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Background: Despite infliximab biosimilars becoming widely used in inflammatory bowel disease (IBD) patients, real-world non-medical switching is sparse. A biosimilar non-medical switch was launched in British Columbia in 2019, the first Canadian province to do so, from Remicade to an approved biosimilar (CT-P13 or SB2). Aims: This study aims to obtain real-world evidence evaluating the clinical outcomes of non-medical switching from Remicade to the infliximab biosimilars. Methods: This is a retrospective observational study of stable IBD patients from the IBD Centre of BC who underwent the non-medical infliximab switch. The primary outcome is treatment continuation at 12 ± 2 months post-switch. Secondary outcomes include frequency of loss of response, adverse events, and immunogenicity within the first 12 months post-switch. A control group of patients maintained on the originator served as a comparison. Results: Patients in the biosimilar switch group (n = 264) and originator group (n = 99), show similar demographics and disease characteristics. There was no difference in infliximab continuation between the biosimilar group (94.9%) and the originator group (90.1%) (P = 0.18). Reasons for discontinuation of infliximab included loss of response (4.04% vs 4.91%), immunogenicity (1.01% vs 0.75%), or adverse effect (1.01% vs 2.3%) in the infliximab originator vs biosimilar switch group, respectively. Similarly, no differences in safety or efficacy were observed between patients switched to CT-P13 or SB2. Conclusions: Non-medical biosimilar switch of infliximab demonstrates similar clinical outcomes compared to originator molecule continuation for therapy of IBD. These data support the safety and efficacy of non-medical infliximab switching in IBD patients.
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Although FOXP3+ regulatory T cells (Treg) depend on IL-2 produced by other cells for their survival and function, the levels of IL-2 in inflamed tissue are low, making it unclear how Treg access this critical resource. Here, we show that Treg use heparanase (HPSE) to access IL-2 sequestered by heparan sulfate (HS) within the extracellular matrix (ECM) of inflamed central nervous system tissue. HPSE expression distinguishes human and murine Treg from conventional T cells and is regulated by the availability of IL-2. HPSE-/- Treg have impaired stability and function in vivo, including in the experimental autoimmune encephalomyelitis (EAE) mouse model of multiple sclerosis. Conversely, endowing monoclonal antibody-directed chimeric antigen receptor (mAbCAR) Treg with HPSE enhances their ability to access HS-sequestered IL-2 and their ability to suppress neuroinflammation in vivo. Together, these data identify a role for HPSE and the ECM in immune tolerance, providing new avenues for improving Treg-based therapy of autoimmunity.
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Encefalomielite Autoimune Experimental , Linfócitos T Reguladores , Camundongos , Animais , Humanos , Interleucina-2/metabolismo , Glucuronidase/genética , Glucuronidase/metabolismo , Matriz Extracelular/metabolismo , Heparitina Sulfato/metabolismoRESUMO
Evidence indicates that dysfunction of older Schwann cells and macrophages contributes to poor regeneration of more mature peripheral nervous system (PNS) neurons after damage. Since the underlying molecular factors are largely unknown, we investigated if CRYAB, a small heat shock protein that is expressed by Schwann cells and axons and whose expression declines with age, impacts prominent deficits in the injured, older PNS including down-regulation of cholesterol biosynthesis enzyme genes, Schwann cell dysfunction, and macrophage persistence. Following sciatic nerve transection injury in 3- and 12-month-old wildtype and CRYAB knockout mice, we found by bulk RNA sequencing and RT-PCR, that while gene expression of cholesterol biosynthesis enzymes is markedly dysregulated in the aging, injured PNS, CRYAB is not involved. However, immunohistochemical staining of crushed sciatic nerves revealed that more macrophages of the pro-inflammatory but not immunosuppressive phenotype persisted in damaged 12-month-old knockout nerves. These pro-inflammatory macrophages were more efficient at engulfing myelin debris. CRYAB thus appears to play a role in resolving pro-inflammatory macrophage responses after damage to the older PNS.
