiving midazolam alone (p less than 0.05).

Reducing failure rates for in-patient oral surgery. The use of a pre-admission clinic

A large proportion of oral and maxillofacial surgery operations are non-urgent, elective procedures. Approximately 30% of patients called for operation from routine waiting lists consistently fail to attend, thus leading to inefficient bed utilisation and wastage of theatre time. In an attempt to reduce patient failure rates and to investigate reasons for non-attendance, the Department of Oral and Maxillofacial Surgery developed a new pre-admission clinic; admission dates for in-patient surgery are only arranged following successful attendance and satisfactory 'clerking in' at the pre-admission clinic. Over an initial 5-month period, in-patient attendance rates increased to 87% and, at the same time, validation of waiting lists was facilitated, with nearly three-quarters of clinic non-attenders eventually being removed from the lists. The pre-admission clinic thus appears to offer a useful and versatile approach towards more efficient in-patient management.