Non-invasive screening of a microRNA-based dysregulation signature in oral cancer and oral potentially malignant disorders.

INTRODUCTION: We have previously shown that oral swirls are a robust source of microRNA protected by extracellular vesicles, potentially useful to detect oral squamous cell carcinoma (OSCC)-associated molecular aberration. OBJECTIVES: To study a developed dysregulation score and risk classification algorithm based upon a panel of OSCC-associated microRNA in oral swirls from individuals with OSCC and oral potentially malignant disorders (OPMDs). MATERIALS AND METHODS: An OSCC-associated panel of 5 microRNAs (miR-24; miR-21; miR-99a; let-7c; miR-100;) was quantified by qPCR in 190 individuals with and without mucosal abnormalities, including OSCC (n = 53) and OPMDs (n = 74). Each sample was analyzed using a developed dysregulation score (dSCORE) and risk classification algorithm, allocating a LOW- or HIGH-RISK score. The influence of demographic, systemic, oral health and mucosal disease factors on the developed test was analyzed. RESULTS: MicroRNA for analysis can be predictably isolated from oral swirls sourced from individuals with a range of demographic, systemic and oral health findings. Utilizing the presence of HIGH-RISK identified OSCC patients with 86.8% sensitivity and 81.5% specificity. Older age and female gender were associated with higher dSCOREs and higher proportions of HIGH-RISK classification amongst individuals with no mucosal abnormalities. The dSCOREs for all subgroups of OPMDs were significantly different from the OSCC group. CONCLUSION: This is the first comparison of microRNA sourced from oral swirls from individuals with OPMDs with individuals with and without OSCC. A HIGH-RISK dysregulation signature was found to be accurate in indicating the presence of OSCC and exampled to parallel malignant transformation.

Oral swirl samples - a robust source of microRNA protected by extracellular vesicles.

BACKGROUND: MicroRNAs are small non-coding RNAs which are dysregulated in disease states, such as oral cancer. Extracellular vesicles, a potential source of microRNA, are found in saliva. OBJECTIVE: To demonstrate that a quantifiable amount of microRNA can be isolated from oral swirl samples. Additionally, we hypothesized that extracellular vesicles may protect contained microRNA from degradation in these samples. METHOD: A polyethylene glycol-based precipitation was used for extracellular vesicle enrichment of oral swirl samples. Comparison was made between samples treated with and without RNase. Further, samples from three subjects were exposed to a range of conditions over 7 days and assessed for presence of microRNA by reverse-transcription quantitative PCR. Extracellular vesicles from samples were identified under transmission electron microscopy. RESULTS: An adequate quantity of microRNA for qPCR analysis was extractable from samples despite exposure to conditions under which degradation of RNA would be expected. CONCLUSION: A technique was developed to isolate an adequate quantity of microRNA for analysis from oral swirl samples. Extracellular vesicle-associated microRNA may be protected from degradation. This technique moves towards chairside application of translational microRNA research in the field of oral cancer prognostics.

Virulence factors of the oral spirochete Treponema denticola.

There is compelling evidence that treponemes are involved in the etiology of several chronic diseases, including chronic periodontitis as well as other forms of periodontal disease. There are interesting parallels with other chronic diseases caused by treponemes that may indicate similar virulence characteristics. Chronic periodontitis is a polymicrobial disease, and recent animal studies indicate that co-infection of Treponema denticola with other periodontal pathogens can enhance alveolar bone resorption. The bacterium has a suite of molecular determinants that could enable it to cause tissue damage and subvert the host immune response. In addition to this, it has several non-classic virulence determinants that enable it to interact with other pathogenic bacteria and the host in ways that are likely to promote disease progression. Recent advances, especially in molecular-based methodologies, have greatly improved our knowledge of this bacterium and its role in disease.

Spontaneous synchronized neural activity in decerebrate gallamine-paralysed cats.

In decerebrate cats paralysed with gallamine, over a period of several days there develops a remarkable synchronization of discharge in widely different motor nerves throughout the body, including intercostal nerves and limb nerves. These discharges are also in synchrony with slow waves approximately 100 ms in duration in the inferior olive. The slow waves and discharges are at first irregular and only weakly synchronized, but become increasingly strongly synchronized and by about the fourth day exhibit a strong 6-8 Hz rhythm. The degree of synchronization is greater the lower the end-tidal CO2 concentration. Transection of the spinal cord at a high cervical level breaks the synchrony and may abolish the discharge in the nerves, but the slow waves in the inferior olive continue rhythmically. It was shown, however, that gallamine injected subdurally at cervical vertebra 7 or lumbar vertebra 7 has a direct excitatory action on the spinal cord. Slow waves in the inferior olive are elicited by gallamine in the decerebrate, spinalized and decerebellectomized cat, and therefore must originate in the brainstem. Gallamine is known to act directly on olivary neurons and the slow waves may originate in the inferior olive, but further experiments are needed to determine what other structures it affects. The condition of the cat a few days after decerebration and paralysis resembles the clinical condition of reticular reflex myoclonus and it is suggested that the genesis of the myoclonus may be similar in the two conditions.

Evoked skin sympathetic nerve responses in man.

Activity in human unmyelinated efferent nerve fibres was recorded from seven upper limb cutaneous nerve fascicles. The activity induced by contralateral nerve trunk stimulation or tone burst was averaged and could be compared providing the stimuli were delivered at random times and in a random sequence. The average evoked sympathetic nerve responses to nerve trunk stimulation and tone burst were identical in latency and duration.