Trainee as trainer in paediatric laparoscopic appendicectomy.

BACKGROUND: Intraoperative teaching is an essential surgical skill, but there is little literature regarding trainees acting as trainers; we characterised these cases in paediatric laparoscopic appendicectomy. METHODS: This is a retrospective review of casenotes over two years (2015-2017) in a single tertiary paediatric surgical centre in the UK. Operating were: paediatric surgery Core Trainees (CT) (postgraduate year (PGY)3-4), Junior Registrars (JR) (PGY5-6) and Senior Registrars (SR) (PGY7+); collectively described as trainees. RESULTS: A total of 53 (20.7%) of 256 appendicectomies were trainee as trainer (TT) cases; 22 cases (41.5%) were performed by a CT supervised by a Registrar, and 31 (58.4%) by a JR supervised by a SR. Among the cases, 17 (32.1%) were complex, 47 (88.7%) were in working hours (8am-5pm), and 50 (94.3%) took place Monday to Friday. Median (interquartile range) duration of surgery was 65 (52-77) minutes. In the first year, 60 (47%) appendicectomies were performed by JRs. JR 1 was TT in three cases (8.8%) and JR 2 in five cases (19.2%); in all cases, the learner was a CT. Overall, there were 26 (10.6%) negative appendicectomies, 8 (3%) conversions, 19 (7%) readmissions within 30 days of discharge and 3 (1.1%) required reoperation; there was no statistically significant difference in complications between TT and non-TT cases. CONCLUSION: Laparoscopic appendicectomy is an excellent model for trainees to act as trainer; case selection included simple cases during daylight hours. Our outcomes are comparable with published literature, suggesting that this teaching method is safe for patients.

Predictors of firearm purchasing during the coronavirus pandemic in the United States: a cross-sectional study.

OBJECTIVES: This study aimed to compare determinants of firearm purchasing related to the pandemic. STUDY DESIGN: This was a cross-sectional survey. METHODS: A total of 3853 online panel participants completed a survey between December 22, 2020, and January 2, 2021, to approximate a nationally representative sample of US adults (aged ≥18 years). Four firearm ownership groups were created: non-owners, a proxy for first-time COVID-19 owners, prepandemic owners with COVID-19 purchase, and prepandemic owners without COVID-19 purchase. Explanatory variables were in four domains: demographics, concern about the pandemic, actions taken in response to COVID-19, and emotional response to COVID-19. Multivariate analysis estimated the adjusted odds of the outcomes. RESULTS: Respondents were categorized as non-owners (n = 2440), pandemic-related purchasers with no other firearms (n = 257), pandemic-related purchasers with other firearms (n = 350), and those who did not purchase in response to the pandemic but have other firearms (n = 806). Multivariable logistic regression found that compared with non-owners, those who had firearms at home with no pandemic-related purchases are more likely to be male, live in rural settings, have higher income, and be Republican. CONCLUSIONS: The results highlight the changing profile of American firearm owners and identify that those who purchased firearms for the first time (in response to the pandemic) should be the focus of tailored public health interventions, including provision of education about recommended firearm storage to reduce firearm violence, particularly because they are more likely to have children at home, and belong to demographic groups that may have less experience with firearm safety.

Do naps benefit novel word learning? Developmental differences and white matter correlates.

Memory representations of newly learned words undergo changes during nocturnal sleep, as evidenced by improvements in explicit recall and lexical integration (i.e., after sleep, novel words compete with existing words during online word recognition). Some studies have revealed larger sleep-benefits in children relative to adults. However, whether daytime naps play a similar facilitatory role is unclear. We investigated the effect of a daytime nap (relative to wake) on explicit memory (recall/recognition) and lexical integration (lexical competition) of newly learned novel words in young adults and children aged 10-12 years, also exploring white matter correlates of the pre- and post-nap effects of word learning in the child group with diffusion weighted MRI. In both age groups, a nap maintained explicit memory of novel words and wake led to forgetting. However, there was an age group interaction when comparing change in recall over the nap: children showed a slight improvement whereas adults showed a slight decline. There was no evidence of lexical integration at any point. Although children spent proportionally more time in slow-wave sleep (SWS) than adults, neither SWS nor spindle parameters correlated with over-nap changes in word learning. For children, increased fractional anisotropy (FA) in the uncinate fasciculus and arcuate fasciculus were associated with the recognition of novel words immediately after learning, and FA in the right arcuate fasciculus was further associated with changes in recall of novel words over a nap, supporting the importance of these tracts in the word learning and consolidation process. These findings point to a protective role of naps in word learning (at least under the present conditions), and emphasize the need to better understand both the active and passive roles that sleep plays in supporting vocabulary consolidation over development.

