COVID-19 social-distancing measures altered the epidemiology of facial injury: a United Kingdom-Australia comparative study.

The purpose of this study was to undertake a retrospective cross-sectional analysis to compare the frequency and characteristics of facial injury presentations at a UK and an Australian tertiary referral hospital during the implementation of COVID-19 social-distancing measures. The primary predictor variables were a heterogeneous set of factors grouped into logical categories: demographics, injury mechanisms and site, and management. The primary outcome variable was the presentation of a hard or soft tissue facial injury. A descriptive statistical analysis was undertaken on the assembled data. The study found a clinical and statistically significant reduction in the frequency (absolute number) of facial injuries at each study site. In addition, a striking similarity common in both countries was an increase in the number of facial injuries due to falls and a reduction in facial injuries due to interpersonal violence. Conservative (non-operative) management of facial injury increased at both sites. The implementation of COVID-19 social-distancing public health measures, which aimed to limit community transmission of the coronavirus, had a secondary serendipitous effect of reducing the frequency of facial injury presentations and altering their epidemiological characteristics at both a UK and Australian tertiary referral hospital.

The provision of surgical tracheostomies by maxillofacial surgeons in the UK: time for a dedicated tracheostomy team?

Surgical tracheostomy is a commonly provided service by surgical teams for patients in intensive care where percutaneous dilatational tracheostomy is contraindicated. A number of factors may interfere with its provision on shared emergency operating lists, potentially prolonging the stay in intensive care. We undertook a two-part project to examine the factors that might delay provision of surgical tracheostomy in the intensive care unit. The first part was a prospective audit of practice within the University Hospital Coventry. This was followed by a telephone survey of oral and maxillofacial surgery units throughout the UK. In the intensive care unit at University Hospital Coventry, of 39 referrals, 21 (53.8%) were delayed beyond 24 hours. There was a mean (standard deviation) time to delay of 2.2 days (0.9 days) and the most common cause of delay was surgeon decision, accounting for 13 (61.9%) delays. From a telephone survey of 140 units nationwide, 40 (28.4%) were regularly involved in the provision of surgical tracheostomies for intensive care and 17 (42.5%) experienced delays beyond 24 hours, owing to a combination of theatre availability (76.5%) and surgeon availability (47.1%). There is case for having a dedicated tracheostomy team and provisional theatre slot to optimise patient outcomes and reduce delays. We aim to implement such a move within our unit and audit the outcomes prospectively following this change.

Comparison of the interaction of cyclic nucleotide-dependent protein kinases with mononucleosomes and free histones.

Arginine-rich histones H2A, H2B, H3 and H4 contain two regions of interaction with cyclic nucleotide-dependent protein kinases: a substrate phosphorylation site and a region which noncompetitively inhibits cyclic nucleotide binding to the protein kinases. We have compared the interaction of cyclic nucleotide-dependent protein kinases with these two sites in histones which are organized in nucleosome structures with the interaction of the enzymes with free histones. Whereas histones in solution are readily phosphorylated by cyclic GMP-dependent protein kinase and the catalytic subunit of cyclic AMP-dependent protein kinase, mononucleosomes are not phosphorylated by these enzymes. Histones extracted from mononucleosomes can be phosphorylated, indicating that the lack of phosphorylation of nucleosomes is not due to covalent modification of the histones but to their organization within the nucleosome structure. Whereas histones in solution are effective noncompetitive inhibitors of cyclic GMP binding to cyclic GMP-dependent protein kinase and of cyclic AMP binding to the regulatory subunits of cyclic AMP-dependent protein kinase, mononucleosomes do not affect cyclic nucleotide binding. These studies indicate that histones which are organized in nucleosome structures are neither substrates nor modifiers of cyclic nucleotide-dependent protein kinases.

Nucleotide regulation of a eukaryotic protein synthesis initiation complex;.

Formation of a ternary initiation complex containing Met-tRNAf, GTP and eukaryotic initiation factor 2, is the first step in sequential assembly of the initiation complex. The concentration of GTP required for half maximal formation of the ternary complex is 2.5 with 10(-6) M. GDP is a potent competitive inhibitor of ternary complex formation with Ki = 3.4 with 10(-7) M. The nucleotide binding site on eukaryotic initiation factor 2 demonstrates relative specificity for GDP with KD(GDP) = 3.0 with 10(-8) M; 100-fold higher concentrations of GTP than GDP are required for displacement of either [(3)H]GDP or [(3)h]gtp from the necleotide binding site. An ATP-dependent stimulation of ternary complex formation observed in partially purified initiation factor preparations is due to nucleoside diphosphate kinase (EC 2.7.4.6) which serves to remove inhibitory levels of GDP by phosphorylation with ATP. Since GTP is hydrolyzed to GDP during protein synthesis, this provides a mechanism by which the ATP:ADP ratio may regulate the rate of initiation of protein synthesis.

Regulation of ternary (Met-tRNAf - GTP - eukaryotic initiation factor 2) protein synthesis initiation complex formation by the adenylate energy charge.

