The acute vapour inhalation toxicity of 2-butoxyethanol. Points considered when designing and conducting a study in Guinea pigs and evaluating existing inhalation toxicity data on low volatility solvents.

This publication reports the outcome of an acute inhalation toxicity study with guinea pigs by nose-only exposure to the substance 2-butoxyethanol at exposures close to the maximum attainable saturation vapour concentration. We describe the methods used to ensure exposure only to saturation vapour at a level as high as could be practically achieved whilst avoiding aerosol formation. We consider the practical difficulties and implications of testing substances at or close to their saturation vapour concentration and the criteria that should be used to critically assess such studies, especially with reference to the GHS (Globally Harmonised System) for classification and labelling, where a clear differentiation between gases, vapours and dust and mists applies. Guinea pigs showed no adverse effects when exposed for 4 h to the maximum attainable concentration of pure 2-butoxyethanol vapour. If guinea pigs are regarded as the most appropriate species to assess short term toxicity to humans from exposure to 2-butoxyethanol, because they are like humans not sensitive to haemolysis of red blood cells caused by exposure to the substance, then the data from this study shows that 2-butoxyethanol presents a low acute inhalation toxicity hazard.

Affect labelling increases the intensity of positive emotions.

Although affect labelling has been widely reported to decrease negative emotions, it is less clear whether affect labelling also decreases positive emotions. In four studies, we explored how affect labelling (choosing the emotion that best corresponds with the image), content labelling (choosing the word that best corresponds with the content of the image), and simply viewing images influence positive and negative emotions. Labelling positive emotions led participants to report higher positive emotional intensity than did content labelling or just viewing the image (Study 1, N = 49), and this effect persisted regardless of whether they labelled emotions during or after the image (Study 2, N = 116), rated the intensity or positivity of their emotions (Study 3, N = 120), or rated their emotions after a delay or no delay (Study 4, N = 120). Surprisingly, we did not replicate the previous findings on affect labelling and negative emotion, instead showing that content labelling of negative emotional images tended to be the most consistent predictor of decreased negative emotions. Our results challenge the formulation that affect labelling leads to the automatic downregulation of emotions and instead suggest that it might be an effective mechanism in the upregulation of positive emotions.

Intraoperative ketamine for prevention of postoperative delirium or pain after major surgery in older adults: an international, multicentre, double-blind, randomised clinical trial.

BACKGROUND: Delirium is a common and serious postoperative complication. Subanaesthetic ketamine is often administered intraoperatively for postoperative analgesia, and some evidence suggests that ketamine prevents delirium. The primary purpose of this trial was to assess the effectiveness of ketamine for prevention of postoperative delirium in older adults. METHODS: The Prevention of Delirium and Complications Associated with Surgical Treatments [PODCAST] study is a multicentre, international randomised trial that enrolled adults older than 60 years undergoing major cardiac and non-cardiac surgery under general anaesthesia. Using a computer-generated randomisation sequence we randomly assigned patients to one of three groups in blocks of 15 to receive placebo (normal saline), low-dose ketamine (0·5 mg/kg), or high dose ketamine (1·0 mg/kg) after induction of anaesthesia, before surgical incision. Participants, clinicians, and investigators were blinded to group assignment. Delirium was assessed twice daily in the first 3 postoperative days using the Confusion Assessment Method. We did analyses by intention-to-treat and assessed adverse events. This trial is registered with clinicaltrials.gov, number NCT01690988. FINDINGS: Between Feb 6, 2014, and June 26, 2016, 1360 patients were assessed, and 672 were randomly assigned, with 222 in the placebo group, 227 in the 0·5 mg/kg ketamine group, and 223 in the 1·0 mg/kg ketamine group. There was no difference in delirium incidence between patients in the combined ketamine groups and the placebo group (19·45% vs 19·82%, respectively; absolute difference 0·36%, 95% CI -6·07 to 7·38, p=0·92). There were more postoperative hallucinations (p=0·01) and nightmares (p=0·03) with increasing ketamine doses compared with placebo. Adverse events (cardiovascular, renal, infectious, gastrointestinal, and bleeding), whether viewed individually (p value for each >0·40) or collectively (36·9% in placebo, 39·6% in 0·5 mg/kg ketamine, and 40·8% in 1·0 mg/kg ketamine groups, p=0·69), did not differ significantly across groups. INTERPRETATION: A single subanaesthetic dose of ketamine did not decrease delirium in older adults after major surgery, and might cause harm by inducing negative experiences. FUNDING: National Institutes of Health and Cancer Center Support.