Brain activity changes associated with pain perception variability.

Pain perception can be modulated by several factors. Phenomena like temporal summation leads to increased perceived pain, whereas behavioral conditioning can result in analgesic responses. Furthermore, during repeated, identical noxious stimuli, pain intensity can vary greatly in some individuals. Understanding these variations is important, given the increase in investigations that assume stable baseline pain for accurate response profiles, such as studies of analgesic mechanisms. We utilized functional magnetic resonance imaging to examine the differences in neural circuitry between individuals displaying consistent pain ratings and those who experienced variable pain during a series of identical noxious stimuli. We investigated 63 healthy participants: 31 were assigned to a "consistent" group, and 32 were assigned to a "variable" group dependent on pain rating variability. Variable pain ratings were associated with reduced signal intensity in the dorsolateral prefrontal cortex (dlPFC). Furthermore, the dlPFC connectivity with the primary somatosensory cortex and temperoparietal junction was significantly reduced in variable participants. Our results suggest that investigators should consider variability of baseline pain when investigating pain modulatory paradigms. Additionally, individuals with consistent and variable pain ratings differ in their dlPFC activity and connectivity with pain-sensitive regions during noxious stimulation, possibly reflecting the differences in attentional processing and catastrophizing during pain.

Quantifying graft impingement in anterior cruciate ligament reconstruction.

BACKGROUND: Anterior cruciate ligament reconstructions (ACLR) fail at a rate of 10-15%, with graft impingement often a cause. In this study we investigate the prevalence and causes of impingement seen during ACLR surgery. METHODS: We reviewed consecutive primary ACLR from 2012-2018. Graft impingement was estimated intraoperatively by placing the arthroscope through the tibial tunnel and passively extending the knee, observing how much was obscured by the lateral femoral condyle from an anterior and lateral direction. Preoperative MRI scans were used to measure the intercondylar notch; Notch Width Index (NWI) and Notch Depth Index (NDI). Positioning of the tunnels was determined on postoperative radiographs. RESULTS: There were 283 ACLRs performed with 33 failures diagnosed on MRI (11.7%). 257 patients had complete imaging and follow up (91%). The mean age was 28 (±9) years and mean follow-up 5.3 (±1.8) years. The mean NWI was 0.26(±0.03), and NDI was 0.49(±0.06). The tibial tunnel aperture was located 42(±6) % of the way from anterior-posterior and 39(±6) % from medial-lateral. Impingement requiring a notchplasty was observed in 80% of cases, with lateral impingement more prominent. CONCLUSIONS: The amount of impingement did not correlate with tunnel position, which was located within the recommended area. There was a weak negative correlation between NWI and lateral impingement (rs = -0.16, p = 0.01), and NDI and anterior impingement (rs = -0.12, p = 0.04), therefore a smaller notch is associated with greater impingement. Despite optimal tunnel positioning, impingement still occurs in a significant number of cases therefore notchplasty should always be considered to keep revision rates low.

In situ labeling of non-accommodating interneurons based on metabolic rates.

