Abstracts of the 24th international isotope society (UK group) symposium: synthesis and applications of labelled compounds 2015

The 24th annual symposium of the International Isotope Society's United Kingdom Group took place at the Møller Centre, Churchill College, Cambridge, UK on Friday 6th November 2015. The meeting was attended by 77 delegates from academia and industry, the life sciences, chemical, radiochemical and scientific instrument suppliers. Delegates were welcomed by Dr Ken Lawrie (GlaxoSmithKline, UK, chair of the IIS UK group). The subsequent scientific programme consisted of oral presentations, short 'flash' presentations in association with particular posters and poster presentations. The scientific areas covered included isotopic synthesis, regulatory issues, applications of labelled compounds in imaging, isotopic separation and novel chemistry with potential implications for isotopic synthesis. Both short-lived and long-lived isotopes were represented, as were stable isotopes. The symposium was divided into a morning session chaired by Dr Rebekka Hueting (University of Oxford, UK) and afternoon sessions chaired by Dr Sofia Pascu (University of Bath, UK) and by Dr Alan Dowling (Syngenta, UK). The UK meeting concluded with remarks from Dr Ken Lawrie (GlaxoSmithKline, UK).

Practically convenient and industrially-aligned methods for iridium-catalysed hydrogen isotope exchange processes

The use of alternative solvents in the iridium-catalysed hydrogen isotope exchange reaction with developing phosphine/NHC Ir(I) complexes has identified reaction media which are more widely applicable and industrially acceptable than the commonly employed chlorinated solvent, dichloromethane. Deuterium incorporation into a variety of substrates has proceeded to deliver high levels of labelling (and regioselectivity) in the presence of low catalyst loadings and over short reaction times. The preparative outputs have been complemented by DFT studies to explore ligand orientation, as well as solvent and substrate binding energies within the catalyst system.

Key tricyclic synthetic intermediates for the preparation of the sesquiterpenes alpha- and beta-cedrene

A completely novel and direct route towards the synthesis of the natural sesquiterpenes alpha-cedrene and beta-cedrene delivered the compounds (3 beta,3a beta,7 beta)-(+/-)-6,6-ethylenedioxy-3,8,8-trimethyl-2,3,3a,4,5,6,7,8-octahydro-3a,7-methanoazulen-2-one, C(16)H(22)O(3), and (3 beta,3a beta,7 beta,8a alpha)-(+/-)-6,6-ethylenedioxy-3,8,8-trimethyl-1,2,3,3a,4,5,6,7,8,8a-decahydro-3a,7-methanoazulen-2-one, C(16)H(24)O(3), at key stages of the preparative programme. Structural elucidation showed the latter compound to have added an H atom to the same face of the cyclopentenone ring as that occupied by the methyl substituent, and also allowed correct isomer identification for further reaction.

Enantioselective deprotonation reactions using polymer-supported chiral magnesium amide bases

Novel and readily accessible polymer-supported chiral magnesium amide reagents have been prepared and shown to be effective in the asymmetric deprotonation of a series of prochiral cyclohexanones, affording good to excellent levels of both conversion and enantiomeric ratio (up to 93:7); the Merrifield-based chiral amine species has been shown to be readily recyclable.

Formal total synthesis of (+/-)-alpha- and beta-cedrene by preparation of cedrone. Construction of the tricyclic carbon skeleton by the use of a highly efficient intramolecular Khand annulation

The cedrene carbon skeleton was rapidly assembled from a simple monocyclic precursor by the strategic use of a high yielding intramolecular Khand cyclization reaction. Further synthetic manipulations provided a concise formal total synthesis of alpha- and beta-cedrene. Reaction: see text.

Magnesium bisamides as reagents in synthesis

As part of the continued requirement for more selective reagents in organic synthesis, magnesium bisamides are becoming established as a class of organometallic bases with considerable potential. Their relatively mild reactivity, combined with their high degree of steric congestion, leads to a distinct class of reagents with significantly different chemo-, regio-, stereo- and enantioselectivities when compared with existing species and protocols.

