Concurrent chronic hyperplastic candidosis and oral lichenoid lesion as adverse events of secukinumab therapy

Secukinumab (Cosentyx®) is an IL-17A inhibitor which is used for the management of psoriasis, active psoriatic arthritis or ankylosing spondylitis. Oral adverse events of secukinumab therapy are not widely appreciated. This article highlights the presentation of two concurrent oral adverse events of secukinumab therapy; namely chronic hyperplastic candidosis (CHC) and oral lichenoid lesion (OLL). This is the first documented case report of CHC occurring as a consequence of secukinumab therapy, and represents a new adverse effect which general and specialist oral health practitioners should be aware of. This case highlights the importance of correlating the presence of oral lesions with the patient's medical history, keeping up to date with the development of new medications and pharmacotherapeutics, having a deep understanding of underlying biological processes related to various oral diseases, and appreciating the use of clinical adjunctive devices. Accurate diagnosis is key to formulating a correct management plan.

Steroid insensitive fixed airflow obstruction is not related to airway inflammation in older non-smokers with asthma

There is limited evidence linking airway inflammation and lung function impairment in older non-smoking asthmatics with fixed airflow obstruction (FAO), which can develop despite treatment with inhaled corticosteroids (ICS). We assessed lung function (spirometry, forced oscillation technique (FOT)), lung elastic recoil and airway inflammation using bronchoalveolar lavage (BAL) in non-smoking adult asthmatics with FAO, following 2 months treatment with high-dose ICS/long-acting beta-agonist. Subjects demonstrated moderate FAO, abnormal FOT indices and loss of lung elastic recoil. This cross-sectional study showed a lack of a relationship between BAL neutrophils, eosinophils, inflammatory cytokines and lung function impairment. Other inflammatory pathways or the effect of inflammation on lung function over time may explain FAO development.

Narrow Band Imaging-guided resection of oral cavity cancer decreases local recurrence and increases survival

PURPOSE

Overall local recurrence of oral squamous cell carcinoma (OSCC) is estimated at 20%. Incomplete primary tumour excision contributes to localised postsurgical recurrence of OSCC. The purpose of this study was to report on patient outcomes following resection of OSCC using Narrow Band Imaging (NBI).

MATERIALS AND METHODS

Patients with OSCC requiring resection were visualised under conventional white light (WL) then NBI using an Olympus NBI ENF-VQ nasendoscope with CLV-180 light source and processor (Olympus Medical Systems, Tokyo, Japan). OSCC tissue was resected to the NBI-defined surgical margins, and patients followed for a minimum of 5 years postsurgery to assess local recurrence rate (LRR) and disease-free survival (DFS).

RESULTS

Of the 20 patients recruited for this study, one patient (5%) declined follow-up. At the latest follow-up period (up to 7 years postsurgery), 14 of 19 patients (73.68%) were alive with no recurrence. Two patients (10.53%) had died from metastatic disease with no local recurrence, one patient (5.26%) had died from disease with local recurrence, and two patients (10.53%) had died disease-free from other causes. In total, 16 of 19 patients (84.21%) who were followed for a minimum of 5 years were still alive and had not developed local recurrence. Only one patient developed local recurrence. Five-year DFS was 84.21% and LRR was 5.26%.

CONCLUSION

Resection to NBI-defined margins improves survival rates and decreases recurrence rates of OSCC compared to traditional methods and should be adopted as the new gold standard for determining mucosal surgical margins for treatment of oral cavity cancer. These promising results have set the scene for a multicentred randomised controlled trial comparing NBI to WL currently underway.

Diagnostic accuracy of Narrow Band Imaging for the detection of oral potentially malignant disorders

OBJECTIVE

To determine the clinical diagnostic accuracy of Narrow Band Imaging(™) for the detection of oral potentially malignant disorders in a prospective series of patients.

MATERIALS AND METHODS

New and existing patients referred to an oral medicine and pathology specialist clinic for assessment of at least one white, red or red-white oral mucosal lesion underwent conventional oral examination, followed by examination with the white light mode and then narrow band imaging mode of a Narrow Band Imaging(™) system. The clinical presentation, microvascular architecture and relevant histopathology of all lesions were recorded.

