Intermittent PI3Kδ inhibition sustains anti-tumour immunity and curbs irAEs.

Phosphoinositide 3-kinase δ (PI3Kδ) has a key role in lymphocytes, and inhibitors that target this PI3K have been approved for treatment of B cell malignancies1-3. Although studies in mouse models of solid tumours have demonstrated that PI3Kδ inhibitors (PI3Kδi) can induce anti-tumour immunity4,5, its effect on solid tumours in humans remains unclear. Here we assessed the effects of the PI3Kδi AMG319 in human patients with head and neck cancer in a neoadjuvant, double-blind, placebo-controlled randomized phase II trial (EudraCT no. 2014-004388-20). PI3Kδ inhibition decreased the number of tumour-infiltrating regulatory T (Treg) cells and enhanced the cytotoxic potential of tumour-infiltrating T cells. At the tested doses of AMG319, immune-related adverse events (irAEs) required treatment to be discontinued in 12 out of 21 of patients treated with AMG319, suggestive of systemic effects on Treg cells. Accordingly, in mouse models, PI3Kδi decreased the number of Treg cells systemically and caused colitis. Single-cell RNA-sequencing analysis revealed a PI3Kδi-driven loss of tissue-resident colonic ST2 Treg cells, accompanied by expansion of pathogenic T helper 17 (TH17) and type 17 CD8+ T (TC17) cells, which probably contributed to toxicity; this points towards a specific mode of action for the emergence of irAEs. A modified treatment regimen with intermittent dosing of PI3Kδi in mouse models led to a significant decrease in tumour growth without inducing pathogenic T cells in colonic tissue, indicating that alternative dosing regimens might limit toxicity.

Does BRAF mutation status and related clinicopathological factors affect the recurrence rate of ameloblastoma? A systematic review, meta-analysis and metaregression.

OBJECTIVES: This review aims to analyse the recurrence rate in BRAFv600e+ and BRAFv600e- ameloblastomas and explore its association with clinicopathological variables. METHODS: A comprehensive search was conducted using databases including PubMed, Embase, Cochrane Central Register of Controlled Trials, Clinicaltrials.gov, Google Scholar and grey literature, without any limitation on start date or language up to 20 June 2023. A random effect meta-analysis was conducted and Metaregression analyses were performed based on available clinicopathological factors. RESULTS: Fifteen studies met the criteria for meta-analysis of outcomes. There was no significant difference in overall recurrence rates between the two groups (risk difference = 0.001, p-value = 0.987). Increasing male:female ratio in the BRAFv600e+ group was associated with a lower reported recurrence, suggesting a higher recurrence rate in females. The odds of having mandibular lesion were four times higher in BRAFv600e+ cases compared to BRAFv600e- cases (confidence interval: 2.121-7.870, p < 0.001, I2 = 28.37%). CONCLUSION: Within the BRAFv600e+ group, females showed a higher reported recurrence rate. This specific clinical group may benefit from BRAFv600e mutation investigation and potential upscaled surgical treatment and additional BRAF inhibitor therapy, which needs validation in future studies.

How effective is 5-Fluorouracil as an adjuvant in the management of odontogenic keratocyst? A systematic review and meta-analysis.

Odontogenic keratocyst (OKC) is known for its benign but aggressive clinical behaviour, and presents a challenge in its management due to high recurrence rate following surgical intervention. The sourcing of Carnoy's solution, the widely used adjunct in OKC treatment, has lately become difficult especially after its banning by the United States Food and Drugs Agency (FDA). This has generated interest in exploring alternative chemical agents such as 5-Fluorouracil (5-FU) and Modified Carnoy's solution (MCS). We conducted a systematic review and meta-analysis to assess the effectiveness of 5-FU as an adjunct following surgical intervention of OKC. A protocol was registered in PROSPERO prior to the literature search. All studies reporting the use of 5-FU in OKC treatment were included in the initial search of multiple literature databases. Of the 148 initially identified articles, three met the criteria for the final appraisal. The relevant data were extracted and a meta-analysis was undertaken in relation to recurrence rate and nerve paraesthesia. There were no recurrence observed in cases treated with 5-FU (n=56), and the incidence of nerve paraesthesia was 20% (none permanent). This systematic review has revealed early encouraging results for 5-FU as an adjunct, however a caution is recommended due to overall low quality of evidence related to individual studies. We present the cumulative evidence on the effectiveness of 5-FU in OKC treatment with discussion on its mechanism of action, safety profile, application protocol, and the implications for clinical practice.

Alcohol alters DNA methylation patterns and inhibits neural stem cell differentiation.

