Increasing signal-to-noise ratio in over-determined Mueller matrices.

This work investigates how the signal-to-noise ratio (SNR) of an over-determined Mueller matrix can be improved by changing the method of calculation. Specifically, our investigation focused on comparing SNRs achieved using the vector methodology from the field of partial Mueller polarimetry, and the matrix methodology. We use experimentally derived measurements from an investigation into the time-varying signal produced by the Mueller matrix of an electro-optic Bismuth Silicon Oxide (BSO) crystal undergoing cyclical impact of a Helium plasma ionisation wave. Our findings show that the vector methodology is superior to the matrix methodology, with a maximum SNR of 7.54 versus 4.97. We put forth that the superiority of the vector methodology is due to its greater flexibility, which results in the Mueller matrix being calculated with better condition matrices, and higher levels of SNR in the intensity measurements used for calculation.

Deliberate foreign body ingestion in patients with underlying mental illness: A retrospective multicentre study.

OBJECTIVE: Deliberate foreign body ingestion (DFBI) is characterised by recurrent presentations among patients with mental health conditions, intellectual disabilities and in prisoners. We aimed to profile the characteristics and evaluate the care of such patients in this study. METHODS: Adult patients with an endoscopic record of attempted foreign body retrieval between January 2013 and September 2020 were identified at three Australian hospitals. Those with a documented mental health diagnosis were included and their standard medical records reviewed. Presentation history, demographics, comorbidities and endoscopic findings were recorded and described. RESULTS: A total of 166 admissions were accounted for by 35 patients, 2/3 of which had borderline personality disorder (BPD). Repetitive presentations occurred in more than half of the cohort. There was an increased trend of hospital admissions throughout the years. At least half of the cohort had a documented mental health review during their admission. An average of 3.3 (2.9) foreign bodies were ingested per single episode. Endoscopic intervention was performed in 76.5% of incidents. The combined Length of stay for all patients was 680 days. CONCLUSION: Deliberate foreign body ingestion in mental health patients is a common, recurring and challenging problem that is increasing in frequency and requires collaborative research to further guide holistic management.

Synovial tissue perivascular edema is associated with altered gait patterns in patients with knee osteoarthritis.

OBJECTIVE: To explore mechanisms of mechanoinflammation, we investigated the association between the presence of knee synovial perivascular edema and gait biomechanics that serve as surrogate measures of knee load in patients with knee osteoarthritis (OA). DESIGN: Patients with symptomatic, radiographic knee OA and neutral to varus alignment undergoing total knee arthroplasty or high tibial osteotomy participated in this cross-sectional analysis. All participants underwent 3D gait analysis prior to surgery. Synovial biopsies were obtained during surgery for histopathological assessment. The association between the presence of synovial perivascular edema (predictor) and the external knee moment (outcome) in each orthogonal plane was analyzed using multivariate linear regression and polynomial mixed effects regression models, while adjusting for age, sex, BMI, and gait speed. RESULTS: Ninety-two patients with complete gait and histopathological data were included. When fitted over 100% of stance, regression models indicated substantial differences between patients with and without synovial perivascular edema for knee moments in frontal, sagittal and transverse planes. The knee adduction moment was higher in patients with edema from 16 to 74% of stance, with the largest difference at 33% of stance (ß = 6.87 Nm [95%CI 3.02, 10.72]); whereas the knee flexion-extension moment differed from 15 to 92% of stance, with the largest difference in extension at 60% of stance (ß = -10.80 Nm [95%CI -16.20, -5.40]). CONCLUSIONS: In patients with knee OA, the presence of synovial perivascular edema identified by histopathology is associated with aberrant patterns of knee loading throughout stance, supporting the link between biomechanics and synovial inflammation.

Optimizing Mueller polarimetry in noisy systems through over-determination.