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Bainha de Mielina , Traumatismos dos Nervos Periféricos , Animais , Camundongos , Envelhecimento , Axônios , Colesterol , Macrófagos , Camundongos KnockoutRESUMO
BACKGROUND & AIMS: Clinical and radiologic variables associated with perianal fistula (PAF) outcomes are poorly understood. We developed prediction models for anti-tumor necrosis factor (TNF) treatment failure in patients with Crohn's disease-related PAF. METHODS: In a multicenter retrospective study between 2005 and 2022 we included biologic-naive adults (>17 years) who initiated their first anti-TNF therapy for PAF after pelvic magnetic resonance imaging (MRI). Pretreatment MRI studies were prospectively reread centrally by blinded radiologists. We developed and internally validated a prediction model based on clinical and radiologic parameters to predict the likelihood of anti-TNF treatment failure, clinically, at 6 months. We compared our model and a simplified version of MRI parameters alone with existing imaging-based PAF activity indices (MAGNIFI-CD and modified Van Assche MRI scores) by De Long statistical test. RESULTS: We included 221 patients: 32 ± 14 years, 60% males, 76% complex fistulas; 68% treated with infliximab and 32% treated with adalimumab. Treatment failure occurred in 102 (46%) patients. Our prediction model included age at PAF diagnosis, time to initiate anti-TNF treatment, and smoking and 8 MRI characteristics (supra/extrasphincteric anatomy, fistula length >4.3 cm, primary tracts >1, secondary tracts >1, external openings >1, tract hyperintensity on T1-weighted imaging, horseshoe anatomy, and collections >1.3 cm). Our full and simplified MRI models had fair discriminatory capacity for anti-TNF treatment failure (concordance statistic, 0.67 and 0.65, respectively) and outperformed MAGNIFI-CD (P = .002 and < .0005) and modified Van Assche MRI scores (P < .0001 and < .0001), respectively. CONCLUSIONS: Our risk prediction models consisting of clinical and/or radiologic variables accurately predict treatment failure in patients with PAF.
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Doença de Crohn , Imageamento por Ressonância Magnética , Fístula Retal , Falha de Tratamento , Humanos , Doença de Crohn/tratamento farmacológico , Doença de Crohn/diagnóstico por imagem , Doença de Crohn/complicações , Masculino , Feminino , Adulto , Estudos Retrospectivos , Fístula Retal/tratamento farmacológico , Fístula Retal/diagnóstico por imagem , Adalimumab/uso terapêutico , Adulto Jovem , Infliximab/uso terapêutico , Pessoa de Meia-Idade , Fator de Necrose Tumoral alfa/antagonistas & inibidores , Inibidores do Fator de Necrose Tumoral/uso terapêuticoRESUMO
FOXP3+ regulatory T cells (Treg) depend on exogenous IL-2 for their survival and function, but circulating levels of IL-2 are low, making it unclear how Treg access this critical resource in vivo. Here, we show that Treg use heparanase (HPSE) to access IL-2 sequestered by heparan sulfate (HS) within the extracellular matrix (ECM) of inflamed central nervous system tissue. HPSE expression distinguishes human and murine Treg from conventional T cells and is regulated by the availability of IL-2. HPSE-/- Treg have impaired stability and function in vivo, including the experimental autoimmune encephalomyelitis (EAE) mouse model of multiple sclerosis. Conversely, endowing Treg with HPSE enhances their ability to access HS-sequestered IL-2 and their tolerogenic function in vivo. Together, these data identify novel roles for HPSE and the ECM in immune tolerance, providing new avenues for improving Treg-based therapy of autoimmunity.
