Partial Volume Correction in Arterial Spin Labeling Perfusion MRI: A method to disentangle anatomy from physiology or an analysis step too far?

The mismatch in the spatial resolution of Arterial Spin Labeling (ASL) MRI perfusion images and the anatomy of functionally distinct tissues in the brain leads to a partial volume effect (PVE), which in turn confounds the estimation of perfusion to a specific tissue of interest such as grey or white matter. This confound occurs because the image voxels contain a mixture of tissues with disparate perfusion properties, leading to estimated perfusion values that reflect primarily the volume proportions of tissues in the voxel rather than the perfusion of any particular tissue of interest within that volume. It is already recognized that PVE influences studies of brain perfusion, and that its effect might be even more evident in studies where changes in perfusion are co-incident with alterations in brain structure, such as studies involving a comparison between an atrophic patient population vs control subjects, or studies comparing subjects over a wide range of ages. However, the application of PVE correction (PVEc) is currently limited and the employed methodologies remain inconsistent. In this article, we outline the influence of PVE in ASL measurements of perfusion, explain the main principles of PVEc, and provide a critique of the current state of the art for the use of such methods. Furthermore, we examine the current use of PVEc in perfusion studies and whether there is evidence to support its wider adoption. We conclude that there is sound theoretical motivation for the use of PVEc alongside conventional, 'uncorrected', images, and encourage such combined reporting. Methods for PVEc are now available within standard neuroimaging toolboxes, which makes our recommendation straightforward to implement. However, there is still more work to be done to establish the value of PVEc as well as the efficacy and robustness of existing PVEc methods

Paper and electronic versions of HM-PRO, a novel patient-reported outcome measure for hematology: an equivalence study.

© 2019 Goswami, Oliva, Ionova et al.Aim:To determine measurement equivalence of paper and electronic application of the hematologi-cal malignancy-patient-reported outcome (HM-PRO), a specific measure for the evaluation of patient-reported outcomes in HMs.Patients & methods:Following International Society of Pharmacoeconomicsand Outcomes Research ePRO Good Research Practice Task Force guidelines, a total of 193 adult patientswith different HMs were recruited into a multicenter prospective study. The paper and the electronic ver-sion of the instrument were completed in the outpatient clinics in a randomized crossover design with a30-min time interval to minimize the learning effect. Those who completed the paper version first, com-pleted the electronic version after 30 min and vice versa. Instrument version and order effects were testedon total score of the two parts of the HM-PRO (Part A: quality of life and Part B: signs & symptoms) in atwo-way ANOVA with patients as random effects. Intraclass correlation coefficients (95% CI) and Spear-man’s rank correlation coefficients were used to evaluate test–retest reliability and reproducibility. Theeffects of instrument version and order were tested on total score of the two parts of HM-PRO.Results:The questionnaire version and administration order effects were not significant at the 5% level. Therewere no interactions found between these two factors for HM-PRO (Part A [quality of life]; p=0.95); and(part B [signs and symptoms]; p=0.72]. Spearman’s rank correlation coefficients were greater than 0.9, andintraclass correlation coefficients ranged from 0.94 to 0.98; furthermore, the scores were not statisticallydifferent between the two versions, showing acceptable reliability indexes. Noteworthy, the differencebetween the completion time for both paper (mean=6:38 min) and electronic version (mean=7:29 min)was not statistically significant (n=100; p=0.11). Patients did not report any difficulty in completing theelectronic version during cognitive interviews and were able to understand and respond spontaneously.Conclusion:Measurement equivalence has been demonstrated for the paper and electronic applicationof the HM-PRO.Peer reviewe

An Area‐Specific, International Community‐Led Approach to Understanding and Addressing Equality, Diversity, and Inclusion Issues within Supramolecular Chemistry

Diversity, equality, and inclusion (DEI/EDI) are pressing issues in chemistry and the natural sciences. In this Essay we share how an area‐specific approach is “calling in” the community so that it can act to address EDI issues, and support those who are marginalised. Women In Supramolecular Chemistry (WISC) is an international network that aims to support equality, diversity, and inclusion within supramolecular chemistry. WISC has taken a field‐specific approach using qualitative research methods with scientists to identify the support that is needed and the problems the supramolecular community needs to address. Herein, we present survey data from the community which highlight the barriers that are faced by those who take career breaks for any reason, a common example is maternity leave, and the importance of mentoring to aid progression post‐PhD. In conclusion, we set out an interdisciplinary and creative approach to addressing EDI issues within supramolecular chemistry

La pérdida de fitness de Acinetobacter baumannii resistente a colistina está asociada con una menor capacidad para crecer en condiciones deficientes en hierro.