RESULTS

A total of 272 lesions from 95 patients were observed. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy for the detection of oral potentially malignant disorders or worse by Narrow Band Imaging(™) were 100%, 74.63%, 92.38%, 100% and 93.77%, respectively, when compared with conventional oral examination. Narrow Band Imaging(™) aided the detection of 24 lesions undetected by conventional oral examination and 13 lesions undetected by white light endoscopy.

CONCLUSION

Narrow Band Imaging(™) demonstrates great utility as a visualisation adjunct for detecting and monitoring oral potentially malignant diseases, particularly lesions not identified by conventional oral examination or white light examination alone.

Narrow band imaging: clinical applications in oral and oropharyngeal cancer

Narrow Band Imaging (NBI) is an endoscopic optical imaging enhancement technology that improves the contrast of mucosal surface texture, and enhances visualisation of mucosal and submucosal vasculature. White light is filtered to emit two 30-nm narrow bands of blue (415 nm) and green light (540 nm) light simultaneously, the former corresponding to the main peak absorption spectrum of haemoglobin, and the latter allowing visualisation of blood vessels in the deeper mucosal and submucosal layers. NBI has been used to better assess oral potentially malignant disorders (OPMD), identify oral and oropharyngeal squamous cell carcinoma (SCC), and to define surgical margins of head and neck malignancies. NBI shows great potential in improving detection rates of OPMD, facilitating better assessment of oral and oropharyngeal SCC, and reducing the risk of recurrence for oral SCC. Although further research is required to better understand and define intrapapillary capillary loop (IPCL) patterns and to relate these with clinical, histopathological and molecular parameters especially for early mucosal changes, there is building evidence to recommend its use as the new gold standard for endoscopic assessment in head and neck oncology.

Screening and referral of oral mucosal pathology: a check-up of Australian dentists

BACKGROUND

Oral squamous cell carcinomas and potentially malignant oral disorders can be detected early by visually inspecting the oral soft tissues. This study aimed to determine Australian dentists' opinions and practices regarding oral mucosal screening, referral and oral cancer prevention.

METHODS

Nine hundred and ninety-nine randomly selected general dentists were mailed a questionnaire. The questionnaire queried practitioners' opinions and perceptions of oral mucosal screening, their referral practices and their beliefs regarding detection and prevention of oral cancer.

RESULTS

A total of n=640 individuals responded, yielding a response rate of 70.2%. Most Australian dentists reported to routinely perform oral mucosal screening. Lack of training, confidence, time and financial incentives were seen as barriers to performing mucosal screening to at least some degree by participants in this study. Most dentists manage referrals for oral mucosal pathology appropriately; however, only about half believe in following up with referred patients. Only half of dentists surveyed believed that they could influence a patient to quit smoking.

CONCLUSIONS

Australian dentists place importance on oral mucosal screening. Some changes to dental education and training could be made to further improve confidence and ability of dentists in detecting and referring oral mucosal pathology.

Oral health impacts and quality of life in an urban homeless population

BACKGROUND

Homeless people experience a much higher burden of general health conditions and have much poorer oral health than the rest of the population. The aim of this study was to determine the oral health impacts and general quality of life of an urban homeless population.

METHODS

A convenience sample of 58 adults (dentate n = 56) experiencing homelessness were assessed using a survey which included the 14-item Oral Health Impact Profile and the 26-item World Health Organization's Quality of Life - short version. A subset (n = 34) also underwent a dental examination.

RESULTS

The study participants were younger, more likely to be Indigenous, smoked daily and avoided dental care because of cost than the rest of the population. Dentate homeless adults reported significantly greater oral health impacts when compared with the Australian dentate population. General quality of life was significantly poorer than for the rest of the population. Treatment need was associated with greater oral health impacts.

CONCLUSIONS

Poor oral health is prevalent and adversely impacts quality of life for homeless people, but it is only one of a range of complex social and health challenges being faced by these individuals. Dental care should be better integrated within homeless support services.

Oral mucosal screening and referral attitudes of Australian oral health therapists and dental hygienists in Queensland

OBJECTIVES

The aim of this study was to describe oral mucosal screening and referral attitudes of Australian oral health therapists (OHTs) and dental hygienists (DHs).

METHODS

Questionnaires were distributed to participants who attended dental hygiene courses run in both regional and metropolitan Queensland.