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Carbonaceous deposits are ubiquitous, being formed on surfaces in engines, fuel systems and on catalysts operating at high temperatures for hydrocarbon transformations. In internal combustion engines, their formation negatively affects worldwide vehicle emissions and fuel economy, leading to premature deaths and environmental damage. Deposit composition and formation pathways are poorly understood due to their insolubility and the intrinsic complexity of their layered carbonaceous matrix. Here, we apply the in situ high mass resolving power capabilities of 3D Orbitrap secondary ion mass spectrometry (3D OrbiSIMS) argon cluster depth profiling on 16 lab grown deposits and evidence common molecular distributions in deposit depth and in positions relative to the combustion chamber. We observe the products of the growth of both planar and curved polycyclic aromatic hydrocarbons to form small fullerenes over time in the engine and propose possible formation pathways which explain the molecular distributions observed. These include alkyl scission, cyclisation of aliphatic side chains and hydrogen abstraction C2H2 addition to form larger aromatic structures. We apply this pathway to previously unidentified nitrogen containing structures in deposits including quinolines and carbazoles. For the first time, 3D OrbiSIMS results were compared and validated with data from atmospheric pressure matrix assisted laser desorption ionization MS. The comprehensive characterization provided will help the development of a new generation of chemical additives to reduce deposits, and thus improve vehicle emissions and global air quality.
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Poluentes Atmosféricos , Poluição do Ar , Hidrocarbonetos Policíclicos Aromáticos , Poluentes Atmosféricos/análise , Poluição do Ar/análise , Hidrocarbonetos/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , Emissões de Veículos/análiseRESUMO
Modern mass spectrometry techniques produce a wealth of spectral data, and although this is an advantage in terms of the richness of the information available, the volume and complexity of data can prevent a thorough interpretation to reach useful conclusions. Application of molecular formula prediction (MFP) to produce annotated lists of ions that have been filtered by their elemental composition and considering structural double bond equivalence are widely used on high resolving power mass spectrometry datasets. However, this has not been applied to secondary ion mass spectrometry data. Here, we apply this data interpretation approach to 3D OrbiSIMS datasets, testing it for a series of increasingly complex samples. In an organic on inorganic sample, we successfully annotated the organic contaminant overlayer separately from the substrate. In a more challenging purely organic human serum sample we filtered out both proteins and lipids based on elemental compositions, 226 different lipids were identified and validated using existing databases, and we assigned amino acid sequences of abundant serum proteins including albumin, fibronectin, and transferrin. Finally, we tested the approach on depth profile data from layered carbonaceous engine deposits and annotated previously unidentified lubricating oil species. Application of an unsupervised machine learning method on filtered ions after performing MFP from this sample uniquely separated depth profiles of species, which were not observed when performing the method on the entire dataset. Overall, the chemical filtering approach using MFP has great potential in enabling full interpretation of complex 3D OrbiSIMS datasets from a plethora of material types.
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Lipídeos , Espectrometria de Massa de Íon Secundário , Bases de Dados Factuais , Humanos , Íons/químicaRESUMO
Introduction: The objective of this study was to retrospectively analyze clinical data from a referral regenerative medicine practice, to investigate the efficacy of autologous mesenchymal stromal cells (MSC) in 245 dogs deemed unresponsive to conventional treatment by their referring vet. Methods: Diagnostic imaging [radiology and musculoskeletal ultrasound (MSK-US)] identified musculoskeletal pathology holistically. MSCs, produced according to current guidelines, were initially administered with PRP by targeted injection to joints and/or tendons, with a second MSC monotherapy administered 12 weeks later to dogs with severe pathology and/or previous elbow arthroscopic interventions. Dogs with lumbosacral disease received epidural MSCs with additional intravenous MSCs administered to dogs with spondylosis of the cervical, thoracic and lumbar spine. All dogs received laser therapy at 10 J/cm2 at the time of treatment and for 5 sessions thereafter. Objective outcome measures (stance analysis, range of joint motion, pressure algometry) and validated subjective outcome measures (owner reported VetMetrica HRQL™ and veterinary pain and quality of life impact scores) were used to investigate short and long-term (6-104 weeks) efficacy. Outcome data were collected at predetermined time windows (0-6, 7-12, 13-18, 19-24, 25-48, 49-78, 79-104) weeks after initial treatment. Results: There were statistically significant improvements in post compared with pre-treatment measures at all time windows in stance analysis, shoulder and hip range of motion, lumbosacral pressure algometry, and to 49-78 weeks in carpus and elbow range of motion. Improvements in 4 domains of quality of life as measured by VetMetricaTM were statistically significant, as were scores in vet-assessed pain and quality of life impact. In dogs receiving one initial treatment the mean time before a second treatment was required to maintain improvements in objective measures was 451 days. Diagnostic imaging confirmed the regenerative effects of MSCs in tendinopathies by demonstrating resolution of abnormal mineralization and restoration of normal fiber patterns. Discussion: This represents the first study using "real-world" data to show that cell-based therapies, injected into multiple areas of musculoskeletal pathology in a targeted holistic approach, resulted in rapid and profound positive effects on the patient's pain state and quality of life which was maintained with repeat treatment for up to 2 years.