Formation of the ternary [Met-tRNAf - GTP - eukaryotic initiation factor 2] protein synthesis initiation complex in rabbit reticulocyte ribosomal eluates is dependent on the GTP: GDP ratio and on the adenylate energy charge. The elements controlling ternary initiation complex formation have been studied in a reconstituted system contianing eukaryotic initiation factor 2 and nucleoside diphosphate kinase purified from the ribosomal eluate. The concentration of GTP required for half maximal formation of the ternary initiation complex is 2.5 - 10(6) M; GDP is a potent competitive inhibitor with Ki equals 3.4 - 10(7) M. Sensitive control of ternary initiation complex formation by the adenylate energy charge occurs through nucleoside diphosphate kinase regulation of the GTP : GDP ratio. Over a wide range of GTP : GDP ratios, 50% of maximal ternary initiation complex formation is observed at an adenylate energy charge of 0.85-0.90 resembling that seen in the unfractionated system. Small changes in adenylate energy charge near this value result in significant changes in the extent of ternary initiation complex formation. Since GTP is continually hydrolyzed to GDP during protein synthesis and since GDP is a competitive inhibitor of GTP binding to several of the protein factors necessary for mRNA translation, the synthetic process provides sensitive control by product inhibition. Ribosome-associated nucleoside diphosphate kinase control of GTP regeneration in response to the adenylate energy charge provides one mechanism for linking protein synthesis to the nutrient state and energy charge of the cell.

Preferential regulation of protein synthesis initiation complex formation by purine nucleotides.

A comparison of the affinities of eukaryotic initiation factor 2 and eukaryotic elongation factor 1 for GTP and GDP, and of the responses of initiation and elongation complex formation to various GTP mol fractions indicated that the initiation reaction was more sensitive to changes in the GTP: GDP ratio. In vitro regulation of the GTP: GDP ratio by the adenylate energy charge, a sensitive control parameter, also demonstrated a preference for regulation of formation of initiation complexes when compared to elongation complexes. These studies suggest that, based on the availability of energy, initiation is the rate-limiting step in the overall protein synthetic process.

The use of affinity chromatography in purification of cyclic nucleotide receptor proteins.

Biospecific affinity chromatography has been used to purify specific cyclic AMP and cyclic GMP receptor proteins. Several variables are important for successful purification of the cyclic AMP receptor protein, the most critical being the length of the aliphatic spacer side arm. 8-(2-Aminoethyl)-amino-cyclic AMP coupled to the aliphatic spacer side arm. 8-(2-Aminoethyl)-amino-cyclic AMP coupled to agarose specifically retains the cyclic AMP receptor protein by interaction with the immobilized nucleotide. Binding of the cyclic AMP receptor subunit of cyclic AMP-dependent protein kinase to the immobilized nucleotide results in dissociation of the catalytic protein phosphokinase subunit which is not retained. The retained cyclic AMP receptor protein is subsequently eluted by cyclic AMP. Homogeneous cyclic AMP receptor protein prepared from rabbit skeletal muscle by affinity chromatography has been characterized. The molecular weight of the native protein as determined by analytical ultracentrifugation and polyacrylamide gel electrophoresis at varying acrylamide concentrations is 76 800 and 82 000, respectively. The protein is asymmetric with frictional and axial ratios of 1.64 and 12. SDS and urea polyacrylamide gel electrophoresis indicate that the native cyclic AMP receptor is composed of two identical subunits of 42 700 molecular weight. The native protein dimer binds 2 moles of cyclic AMP per mole of protein and is active in suppressing activity of isolated catalytic subunits of cyclic AMP-dependent protein kinase. Cyclic GMP receptor protein from bovine lung has been purified using the same affinity chromatography media. Since cyclic nucleotide binding to cyclic GMP-dependent protein kinase does not result in dissociation of regulatory receptor and catalytic phosphotransferase subunits, the cyclic GMP-dependent protein kinase holoenzyme is retained on the column and can be subsequently specifically eluted with cyclic GMP.

A nuclear protein is required for thyroid hormone receptor binding to an inhibitory half-site in the epidermal growth factor receptor promoter.

The epidermal growth factor (EGF) receptor (EGFR) promoter is negatively regulated by thyroid hormone and retinoic acid. This regulation can be mapped to a 36-basepair GC-rich region of the promoter (EGFR P/E) that functions autonomously as a promoter and an enhancer when placed in front of the thymidine kinase gene TATA element. Direct high affinity binding of the thyroid hormone receptor (T3R) to this element requires a nuclear protein. Through ion exchange chromatography and gel filtration of HeLa nuclear extract, this activity was identified as a protein of approximately 67 kilodaltons. This protein did not bind to DNA alone, but greatly augmented T3R binding to the EGFR P/E sequence in gel mobility shift and DNA precipitation assays. When combined with the T3R auxillary protein (TRAP), the T3R migrated as a larger complex on the DNA. Chemical cross-linking identified this complex as a heterodimer between T3R and TRAP. T3R-TRAP binds to a 7-basepair site in the EGFR P/E (GGGACTC) that has weak homology to a consensus thyroid response element half-site. Thus, on this element, T3R-TRAP heterodimers contact the DNA primarily on a single site that comprises an inhibitory thyroid response element.