Comorbidity scores associated with limited life expectancy in the very elderly with nonmelanoma skin cancer.

BACKGROUND: There is controversy regarding treatment of nonmelanoma skin cancer (NMSC) in very elderly individuals, with some suggesting that this population may not live long enough to benefit from invasive treatments. Tools to assess limited life expectancy (LLE) exist, but performance in the population of very elderly individuals with NMSC has not been well defined. OBJECTIVE: Define comorbidity scores associated with LLE in very elderly individuals presenting for management of NMSC. METHODS: A retrospective review of 488 patients age 85 or older presenting for NMSC management between July 1999 through December 2014 was performed. Comorbidities were scored by using the Adult Comorbidity Evaluation-27 (ACE-27) and age-adjusted Charlson comorbidity index (ACCI). Dates of death, follow-up, and overall survival were determined. RESULTS: ACE-27 and ACCI scores were associated with overall survival; at scores of 3 and 7+, respectively, both were associated with less than 50% survival at 4 years. Patients who underwent Mohs micrographic surgery survived a median of 20 months longer than patients who did not. LIMITATIONS: Retrospective study design and referral bias. CONCLUSIONS: ACE-27 and ACCI scores predicted LLE. The cohort presenting for Mohs micrographic surgery had improved survival, despite similar intercohort comorbidity. This suggests that additional factors contributed to survival and that age and comorbidities alone are inadequate for making NMSC treatment decisions in very elderly individuals.

Quality Control in Human Adipose-Derived Stromal/Stem Cells and Tissue Engineering Fat Models for Aging Studies.

Adipose tissue is recognized not only as an endocrine organ but also as a reservoir for adipose-derived stromal/stem cells (ASCs). ASCs have stimulated the interest of both the scientific and medical communities due to their therapeutic potential and applications in tissue engineering and regenerative medicine. ASCs are leveraged for their multipotency and their paracrine function. ASC behavior is highly variable and donor dependent. Donor age, body mass index, disease status, sex, and ethnicity can lead to differential overall function and quality. The impact of donor age and passage on ASC behavior has been well documented, impacting cell proliferation and differentiation potential and thus must be taken into careful consideration when conducting in vitro studies. Pooling of ASCs from different donors reduces heterogeneity among individual donors and produces ASCs with a consistent differentiation and paracrine profiles, an advantage for studies in biological aging. This chapter provides a detailed overview for studies related to quality control for ASC pools considering biological and chronological aging in ASCs. There are hallmarks of biological aging and specific assays associated with the evaluation of each hallmark. Nevertheless, here we present the assays that provide a standardized characterization and qualification of donor pools for their regenerative potential, considering chronological and biological age of the pool. The assays included in this chapter are considered quality control standards to evaluate cell proliferation, differentiation, colony-forming units, and cellular senescence from different donor age and cell passage cohorts.

Functional Assays in 3D ObaCell® Fat-on-a-Chip Cultures: Lipolysis and Glucose Uptake Assays.

Advancements in three-dimensional in vitro cultures pose a need for modification of established two-dimensional culture functional assay methods. Application of three-dimensional in vitro models in drug screening and target validation, specifically in the development of compounds targeting adipose metabolic activity, requires optimization of current glucose uptake and lipolysis assay protocols to effectively measure adipocyte function in a three-dimensional platform. This chapter describes the establishment of three-dimensional cultures using Obatala Sciences' human-derived hydrogel, maintenance and treatment of the cultures, and evaluation of compound response via lipolysis and glucose uptake assays.