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BACKGROUND: The natural history of perianal Crohn disease (PCD) after fecal diversion in the era of biologics is poorly understood. We assessed clinical and surgical outcomes after fecal diversion for medically refractory PCD and determined the impact of biologics. METHODS: We performed a retrospective, multicenter study from 1999 to 2020. Patients who underwent fecal diversion for refractory PCD were stratified by diversion type (ostomy with or without proctectomy). Times to clinical and surgical outcomes were estimated using Kaplan-Meier methods, and the association with biologics was assessed using multivariable Cox proportional hazards models. RESULTS: Eighty-two patients, from 3 academic institutions, underwent a total of 97 fecal diversions: 68 diversions without proctectomy and 29 diversions with proctectomy. Perianal healing occurred more commonly after diversion with proctectomy than after diversion without proctectomy (83% vs 53%; Pâ =â 0.021). Among the patients who had 68 diversions without proctectomy, with a median follow-up of 4.9 years post-diversion (interquartile range, 1.66-10.19), 37% had sustained healing, 31% underwent surgery to restore bowel continuity, and 22% underwent proctectomy. Ostomy-free survival occurred in 21% of patients. Biologics were independently associated with avoidance of proctectomy (hazard ratio, 0.32; 95% confidence interval, 0.11-0.98) and surgery to restore bowel continuity (hazard ratio, 3.10; 95% confidence interval, 1.02-9.37), but not fistula healing. CONCLUSIONS: In this multicenter study, biologics were associated with bowel restoration and avoidance of proctectomy after fecal diversion without proctectomy for PCD; however, a minority of patients achieved sustained fistula healing after initial fecal diversion or after bowel restoration. These results highlight the refractory nature of PCD.
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Doença de Crohn , Protectomia , Terapia Biológica , Doença de Crohn/complicações , Doença de Crohn/tratamento farmacológico , Doença de Crohn/cirurgia , Fezes , Humanos , Estudos Retrospectivos , Resultado do TratamentoRESUMO
Validity is not an inherent property of a measurement scale and so evidence for validity relating to its use for particular purposes, with defined populations and in specified contexts must be accumulated. We have published the development of a web-based, generic health-related quality of life instrument (VetMetrica™) to measure the affective impact of chronic disease in cats and provided evidence for its validity in a mixed population of cats, some of which, according to veterinary judgement, were healthy and others of which were suffering from chronic conditions likely to affect their quality of life, often with multiple co-morbidities present. The first aim of the current study was to demonstrate the construct validity of the VetMetrica™ generic instrument when used with cats suffering from osteoarthritis, by testing the hypothesis that the health-related quality of life profile of cats with different severities of osteoarthritis would differ and by demonstrating convergent validity between the health-related quality of life profile scores and independently quantified vet-assessed pain and quality of life impact scores. The latter involved simple correlation analysis and investigation of the relationship between health-related quality of life domain scores and vet-assessed scores, when adjusted for other potential explanatory variables including number of comorbidities and age. Responsiveness-the ability to detect clinically relevant change-is an essential quality for an evaluative instrument and it also provides evidence for "longitudinal validity". Therefore, a second aim of this study was to demonstrate that changes in health-related quality of life domain scores concurred with the clinician's impression of change over time in the health status of cats with osteoarthritis, thus providing evidence for the instrument's responsiveness. Previously, we have reported disagreement between owner and vet impression as to health status in cats in general, but not in relation to any specific disease. Accordingly, the third study aim was to investigate the extent of agreement or disagreement between owner impression of the impact of osteoarthritis on their cats' quality of life and vet impression of such impact. Fifty one percentage of cat owners believed their cats to be perfectly healthy despite a clinician diagnosis of osteoarthritis.