RESULTS

One hundred and two participants comprised 58 OHTs and 44 DHs, with a mean of 8.9 years since graduation. Thirty-four participants worked in regional locations, while 68 were from metropolitan areas. 97% of participants agreed that mucosal screening should be performed for all new and recall patients, while a minority (5%) agreed that patients will detect an oral mucosal change themselves. The majority (77%) agreed that oral cancer would be encountered in their practising career. Most participants (81%) felt comfortable discussing the presence of a suspicious lesion with patients and 88% agreed that it was their role to screen. In terms of barriers to oral cancer screening, lack of training was seen as the most prevalent barrier (56%) followed by lack of confidence (51%). Lack of time was seen as the third most prevalent barrier (40%), and lack of financial incentives was the least prevalent barrier (16%).

CONCLUSIONS

Oral health therapists and DHs understand the importance of oral mucosal screening and are likely to be alert to oral mucosal changes. While lack of time and financial incentives was perceived to be impediments to mucosal screening, lack of confidence and training was the most prevalent barriers. This issue should be addressed through implementation of effective continuing education courses targeting oral cancer screening and referral practices.

Oral cancer in Australia 1982-2008: a growing need for opportunistic screening and prevention

BACKGROUND

Globally, a decline in the incidence of oral cancer has been noted, while the mortality rates have remained relatively stable. The aim of this study was to provide an update on the incidence and mortality of oral cancer in Australia on a national and state level.

METHODS

Data regarding new cases and deaths associated with cancer of the lip, oral cavity and oropharynx were obtained from the Australian Institute of Health and Welfare for the period 1982-2008. Crude- and age-standardized incidence and mortality rates were calculated for all of Australia and for each state and territory.

RESULTS

A total of 60 826 cases of lip, oral cavity and oropharyngeal cancer were diagnosed in Australia. Between 1992 and 2008, a decline in the annual percentage change of age-standardized incidence was noted. The lip, followed by the tongue, continue to represent the most common sites of new oral cancer cases. There was no significant change in the rates of mortality for oral cancer over the time period.

CONCLUSIONS

These findings show that the oral cancer mortality rate remains high despite a decline in incidence over the past three decades, highlighting a greater need for dental practitioners to undertake preventive strategies and opportunistic screening for patients.

Harnessing massively parallel sequencing in personalized head and neck oncology

Advances in the management of patients with head and neck squamous cell carcinoma (HNSCC) have not significantly changed the prognosis of this tumor over the past five decades. Molecular heterogeneity of HNSCC and its association with HPV, in addition to the increase in the number of cancers arising in traditionally low-risk patients, are among some of the obstacles to the successful management of this group of tumors. Massively parallel sequencing, otherwise known as next-generation sequencing (NGS), is rapidly changing conventional patient management by providing detailed information about each patient's genome and transcriptome. Despite major advances in technology and a significant reduction in the cost of sequencing, NGS remains mainly limited to research facilities. In addition, there are only a few published studies that have utilized this technology in HNSCC. This paper aims to report briefly on current commercially available NGS platforms and discuss their clinical applications, ethical considerations, and utilization in personalized patient care, particularly as this relates to head and neck cancer.

Oral mucosal lesions: findings from the Australian National Survey of Adult Oral Health

BACKGROUND

The prevalence of oral mucosal lesions (OMLs) and factors associated with these has not previously been reported in the Australian population. This study aimed to report on the prevalence of OMLs in Australian adults and to evaluate their association with socio-demographic factors.

METHODS

This study utilized data from the Australian National Survey of Adult Oral Health 2004-06, which employs a multi-stage, stratified random sample selection procedure. Information on socio-demographics, smoking and presence of OMLs were collected using telephone interview, self-reported questionnaires and comprehensive oral examination. A multivariate regression model was generated to estimate effect of factors on the prevalence of non-ulcerated OMLs.

RESULTS

A total of 3551 dentate adult Australians had complete data for this analysis. Over 20% of study participants presented with an OML on the day of examination. The prevalence of suspected malignancy was less than 1% and over 17% for non-ulcerated OMLs. Prevalence of non-ulcerated OMLs was associated with age, gender, residential location, household income and smoking.

CONCLUSIONS

The study reported that epidemiological survey can provide useful information on OMLs. Certain population groups had a higher risk of having the condition. Preventing smoking uptake and smoking cessation can reduce the prevalence of OMLs in the population.

Support needs and quality of life in oral cancer: a systematic review

PURPOSE

This review aims to systematically review the literature describing quality of life (QoL) outcomes and support needs in patients with oral cancer along the cancer trajectory. This is needed to form an evidence base for the design of interventions that enhance outcomes for this group.

