A stake in the game: Can radiographer image interpretation improve X-ray quality? A scoping review.

BACKGROUND: Image quality is an important factor in imaging optimisation and diagnosis. Many determinants of image quality are controlled by the radiographer; therefore, radiographer-led strategies may be key to improving X-ray image quality. This review examines the literature on radiographer-led diagnostic evaluation to establish its potential to improve X-ray image quality. METHODS: The Preferred Reporting Items for Systematic Reviews and Meta-analyses Extension for Scoping Reviews and the Joanna Briggs Institute Manual for Evidence Synthesis Scoping Review were used to review studies relevant to the impact of radiographer-led diagnostic evaluation on image quality. CINHAL, Embase, Scopus, Web of Science and Medline databases were searched for relevant articles. Search terms synonymous with radiographer, commenting, and image quality were used and studies that examined any type of radiographer-led image interpretation and its relationship to image quality in X-ray based modalities were reviewed. RESULTS: Fourteen studies that met the inclusion criteria were reviewed. All the studies reviewed unanimously reported a positive association between radiographer image interpretation and image quality in X-ray based modalities. Five emerging themes were identified to be responsible for the improvement in image quality: increased understanding of image quality requirements, improved technical skills, enhanced ability to utilise supplementary imaging and repeats, collaborative upskilling of colleagues, and a complementary interaction between diagnostic and radiographic skills that serves to enhance image quality. CONCLUSIONS: The findings demonstrate that radiographer image interpretation is a useful strategy to optimise the quality of X-ray examinations. IMPLICATIONS FOR PRACTICE: The findings highlight a new avenue to improve X-ray quality in the clinical environment and support evidence-based uptake of preliminary image evaluation systems. These findings also support the integration of radiographer commenting alongside technical image quality in teaching curricula.

Can simulation-based education or other education interventions replace clinical placement in medical radiation sciences? A narrative review.

OBJECTIVES: In response to increasing student enrolment and workload pressures from the Covid-19 pandemic, a recent focus on health student preparation programs has been on curricula adaptations and replacement of clinical placement time with alternative education activities. The aim of the narrative review was to explore the current evidence relating to education activities in Medical Radiation Sciences (MRS) used to replace clinical placements or part of clinical placements. Medline, CINAHL and Web of Science databases were used to search for articles published between 2017 and 2022. Data from the literature was summarised into (1) planning and development of clinical replacement learning activities in MRS, (2) evaluation of clinical replacement activities, and (3) benefits and challenges of clinical replacement in MRS. KEY FINDINGS: Planning and development of clinical replacement learning activities in MRSrequires support from a wide range of stakeholders, and evidence from activities already implemented exists. Activities largely encompass an institution-specific focus. Developed clinical replacement activities use a blended approach, with simulation-based education (SBE) as a main teaching platform. Evaluation of clinical replacement activities are largely focused on students' achievement of learning objectives relating to practical and communication skills. Emerging evidence based on small student samples shows that clinical and clinical replacement activities provide similar results in terms of learning objectives. CONCLUSION: Benefits and challenges of clinical replacement in MRS are similar to those presented in the other health professions. The balance between quality and quantity of teaching and learning experiences for clinical skill development in MRS needs to be further investigated. IMPLICATIONS FOR PRACTICE: To meet the dynamic challenges of the health care environment and MRS profession, a major goal in the future will be to affirm the benefit of clinical replacement activities for MRS students.

High-concentration nonavian high-molecular weight hyaluronan injections and time-to-total knee replacement surgery.

Aim: To examine the time-to-total knee replacement (TKR) surgery among patients with high-concentration nonavian high-molecular-weight hyaluronan injection (HMW-HA) compared with those without HA injections. Materials & methods: Using MarketScan® Commercial claims all patients aged 18-64 who underwent TKR surgery between 2008 and 2017 were identified. Time-to-TKR surgery was compared between patients receiving Orthovisc® (Anika Therapeutics Inc. Bedford MA, USA, referred to as nonavian HMW-HA) injections and patients who did not receive an HA injection. Results: The median time-to-TKR surgery was 893 days in the nonavian HMW-HA cohort and 399 days in the non-HA cohort (p < 0.001), a difference of 494 days (16.2 months). Conclusion: This study demonstrates that the time-to-TKR surgery is 16.2 months longer in patients who received treatment with nonavian HMW-HA injections.