Motivación: En un estudio anterior demostramos que las cepas de Acinetobacter baumannii que adquieren resistencia a colistina gracias a mutaciones en el sistema PmrAB presentan reducción in vivo del fitness y disminución de la virulencia1. El objetivo del presente estudio es caracterizar el papel del hierro libre en el fitness in vitro de estas cepas. Métodos: Se utilizaron las cepas de A. baumannii ATTCC 19606 (CMI colistina = 0,5 mg/L) y RC64, su derivado colistina-resistente obtenido mediante crecimiento en presencia de colistina (CMI colistina = 64 mg/L)2. Se realizaron curvas de crecimiento durante 24 horas en Mueller Hinton Broth (MHB) y suero humano (SH). Posteriormente, se determinó el crecimiento en Mueller Hinton Agar (MHA) con o sin el quelante de hierro 2,2'-bipiridil (Bip) mediante el cultivo en gotas de concentraciones decrecientes de las cepas (de 8 a 3 Log10 UFC/mL). Además, se determinó la CMI de Bip para ambas cepas, así como la concentración de hierro necesaria para permitir el crecimiento en SH. Por último, se caracterizó el crecimiento de ambas cepas en SH suplementado con Fe2+. Resultados: Ambas cepas presentaron un crecimiento similar al ser cultivadas en MHB; sin embargo, en SH la cepa RC64 mostró un crecimiento reducido. Adicionalmente, RC64 presentó un menor crecimiento en comparación con ATCC 19606 en placas de MHA suplementadas con Bip; sin embargo, cuando se crecieron en MHA sin Bip el crecimiento fue similar. La CMI de Bip en MHB fue de 64 mg/L para la cepa ATCC 19606 y 32 mg/L para RC64. Cuando se suplementó el SH con Fe2+, ATCC 19606 creció sin necesidad de dicho suplemento, mientras que RC64 requirió la adición de 0,5 mg/L de Fe2+. La cepa RC64 presentó una mayor tasa de crecimiento en SH suplementado con Fe2+ en comparación con su crecimiento en SH no suplementado. Conclusiones: La pérdida de fitness y virulencia en Acinetobacter baumannii asociada a la resistencia a colistina adquirida por mutaciones en el sistema PmrAB podría estar relacionada con una menor capacidad para crecer en condiciones pobres en hierro libre

Patterns of analgesic use, pain and self-efficacy: a cross-sectional study of patients attending a hospital rheumatology clinic

Background: Many people attending rheumatology clinics use analgesics and non-steroidal anti-inflammatories for persistent musculoskeletal pain. Guidelines for pain management recommend regular and pre-emptive use of analgesics to reduce the impact of pain. Clinical experience indicates that analgesics are often not used in this way. Studies exploring use of analgesics in arthritis have historically measured adherence to such medication. Here we examine patterns of analgesic use and their relationships to pain, self-efficacy and demographic factors. Methods: Consecutive patients were approached in a hospital rheumatology out-patient clinic. Pattern of analgesic use was assessed by response to statements such as 'I always take my tablets every day.' Pain and self-efficacy (SE) were measured using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and Arthritis Self-Efficacy Scale (ASES). Influence of factors on pain level and regularity of analgesic use were investigated using linear regression. Differences in pain between those agreeing and disagreeing with statements regarding analgesic use were assessed using t-tests. Results: 218 patients (85% of attendees) completed the study. Six (2.8%) patients reported no current pain, 26 (12.3%) slight, 100 (47.4%) moderate, 62 (29.4%) severe and 17 (8.1%) extreme pain. In multiple linear regression self efficacy and regularity of analgesic use were significant (p < 0.01) with lower self efficacy and more regular use of analgesics associated with more pain. Low SE was associated with greater pain: 40 (41.7%) people with low SE reported severe pain versus 22 (18.3%) people with high SE, p < 0.001. Patients in greater pain were significantly more likely to take analgesics regularly; 13 (77%) of those in extreme pain reported always taking their analgesics every day, versus 9 (35%) in slight pain. Many patients, including 46% of those in severe pain, adjusted analgesic use to current pain level. In simple linear regression, pain was the only variable significantly associated with regularity of analgesic use: higher levels of pain corresponded to more regular analgesic use (p = 0.003). Conclusion: Our study confirms that there is a strong inverse relationship between self-efficacy and pain severity. Analgesics are often used irregularly by people with arthritis, including some reporting severe pain