Mueller polarimetry measurements are increasingly being used to image highly dynamic and short-lived phenomena such as plasma discharges. For phenomena such as these, exposure times below 1 µs must be used. Unfortunately, these low exposure times significantly reduce the signal-to-noise ratio, making accurate and consistent measurements difficult. To overcome this limitation, we investigated increasing the number of Stokes vectors produced from a polarization state analyzer and polarization state generator, a process known as over-determination. To conduct our analysis, we used results from physical experiments using Stokes vectors generated by liquid crystal variable retarders. These results were then verified using data from simulations. First, we conclude that increasing the degree of over-determination is a simple and effective way of dealing with this noise; however, we also convey that choosing the best scheme is not an entirely trivial process. Second, we demonstrate that over-determination gives rise to hitherto inaccessible information that allows for the quantification of statistical noise and, crucially, the pinpointing of the origin of systematic error, a highly beneficial process that has been lacking until now.

Systematic review: adrenal insufficiency secondary to swallowed topical corticosteroids in eosinophilic oesophagitis.

BACKGROUND: Swallowed topical corticosteroids are prescribed for eosinophilic oesophagitis (EoE), but there is a theoretical risk of adrenal insufficiency from their use. AIMS: To determine if the use of topical corticosteroids to treat EoE is associated with the development of adrenal insufficiency. METHOD: We conducted a systematic review of the published literature from January 1, 1950 to April 1, 2017 using Pubmed, Embase, Web of Science and Cochrane Central. Studies and meeting abstracts were included that described patients with EoE who received swallowed topical corticosteroids and any investigation for adrenal insufficiency. RESULTS: The search revealed 1610 unique publications, and 17 met inclusion criteria. There were 7 randomised controlled trials (RCTs), 6 prospective observational studies, 3 retrospective observational studies, and 1 case report. Cortisol measurements were performed on 596 individuals with EoE who received topical corticosteroids. Adrenal testing was abnormal, as defined by each study, in 94/596 patients (crude rate of 15.8%). Only 2 studies were considered to have a low risk of bias, being randomised controlled trials that estimated adrenal insufficiency in the active treatment and placebo groups, before and after treatment. None of the seven randomised controlled trials demonstrated statistically significantly different rates of adrenal insufficiency between topical corticosteroid and placebo over treatment intervals of 2-12 weeks. CONCLUSION: Topical corticosteroids were associated with adrenal insufficiency in a minority of patients. Most cases came from uncontrolled observational studies, with widely varying definitions of adrenal insufficiency. Longer follow-up and larger controlled studies are needed to quantify the risk of adrenal insufficiency with maintenance topical corticosteroid therapy in EoE.

Randomised clinical trial: the efficacy of gut-directed hypnotherapy is similar to that of the low FODMAP diet for the treatment of irritable bowel syndrome.

BACKGROUND: A low fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP) diet is effective in treating irritable bowel syndrome (IBS). AIM: To compare the effects of gut-directed hypnotherapy to the low FODMAP diet on gastrointestinal symptoms and psychological indices, and assess additive effects. METHODS: Irritable bowel syndrome patients were randomised (computer-generated list), to receive hypnotherapy, diet or a combination. Primary end-point: change in overall gastrointestinal symptoms across the three groups from baseline to week 6. Secondary end-points: changes in psychological indices, and the durability of effects over 6 months. RESULTS: Of 74 participants, 25 received hypnotherapy, 24 diet and 25 combination. There were no demographic differences at baseline across groups. Improvements in overall symptoms were observed from baseline to week 6 for hypnotherapy [mean difference (95% CI): -33 (-41 to -25)], diet [-30 (-42 to -19)] and combination [-36 (-45 to -27)] with no difference across groups (P = 0.67). This represented ≥20 mm improvement on visual analogue scale in 72%, 71% and 72%, respectively. This improvement relative to baseline symptoms was maintained 6 months post-treatment in 74%, 82% and 54%. Individual gastrointestinal symptoms similarly improved. Hypnotherapy resulted in superior improvements on psychological indices with mean change from baseline to 6 months in State Trait Personality Inventory trait anxiety of -4(95% CI -6 to -2) P < 0.0001; -1(-3 to 0.3) P = ns; and 0.3(-2 to 2) P = ns, and in trait depression of -3(-5 to -0.7) P = 0.011; -0.8(-2 to 0.2) P = ns; and 0.6(-2 to 3) P = ns, respectively. Groups improved similarly for QOL (all p ≤ 0.001). CONCLUSIONS: Durable effects of gut-directed hypnotherapy are similar to those of the low FODMAP diet for relief of gastrointestinal symptoms. Hypnotherapy has superior efficacy to the diet on psychological indices. No additive effects were observed.