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.

Cardiopulmonary performance following changes in position and the administration of intravenous Diazemuls.

Twenty healthy volunteers entered a study to assess cardiopulmonary responses, as measured by pulse oximetry, following changes in posture in the dental chair and the administration of Diazemuls (diazepam) in doses sufficient to instill sedation (up to a maximum dose of 20 mg) in the volunteers to a degree such that ptosis was seen. The results indicate that SaO2 values remained above 95 per cent throughout the study. It is concluded that although changes in SaO2 and pulse rate do occur, these differences are not important in healthy individuals, although they may be more serious in patients with pre-existing cardiopulmonary disease.

Complications of percutaneous gastrostomy in patients with head and neck cancer--an analysis of 42 consecutive patients.

A total of 42 patients, who underwent insertion of a percutaneous gastrostomy tube prior to resection for oral squamous cell carcinoma, were investigated to examine the incidence and severity of complications associated with use of this technique. The team performing the procedure and the grade of operator was noted together with any subsequent complications and their outcome. Previously reported complication rates were 2.7-2.8% and 6-7.1% for major and minor complications, respectively, but, in this series, a major complication rate of 22.5% and minor complication rate of 17.5% were identified. The findings of this study have led to the introduction of a further prospective audit of this technique in the maxillofacial unit and a more selective policy of PEG prescription for patients undergoing resection for head and neck cancer.

A comparison of ibuprofen and ibuprofen-codeine combination in the relief of post-operative oral surgery pain.

Non-steroidal anti-inflammatory analgesics are commonly prescribed to out-patients who have undergone oral surgical procedures, since they are said to provide excellent pain relief for mild to moderate pain, allied with minimal side-effects. One hundred patients were entered into a randomised clinical trial to compare the efficacy of a simple non-steroidal analgesic with that of a combination analgesic compound following the removal of lower third molars under local anaesthesia. Pain scores were measured for patients post-operatively by means of a verbal rating scale for 3 days and data were analysed using the Mann-Whitney U-test. Results suggest that this combination product offers no advantages (but shows definite disadvantages) when compared to an effective non-steroidal anti-inflammatory product.

Free tissue flaps: a new way to position the pedicle.

A simple and atraumatic method for passing the pedicle from a free flap through a subcutaneous tunnel using a modified Yankauer sucker tube is described.

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).

Ketorolac and diclofenac for postoperative pain relief following oral surgery.

A double-blind clinical study was designed to compare the efficacy and safety of intramuscular and oral ketorolac, a new non-steroidal anti-inflammatory analgesic with that of diclofenac and placebo for patients undergoing removal of impacted mandibular third molar teeth. Results showed that both analgesic preparations were more effective than placebo (p = 0.0029) and that ketorolac provided a similar degree of pain relief to that of diclofenac. It is concluded that ketorolac is important new addition to the available intra-muscular NSAID preparations.

Fracture of the mandible in a child.

If unusual injuries to the teeth are present, these should serve as a warning to practitioners that further investigations may be necessary. In the case reported here an undisplaced fracture of the jaw in a young child was only revealed by radiographic investigation.

Osteomyelitis complicating osteopetrosis--a case report.

Osteomyelitis of the jaws is uncommon but can be a complication of extraction or exposure of teeth in patients who are immunosuppressed or have undergone radiotherapy to the head and neck region. We report a case of osteomyelitis in a patient who has osteopetrosis. The initial clinical presentation was that of an infected retained root, secondary to denture trauma to the supporting tissues. Radiological interpretation was difficult owing to the increased bone density and surgical exploration revealed only a dense region of necrotic bone.

Aberrant anatomy of the hypoglossal nerve.

OBJECTIVE: Variant anatomy of the hypoglossal nerve is very rare. We report an unusual intra-operative finding of an aberrant branch of the hypoglossal nerve, encountered during a facial reanimation procedure. CASE REPORT: A 50-year-old man was referred to the head and neck surgery department by the neurosurgeons for hypoglossal-facial nerve anastomosis to treat his facial paralysis, which had occurred following the removal of an intracranial neoplasm. During surgery, we identified an aberrant branch of the hypoglossal nerve, which took a more ventral and superior course in the carotid triangle, prior to entering the base of the tongue. Following further dissection, we found the main trunk of the 'true' hypoglossal nerve. Several interconnecting strands were seen in the proximal aspect of both the aberrant branch and the main trunk of the hypoglossal nerve. These interconnecting fibres appeared to have tethered the main trunk into an abnormal anatomical position. CONCLUSION: As far as we can ascertain, this is the first report of an aberrant branch of the hypoglossal nerve. Although this variant would appear to be extremely rare, surgeons must consider all variations of this nerve during head and neck procedures, in order to minimise iatrogenic complications.