Describing shape changes in the human mandible using elliptical Fourier functions

Elliptical Fourier functions (EFF) were generated for the boundary outline of the mandibular form in 24 non-orthodontic growth study subjects at 9, 11, 13, and 15 years of age. The mean residual fit (observed versus predicted points) of the mandibular form was 0.11 mm, with a range from 0.09 to 0.14 mm, suggesting an accurate fit. The mean plot for each of the four age groups was area standardized and superimposed on the centroid. Shape changes in males and females were found to be similar. No significant shape changes were found between 9 and 11 years. Shape changes were observed in the lower incisor area, the mental region, the body of the mandible, and the gonial angle area between 11 and 15 years. These changes coincided with the onset of the pubertal growth spurt.

Orthodontic treatment with fixed appliances in the General Dental Service in Scotland

The records of 128 subjects treated by orthodontic specialists with fixed appliances in the General Dental Service in Scotland were randomly selected from the Scottish Dental Practice Board for analysis. The results of the study revealed that: (1) Mean post-treatment Peer Assessment Rating was 7.8 +/- 4.6 PAR points. (2) Mean reduction in PAR score was 14.9 +/- 10.6 PAR points. (3) Mean percentage reduction in PAR was 59 per cent. (4) Twenty-eight per cent of the cases were 'greatly improved', 15 per cent of the cases were made 'worse or no different'. (5) Median duration of treatment was 15 months, with a range of 2-41 months. (6) Multiple regression analysis showed that 82 per cent of the variability of PAR change could be predicted by the pretreatment PAR scores and the number of arches treated. Post-treatment PAR scores and duration of treatment could not be predicted with adequate reliability. It was concluded that although about 75 per cent of the cases were treated to at least acceptable alignment and occlusion, the modest average percentage reduction in PAR score could be explained by the low average initial PAR score and the borderline need for treatment in many cases.

The first orthodontic diploma

The advent of the Inter-Collegiate Membership in Orthodontics in the year 2000 will mark the end of an orthodontic diploma specific to the Royal College of Physicians and Surgeons of Glasgow. The Diploma in Dental Orthopaedics (RCPS) was the first orthodontic diploma in the United Kingdom. The fact that such a diploma has existed first as a DDO and latterly as the MDO (Membership) for some 50 years is remarkable in view of the relative infancy of most dental specialties and the fact that the General Dental Council has instigated a specialist register in orthodontics as recently as 1998. It was 1965, before other specialty diplomas became available in the British Isles, with the introduction of the FFD by the Royal College of Surgeons in Ireland.

An evaluation of CASES--an educational audit programme for orthodontists

A regional approach to a national clinical audit programme in orthodontics in the UK is described and evaluated. The programme was designed using the CRISIS criteria for effective continuing education. Programme participants completed duplicate questionnaires on 6 simulated patient scenarios, chosen for their relevance to everyday practice while posing important clinical dilemmas. The participation rate was 77% from hospital-based practitioners and 29% from specialist practitioners. Feedback to programme participants was given in the form of histograms, and provided a snapshot of national approaches to patient investigation, treatment and expected outcomes. A commentary on the data and references to appropriate articles in the literature were included. Evaluation of the programme by questionnaire survey showed that it was extensively used by hospital-based practitioners. It is concluded that the model used provided an effective and efficient framework for conducting clinical audit and delivering continuing education to the hospital-based group.

Light-curing acrylic resin as an orthodontic baseplate material

Heat-curing autopolymerizing (self-cure or cold-cure), thermoplastic, and light-curing acrylic resin are the most commonly used orthodontic baseplate materials. While cured acrylic resins present few problems to the patient, in the laboratory acrylic resin has to be sprayed, mixed, or packed in a fume-extraction unit because of the harmful fumes emitted by the raw inflammable chemicals. Light-curing material, on the other hand, is virtually nonflammable and has virtually no aroma. A light-cure technique for the construction of orthodontic baseplates is described. While buildup of the baseplate is slightly slower than for self-cured material, the shorter time involved in trimming and polishing means that overall construction is faster. It is easier to obtain a uniform thickness with light-cured material, and it provides superior fit. These results, however, are subject to more extensive clinical trials. The only apparent disadvantage is the fine powder produced during trimming. Even with a bench equipped with an extraction unit, it is advisable to use a face mask to prevent the inhalation of dust.