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The measurement and treatment of acute pain in animals is essential from a welfare perspective. Valid pain-related outcome measures are also crucial for ensuring reliable and translatable findings in veterinary clinical trials. The short form of the Glasgow Composite Measure Pain Scale (CMPS-SF) is a multi-item behavioral pain assessment tool, developed and validated using a psychometric approach, to measure acute pain in the dog. Here we conduct a scoping review to identify prospective research studies that have used the CMPS-SF. We aim to describe the contexts in which it has been used, verify the correct use of the scale, and examine whether these studies are well-designed and adequately powered. We identify 114 eligible studies, indicating widespread use of the scale. We also document a limited number of modifications to the scale and intervention level, which would alter its validity. A variety of methods, with no consensus, were used to analyse data derived from the scale. However, we also find many deficiencies in reporting of experimental design in terms of the observers used, the underlying hypothesis of the research, the statement of primary outcome, and the use of a priori sample size calculations. These deficiencies may predispose to both type I and type II statistical errors in the small animal pain literature. We recommend more robust use of the scale and derived data to ensure success of future studies using the tool ensuring reliable and translatable outcomes.
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Astrocyte heterogeneity is a rapidly evolving field driven by innovative techniques. Inflammatory astrocytes, one of the first described subtypes of reactive astrocytes, are present in a variety of neurodegenerative diseases and may play a role in their pathogenesis. Moreover, genetic and therapeutic targeting of these astrocytes ameliorates disease in several models, providing support for advancing the development of astrocyte-specific disease modifying therapies. This review aims to explore the methods and challenges of identifying inflammatory astrocytes, the role these astrocytes play in neurological disorders, and future directions in the field of astrocyte heterogeneity.
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[This corrects the article DOI: 10.3389/fvets.2020.575795.].
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Homoleptic LiNacNac forms simple donor-acceptor complexes with N,N'-dicyclohexylcarbodiimide (CyNâCâNCy), triphenylphosphine oxide (Ph3PâO), and benzophenone (Ph2CO). These crystallographically characterized compounds could be regarded as model intermediates en route to reducing the NâC, PâO, and CâO bonds of unsaturated substrates. Heteroleptic NacNacMg(TMP) intriguingly functions as a TMP nucleophile both with t-BuNCO and t-BuNCS, producing a urea or thiourea derivative respectively attached to Mg, though the NacNac ligand in the former reaction also engages noninnocently with a second t-BuNCO molecule via insertion at the reactive NacNac backbone γ-carbon site.
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Using an app, this exploratory study generated information on HRQL in a large cohort of dogs deemed healthy according to the owner. It forms the basis for further studies investigating the natural history of HRQL of dogs to inform the interpretation of interventional studies, but highlights the risks of relying on owner impression of health status. A previously published health-related quality of life (HRQL) instrument (VetMetrica™) that generates scores in four domains of quality of life in dogs - Energetic and Enthusiastic (E/E), Happy and Content (H/C), Active and Comfortable (A/C), and Calm and Relaxed (C/R), generated information on HRQL in 4,217 dogs (3 months-21 years). Dogs were categorized by age; young, 3-47 months, middle-aged, 48-95 months, and old, 96 months and older. Owners considered 2,959 dogs (3-95 months) to be "in perfect health" and these were used to explore the relationship between age, sex, breed and HRQL in apparently healthy dogs. Mean score was significantly greater (better) in young compared to middle-aged dogs in E/E, H/C and A/C and declined with advancing age. In H/C there was a small but significant difference in mean score between female and male dogs (mean greater in females), with a similar rate of decline in each gender with advancing age. In E/E there were very small but statistically significant differences in mean scores between certain breeds. In A/C there was a statistically significant interaction between breed and age and the rate of decline with advancing age differed with breed. Overall, age, breed, and sex predicted very little of the variation seen in HRQL scores. Data from a subset of 152 dogs, for whom clinical information was available, were used to examine the agreement between clinical evidence and owner opinion. According to the clinical records, 89 dogs were healthy and 63 had evidence of chronic disease. There was an approximately 40% disagreement between owner opinion on health status and clinical evidence of chronic disease (35% disagreement in all dogs and 43% in old dogs). HRQL scores were generally higher in dogs for whom there was no evidence of disease in the clinical record.