METHODS

Six electronic databases were searched. The results were screened for eligibility, and articles were included if they described patient-reported QoL outcomes that were translatable to support needs in patients with oral cancer. Data were extracted and synthesized according to the support needs identified and their relative impact on QoL. Methodological quality was assessed using the Effective Public Health Practice Project (EPHPP) Quality Assessment Tool.

RESULTS

Thirty-one articles met the inclusion criteria. Support needs related to coping with the burden of radiotherapy in both psychosocial and physical aspects, swallowing dysfunction, dry mouth and oral functional deficits. Issues of depression, anxiety and malnutrition were identified as having a significant impact on QoL.

CONCLUSIONS

Oral cancer support needs are highly subjective and varied in severity across the cancer continuum. Support needs that may warrant further investigation include management of changes to oral health and functioning, swallowing and nutritional compromise and psychological effects of cancer and treatment.

Digital interactive learning of oral radiographic anatomy

INTRODUCTION

Studies reporting high number of diagnostic errors made from radiographs suggest the need to improve the learning of radiographic interpretation in the dental curriculum. Given studies that show student preference for computer-assisted or digital technologies, the purpose of this study was to develop an interactive digital tool and to determine whether it was more successful than a conventional radiology textbook in assisting dental students with the learning of radiographic anatomy.

MATERIALS AND METHODS

Eighty-eight dental students underwent a learning phase of radiographic anatomy using an interactive digital tool alongside a conventional radiology textbook. The success of the digital tool, when compared to the textbook, was assessed by quantitative means using a radiographic interpretation test and by qualitative means using a structured Likert scale survey, asking students to evaluate their own learning outcomes from the digital tool.

RESULTS

Student evaluations of the digital tool showed that almost all participants (95%) indicated that the tool positively enhanced their learning of radiographic anatomy and interpretation.

DISCUSSION

The success of the digital tool in assisting the learning of radiographic interpretation is discussed in the broader context of learning and teaching curricula, and preference (by students) for the use of this digital form when compared to the conventional literate form of the textbook.

CONCLUSION

Whilst traditional textbooks are still valued in the dental curriculum, it is evident that the preference for computer-assisted learning of oral radiographic anatomy enhances the learning experience by enabling students to interact and better engage with the course material.

Early activation of the interleukin-23-17 axis in a murine model of oropharyngeal candidiasis

Candida albicans is an oral commensal yeast that causes oropharyngeal candidiasis (OPC) in immunocompromised individuals. The immunological pathways involved in OPC have been revisited after the interleukin-17 (IL-17) pathway was implicated in fungal immunity. We studied immediate (<24 h) and adaptive (3-6 day) IL-12 and IL-23-17 pathway activation in naive p40(-/-) mice, which lack IL-12 and IL-23 and develop severe, chronic OPC upon oral inoculation with C. albicans. Macrophages from p40(-/-) mice were less efficient than C57BL/6J controls at killing C. albicans in vitro but very low numbers in the oral mucosae of infected C57BL/6J mice suggest that they are not critical in vivo, at least in this strain. Migration of macrophages to regional lymph nodes of infected p40(-/-) mice was impaired; however, dendritic cell migration was not affected. Recombinant IL-12 therapy provided only temporary relief from OPC, suggesting that IL-23 is required for full protection. In C57BL/6J mice, but not p40(-/-) mice, messenger RNAs encoding IL-23p19 and IL-17 were induced in the oral mucosa within 24 h of infection (6 ± 0.6 and 12 ± 2.7-fold). By day 6 of infection in C57BL/6J mice, IL-17A messenger RNA level had increased 5.1 ± 1.8 and 83 ± 21-fold in regional lymph nodes and oral tissues respectively. Ablation of p40 was associated with delayed or abrogated induction of IL-17A pathway targets (monocyte chemoattractant protein-1, IL-6 and macrophage inflammatory protein-2), and a lack of organized recruitment of neutrophils to the infected oral mucosa. Overall our data show that the IL-23-17A axis is activated early in the oral mucosae of immunologically naive mice with OPC.