Maintaining high frequency firing of narrow action potentials puts a large metabolic load on fast spiking (FS), perisomatic-inhibitory interneurons compared to their slow-spiking, dendrite targeting counterparts. Although the relationship of action potential (AP) firing and metabolism is firmly established, there is no single method to differentiate interneurons in situ based on their firing properties. In this study, we explore a novel strategy to easily identify the metabolically active FS cells among different classes of interneurons. We found that the oxidation of the fluorescent free radical marker 2,7-dichlorodihydrofluorescein (H2DCF) preferentially occurs in interneurons both in slice cultures and acute brain slices. Despite their morphological heterogeneity, almost all DCF-positive (DCF+) neurons belonged to the cluster of non-accommodating FS interneurons. Furthermore, all FS interneurons expressing parvalbumin (PV) both in slice cultures and in acute slices from tdTomato-PVCre transgenic mice were also DCF+. However, only half of the recorded DCF + cells were also PV+, indicating that H2DCF-oxidation occurs in different interneuron classes characterized by non-accomodating AP-firing. Comprehensively enhancing spontaneous neuronal activity led to mitochondrial oxidation of DCF in pyramidal cells as well as interneurons, suggesting that the apparent selectivity towards interneurons represents differences in the underlying metabolic load. While radical-scavenging, inhibition of APs or NO-synthesis, and iron chelation had no effect on the staining pattern, exposure to the complex-I inhibitor, rotenone, prevented interneuronal DCF accumulation. We conclude that H2DCF oxidation is independent of free radicals but correlates with the intensive oxidative energy metabolism and high mitochondrial mass in interneurons sharing the non-accommodating FS phenotype.

Transcriptional profiling of the L. monocytogenes PrfA regulon identifies six novel putative PrfA-regulated genes.

The transcriptional activator Positive Regulatory Factor A (PrfA) regulates expression of genes essential for virulence in Listeria monocytogenes. To define the PrfA regulon, the 10403S wildtype (WT) strain, a constitutively active prfA* mutant, and an isogenic ∆prfA mutant were grown under PrfA-inducing conditions in a medium containing glucose-1-phosphate and pre-treated with 0.2% activated charcoal. RNA-seq-generated transcript levels were compared as follows: (i) prfA* and WT; (ii) WT and ∆prfA and (iii) prfA* and ∆prfA. Significantly higher transcript levels in the induced WT or constitutively active PrfA* were identified for 18 genes and 2 ncRNAs in at least one of the three comparisons. These genes included: (i) 10/12 of the genes previously identified as directly PrfA-regulated; (ii) 2 genes previously identified as PrfA-regulated, albeit likely indirectly; and (iii) 6 genes newly identified as PrfA-regulated, including one (LMRG_0 2046) with a σA-dependent promoter and PrfA box located within an upstream open reading frame. LMRG_0 2046, which encodes a putative cyanate permease, is reported to be downregulated by a σB-dependent anti-sense RNA. This newly identified overlap between the σB and PrfA regulons highlights the complexity of regulatory networks important for fine-tuning bacterial gene expression in response to the rapidly changing environmental conditions associated with infection.

Growing up with interfering neighbours: the influence of time of learning and vocabulary knowledge on written word learning in children.

Evidence suggests that new vocabulary undergoes a period of strengthening and integration offline, particularly during sleep. Practical questions remain, however, including whether learning closer to bedtime can optimize consolidation, and whether such an effect varies with vocabulary ability. To examine this, children aged 8-12-years-old (n 59) were trained on written novel forms (e.g. BANARA) in either the morning (long delay) or the evening (short delay). Immediately after training and the next day, lexical competition (a marker of integration) was assessed via speeded semantic decisions to neighbouring existing words (e.g. BANANA); explicit memory was measured via recognition and recall tasks. There were no main effects indicating performance changes across sleep for any task, counter to studies of spoken word learning. However, a significant interaction was found, such that children with poorer vocabulary showed stronger lexical competition on the day after learning if there was a short delay between learning and sleep. Furthermore, while poorer vocabulary was associated with slower novel word recognition speed before and after sleep for the long delay group, this association was only present before sleep for the short delay group. Thus, weak vocabulary knowledge compromises novel word acquisition, and when there is a longer period of post-learning wake, this disadvantage remains after a consolidation opportunity. However, when sleep occurs soon after learning, consolidation processes can compensate for weaker encoding and permit lexical integration. These data provide preliminary suggestion that children with poorer vocabulary may benefit from learning new words closer to bedtime.

Validation of the Manchester spoken language development scale (MSLDS).