Development of a Novel Hematological Malignancy Specific Patient-Reported Outcome Measure (HM-PRO) : Content Validity

Copyright © 2020 Goswami, Oliva, Ionova, Else, Kell, Fielding, Jennings, Karakantza, Al-Ismail, Collins, McConnell, Langton and Salek.Background: The quality of life of patients at all stages of hematological malignancy is greatly affected by the disease and its treatment. There is a wide range of health-related quality of life (HRQoL) issues important to these patients. Any new instrument developed to measure HRQoL of such patients should be content valid, i.e., the items should be comprehensively relevant to the patients and their health condition. The aim of the present study was to examine content validity of a hematological malignancy specific patient reported outcome measure (HM-PRO) developed for use in routine clinical practice. Methods: Following literature review and semi-structured interviews, the generated themes and sub-themes were discussed to develop the prototype version of the HM-PRO. A 4-step approach was used for content validation: initial testing and cognitive interviewing; item rating; content validity panel meeting; final field testing and cognitive interviewing. Additional questions related to patients' perception of recall period and preferred sentence structure (i.e., question or statement) of the items were also asked during cognitive interviews. Results: The content analysis of 129 transcribed semi-structured interviews resulted in the prototype version of the instrument consisting of 58 items grouped into two parts: Part A (impact/HRQoL - 34 items) and Part B (signs and symptoms - 24 items). The initial testing showed intra-class correlation coefficient (ICC) of >0.8 for both Part A and Part B. Item rating for language clarity, completeness, relevance, and response scale by experts and patients showed content validity index for scales average >0.8 for both Part A and Part B, except 0.64 for relevance for Part A by the patient panel. The final testing of the revised version of the instrument showed the Cronbach's alpha value of 0.91 for Part A and 0.76 for Part B, suggesting high internal consistency, and ICC of 0.91 for Part A and 0.76 for Part B. The recall period of "today" for Part-A and "last 3 days" for Part-B were the patients' preferred "recall period." Furthermore, the patients expressed preference to the HM-PRO items as statements. Conclusion: The findings of this study confirm that the HM-PRO possesses a strong content validity, includes all the issues important to patients and is easy to read, understand and respond to spontaneously.Peer reviewedFinal Published versio

Role of Fibronectin in the Adhesion of Acinetobacter baumannii to Host Cells

Adhesion to host cells is an initial and important step in Acinetobacter baumannii pathogenesis. However, there is relatively little information on the mechanisms by which A. baumannii binds to and interacts with host cells. Adherence to extracellular matrix proteins, such as fibronectin, affords pathogens with a mechanism to invade epithelial cells. Here, we found that A. baumannii adheres more avidly to immobilized fibronectin than to control protein. Free fibronectin used as a competitor resulted in dose-dependent decreased binding of A. baumannii to fibronectin. Three outer membrane preparations (OMPs) were identified as fibronectin binding proteins (FBPs): OMPA, TonB-dependent copper receptor, and 34 kDa OMP. Moreover, we demonstrated that fibronectin inhibition and neutralization by specific antibody prevented significantly the adhesion of A. baumannii to human lung epithelial cells (A549 cells). Similarly, A. baumannii OMPA neutralization by specific antibody decreased significantly the adhesion of A. baumannii to A549 cells. These data indicate that FBPs are key adhesins that mediate binding of A. baumannii to human lung epithelial cells through interaction with fibronectin on the surface of these host cells

Synchrotron tomography of intervertebral disc deformation quantified by digital volume correlation reveals microstructural influence on strain patterns