Oral mucosal malignancy and potentially malignant lesions: an update on the epidemiology, risk factors, diagnosis and management

An oral examination for the assessment for malignant and potentially malignant oral mucosal lesions is routine in general dental practice. It may be uncommon for general dental practitioners to encounter oral cancer, with anecdotal reports suggesting that this occurs about once every 10 years in a busy general dental practice. However, potentially malignant oral mucosal lesions are relatively common, occurring in about 2.5% of the population. This update highlights the epidemiology, risk factors, diagnosis and management of these oral mucosal lesions.

Oral fungal infections: an update for the general practitioner

Oral candidosis is the most common fungal infection encountered in general dental practice. It manifests in a variety of clinical presentations which may mimic more sinister diseases, and can occasionally be refractory to treatment requiring the attention of an oral medicine specialist. Management of oral candidosis should always include a thorough investigation of underlying predisposing conditions, as the disease often presents when the patient is systemically compromised. This update highlights the pathogenesis, clinical presentation, and management strategies of oral Candidal lesions commonly encountered in dental practice.

Implementing digital technology to enhance student learning of pathology

INTRODUCTION

The introduction of digital technologies into the dental curriculum is an ongoing feature of broader changes going on in tertiary education. This report examines the introduction of digital virtual microscopy technology into the curriculum of the School of Dentistry at the University of Queensland (UQ) in Brisbane, Australia.

METHODS AND MATERIALS

Sixty students studying a course in pathology in 2005 were introduced to virtual microscopy technology alongside the more traditional light microscope and then asked to evaluate their own learning outcomes from this technology via a structured 5-point LIKART survey.

RESULTS

A wide variety of questions dealing the pedagogic implications of the introduction of virtual microscopy into pathology were asked of students with the overall result being that it positively enhanced their learning of pathology via digital microscopic means.

DISCUSSION

The success of virtual microscopy in dentistry at UQ is then discussed in the larger context of changes going on in tertiary education. In particular, the change from the print-literate tradition to the electronic one, that is from 'literacy to electracy'. Virtual microscopy is designated as a component of this transformation to electracy.

CONCLUSION

Whilst traditional microscopic skills may still be valued in dental curricula, the move to virtual microscopy and computer-assisted, student-centred learning of pathology appears to enhance the learning experience in relation to its effectiveness in helping students engage and interact with the course material.

Gene targeting demonstrates that inducible nitric oxide synthase is not essential for resistance to oral candidiasis in mice, or for killing of Candida albicans by macrophages in vitro

INTRODUCTION

Oral candidiasis is caused by opportunistic infections with the yeast Candida albicans. Previous studies have demonstrated important roles for innate immunity and T helper type 1-mediated inflammatory reactions in recovery from infection, with macrophages and neutrophils as key effector cells. Both effector cell types use the inducible isoform of nitric oxide synthase (iNOS) to generate candidacidal molecules, but it is not clear whether nitric oxide (NO) is an absolute requirement for candidacidal effector activity.

METHODS

In this study we directly investigated the role of iNOS-derived NO in resistance to murine experimental oral candidiasis, using iNOS knockout mice.

RESULTS

Knockout mice were no more susceptible to oral candidiasis than wild-type controls. Bone marrow-derived macrophages from the knockout mice killed C. albicans yeasts efficiently in vitro, and were still able to produce nitrites in an iNOS-independent manner, albeit less efficiently than wild-type controls. There were no significant differences in local mucosal production of interleukins 6, 12, 17A, or 23, interferon-gamma, or transforming growth factor-beta 24 h after oral challenge with C. albicans.

CONCLUSION

These data suggest that iNOS-derived NO is not required for resistance to oral candidiasis in vivo, and that bone marrow-derived macrophages may have iNOS-independent means of generating reactive nitrogen species.

The role of cytokines in a Porphyromonas gingivalis-induced murine abscess model

INTRODUCTION

Porphyromonas gingivalis is an important periodontopathic bacterium that is strongly associated with periodontal disease and is part of human dental plaque. Periodontal disease results from the interaction of the host with bacterial products, and T-cell-derived cytokines remain critical in the immunoregulation of periodontal disease.

METHODS

The aim of this study was to examine the role of T helper type 1 [interleukin-12p40 (IL-12p40), interferon-gamma, tumour necrosis factor (TNF)] and type 2 (IL-4, IL-10) cytokines in the immune response to a subcutaneous challenge with P. gingivalis using a well-established murine abscess model, in genetically modified cytokine-specific knockout mice.