An adult with a severe Class II division 1 malocclusion: Frances' case

This article describes treatment options for an adult with a severe Class II division 1 malocclusion. The opinions of British orthodontists, as obtained through the CASES project, are summarized and the patient's actual treatment is discussed.

An adolescent with a Class II division 2 malocclusion complicated by unerupted palatal canines: Linda's case

This article describes treatment options for a teenager with a class II division 2 malocclusion complicated by unerupted and palatally displaced upper canines. The opinions of British orthodontists, as obtained through the CASES project, are summarized and the patient's actual treatment is discussed.

Soft and hard tissue changes in Class III patients treated by bimaxillary surgery

A cephalometric study of 17 non-growing dentate Class III subjects treated by bimaxillary surgery was undertaken to assess the results of treatment and to evaluate the correlation between soft and hard tissue change. It was concluded that: (i) the orthognathic profiles achieved were brought about by a combination of maxillary advancement and mandibular setback; (ii) a strong correlation in the horizontal direction occurred between all the selected landmarks of the lower lip and chin, but only between superior labial sulcus and point A in the upper lip; highest intra-group correlations were seen between corresponding soft and hard tissue points; the ratios of soft tissue to corresponding hard tissue movements in lower lip and chin approached 1:1; (iii) in the vertical direction, a strong correlation occurred in the lower lip and chin; highest intra-group correlations were not necessarily with corresponding landmarks; and (iv) vertical movement of landmarks on the nasal base and upper lip generally showed poor or weak correlation with corresponding soft tissue points. The most reliable hard tissue predictors of horizontal and vertical soft tissue change are tabulated for application in bimaxillary surgery for the Class III patient.

The laryngeal mask as an antipollution device

Anaesthetic pollution is still a problem and recent UK Control of Substances Hazardous to Health (COSHH) recommendations require employers to attempt to control the risk. Fifteen day-case urology operating lists were studied to compare the level of nitrous oxide exposure using face mask or laryngeal mask anaesthesia. Nitrous oxide was avoided in one group until the laryngeal mask was inserted. The use of the laryngeal mask airway showed a significant reduction in the level of pollution, such that recent COSHH recommendations were attained. However, (US) NIOSH levels were only reliably attained by avoiding nitrous oxide until the laryngeal mask was inserted. The laryngeal mask was therefore shown to be a reliable antipollution device.

Surgery, growth modification or orthodontic camouflage? Brian's case

A skeletal class II malocclusion can be dealt with in a number of ways. The preferred option is to use orthodontic treatment and growth modification if at all possible, but in cases where this is not possible the problem might be camouflaged or treated by surgery. In the case reported here the options are fully discussed and the opinions of the orthodontists expressed in the CASES project made clear. The actual treatment undertaken is also described.

An extraction dilemma: Cheryl's case

This article describes treatment options for a teenager with a mild, although aesthetically unpleasing, malocclusion. The opinions of British orthodontists, as obtained through the CASES project, are summarized and the patient's actual treatment is discussed.

Hypodontia: George's case

Five questions are posed regarding the treatment of a patient with hypodontia. The treatment options are discussed, and the actual treatment carried out demonstrated. The treatment preferences of British Orthodontists, elicited through the CASES project, are also included.

Early treatment of Class III malocclusion? Colin's case

This is the first of six simulated case reports accompanying the questionnaire detailed in the article 'How to Do It: Making Clinical Audit Work' found earlier in this issue. You will find comprehensive discussion of the problem of making a decision about the early treatment of Class III malocclusion.

How to do it: making audit work

The orthodontic Audit Working Party of the Faculty of Dental Surgery, Royal College of Surgeons of England, in collaboration with the Centre for Medical Education, Ninewells Hospital and Medical School, Dundee developed an audit project entitled 'Clinical Audit: Scenarios for Evaluation and Study'. The aim of the project was to contribute to the construction of clinical guidelines for orthodontists. This article, the first of a short series, describes the background to and general results of the study. Further articles will study individual aspects of the project.