The intervertebral disc (IVD) has a complex and multiscale extracellular matrix structure which provides unique mechanical properties to withstand physiological loading. Low back pain has been linked to degeneration of the disc but reparative treatments are not currently available. Characterising the disc’s 3D microstructure and its response in a physiologically relevant loading environment is required to improve understanding of degeneration and to develop new reparative treatments. In this study, techniques for imaging the native IVD, measuring internal deformation and mapping volumetric strain were applied to an in situ compressed ex vivo rat lumbar spine segment. Synchrotron X-ray micro-tomography (synchrotron CT) was used to resolve IVD structures at microscale resolution. These image data enabled 3D quantification of collagen bundle orientation and measurement of local displacement in the annulus fibrosus between sequential scans using digital volume correlation (DVC). The volumetric strain mapped from synchrotron CT provided a detailed insight into the micromechanics of native IVD tissue. The DVC findings showed that there was no slipping at lamella boundaries, and local strain patterns were of a similar distribution to the previously reported elastic network with some heterogeneous areas and maximum strain direction aligned with bundle orientation, suggesting bundle stretching and sliding. This method has the potential to bridge the gap between measures of macro-mechanical properties and the local 3D micro-mechanical environment experienced by cells. This is the first evaluation of strain at the micro scale level in the intact IVD and provides a quantitative framework for future IVD degeneration mechanics studies and testing of tissue engineered IVD replacements

Enhanced Protection against Ebola Virus Mediated by an Improved Adenovirus-Based Vaccine

Jason S. Richardson is with the Public Health Agency of Canada, Michel K. Yao is with the Public Health Agency of Canada, Kaylie N. Tran is with the Public Health Agency of Canada and University of Manitoba, Maria A. Croyle is with UT Austin, James E. Strong is with the Public Health Agency of Canada and University of Manitoba, Heinz Feldmann is with the Public Health Agency of Canada and University of Manitoba, Gary P. Kobinger is with the Public Health Agency of Canada and University of Manitoba.Background -- The Ebola virus is transmitted by direct contact with bodily fluids of infected individuals, eliciting death rates as high as 90% among infected humans. Currently, replication defective adenovirus-based Ebola vaccine is being studied in a phase I clinical trial. Another Ebola vaccine, based on an attenuated vesicular stomatitis virus has shown efficacy in post-exposure treatment of nonhuman primates to Ebola infection. In this report, we modified the common recombinant adenovirus serotype 5-based Ebola vaccine expressing the wild-type ZEBOV glycoprotein sequence from a CMV promoter (Ad-CMVZGP). The immune response elicited by this improved expression cassette vector (Ad-CAGoptZGP) and its ability to afford protection against lethal ZEBOV challenge in mice was compared to the standard Ad-CMVZGP vector. Methodology/Principal Findings -- Ad-CMVZGP was previously shown to protect mice, guinea pigs and nonhuman primates from an otherwise lethal challenge of Zaire ebolavirus. The antigenic expression cassette of this vector was improved through codon optimization, inclusion of a consensus Kozak sequence and reconfiguration of a CAG promoter (Ad-CAGoptZGP). Expression of GP from Ad-CAGoptZGP was substantially higher than from Ad-CMVZGP. Ad-CAGoptZGP significantly improved T and B cell responses at doses 10 to 100-fold lower than that needed with Ad-CMVZGP. Additionally, Ad-CAGoptZGP afforded full protections in mice against lethal challenge at a dose 100 times lower than the dose required for Ad-CMVZGP. Finally, Ad-CAGoptZGP induced full protection to mice when given 30 minutes post-challenge. Conclusions/Significance -- We describe an improved adenovirus-based Ebola vaccine capable of affording post-exposure protection against lethal challenge in mice. The molecular modifications of the new improved vaccine also translated in the induction of significantly enhanced immune responses and complete protection at a dose 100 times lower than with the previous generation adenovirus-based Ebola vaccine. Understanding and improving the molecular components of adenovirus-based vaccines can produce potent, optimized product, useful for vaccination and post-exposure therapy.Financial support was received from the following sources: The Public Health Agency of Canada and the Chemical, Biological, Radiological or Nuclear Research and Technology Initiative (grant #CRTI-06-0218RD awarded to GPK). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Pharmac