Allergy tests do not predict food triggers in adult patients with eosinophilic oesophagitis. A comprehensive prospective study using five modalities.

BACKGROUND: The use of allergy tests to guide dietary treatment for eosinophilic oesophagitis (EoE) is controversial and data are limited. Aeroallergen sensitisation patterns and food triggers have been defined in Northern Hemisphere cohorts only. AIMS: To determine if allergy tests that are routinely available can predict food triggers in adult patients with EoE. To define the food triggers and aeroallergen sensitisation patterns in a novel Southern Hemisphere (Australian) cohort of patients. METHODS: Consecutive patients with EoE who elected to undergo dietary therapy were prospectively assessed, demographic details and atopic characteristics recorded, and allergy tests, comprising skin-prick and skin-patch tests, serum allergen-specific IgE, basophil activation test and serum food-specific IgG, were performed. Patients underwent a six-food elimination diet with a structured algorithm that included endoscopic and histological examination of the oesophagus a minimum of 2 weeks after each challenge. Response was defined as <15 eosinophils per HPF. Foods defined as triggers were considered as gold standard and were compared with those identified by allergy testing. RESULTS: No allergy test could accurately predict actual food triggers. Concordance among skin-prick and serum allergen-specific IgE was high for aeroallergens only. Among seasonal aeroallergens, rye-grass sensitisation was predominant. Food triggers were commonly wheat, milk and egg, alone or in combination. CONCLUSIONS: None of the currently-available allergy tests predicts food triggers for EoE. Exclusion-rechallenge methodology with oesophageal histological assessment remains the only effective investigation. The same food triggers were identified in this southern hemisphere cohort as previously described.

A prospective open clinical trial of a proton pump inhibitor, elimination diet and/or budesonide for eosinophilic oesophagitis.

BACKGROUND: Elimination diets and high-dose proton pump inhibitors (PPI) are advocated as first-line treatments in patients with eosinophilic oesophagitis (EoE). AIM: To record the treatment outcome for patients with EoE prospectively managed according to a clinical algorithm. METHODS: Patients with oesophageal eosinophilia commenced esomeprazole 40 mg twice daily for 8 weeks. Those in histological remission were re-classified as PPI-responsive oesophageal eosinophilia. Nonresponders were offered the 6-food elimination diet with a PPI, or topical budesonide monotherapy (1 mg orally twice daily as an aqueous gel). Once disease control was achieved remission was reassessed at 3 months (all modalities) and an additional 6 months (diet group). RESULTS: Of 107 patients who completed 8 weeks of PPI, 25 (23%) were PPI-responsive. 56 of 81 (69%) of patients with EoE chose the elimination diet with PPI. 29 (52%) had complete remission, 23 completed dietary reintroduction and food triggers were identified in 20 (36%). 25 chose budesonide with 23/25 (92%) responding. Remission was sustained in >85% of patients at 3 months with all treatment modalities. At 9 months, only 10/18 (55%) of patients who responded to the elimination diet with PPI remained complaint and sustained remission. CONCLUSIONS: Many patients previously diagnosed with EoE will respond to PPI. Initial response >50% is possible with the elimination diet plus PPI, but many will fail to undergo food reintroduction, or will cease the diet and relapse, resulting in only one in four patient sustaining remission at 9 months. Budesonide is very effective short term, but longer term study is needed.