Introduction: Standardized outcome measures are importantfor accurately monitoring the language development of pre-lingually deaf children receiving auditory implants. Current commonly used outcome measures are time-consuming,limiting the practicality of regular testing. To address these limitations, the Manchester Spoken Language Development Scale (MSLDS) was developed as a quick and easily applicable interim measurement. This is an 11-point scale designed to provide a streamlined overview of a child's expressive language development. This study describes the MSLDS, evaluates its ease of use and inter-rater reliability, and outlines its application in the paediatric auditory implant population. Methods: Sixteen speech therapists and teachers for the deaf reviewed videos of paediatric cochlear implant assessmentsand rehabilitation sessions at a UK auditory implant centre. Twenty-five videos from fourteen children were used in this validation study. Reviewers were asked to evaluate a child's language development using the MSLDS by assigning a score for each video and to evaluate the ease of use of the scale. Each video wasrated by three different reviewers. Results: MSLDS scores showed a high degree of consistency between raters for each child. 8/25 (32%) videos demonstrated perfect agreement on the MSLDS. In 15/25 (60%) videos, there was a one-point difference between MSLDS scores. The remaining 2/25 (8%) videos varied by 2 points. Statistical analysis demonstrated an intra-class correlation coefficient (ICC) of 0.987, indicating a high level of agreement between users of the scale. Qualitative feedback from the raters suggested further modifications which have been incorporated into the scale. Conclusion: The high inter-rater agreement reflects the potential for the MSLDS to be a reliable tool for monitoring language development in the paediatric auditory implant population.

Nevertheless, She Resisted - Role of the Environment on Listeria monocytogenes Sensitivity to Nisin Treatment in a Laboratory Cheese Model.

The growth of Listeria monocytogenes on refrigerated, ready-to-eat food products is a major health and economic concern. The natural antimicrobial nisin targets the bacterial cell wall and can be used to inhibit L. monocytogenes growth on cheese. Cell wall composition and structure, and therefore the efficacy of cell wall acting control strategies, can be severely affected by environmental and stress conditions. The goal of this study was to determine the effect of a range of pH and temperatures on the efficacy of nisin against several strains of L. monocytogenes in a lab-scale, cheese model. Cheese was made with or without the addition of nisin at different pH and then inoculated with L. monocytogenes; L. monocytogenes numbers were quantified after 1, 7, and 14 days of incubation at 6, 14, or 22°C. While our data show that nisin treatment is able to reduce L. monocytogenes numbers, at least initially, growth of this pathogen can occur even in the presence of nisin, especially when cheese is stored at higher temperatures. Several environmental factors were found to affect nisin efficacy against L. monocytogenes. For example, nisin is more effective when cheese is stored at lower temperatures. Nisin is also more effective when cheese is made at higher pH (6 and 6.5), compared to cheese made at pH 5.5, and this effect is at least partially due to the activity of cell envelope modification genes dltA and mprF. Serotype was also found to affect nisin efficacy against L. monocytogenes; serotype 4b strains showed lower susceptibility to nisin treatment compared to serotype 1/2 strains. Overall, our results highlight the importance of considering environmental conditions specific to a food matrix when developing and applying nisin-based intervention strategies against L. monocytogenes.

Elastic nail fixation versus plate fixation of paediatric femoral fractures in school age patients - A retrospective observational study.

INTRODUCTION: The management of paediatric femoral fractures continues to spark debate in published literature, with poor quality evidence guiding current guidelines on the optimum treatment in children. Many centres report excellent results for both elastic intramedullary nailing and plate fixation of diaphyseal femoral fractures. This study aimed to investigate the outcomes of femoral fractures treated with elastic nail fixation versus those treated with plate fixation in a tertiary children's trauma unit, and discuss the advantages and disadvantages of each technique. MATERIALS AND METHODS: A retrospective review of all femoral fractures undergoing fixation at a level one paeditric trauma and tertiary referral unit, between 1st April 2009 and 30th April 2017, was performed.Clinical notes and radiographs were reviewed to determine patient demographics and injury, operative and hospital stay data. Radiological union, defined as bridging callus present on at least three out of four cortices on orthogonal radiographs, was determined at 12 weeks. Outcomes were determined using the Flynn Criteria. Patients were followed up for a minimum of 2 years. Data was statistically analysed, and a p value < 0.05 was considered significant. RESULTS: There were a total of 28 patients- 14 in each treatment group. Patients undergoing elastic nail fixation were significantly older than plate fixation (9.7 ± 1.9 Vs 7.7 ± 1.8; p = 0.008). A male preponderance was noted (21/28), with no difference between groups (10 Vs 11; p = 1.00). Plate fixation demonstrated a tendency towards shorter length of stay (6.3 ± 2.1 Vs 7.8 ± 3.0; p = 0.134), earlier radiological union at 12 weeks (14 Vs 10; p = 0.098), lower postoperative analgesia requirements (0.82 ± 0.45 Vs 1.12 ± 0.97; p = 0.200), and better outcomes, as determined by the Flynn criteria. CONCLUSIONS: In the authors opinion, plate fixation is a safe, effective alternative to elastic nail fixation with equivocal outcomes as determined by the Flynn Criteria. Plate fixation may offer advantages in shorter length of stay, reduced postoperative pain and earlier weightbearing. Further large scale, prospective research is required to determine whether these are borne out in practice.