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Preventive measures in human healthcare are recognized as a means of providing early detection of disease, however, the veterinary profession has not been as effective in communicating the benefits of preventive measures to pet owners. Readily available pet healthcare information on the internet, owners not understanding that regular health evaluations can ensure the well-being of their pets and owners confusing the signs of chronic disease with normal aging have contributed to declining numbers of veterinary visits. The use of web-based generic health-related quality of life (HRQL) measures to evaluate health status (wellness) remotely could facilitate veterinary preventive medicine. This publication describes the development and practical application of an integrated alert system for an online generic HRQL measurement instrument (VetMetrica™) which generates scores in four domains of HRQL-Energetic/Enthusiastic (E/E), Happy/Content (H/C), Active/Comfortable (A/C), and Calm/Relaxed (C/R)-for 2 age groups (young/middle-aged, ≤7 years and old, ≥8 years). The alert provides an early warning, via email to owners, that a potentially significant deterioration in health status has occurred. The model accurately predicted the health status of 93 and 83% of sick young/middle aged and old dogs respectively, with healthy dogs predicted with 83% accuracy. HRQL data, collected via a white-labeled veterinary clinic branded app designed to facilitate connected care between owner and veterinarian, were analyzed for 6,108 dogs, aged between 6 weeks and 16 years. Of these 5,002 were deemed to be in perfect health by their owners, yet the alert was triggered for 1,343 (27%) of these, 75% of which were young/middle-aged and 25% were old, indicating that acute injuries notwithstanding, many middle aged dogs may have been suffering from undetected chronic disease such as osteoarthritis. This work has demonstrated that the use of VetMetrica™ delivered via the PetDialog™ app, which supports 24/7 remote health monitoring is an efficient way for vets to provide all their owners with the opportunity to monitor their animal's wellness throughout their lifetime, providing the vet with a mechanism to identify health problems early while stimulating owners to be more proactive in seeking veterinary attention.
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Internal combustion engines are used heavily in diverse applications worldwide. Achieving the most efficient operation is key to improving air quality as society moves to a decarbonized energy system. Insoluble deposits that form within internal combustion engine components including fuel injectors and filters negatively impact CO2 and pollutant emissions. Understanding the composition, origins, and formation mechanisms of these complex materials will be key to their mitigation however, previous attempts only afforded nondiagnostic chemical assignments and limited knowledge toward this. Here, we uncover the identity and spatial distribution of molecular species from a gasoline direct injector, diesel injector, and filter deposit in situ using a new hyphenation of secondary ion mass spectrometry and the state-of-the-art Orbitrap mass analyzer (3D OrbiSIMS) and elemental analysis. Through a high mass resolving power and tandem MS we unambiguously uncovered the identity, distribution, and origin of species including alkylbenzyl sulfonates and provide evidence of deposit formation mechanisms including formation of longer chain sulfonates at the gasoline deposit's surface as well as aromatization to form polycyclic aromatic hydrocarbons up to C66H20, which were prevalent in the lower depth of this deposit. Inorganic salts contributed significantly to the diesel injector deposit throughout its depth, suggesting contamination over multiple fueling cycles. Findings will enable several strategies to mitigate these insoluble materials such as implementing stricter worldwide fuel specifications, modifying additives with adverse reactivity, and synthesizing new fuel additives to solubilize deposits in the engine, thereby leading to less polluting vehicles.