Seasonal recurrence of food bolus obstruction in eosinophilic esophagitis.

BACKGROUND: Eosinophilic esophagitis (EoE) is a newly recognised condition that is apparently increasing in prevalence, and the aetiology is poorly understood. The role of aeroallergens in EoE is controversial, given the success of dietary therapy. Massive aeroallergen exposure leading to food bolus obstruction events (FBOE) has been described, and the diagnosis of EoE by esophageal biopsy noted to be more common in the pollen season according to previous case series. AIM: To determine if a seasonal variation and a geographical variation occurred in EoE presenting as FBOE in adults, and to track the prevalence of FBOE and EoE over time. METHOD: A retrospective case-control study analysis was performed from January 2002 to January 2012 to identify all FBOE in adults presenting to five tertiary hospitals in Melbourne, Australia. Endoscopy, histopathological reports, case notes and blood tests were examined, and postcodes recorded. Records of pollen counts were obtained. Cases were defined according to esophageal biopsy and grouped based on month of diagnosis. All other causes of FBOE served as controls. RESULTS: One thousand, one hundred and thirty-two FBOE were identified. Biopsies were only performed in 278 of these cases, and 85 patients were found to have EoE after biopsy. Patients with EoE were younger (mean age 38 years, range 18-72) compared with those with alternative diagnosis (mean age 64.4 range 22-92), more likely to be male (M : F = 4:1 compared with 1.68:1 ) and had a higher eosinophil count in venous blood. Overall no seasonality was demonstrated in FBOE secondary to any diagnosis, although the six cases of recurrent FBOE secondary to EoE mainly occurred in the grass pollen season in subsequent years. FBOE cases were evenly distributed throughout metropolitan Melbourne irrespective of population density. EoE as a percentage of FBOE increased over time. CONCLUSION: Seasonal aeroallergens may be important for a subgroup of patients with EoE presenting as recurrent FBOE. Esophageal biopsies are performed in a minority of patients, representing a significant departure from ideal management and contributing to recurrent unnecessary FBOE. EoE is an increasingly important cause of FBOE.

Risk factors for eosinophilic esophagitis.

Eosinophilic esophagitis (EoE) is a chronic antigen driven disease, whereby food and/or aeroallergens result in inflammation and luminal narrowing, and the clinical symptoms of dysphagia and food bolus obstruction events (FBOE). Established risk factors are male gender, Caucasian race and atopy. Increased risk amongst family members, and a single nucleotide polymorphism (SNP) in a gene coding thymic stromal lymphopoietin (TSLP) on the pseudoautosomal region of the X and Y chromosomes supports a genetic predisposition. Environmental factors including the timing and nature of food and aeroallergen exposure to the developing immune system may be important, whilst esophageal barrier function integrity and the influence of microbiota are worthy of future research.

Drug-induced gastrointestinal disorders.

Drug-induced gastrointestinal disorders can mimic conditions, such as inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS) and, hence, recognition can prevent unnecessary investigations and treatment. While the knowledge and awareness relating to the adverse gastrointestinal effects of some medications, such as non-steroidal anti-inflammatory drugs are well established, other commonly prescribed drugs, such as antipsychotics, antidepressants and metformin are less well understood and warrant further study. This review attempts to integrate recent information regarding adverse drug reactions and place this in a useful clinical context.

Drug-induced gastrointestinal disorders.

Drug-induced gastrointestinal disorders can mimic conditions, such as inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS) and, hence, recognition can prevent unnecessary investigations and treatment. While the knowledge and awareness relating to the adverse gastrointestinal effects of some medications, such as non-steroidal anti-inflammatory drugs are well established, other commonly prescribed drugs, such as antipsychotics, antidepressants and metformin are less well understood and warrant further study. This review attempts to integrate recent information regarding adverse drug reactions and place this in a useful clinical context.