Environmental conditions and serotype affect Listeria monocytogenes susceptibility to phage treatment in a laboratory cheese model.

Listeria monocytogenes can survive and grow in a variety of environments, including refrigeration, making it difficult to control and highlighting the importance of optimizing control strategies against this pathogen. Listeria phages are attractive biocontrol agents because phages bind to specific wall teichoic acids (WTA) on the bacterial cell wall, inhibiting pathogens without disrupting the normal microbiota or structure of the food. Common stresses found on dairy products can affect cell wall composition and structure and subsequently affect the efficiency of control strategies that target the cell wall. The goal of this study was to determine the effect of a range of pH and temperatures on the effectiveness of a commercial phage cocktail treatment against several strains of L. monocytogenes in a cheese matrix. We developed a laboratory-scale cheese model that was made at different pH, treated with phage, and then inoculated with L. monocytogenes. Cheeses were incubated at 6, 14, or 22°C for 14 d, and bacterial counts were determined on d 1, 7, and 14. Our data show that phage treatment has a limited ability to reduce L. monocytogenes counts at each temperature tested; however, it was more effective on specific strains of L. monocytogenes when cheese was stored at higher temperatures. More specifically, the average counts of L. monocytogenes on phage-treated cheese stored at 22°C were significantly lower than those on phage-treated cheese stored at 6 or 14°C. Similarly, phage treatment was significantly more effective at inhibiting L. monocytogenes on cheese made at higher pH (6 and 6.5) compared with counts on cheese made at pH 5.5, where L. monocytogenes did not grow. Furthermore, serotype was found to affect the susceptibility of L. monocytogenes to phage treatment; serotype 1/2 strains showed significantly higher susceptibility to phage treatment than serotype 4b strains. Overall, our results suggest the importance of considering the efficacy of phage under conditions (i.e., temperature and pH) specific to a given food matrix when applying interventions against this important foodborne pathogen.

Learning to live with interfering neighbours: the influence of time of learning and level of encoding on word learning.

New vocabulary is consolidated offline, particularly during sleep; however, the parameters that influence consolidation remain unclear. Two experiments investigated effects of exposure level and delay between learning and sleep on adults' consolidation of novel competitors (e.g. BANARA) to existing words (e.g. BANANA). Participants made speeded semantic decisions (i.e. a forced choice: natural versus man-made) to the existing words, with the expectation that novel word learning would inhibit responses due to lexical competition. This competition was observed, particularly when assessed after sleep, for both standard and high exposure levels (10 and 20 exposures per word; Experiment 1). Using a lower exposure level (five exposures; Experiment 2), no post-sleep enhancement of competition was observed, despite evidence of consolidation when explicit knowledge of novel word memory was tested. Thus, when encoding is relatively weak, consolidation-related lexical integration is particularly compromised. There was no evidence that going to bed soon after learning is advantageous for overnight consolidation; however, there was some preliminary suggestion that longer gaps between learning and bed-onset were associated with better explicit memory of novel words one week later, but only at higher levels of exposure. These findings suggest that while lexical integration can occur overnight, weaker lexical traces may not be able to access overnight integration processes in the sleeping brain. Furthermore, the finding that longer-term explicit memory of stronger (but not weaker) traces benefit from periods of wake following learning deserves examination in future research.

Optogenetic manipulation of stomatal kinetics improves carbon assimilation, water use, and growth.