Real-world impact of the high concentration non-avian high molecular weight hyaluronan on pain medication use among osteoarthritis patients.

Objective: A prior study found that hyaluronic acid (HA) treatment may help reduce pain medication use (such as steroids, non-steroidal anti-inflammatory drugs [NSAIDs] and opioids) among knee osteoarthritis (OA) patients in the real-world setting. This study aims to update the prior study results to include only the high concentration non-avian high molecular weight hyaluronan (HMW-HA) injectables using data from recent years.Study design: This was a retrospective cohort study utilizing IBM MarketScan Commercial data from 2008 to 2015.Methods: Commercially insured patients between 18 and 64 years of age who received high concentration non-avian HMW-HA (Orthovisc1) between 1 January 2008 and 30 June 2015 were identified. Utilization of three prescription pharmacotherapies commonly used in the treatment for knee OA - NSAIDs, corticosteroid injections and opioids - in the 6 month pre and post periods was assessed. Utilization was measured as number of prescriptions and any prescription (yes/no). The independent variable was receiving the high concentration non-avian HMW-HA injection. Paired sample t-test and McNemar's test were used to assess pre-post changes.Results: The utilization of NSAIDs and steroids prescriptions was reduced significantly during the post period among the study cohort. The proportion of patients filling these prescriptions during the post period was also reduced (p < .001). In addition, the number of patients getting any opioid prescriptions was reduced significantly during the post period (p < .001).Conclusions: Based on this retrospective cohort study, the high concentration non-avian HMW-HA may offer effective pain alleviation among knee OA patients while reducing prescription pain medications such as steroids, NSAIDs and opioids.

The BDA First World War Memorial.

The First World War cost many lives and the dental profession was not exempt. Some were serving in their professional capacity within the forces, but many were not. The British Dental Association wished to commemorate those members who had sacrificed their lives by providing a Memorial plaque at the association's headquarters.

The first dentists sent to the Western Front during the First World War.

At the outbreak of the First World War there was insufficient dental provision for serving military personnel. No army dental specialists were available overseas when the troops joined the British Expeditionary Force (BEF). However, the pain of toothache together with the ensuing limited mastication was debilitating and demoralising for the British soldiers. The result was that men were being withdrawn from the front for treatment at base hospitals. This was limited to extractions by medical officers, which frequently incurred unnecessary loss of dentition when restorative work would have been preferable. Other consequences of dental neglect were indigestion and malnutrition. Additionally, the painful condition of acute necrotising ulcerative gingivitis, then commonly referred to as 'trench mouth', was prevalent.

Simulation of dissolution in porous media in three dimensions with lattice Boltzmann, finite-volume, and surface-rescaling methods.

We present a pore-scale dissolution model for the simulation of reactive transport in complex porous media such as those encountered in carbon-storage injection processes. We couple a lattice Boltzmann model for flow calculation with a finite-volume method for solving chemical transport equations, and allow the computational grid to change as mineral surfaces are dissolved according to first-order reaction kinetics. We appraise this scheme for use with high Péclet number flows in three-dimensional geometries and show how the popular first-order convection scheme is affected by severe numerical diffusion when grid Péclet numbers exceed unity, and confirm that this can be overcome relatively easily by using a second-order method in conjunction with a flux-limiter function. We then propose a surface rescaling method which uses parabolic elements to counteract errors in surface area exposed by the Cartesian grid and avoid the use of more complex embedded surface methods when surface reaction kinetics are incorporated. Finally, we compute dissolution in an image of a real porous limestone rock sample injected with HCl for different Péclet numbers and obtain dissolution patterns in concordance with theory and experimental observation. A low injection flow rate was shown to lead to erosion of the pore space concentrated at the face of the rock, whereas a high flow rate leads to wormhole formation.

Non-canonical actions of mismatch repair.