CASES--clinical audit; scenarios for evaluation and study

CASES, an audit and continuing education programme, evaluated aspects of current orthodontic practice and allowed orthodontists to identify areas where their practice differed from regional and national results. Evaluation of the CASES programme verified its value in audit and continuing education and the authors hope it will encourage similar projects in other disciplines too.

Appliance wear: the patient's point of view

Fifty-two patients (35 female, 17 male) completed questionnaires related to their experiences during the first 7 days of appliance wear (31 fixed, 21 removable) and then after 14 and 90 days. Most problems relating to discomfort and pain resolved within 4-7 days. The problems encountered with fixed appliances were generally more severe than with removable appliances. Swallowing and speech were more difficult with removable appliances and these problems persisted to some degree. Surprisingly, the embarrassment caused by wearing the appliance in public was similar whether it was fixed or removable.

Factors associated with the standard and duration of orthodontic treatment

The pretreatment and post-treatment study casts and records of 156 completed fixed appliance and removable appliance cases were analysed, and the influence of various factors on the standard of result, as measured by the change in PAR score produced by treatment and the duration of treatment, was assessed. For the purpose of analysis the sample was divided into two groups; a two-arch fixed appliance group (n = 81) and a removable/mini fixed appliance group (n = 75). Multiple regression procedures were carried out separately for both groups, first, with all gathered data and, secondly, with only information which would be known at the start of treatment. For fixed appliances the initial PAR score was consistently an influential variable on change in PAR score and duration of treatment. Patient compliance, the need to extract a permanent first molar and the presence of an anterior crossbite were also important. The initial PAR score also explained much of the variation in change in PAR for removable/mini fixed appliances, but generally, regression models for this group were less well fitting.

A method of measuring the apical base

The maxillary and mandibular apical base areas were measured, using a gnathograph, on the study casts of 156 adults and children representing Class II division 1, Class II division 2 and Class III malocclusions. There were significant differences between the groups at each age. The maxillary apical base areas tended to be smaller for the adults than for the children in all three occlusal classes. By contrast, the mandibular apical base areas tended to be larger for the adults than for the children, except in Class II division 1 malocclusion. Following a logarithmic transformation to stabilize the variance, regression lines were fitted to relate the size of the maxillary and mandibular apical bases to one another, for the malocclusion groups within each age group. The method gives additional information regarding the degree of apical base discrepancy in a given case, but more work is required before it can be used as a diagnostic tool.

The use of removable orthodontic appliances in the General Dental Service

One hundred and fifty removable appliance cases consecutively sampled by the Scottish Dental Practice Board were analysed using the PAR index. The cases were assessed as being suited or unsuited to the removable appliance approach based on the presenting features previously shown to be effectively treated by removable appliances. Using chi-squared tests of association, suitable cases were characterised as being in the mixed dentition, had one feature treated and one appliance used. Suitable cases on average showed 3-4 PAR points more improvement as a result of treatment than equivalent unsuitable cases; regression equations are given. Because of the wide variability within the sample it proved impossible to predict accurately the expected duration of treatment in the General Dental Service.

An evaluation of two concentrations of hyaluronidase for supplementation of peribulbar anaesthesia

We studied the effect of the addition of hyaluronidase to a mixture of lignocaine 2% and bupivacaine 0.75% for peribulbar anaesthesia in 60 patients presenting for elective intra-ocular surgery. Using a randomised, double-blind design, patients were allocated to one of three groups: no hyaluronidase (group A) (n = 20); hyaluronidase 50 iu.ml-1 (group B) (n = 20); hyaluronidase 150 iu.ml-1 (group C) (n = 20). The speed of onset of the block, the presence of akinesia, analgesia and the need for supplementary injections were assessed. The addition of 150 iu.ml-1 of hyaluronidase resulted in a mean (SEM) time to akinesia of 9.2 (0.9) min compared to 10.9 (0.9) min in the control group and 10.7 (1.1) min in those receiving the lower dose. Fewer patients in group C required a further injection (20%) than those in groups A (40%) or B (45%). None of the findings were statistically significant. Hyaluronidase was not associated with any complications.