Stomata serve dual and often conflicting roles, facilitating carbon dioxide influx into the plant leaf for photosynthesis and restricting water efflux via transpiration. Strategies for reducing transpiration without incurring a cost for photosynthesis must circumvent this inherent coupling of carbon dioxide and water vapor diffusion. We expressed the synthetic, light-gated K+ channel BLINK1 in guard cells surrounding stomatal pores in Arabidopsis to enhance the solute fluxes that drive stomatal aperture. BLINK1 introduced a K+ conductance and accelerated both stomatal opening under light exposure and closing after irradiation. Integrated over the growth period, BLINK1 drove a 2.2-fold increase in biomass in fluctuating light without cost in water use by the plant. Thus, we demonstrate the potential of enhancing stomatal kinetics to improve water use efficiency without penalty in carbon fixation.

Lessons learned from a pneumocystis pneumonia outbreak at a Scottish renal transplant centre.

BACKGROUND: Pneumocystis pneumonia (PCP) is an opportunistic infection occurring in renal transplant patients. Over a 14-month period an increase in PCP cases was identified among our renal transplant cohort. AIM: The outbreak population was studied to identify potential risk factors for the development of PCP. METHODS: A retrospective analysis of hospital records was carried out, with each case being matched with two case-linked controls. Information was collected on patient demographics, laboratory tests, and hospital visits pre and post development of infection. FINDINGS: No patients were receiving PCP prophylaxis at the time of infection and mean time from transplantation to developing PCP was 4.7 years (range: 0.51-14.5). The PCP group had a significantly lower mean estimated glomerular filtration rate than the control group (29.3 mL/min/1.73 m2 vs 70 mL/min-1 (P = 0.0007)). Three patients were treated for active cytomegalovirus (CMV) infection prior to PCP diagnosis and two had active CMV at the time of diagnosis compared to none in the control group (P = 0.001). Those who developed PCP were more likely to have shared a hospital visit with another patient who went on to develop PCP; 37% of clinic visits vs 19% (P = 0.014). CONCLUSION: This study highlights the ongoing risk of opportunistic infection several years after transplantation and adds weight to potential person-to-person Pneumocystis jirovecii transmission. Risk factors have been identified which may highlight those most at risk, enabling targeted rather than blanket long-term PCP prophylaxis.

Improved speech and language development after unilateral cochlear implantation in children with a potentially useable contralateral ear.

OBJECTIVES: Increasingly, children are considered for a unilateral cochlear implant (CI), even if the contralateral ear falls outside current audiological guidelines, especially if they are not considered to be reaching their educational potential. Here we present the outcomes of CI in children with potentially useable hearing in the contralateral ear. METHODS: A retrospective case note review was performed for a total of 57 patients. Primary outcome was speech and language (SaL) development, as measured by the Manchester Speech and Language Development Scale (MSLDS) and SaL age equivalent. Secondary outcomes were auditory perception, perceived parental benefit and compliance; respectively measured by Categories of Auditory Performance (CAP), Brief Assessment of Parental Perception (BAPP) and reported use. RESULTS: SaL development improved after CI with a mean pre-operative MSLDS score of 5.8 to a postoperative score of 8.0 (n = 57) and a mean SaL age equivalent of 14 months in a one-year period (n = 14). Furthermore, CAP scores improved from 4.9 to 7.0 (n = 57). Analysis of BAPP scores showed improved quality of life in 18/19 patients (94.7%). With regards to compliance, 50/57 (87.7%) are fulltime users of both their CI and their HA. CONCLUSION: The present study indicates that despite one ear having potentially useable hearing outside national audiological criteria, the majority of participants received benefit from a CI in the poorer hearing ear. We suggest that assessment of each ear separately and treatment with the most appropriate amplification device, has given these children a benefit they may not otherwise have acquired if they only had bilateral HA.

Plumage coloration and social context influence male investment in song.

Animals use multiple signals to attract mates, including elaborate song, brightly coloured ornaments and physical displays. Female birds often prefer both elaborate male song and intense carotenoid-based plumage coloration. This could lead less visually ornamented males to increase song production to maximize their attractiveness to females. We tested this possibility in the highly social and non-territorial house finch (Haemorhous mexicanus), in which females discriminate among males based on both song and on the intensity of red carotenoid-based plumage coloration. We manipulated male plumage coloration through carotenoid supplementation during moult, so that males were either red or yellow. Males were then housed under three social environments: (i) all red birds, (ii) all yellow birds or (iii) a mixture of red/yellow birds. We recorded song after presentation of a female. Red males produced more song than yellow males. But when yellow males were housed with red conspecifics, they produced more song relative to yellow males housed with equally unattractive yellow males. This study provides novel evidence that a male's plumage coloration and the plumage colour of his social competitors influence investment in song.