BACKGROUND: Potential epigenetic mechanisms underlying fetal alcohol syndrome (FAS) include alcohol-induced alterations of methyl metabolism, resulting in aberrant patterns of DNA methylation and gene expression during development. Having previously demonstrated an essential role for epigenetics in neural stem cell (NSC) development and that inhibiting DNA methylation prevents NSC differentiation, here we investigated the effect of alcohol exposure on genome-wide DNA methylation patterns and NSC differentiation. METHODS: Neural stem cells in culture were treated with or without a 6-hour 88 mM ("binge-like") alcohol exposure and examined at 48 hours, for migration, growth, and genome-wide DNA methylation. The DNA methylation was examined using DNA-methylation immunoprecipitation followed by microarray analysis. Further validation was performed using Independent Sequenom analysis. RESULTS: Neural stem cell differentiated in 24 to 48 hours with migration, neuronal expression, and morphological transformation. Alcohol exposure retarded the migration, neuronal formation, and growth processes of NSC, similar to treatment with the methylation inhibitor 5-aza-cytidine. When NSC departed from the quiescent state, a genome-wide diversification of DNA methylation was observed-that is, many moderately methylated genes altered methylation levels and became hyper- and hypomethylated. Alcohol prevented many genes from such diversification, including genes related to neural development, neuronal receptors, and olfaction, while retarding differentiation. Validation of specific genes by Sequenom analysis demonstrated that alcohol exposure prevented methylation of specific genes associated with neural development [cut-like 2 (cutl2), insulin-like growth factor 1 (Igf1), epidermal growth factor-containing fibulin-like extracellular matrix protein 1 (Efemp1), and SRY-box-containing gene 7 (Sox 7)]; eye development, lens intrinsic membrane protein 2 (Lim 2); the epigenetic mark Smarca2 (SWI/SNF related, matrix associated, actin dependent regulator of chromatin, subfamily a, member 2); and developmental disorder [DiGeorge syndrome critical region gene 2 (Dgcr2)]. Specific sites altered by DNA methylation also correlated with transcription factor binding sites known to be critical for regulating neural development. CONCLUSION: The data indicate that alcohol prevents normal DNA methylation programming of key neural stem cell genes and retards NSC differentiation. Thus, the role of DNA methylation in FAS warrants further investigation.

Dental emergencies presenting to maxillofacial units during the COVID-19 pandemic: a five-centre UK hospital study.

Introduction Coronavirus disease (COVID-19) represents an unprecedented challenge to healthcare. Provision of dental services was significantly affected, with limited provision for emergencies resulting in patients increasingly attending hospitals.Objectives and methods The aim of the study was to assess the provision of emergency dental services by the maxillofacial departments during the initial COVID-19 pandemic lockdown in the United Kingdom. At the outset of the first lockdown, we initiated a prospective study to monitor the presentation and management of dental emergencies at five hospital trusts. Data were collected onto an online live database until the lockdown relaxation.Results Of a total of 211 dental emergencies, 156 were infection-related, 42 were trauma-related and 12 were cases of post-operative complications. A proportion of patients (76%) could have been treated in primary care, with 52% of presentations having already been 'triaged' on several occasions by urgent dental hubs and given multiple antibiotic courses, rather than any direct treatment.Conclusion There is a need to restructure emergency dental service provision as well as planning for possible further COVID-19 spikes and future pandemics.

Should we recruit trainees into the Oral and Maxillofacial Surgery pathway at the beginning of the second degree to ensure the long term viability of the specialty?

There has been a sustained decline in the number of trainees applying for entry into the Oral and Maxillofacial Surgery (OMFS) training program, which has sparked further debate on the issue of OMFS training and the future of the specialty in the United Kingdom. Here I discuss the option of recruiting the trainees into the program at the beginning of their second degree to streamline the training, and to improve the recruitment drive to ensure long term viability of the specialty.

Retentive multipotency of adult dorsal root ganglia stem cells.

Preservation of neural stem cells (NSCs) in the adult peripheral nervous system (PNS) has recently been confirmed. However, it is not clear whether peripheral NSCs possess predestined, bona fide phenotypes or a response to innate developmental cues. In this study, we first demonstrated the longevity, multipotency, and high fidelity of sensory features of postmigrating adult dorsal root ganglia (aDRG) stem cells. Derived from aDRG and after 4-5 years in culture without dissociating, the aDRG NSCs were found capable of proliferation, expressing neuroepithelial, neuronal, and glial markers. Remarkably, these aDRG NSCs expressed sensory neuronal markers vesicular glutamate transporter 2 (VGluT2--glutamate terminals), transient receptor potential vanilloid 1 (TrpV1--capsaicin sensitive), phosphorylated 200 kDa neurofilaments (pNF200--capsaicin insensitive, myelinated), and the serotonin transporter (5-HTT), which normally is transiently expressed in developing DRG. Furthermore, in response to neurotrophins, the aDRG NSCs enhanced TrpV1 expression upon exposure to nerve growth factor (NGF), but not to brain-derived neurotrophic factor (BDNF). On the contrary, BDNF increased the expression of NeuN. Third, the characterization of aDRG NSCs was demonstrated by transplantation of red fluorescent-expressing aDRG NSCs into injured spinal cord. These cells expressed nestin, Hu, and beta-III-tubulin (immature neuronal markers), GFAP (astrocyte marker) as well as sensory neural marker TrpV1 (capsaicin sensitive) and pNF200 (mature, capsaicin insensitive, myelinated). Our results demonstrated that the postmigrating neural crest adult DRG stem cells not only preserved their multipotency but also were retentive in sensory potency despite the age and long-term ex vivo status.