The effect of hyaluronidase on peribulbar block

The effect of supplementing a standardised local anaesthetic mixture with hyaluronidase was studied in 60 patients undergoing peribulbar block for intra-ocular surgery. All the patients had the block performed with a 2:1 mixture of lignocaine 2% and bupivacaine 0.75%, but in half of the cases hyaluronidase 50 u.ml-1 was added to the solution by random allocation. The mean volumes of solution injected were 8.9 and 9.0 ml in the control and hyaluronidase groups respectively. Five minutes after injection the block was deemed unsuccessful in one third of the patients in each group and these patients required supplementary injections. At 15 min all but one patient in each group had satisfactory block and these two patients subsequently required retrobulbar block. There were no statistically significant differences between the two solutions in rate of onset of block, requirement for supplementation, block failure, or surgical conditions. There were no significant complications. We conclude that the addition of hyaluronidase 50 u.ml-1 to the local anaesthetic mixture described confers no advantage at the volumes of local anaesthetic used.

Mandibular form and position in 10-year-old boys

It is unclear whether malocclusion characterized by jaw discrepancy is caused by variations in mandibular position, mandibular size, or a combination of the two. To clarify the situation, the mandibular outlines of 124 10-year-old boys, equally divided among the Angle classes, were generated from cephalograms with a computer plotting technique. The mean plots for each of the groups were superimposed on S-N and Go-Gn. These showed mandibular form and size to be similar in the Class I and Class III groups and in both divisions of Class II. The position of Class III mandibles was more anterior and rotated forward in relation to the cranial base compared with the other groups. Statistical analysis confirmed these findings. There was evidence to support the idea that Class II, Division 2 malocclusion is largely a dentoalveolar rather than a skeletal entity.

The general dental status of patients referred to the orthodontic department of the Glasgow Dental Hospital

A survey of 280 orthodontic referrals to the Glasgow Dental Hospital, consecutively screened for orthodontic needs, revealed that 1 in 5 had untreated caries and more than half had a level of oral hygiene incompatible with wearing an orthodontic appliance. The suitability and motivation of such patients, therefore, must be questioned before prescribing orthodontic treatment.

Quantification of function regulator therapy using elliptical Fourier functions

The application of various functional appliances to correct antero-posterior skeletal discrepancies in the treatment of Class III malocclusion has received increased attention. In this context, elliptical Fourier functions (EFF) are particularly useful for eliciting boundary-outline information. This longitudinal study was undertaken to visually and numerically describe the shape alterations arising as a response to treatment with the FR-3 appliance of Fränkel. The subjects chosen were Caucasians (n = 14) from the Glasgow Dental Hospital and School who presented with Class III incisor relationships. Lateral cephalometric head-films were available prior to the initiation of treatment, at the end of active treatment, and at least one year out of retention. Maxillary and mandibular boundary outlines were carefully traced. A set of points, 42 on the maxilla, and 78 on the mandible, were precisely located. These points were then digitized and used to compute EFF's with 20 harmonics. These equations were then standardized for size. Subsequently, 102 maxillary and 150 mandibular closely spaced points on the outline were calculated from the EFF's. After superimposition on the centroid, expected vectors were then computed to these points from the centroid. Statistically significant dento-alveolar shape changes could be discerned with treatment. These involved a localized anterior repositioning of the maxillary incisal aspect with a concomitant posterior displacement of the mandibular incisal aspect. There was no evidence of shape changes in the basal areas of either the maxilla or mandible. This method of fitting Fourier descriptors, specifically EFF's, provides a precise numerical and visual description of the changes arising from functional regulator therapy.

Use of the PAR index in assessing the effectiveness of removable orthodontic appliances

The dental study casts of 150 consecutively completed removable appliance cases were examined before and after orthodontic treatment using the PAR index. Eighty-nine per cent were classified either as 'improved' or 'greatly improved'. Of the 16 cases classified as 'worse, no different', six were mixed dentition cases with limited treatment objectives (which were successfully achieved) and three were permanent dentition cases where only one tooth was being aligned. Using predefined criteria removable appliances were shown to be most effective in treating cross-bites, ectopic tooth position, anterior spacing, and overjet, and less effective in treating crowding, rotations, and molar relationships.