RESULTS

IL-12p40(-/-) mice exhibited more advanced tissue destruction and a reduced inflammatory cell infiltrate after subcutaneous P. gingivalis challenge. Deficiency of IL-4 or IL-10 did not result in increased susceptibility to P. gingivalis-mediated tissue destruction. Furthermore, TNF deficiency appeared to reduce local tissue destruction. Interestingly, serum-specific antibodies suggested a strong T helper type 2 response.

CONCLUSION

The results of our study indicate an important role for IL-12 in a primary P. gingivalis subcutaneous challenge.

Alveolar bone loss in T helper 1/T helper 2 cytokine-deficient mice

BACKGROUND AND OBJECTIVES

The role of cytokines in bone loss is important in the context of periodontitis, where inflammation-induced bone destruction is a major manifestation. Numerous cytokines have been implicated as mediators of bone resorption. The purpose of this study was to observe the impact of targeted gene deletion of T helper 1 (Th1) and T helper 2 (Th2) cytokines on naturally occurring alveolar bone loss in genetically modified mice.

MATERIAL AND METHODS

Alveolar bone loss was measured histomorphometrically in interleukin-4, interleukin-10, interleukin-12p40, interferon-gamma (IFN-gamma) and tumor necrosis factor (TNF) knockout mice at 6, 16 and 30 wk of age.

RESULTS

Both Th1 (interleukin-12p40, IFN-gamma, TNF) and Th2 (interleukin-10, interleukin-4) knockout mice exhibited significantly more alveolar bone loss than their respective wild-type control mice (p<0.001). Interleukin-10-/- and interleukin-12p40-/- mice exhibited a three-fold increase in alveolar bone loss at 30 wk of age, whereas bone loss in IFN-gamma-/-, TNF-/- and interleukin-4-/- mice was 1.5- to two-fold higher compared with wild-type control mice.

CONCLUSION

The results of the present study indicate that both Th1 and Th2 cytokines play an important role in maintaining alveolar bone homeostasis. The kinetics of alveolar bone loss seen in cytokine gene knockout mice indicates that bone loss is age dependent and late in onset.

Deficiency of iNOS contributes to Porphyromonas gingivalis-induced tissue damage

Periodontitis is a chronic inflammatory disease that results in extensive soft and hard tissue destruction of the periodontium. Porphyromonas gingivalis possesses an array of virulence factors and has been shown to induce expression of inducible nitric oxide synthase (iNOS) in inflammatory cells. The aim of this study was to investigate the effect of eliminating iNOS in a murine model of P. gingivalis infection. This was achieved by utilizing a P. gingivalis-induced skin abscess model, and an alveolar bone loss model employing an oral infection of P. gingivalis in iNOS knockout mice. The results indicated that iNOS knockout mice exhibit more extensive soft tissue damage and alveolar bone loss in response to P. gingivalis infection compared to wild-type mice. The local immune response to P. gingivalis in iNOS knockout mice was characterized by increased numbers of polymorphonuclear monocytes, while the systemic immune response was characterized by high levels of interleukin-12. The iNOS is required for an appropriate response to P. gingivalis infection.

Distinct roles for interleukin-12p40 and tumour necrosis factor in resistance to oral candidiasis defined by gene-targeting

Cell-mediated immunity is important for anti-Candida host defence in mucosal tissues. In this study we used cytokine-specific gene knockout mice to investigate the requirement for T helper type 1 (Th1) and Th2 cytokines in recovery from oral candidiasis. Knockout mice used in this study included interleukin-4 (IL-4), IL-10, IL-12p40, interferon-gamma (IFN-gamma), and tumour necrosis factor (TNF). The mice were challenged either orally or systemically with Candida albicans yeasts, and levels of colonization were determined. IL-12p40 knockout mice developed chronic oropharyngeal candidiasis, but were not more susceptible to systemic challenge. On the other hand, TNF knockout mice displayed increased susceptibility to both oral and systemic challenge, but only in the acute stages of infection. TNF apparently has a protective effect in the acute stages of both oral and systemic candidiasis, whereas IL-12p40 is essential for recovery from oral but not systemic candidiasis. The role of IL-12p40, and its relation to T-cell-mediated responses remain to be determined.