The versatility of the Karapandzic flap: A review of 65 cases with patient-reported outcomes.

OBJECTIVE: The Karapandzic flap is an established technique for reconstruction of large lip defects and in our experience is particularly valuable in repair of the upper lateral lip and the commissures as well. We present our experience in a case series of 65 patients under one consultant. METHOD: This is a retrospective study of patients who underwent Karapandzic flap repair for lip defects following cancer resection from 2007 to 2014 in North Yorkshire. A data collection tool was used which incorporated patient demographics, tumour location, histology, complications, resection margins and recurrence including functional and aesthetic outcomes. The Patient and Observer Scar Assessment Scale (POSAS) was used to assess postoperative outcome at more than 1 year. RESULTS: The clearance rate was 98.4%. For those with a follow-up greater than 1 year, there was no recurrence or surgical revision, whilst the most common concern was temporary lip paraesthesia. The mean POSAS scores were low for both patients and observers reflecting a high satisfaction rate. CONCLUSION: The technique of Karapandzic flap reconstruction for defects in both upper and lower lip allows adequate margin clearance with a low level of complications. The advantages of this technique include preservation of both function and sensation utilising local tissue to allow successful aesthetic outcomes.

Antimicrobial prophylaxis in open reduction and internal fixation of compound mandibular fractures: a collaborative regional audit of outcome.

We conducted a regional 2-stage prospective audit involving 5 different maxillofacial units in the Yorkshire region of the UK to evaluate the effectiveness of perioperative antimicrobial prophylaxis in the treatment of mandibular fractures. In the first stage (145 patients) we surveyed current practice concerning antimicrobial prophylaxis and found out the current infection rate after open reduction and internal fixation (ORIF) of mandibular fractures. In the second stage (157 patients) we implemented a common antimicrobial protocol in all units and recorded the infection rates using the new regimen. In the first stage a wide range of antimicrobial prophylaxis was used in different units. The agreed perioperative antimicrobial protocol in the second stage was to begin amoxicillin or clarithromycin and metronidazole intravenously on admission and include 2 postoperative doses. The infection rates were 10.3% and 8.9%, respectively, and the difference between the two groups was not significant (χ(2)=0.051, df=1, p=0.83). The infection rate in the Yorkshire region was similar to results from other centres. We recommend short perioperative antimicrobial prophylaxis with a maximum of 2 postoperative doses after ORIF of mandibular fractures.

Cellular epigenetic modifications of neural stem cell differentiation.

Emerging information indicates that epigenetic modification (i.e., histone code and DNA methylation) may be integral to the maintenance and differentiation of neural stem cells (NSCs), but their actual involvement has not yet been illustrated. In this study, we demonstrated the dynamic nature of epigenetic marks during the differentiation of quiescent adult rat NSCs in neurospheres. A subpopulation of OCT4(+) NSCs in the neurosphere contained histone marks, trimethylated histone 3 on lysine 27 (3me-H3K27), 2me-H3K4, and acetylated H4 (Ac-H4). A major decrease of these marks was found prior to or during differentiation, and was further diminished or reprogrammed in diverse subpopulations of migrated NSCs expressing nestin or beta-III-tubulin. The DNA methylation mark 5-methyl-cytosine (5-MeC), and DNA methyltransferase (DNMT) 1 and 3a expression also correlated to the state of differentiation; they were highly present in undifferentiated NSCs but downregulated in migrated populations. In contrast, DNA methyl-CpG-binding protein (MBD1) was low in undifferentiated NSCs in neurospheres, but highly appeared in differentiating NSCs. Furthermore, we found an outward translocation of DNA methylation marker 5-MeC, DNMT1, DNMT3a, and MBD1 in NSCs as differentiation began and proceeded; 5-MeC from homogeneous nucleus to peripheral nucleus, and DMNT1a and 3a from nuclear to cytoplasm, indicating chromatin remodeling. Treatment with DNA methylation inhibitor, 5-aza-cytidine, altered DNA methylation and disrupted migration as indicated by a reduction of migrated neurons and differentiation. These results indicate that chromatin is dynamically remodeled when NSCs transform from the quiescent state to active growth, and that DNA methylation modification is essential for neural stem cell differentiation.

Adult head and neck soft tissue sarcomas: treatment and outcome.

We have retrospectively analysed the experience of a musculoskeletal oncological unit in the management of adult head and neck soft tissue sarcomas from 1990 to 2005. Thirty-six patients were seen, of whom 24 were treated at this unit, the remainder only receiving advice. The median age of the patients was 46 years. Most of the sarcomas were deep and of high or intermediate grade with a median size of 5.5 cm. Eleven different histological subtypes were identified. Wide excision was possible only in 21% of the cases. 42% of the patients developed local recurrence and 42% developed metastatic disease usually in the lungs. Overall survival was 49% at 5 years. Tumour size was the most important prognostic factor. Adult head and neck soft tissue sarcomas have a high mortality rate with a high risk of local recurrence and metastatic disease. The rarity of the disease would suggest that centralisation of care could lead to increased expertise and better outcomes.