Altered regional brain T2 relaxation times in individuals with chronic orofacial neuropathic pain.

The neural mechanisms underlying the development and maintenance of chronic pain following nerve injury remain unclear. There is growing evidence that chronic neuropathic pain is associated with altered thalamic firing patterns, thalamocortical dysrhythmia and altered infra-slow oscillations in ascending pain pathways. Preclinical and post-mortem human studies have revealed that neuropathic pain is associated with prolonged astrocyte activation in the dorsal horn and we have suggested that this may result in altered gliotransmission, which results in altered resting neural rhythm in the ascending pain pathway. Evidence of astrocyte activation above the level of the dorsal horn in living humans is lacking and direct measurement of astrocyte activation in living humans is not possible, however, there is evidence that regional alterations in T2 relaxation times are indicative of astrogliosis. The aim of this study was to use T2 relaxometry to explore regional brain anatomy of the ascending pain pathway in individuals with chronic orofacial neuropathic pain. We found that in individuals with trigeminal neuropathic pain, decreases in T2 relaxation times occurred in the region of the spinal trigeminal nucleus and primary somatosensory cortex, as well as in higher order processing regions such as the dorsolateral prefrontal, cingulate and hippocampal/parahippocampal cortices. We speculate that these regional changes in T2 relaxation times reflect prolonged astrocyte activation, which results in altered brain rhythm and ultimately the constant perception of pain. Blocking prolonged astrocyte activation may be effective in preventing and even reversing the development of chronic pain following neural injury.

Recurrent injury patterns in adolescent rugby.

OBJECTIVES: To establish patterns of subsequent injury in U18 rugby, to quantify the burden of within season injury recurrence. DESIGN: Secondary analysis of prospective data. SETTING: 28 Schools in Ireland. PARTICIPANTS: 825 male rugby players (aged 15-18 years). MAIN OUTCOME MEASURES: Subsequent injuries were classified as: new, local or recurrent (same site and type as index injury). All recurrent injuries were sub-grouped by body part and diagnosis. Burden was based on frequency, days lost and injury proportion ratios. RESULTS: A total of 426 injuries were eligible for analysis, of which, 121 were subsequent injuries. The majority of subsequent injuries involved a different body part than their index injury. There were n = 23 cases of within season recurrence. 78% of recurrences occurred within 2 months of return to play. Recurrent injuries comprised 5% of all injuries and their cumulative time loss was 1073 days. Recurrent injury to the ankle ligaments, lumbar muscles and concussions carried the greatest burden. CONCLUSION: The burden of recurrent injury in U18 rugby is lower than in the professional game. However, this population could benefit from targeted secondary prevention efforts including reconsideration of return-to-play protocols for ankle sprain, lumbar muscles and potentially concussion.

Preoperative breast MRI and mortality in older women with breast cancer.

PURPOSE: The survival benefit from detecting additional breast cancers by preoperative magnetic resonance imaging (MRI) continues to be controversial. METHODS: We followed a cohort of 4454 women diagnosed with non-metastatic breast cancer (stage I-III) from 2/2005-6/2010 in five registries of the breast cancer surveillance consortium (BCSC). BCSC clinical and registry data were linked to Medicare claims and enrollment data. We estimated the cumulative probability of breast cancer-specific and all-cause mortality. We tested the association of preoperative MRI with all-cause mortality using a Cox proportional hazards model. RESULTS: 917 (20.6%) women underwent preoperative MRI. No significant difference in the cumulative probability of breast cancer-specific mortality was found. We observed no significant difference in the hazard of all-cause mortality during the follow-up period after adjusting for sociodemographic and clinical factors among women with MRI (HR 0.90; 95% CI 0.72-1.12) compared to those without MRI. CONCLUSION: Our findings of no breast cancer-specific or all-cause mortality benefit supplement prior results that indicate a lack of improvement in surgical outcomes associated with use of preoperative MRI. In combination with other reports, the results of this analysis highlight the importance of exploring the benefit of preoperative MRI in patient-reported outcomes such as women's decision quality and confidence levels with decisions involving treatment choices.