Cryotherapy for treatment of oral lesions

Cryotherapy is the deliberate destruction of tissue by application of extreme cold. It is well received by patients due to a relative lack of discomfort, the absence of bleeding and minimal to no scarring after healing. It has many applications in oral medicine and clinical oral pathology, and is extremely usefu in patients for whom surgery is contra-indicated due to either age or medical history. In this paper we outline the principles, mechanisms of action, and current applications of cryotherapy in the treatment of oral lesions, and present some clinical cases.

Isolates of Candida albicans that differ in virulence for mice elicit strain-specific antibody-mediated protective responses

Three distinct isolates of Candida albicans were used to establish systemic and oral infections in inbred mice that are genetically resistant or susceptible to tissue damage. Patterns of infection differed significantly between both yeasts and mouse strains. Systemic infection conferred significant protection against re-challenge with the homologous, but not the heterologous yeast; however, the protective effect was more evident in the tissue-susceptible CBA/CaH mice than in the resistant BALB/c strain. In contrast, oral infection induced protection against both homologous and heterologous oral challenge, although this was significant only in the CBA/CaH mice. CBA/CaH mice produced antibodies of both IgG1 and IgG2a subclasses, whereas BALB/c mice produced predominantly IgG1. Western blotting demonstrated considerable differences between epitopes recognised by serum antibodies from mice of both strains after immunisation with each of the three yeasts. Thus, different strains of yeast show considerable specificity in antibody responses elicited by either systemic or oral infection.

Active and passive immunization against oral Candida albicans infection in a murine model

BACKGROUND/AIMS

Clinical and laboratory studies are consistent with a major role for cell-mediated immunity in recovery from oral infection with Candida albicans, but the role of humoral immunity remains controversial. The purpose of this study was to establish the relative contributions of cellular and humoral immunity to protection against oral candidiasis in a murine model, and to determine whether host responses could be enhanced by different immunization strategies.

RESULTS

Active oral immunization was protective in BALB/c and CBA/CaH mice, reducing both fungal burden and duration of infection after secondary challenge, whereas systemic immunization failed to protect against subsequent oral challenge. Candida-specific IgM was the predominant antibody detected in serum following both primary and secondary oral challenge; however, Candida-specific salivary IgA was not detectable. Immunization by passive transfer of either lymphocytes or immune serum did not confer any significant protection against oral infection in either susceptible or resistant mouse strain.

CONCLUSION

The data demonstrate a possible role for mucosa-associated immunity following active immunization by the oral route, most likely exerted by local T lymphocytes resident in the oral mucosa, but there was no evidence to support a role for humoral immunity in protection against oral candidiasis.

Oral ulceration with bone sequestration

Oral mucosal ulceration is a common manifestation of various disease processes. Identification of the aetiological factor(s) involved greatly facilitates the management of such conditions. This report describes oral ulceration of the mucosa overlying the lingual shelf and mylohyoid ridge of the mandible and, less commonly on tori and exostoses, in association with bone sequestration. Trauma, which involves the subjacent periosteum resulting in a focus of ischaemic bone necrosis, in conjunction with local anatomical and perhaps other systemic predisposing factors, forms the aetiopathogenesis for this particular type of focal ulcerative lesion.

Cytokines in the oral mucosa of mice infected with Candida albicans

Oropharyngeal candidiasis is associated with defects in cell-mediated immunity, and is commonly seen in immunocompromised patients. We have previously shown that T-cell-deficient BALB/c nude (nu/nu) mice are extremely susceptible to oropharyngeal candidiasis, and that recovery from a chronic infection is dependent on CD4 T lymphocytes. In this study we describe the local tissue cytokine profile in lymphocyte-reconstituted immunodeficient mice and their euthymic counterparts. Mice were infected orally with 108 cells of the yeast Candida albicans, and oral tissues sampled on days 0, 4, 8, and 14. Nude mice were reconstituted with 3 x 107 naïve lymphocytes following oral inoculation. Interleukin (IL)-6, interferon (IFN)-gamma and tumour necrosis factor (TNF)-alpha were identified in the oral tissues of infected euthymic mice recovering from oral infection, as well as naïve controls. TNF-alpha was identified in nude oral tissue on days 4 and 8, but only after lymphocyte reconstitution. No IL-2, IL-4 or IL-10 was detected in either euthymic or athymic mice at any time-point throughout the experiment. This study confirms the functional activity of T lymphocytes in reconstituted nude mice, and suggests that TNF-alpha may be an important mediator in the recovery from oropharyngeal candidiasis.