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Using methodology previously described for the dog health-related quality of life (HRQL) tool (VetMetrica™), the aim was to optimize the scores profile of a comparable feline online HRQL instrument for monitoring HRQL in cats, to assist in its interpretation. Measuring HRQL helps quantify the impact of disease and its treatment on well-being, aids clinical decision making and provides information in clinical trials. In Study 1, using data collected from previous studies, scores generated for three domains of HRQL (Vitality, Comfort, Emotional Well-being) in healthy cats were normalized using standard statistical techniques of logit transformation and T-scores, such that the average healthy cat has a score of 50 in all three HRQL domains. Using normalized scores from healthy and sick cats, a threshold score of 44.8 was determined, above which 70% of healthy cats should score. Study 2 determined the Minimal Important Difference (MID) in normalized score that constituted a clinically significant improvement in each domain. Three methods were tested in order to determine the MID, with the final choice made based on statistical and clinical considerations. Thresholds of 5, 7.5, and 5 were chosen for the three HRQL domains representing Vitality, Comfort and Emotional Well-being, respectively. This study makes available a means of displaying HRQL scores from an online application in an easily interpretable manner and quantifies a clinically meaningful improvement in score. To illustrate the practical application of these developments, three case examples are presented. Example 1 illustrates the raw and normalized scores for a group of overweight cats enrolled in a Feline Weight Management Programme. Example 2 shows three groups of osteoarthritic cats, each with different severity of disease. The third is an elderly, un-well cat whose HRQL was recorded over time, specifically to facilitate end of life discussion between owner and veterinary clinician.
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The dentate nucleus (DN) is a gray matter structure deep in the cerebellum involved in motor coordination, sensory input integration, executive planning, language, and visuospatial function. The DN is an emerging biomarker of disease, informing studies that advance pathophysiologic understanding of neurodegenerative and related disorders. The main challenge in defining the DN radiologically is that, like many deep gray matter structures, it has poor contrast in T1-weighted magnetic resonance (MR) images and therefore requires specialized MR acquisitions for visualization. Manual tracing of the DN across multiple acquisitions is resource-intensive and does not scale well to large datasets. We describe a technique that automatically segments the DN using deep learning (DL) on common imaging sequences, such as T1-weighted, T2-weighted, and diffusion MR imaging. We trained a DL algorithm that can automatically delineate the DN and provide an estimate of its volume. The automatic segmentation achieved higher agreement to the manual labels compared to template registration, which is the current common practice in DN segmentation or multiatlas segmentation of manual labels. Across all sequences, the FA maps achieved the highest mean Dice similarity coefficient (DSC) of 0.83 compared to T1 imaging ( DSC = 0.76 ), T2 imaging ( DSC = 0.79 ), or a multisequence approach ( DSC = 0.80 ). A single atlas registration approach using the spatially unbiased atlas template of the cerebellum and brainstem template achieved a DSC of 0.23, and multi-atlas segmentation achieved a DSC of 0.33. Overall, we propose a method of delineating the DN on clinical imaging that can reproduce manual labels with higher accuracy than current atlas-based tools.
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Though alkali metal NacNac (ß-diketiminate) complexes have been utilised in synthesis as NacNac-transfer agents, studies of them in their own right with small molecules are exceptionally rare. Here, the lithium compound of the common 2,6-diisopropylphenyl-ß-methyldiketiminate [NacNac(Dipp, Me)] ligand is investigated with carbon dioxide and isocyanates. In all four cases reaction occurs at the backbone γ-C atom of the NacNac ligand, which redistributes electronically into a diimine. Insertion of CO2 gives an eight-atom carboxylate (Li2 O4 C2 ) ring at the γ-C site in a dimer. Insertion of tBuNCO gives a secondary amide at the γ-C site in a monomer with TMEDA chelating lithium. Double insertion of tBuNCO and (adventitious) oxygen gives a dimer with a (LiO)2 central core involving the latter source. Insertion of less bulky (iPrNCO) gives a dimer with dimerisation through the C=O bonds of the emergent secondary amide function.