At the heart of the mismatch repair (MMR) system are proteins that recognize mismatches in DNA. Such mismatches can be mispairs involving normal or damaged bases or insertion/deletion loops due to strand misalignment. When such mispairs are generated during replication or recombination, MMR will direct removal of an incorrectly paired base or block recombination between nonidentical sequences. However, when mispairs are recognized outside the context of replication, proper strand discrimination between old and new DNA is lost, and MMR can act randomly and mutagenically on mispaired DNA. Such non-canonical actions of MMR are important in somatic hypermutation and class switch recombination, expansion of triplet repeats, and potentially in mutations arising in nondividing cells. MMR involvement in damage recognition and signaling is complex, with the end result likely dependent on the amount of DNA damage in a cell.

Replicative DNA polymerase δ but not ε proofreads errors in Cis and in Trans.

It is now well established that in yeast, and likely most eukaryotic organisms, initial DNA replication of the leading strand is by DNA polymerase ε and of the lagging strand by DNA polymerase δ. However, the role of Pol δ in replication of the leading strand is uncertain. In this work, we use a reporter system in Saccharomyces cerevisiae to measure mutation rates at specific base pairs in order to determine the effect of heterozygous or homozygous proofreading-defective mutants of either Pol ε or Pol δ in diploid strains. We find that wild-type Pol ε molecules cannot proofread errors created by proofreading-defective Pol ε molecules, whereas Pol δ can not only proofread errors created by proofreading-defective Pol δ molecules, but can also proofread errors created by Pol ε-defective molecules. These results suggest that any interruption in DNA synthesis on the leading strand is likely to result in completion by Pol δ and also explain the higher mutation rates observed in Pol δ-proofreading mutants compared to Pol ε-proofreading defective mutants. For strains reverting via AT→GC, TA→GC, CG→AT, and GC→AT mutations, we find in addition a strong effect of gene orientation on mutation rate in proofreading-defective strains and demonstrate that much of this orientation dependence is due to differential efficiencies of mispair elongation. We also find that a 3'-terminal 8 oxoG, unlike a 3'-terminal G, is efficiently extended opposite an A and is not subject to proofreading. Proofreading mutations have been shown to result in tumor formation in both mice and humans; the results presented here can help explain the properties exhibited by those proofreading mutants.

Different roles of eukaryotic MutS and MutL complexes in repair of small insertion and deletion loops in yeast.

DNA mismatch repair greatly increases genome fidelity by recognizing and removing replication errors. In order to understand how this fidelity is maintained, it is important to uncover the relative specificities of the different components of mismatch repair. There are two major mispair recognition complexes in eukaryotes that are homologues of bacterial MutS proteins, MutSα and MutSß, with MutSα recognizing base-base mismatches and small loop mispairs and MutSß recognizing larger loop mispairs. Upon recognition of a mispair, the MutS complexes then interact with homologues of the bacterial MutL protein. Loops formed on the primer strand during replication lead to insertion mutations, whereas loops on the template strand lead to deletions. We show here in yeast, using oligonucleotide transformation, that MutSα has a strong bias toward repair of insertion loops, while MutSß has an even stronger bias toward repair of deletion loops. Our results suggest that this bias in repair is due to the different interactions of the MutS complexes with the MutL complexes. Two mutants of MutLα, pms1-G882E and pms1-H888R, repair deletion mispairs but not insertion mispairs. Moreover, we find that a different MutL complex, MutLγ, is extremely important, but not sufficient, for deletion repair in the presence of either MutLα mutation. MutSß is present in many eukaryotic organisms, but not in prokaryotes. We suggest that the biased repair of deletion mispairs may reflect a critical eukaryotic function of MutSß in mismatch repair.

In vivo bypass of 8-oxodG.