Pericoronal radiolucencies and the significance of early detection

Pericoronal radiolucencies are common radiographic findings encountered in general dental practice. They usually represent a normal or enlarged dental follicle that requires no intervention; alternatively they may represent a pathological entity that requires appropriate management and histopathological interpretation. A pericoronal space of greater than 2.5mm on an intraoral radiograph and greater than 3mm on a rotational panoramic radiograph should be regarded as suspicious. Although many pathological processes may present radiographically as pericoronal radiolucencies associated with unerupted teeth, the most common is the dentigerous cyst. These lesions may enlarge considerably if allowed to develop unchecked, and have the potential for pathological transformation. In this report we present four cases of large pericoronal radiolucencies associated with unerupted teeth, and highlight the importance of early detection and management of such lesions.

Comparison of the genomes of two Xanthomonas pathogens with differing host specificities

The genus Xanthomonas is a diverse and economically important group of bacterial phytopathogens, belonging to the gamma-subdivision of the Proteobacteria. Xanthomonas axonopodis pv. citri (Xac) causes citrus canker, which affects most commercial citrus cultivars, resulting in significant losses worldwide. Symptoms include canker lesions, leading to abscission of fruit and leaves and general tree decline. Xanthomonas campestris pv. campestris (Xcc) causes black rot, which affects crucifers such as Brassica and Arabidopsis. Symptoms include marginal leaf chlorosis and darkening of vascular tissue, accompanied by extensive wilting and necrosis. Xanthomonas campestris pv. campestris is grown commercially to produce the exopolysaccharide xanthan gum, which is used as a viscosifying and stabilizing agent in many industries. Here we report and compare the complete genome sequences of Xac and Xcc. Their distinct disease phenotypes and host ranges belie a high degree of similarity at the genomic level. More than 80% of genes are shared, and gene order is conserved along most of their respective chromosomes. We identified several groups of strain-specific genes, and on the basis of these groups we propose mechanisms that may explain the differing host specificities and pathogenic processes.

Primary role for CD4(+) T lymphocytes in recovery from oropharyngeal candidiasis

Oropharyngeal candidiasis is associated with defects in cell-mediated immunity and is commonly seen in human immunodeficiency virus positive individuals and AIDS patients. A model for oral candidiasis in T-cell-deficient BALB/c and CBA/CaH nu/nu mice was established. After inoculation with 10(8) Candida albicans yeasts, these mice displayed increased levels of oral colonization compared to euthymic control mice and developed a chronic oropharyngeal infection. Histopathological examination of nu/nu oral tissues revealed extensive hyphae penetrating the epithelium, with polymorphonuclear leukocyte microabscess formation. Adoptive transfer of either naive or immune lymphocytes into immunodeficient mice resulted in the recovery of these animals from the oral infection. Reconstitution of immunodeficient mice with naive CD4(+) but not CD8(+) T cells significantly decreased oral colonization compared to controls. Interleukin-12 and gamma interferon were detected in the draining lymph nodes of immunodeficient mice following reconstitution with naive lymphocytes. This study demonstrates the direct requirement for T lymphocytes in recovery from oral candidiasis and suggests that this is associated with the production of cytokines by CD4(+) T helper cells.

Irradiation-induced oral candidiasis in an experimental murine model

The aim of this experiment was to establish a mouse model of irradiation-induced oral candidiasis and to explore the cellular populations and mechanisms by which the infection is cleared from the oral mucosa. BALB/c mice received irradiation to the head and neck equivalent to 800 Rad using a Cobalt 60 gamma source. Both irradiated and non-irradiated mice were infected orally with 1 x 10(8) Candida albicans yeasts. Compared with untreated controls, irradiated animals developed a more severe infection of longer duration, with hyphae penetrating the oral mucosa. Monoclonal antibody depletion of CD4+ but not CD8+ T cells from the systemic circulation prolonged the infection in irradiated mice, but not in controls. Supernatants of submandibular and superficial cervical lymph node cultures from irradiated animals demonstrated significantly higher titers of interleukin-12, but similar levels of interferon-gamma compared with controls. Screening for cytokine production by an RNase protection assay detected only macrophage migration inhibition factor in irradiated and non-irradiated oral tissues from day 8 onwards. The results of this study demonstrate a requirement for CD4+ T cells in the recovery from oral candidiasis induced by head and neck irradiation in mice, and are consistent with a role for Th1-type cytokines in host resistance.