Specialist postgraduate orthodontic training: a comparison of two European universities

The background to current specialist training programmes in orthodontics in the United Kingdom and France is discussed, and the examination structure in the two countries compared with reference to those pertaining in Glasgow and Strasbourg. A sample of 40 of the most recently treated cases submitted by students in each of these two Universities for their final examinations is compared revealing marked differences in case type and treatment philosophy. The differences are explained, to some extent, by the circumstances pertaining to the delivery of orthodontic care in the two countries.

Effect of nitrous oxide on post-operative nausea and vomiting during propofol anaesthesia for short surgical operations

One hundred patients of ASA status I or II, undergoing gynaecological or urological surgery were studied. Opioids were omitted from premedication and anaesthesia. Patients were allocated randomly to one of two equal groups and were anaesthetized using a computer controlled infusion system, programmed to achieve theoretically any target blood propofol concentration. One group received 60% nitrous oxide in oxygen while the other group received 100% oxygen. Six patients in the nitrous oxide group had nausea and three of these patients vomited. Two patients in the oxygen group had nausea but no patient vomited. The frequency of nausea and vomiting in the two groups was not statistically different (P > 0.05). Theoretical blood propofol concentration shown to produce surgical anaesthesia was maintained in all patients. However 12% of the patients that received nitrous oxide and 40% of the patients that did not, responded to the surgical stimulus by limb movement. Patients in the oxygen group required higher rates of propofol infusion to maintain surgical anaesthesia.

A comparison of laryngeal mask airway with tracheal tube for intra-ocular ophthalmic surgery

The use of the laryngeal mask was compared with tracheal intubation in 30 patients who underwent intra-ocular ophthalmic surgery and who received intravenous anaesthesia with propofol. Changes in intra-ocular pressure, heart rate and mean arterial pressure after the insertion of the laryngeal mask airway or the tracheal tube were not significantly different. However, at the end of the procedure, a significantly higher percentage of patients with a tracheal tube coughed, reacted to head movement and suffered breath-holding. In addition, significantly more patients in this group complained of a sore throat (p less than 0.05). During intravenous propofol anaesthesia, the laryngeal mask airway does not offer any advantage over tracheal intubation in the control of intra-ocular pressure for intra-ocular ophthalmic surgery. However, there were fewer complications immediately following surgery in the laryngeal mask group.

A new look at mandibular growth--a preliminary report

Cephalometric radiographs of 42 growth study subjects (21 males, 21 females) were the basis of an investigation into the longitudinal growth of the mandible from 5 to 20 years using a digitizer program capable of generating curved outlines through groups of four points. In this presentation mean plots for all subjects at 5, 10, 15, and 20 years of age, variously superimposed, confirmed the previous theories of Björk and Skieller (1983) with regard to mandibular rotation and provide a visual representation of the processes of mandibular growth.

Class III malocclusion: surgery or orthodontics?

The pre-treatment lateral cephalograms of two groups of 20 subjects with severe Class III malocclusions were compared. One group had been considered suitable for orthodontic correction by the diagnosing clinician and the other offered orthognathic surgery. The most significant differences between the groups were in angle ANB, M/M ratio (P less than 0.001), lower incisor inclination and Holdaway angle (P less than 0.01). Threshold values for angle ANB and lower incisor angulation below which surgery was almost always carried out were--4 and 83 degrees, respectively.

The areas of various surfaces in the human mouth from nine years to adulthood

Surface area measurements of five regions of the oral cavity were made from study casts of 57 subjects with an age range from 9.3 to 19 years. While the longitudinal pattern of growth exhibited by the total of the five areas, when subgroups were compared, was characterized by a steady increase to around puberty (13 years), followed by a plateau, different areas showed different patterns of growth. Increase in the surface area of the teeth was associated with the eruption of the second and third molars, whereas the area of the buccal lingual mucosa continued to increase into adult life. The palate, buccal vestibular mucosa, and dorsum of the tongue demonstrated a typically skeletal pattern of growth, i.e., increase until puberty with a rapid cessation thereafter. The results of this study indicate the need for longitudinal data to further knowledge concerning growth of the oral cavity.