8-oxoG is one of the most common and mutagenic DNA base lesions caused by oxidative damage. However, it has not been possible to study the replication of a known 8-oxoG base in vivo in order to determine the accuracy of its replication, the influence of various components on that accuracy, and the extent to which an 8-oxoG might present a barrier to replication. We have been able to place a single 8-oxoG into the Saccharomyces cerevisiae chromosome in a defined location using single-strand oligonucleotide transformation and to study its replication in a fully normal chromosome context. During replication, 8-oxoG is recognized as a lesion and triggers a switch to translesion synthesis by Pol η, which replicates 8-oxoG with an accuracy (insertion of a C opposite the 8-oxoG) of approximately 94%. In the absence of Pol η, template switching to the newly synthesized sister chromatid is observed at least one third of the time; replication of the 8-oxoG in the absence of Pol η is less than 40% accurate. The mismatch repair (MMR) system plays an important role in 8-oxoG replication. Template switching is blocked by MMR and replication accuracy even in the absence of Pol η is approximately 95% when MMR is active. These findings indicate that in light of the overlapping mechanisms by which errors in 8-oxoG replication can be avoided in the cell, the mutagenic threat of 8-oxoG is due more to its abundance than the effect of a single lesion. In addition, the methods used here should be applicable to the study of any lesion that can be stably incorporated into synthetic oligonucleotides.

Oxidative damage and mutagenesis in Saccharomyces cerevisiae: genetic studies of pathways affecting replication fidelity of 8-oxoguanine.

Oxidative damage to DNA constitutes a major threat to the faithful replication of DNA in all organisms and it is therefore important to understand the various mechanisms that are responsible for repair of such damage and the consequences of unrepaired damage. In these experiments, we make use of a reporter system in Saccharomyces cerevisiae that can measure the specific increase of each type of base pair mutation by measuring reversion to a Trp+ phenotype. We demonstrate that increased oxidative damage due to the absence of the superoxide dismutase gene, SOD1, increases all types of base pair mutations and that mismatch repair (MMR) reduces some, but not all, types of mutations. By analyzing various strains that can revert only via a specific CG→AT transversion in backgrounds deficient in Ogg1 (encoding an 8-oxoG glycosylase), we can study mutagenesis due to a known 8-oxoG base. We show as expected that MMR helps prevent mutagenesis due to this damaged base and that Pol η is important for its accurate replication. In addition we find that its accurate replication is facilitated by template switching, as loss of either RAD5 or MMS2 leads to a significant decrease in accurate replication. We observe that these ogg1 strains accumulate revertants during prolonged incubation on plates, in a process most likely due to retromutagenesis.

Measurement of muon capture on the proton to 1% precision and determination of the pseudoscalar coupling gP.

The MuCap experiment at the Paul Scherrer Institute has measured the rate Λ(S) of muon capture from the singlet state of the muonic hydrogen atom to a precision of 1%. A muon beam was stopped in a time projection chamber filled with 10-bar, ultrapure hydrogen gas. Cylindrical wire chambers and a segmented scintillator barrel detected electrons from muon decay. Λ(S) is determined from the difference between the µ(-) disappearance rate in hydrogen and the free muon decay rate. The result is based on the analysis of 1.2 × 10(10) µ(-) decays, from which we extract the capture rate Λ(S) = (714.9 ± 5.4(stat) ± 5.1(syst)) s(-1) and derive the proton's pseudoscalar coupling g(P)(q(0)(2) = -0.88 m(µ)(2)) = 8.06 ± 0.55.

Transformation with oligonucleotides creating clustered changes in the yeast genome.

We have studied single-strand oligonucleotide (oligo) transformation of yeast by using 40-nt long oligos that create multiple base changes to the yeast genome spread throughout the length of the oligos, making it possible to measure the portions of an oligo that are incorporated during transformation. Although the transformation process is greatly inhibited by DNA mismatch repair (MMR), the pattern of incorporation is essentially the same in the presence or absence of MMR, whether the oligo anneals to the leading or lagging strand of DNA replication, or whether phosphorothioate linkages are used at either end. A central core of approximately 15 nt is incorporated with a frequency of >90%; the ends are incorporated with a lower frequency, and loss of the two ends appears to be by different mechanisms. Bases that are 5-10 nt from the 5' end are generally lost with a frequency of >95%, likely through a process involving flap excision. On the 3' end, bases 5-10 nt from the 3' end are lost about 1/3 of the time. These results indicate that oligos can be used to create multiple simultaneous changes to the yeast genome, even in the presence of MMR.

Mismatch repair-dependent mutagenesis in nondividing cells.

Mismatch repair (MMR) is a major DNA repair pathway in cells from all branches of life that removes replication errors in a strand-specific manner, such that mismatched nucleotides are preferentially removed from the newly replicated strand of DNA. Here we demonstrate a role for MMR in helping create new phenotypes in nondividing cells. We show that mispairs in yeast that escape MMR during replication can later be subject to MMR activity in a replication strand-independent manner in nondividing cells, resulting in either fully wild-type or mutant DNA sequence. In one case, this activity is responsible for what appears to be adaptive mutation. This replication strand-independent MMR activity could contribute to the formation of tumors arising in nondividing cells and could also contribute to mutagenesis observed during somatic hypermutation of Ig genes.

Measurement of the positive muon lifetime and determination of the Fermi constant to part-per-million precision.

We report a measurement of the positive muon lifetime to a precision of 1.0 ppm; it is the most precise particle lifetime ever measured. The experiment used a time-structured, low-energy muon beam and a segmented plastic scintillator array to record more than 2×10(12) decays. Two different stopping target configurations were employed in independent data-taking periods. The combined results give τ(µ(+)) (MuLan)=2 196 980.3(2.2) ps, more than 15 times as precise as any previous experiment. The muon lifetime gives the most precise value for the Fermi constant: G(F) (MuLan)=1.166 378 8(7)×10(-5) GeV(-2) (0.6 ppm). It is also used to extract the µ(-)p singlet capture rate, which determines the proton's weak induced pseudoscalar coupling g(P).

Intra-aneurysmal thrombosis as a possible cause of delayed aneurysm rupture after flow-diversion treatment.

BACKGROUND AND PURPOSE: FD technology enables reconstructive repair of otherwise difficult-to-treat intracranial aneurysms. These stentlike devices may induce progressive aneurysm thrombosis without additional implants and may initiate complete reverse vessel remodeling. The associated vascular biologic processes are as yet only partially understood. MATERIALS AND METHODS: From 12 different centers, 13 cases of delayed postprocedural aneurysm rupture were recorded and analyzed. Symptom, aneurysm location and morphology, and the time elapsed from treatment until rupture were analyzed. RESULTS: There were 10 internal carotid and 3 basilar artery aneurysms. Mean aneurysm diameter was 22 ± 6 mm. Eleven patients were symptomatic before treatment. A single FD was used for all saccular aneurysms, while fusiform lesions were treated by using multiple devices. A supplementary loose coiling of the aneurysm was performed in 1 patient only. Ten patients developed early aneurysm rupture after FD treatment (mean, 16 days; range, 2-48 days); in 3 patients, rupture occurred 3-5 months after treatment. In all cases, most of the aneurysm cavity was thrombosed before rupture. The biologic mechanisms predisposing to rupture under these conditions are reviewed and discussed CONCLUSIONS: FDs alone may modify hemodynamics in ways that induce extensive aneurysm thrombosis. Under specific conditions, however, instead of reverse remodeling and cicatrization, aggressive thrombus-associated autolysis of the aneurysm wall may result in delayed rupture.

Hyaline astrocytic inclusions in pediatric epilepsy: report of two cases.

Distinctive hyaline inclusion bodies in the cytoplasm of neocortical astrocytes were observed in surgical resection specimens of a frontal epileptic focus, in 2 patients aged 16 and 10 who had suffered intractable partial seizures since the age of 2 years. One case had minimal neurological impairment and no brain malformation on MRI and recovered completely following surgery. The second case had mental retardation and surgery reduced the frequency and generalization of seizures. In both cases, the astrocytic inclusions were strongly eosinophilic, hyaline and refractile. They were PAS negative. Electron microscopy in the first case, confirmed their granular osmiophilic structure. By immunohistochemistry, the inclusions were strongly positive for filamin in the first case, only some were weakly positive in the second case. They also variably expressed other proteins such as alpha-B-crystallin, GFAP, S-100 protein and cytoglobin. We compare our findings with previously reported cases and discuss the clinical significance of the inclusions and the pathophysiologic relevance of filamin A and other proteins accumulation in astrocytes.