The importance of the patient's perspective in decision-making in multiple sclerosis: Results of the OwnMS patient perspectives study.

BACKGROUND: Research is needed to identify the unmet disease education and communication needs of people with multiple sclerosis (PwMS) to support informed decision-making, enable self-management and maintain independence for PwMS for as long as possible. METHODS: An Expert Steering Group co-developed two studies for PwMS aged 18 years and over: a qualitative, online, patient community activity and a quantitative anonymised online survey. The quantitative survey was conducted in the UK from 12 September 2019 to 18 November 2019 amongst PwMS recruited via the Multiple Sclerosis (MS) Trust newsletter and their closed Facebook group. Questions explored the goals, desires, and knowledge gaps of PwMS. Self-reported data from people with relapsing-remitting multiple sclerosis (RRMS) were collated and reviewed, and discussed by the Steering Group. This paper presents descriptive statistics of the quantitative survey findings. RESULTS: The sample consisted of 117 participants with RRMS. Most respondents (73%) had personal goals related to lifestyle and many (69%) were concerned about maintaining independence. More than half of respondents were worried about planning for the future in relation to income (56%), housing (40%) and most respondents also indicated MS had a negative impact on their lives, including their work life (73%) and social life (69%). Limited occupational support was forthcoming (17% were not provided with any support and only 27% report their work environment being adjusted to suit their needs). The ability to plan for the future and to understand the course of MS were highlighted as key priorities by respondents. A positive trend was observed between those who felt able to plan for the future and their knowledge of MS progression. The proportion of patients who report knowing a 'great deal' about MS prognosis and disability progression was low (16% and 9%, respectively), suggesting an increased role for clinical teams to provide information and education for PwMS. Communication between respondents and their clinical teams highlighted the role of specialist nurses for PwMS to provide holistic, informative support and demonstrated the level of comfort that PwMS have in discussing less clinical topics with these providers. CONCLUSION: This UK nationwide survey highlighted some of the unmet needs in disease education and communication in a subgroup of UK patients with RRMS, which can impact quality of life. Discussing goals and planning alongside prognosis and disability progression with MS care teams may enable people with RRMS not only to make informed treatment decisions, but also to self-manage and plan for the future, factors which are important to maintain independence.

Acceptability and playability of an organization training videogame for young adolescents with ADHD: The development of ATHEMOS.

An estimated 8.7% to 9.8% of school-age children in the United States have attention deficit hyperactivity disorder (ADHD), affecting 4.3 to 4.9 million public school students. ADHD is a costly disorder that often goes untreated, especially among adolescents. Accessible computer-based programs have emerged to address the neurocognitive deficits of ADHD, but results to date have been disappointing. In this study, we tested the acceptability, playability, and user satisfaction of a novel planning/organization skills training game, called "ATHEMOS," based on an established psychosocial treatment package (i.e., Challenging Horizons Program). We conducted eight focus groups during a three-year development period, using feedback from 72 young adolescents with ADHD to iteratively improve the game. Then, during a pilot study in the fourth year, we collected data from 16 young adolescents who played the game as part of a 6- to 16-week school-based intervention. Our findings suggest that the serious game resulted in acceptability and playability ratings only moderately below that of recreational games (δ = -0.40). Critically, average perceptions remained positive when delivered within a school-based ADHD intervention over several weeks or months, with strong overall user satisfaction. Boys found the game more acceptable than girls, with ratings near that of recreational games (δ = -0.23). We conclude that computer-assisted behavior interventions appeal to adolescents with ADHD and offer a potentially promising treatment delivery method in schools.

Biomechanical and Biological Characterization of XGel, a Human-Derived Hydrogel for Stem Cell Expansion and Tissue Engineering.

Hydrogels are 3D scaffolds used as alternatives to in vivo models for disease modeling and delivery of cells and drugs. Existing hydrogel classifications include synthetic, recombinant, chemically defined, plant- or animal-based, and tissue-derived matrices. There is a need for materials that can support both human tissue modeling and clinically relevant applications requiring stiffness tunability. Human-derived hydrogels are not only clinically relevant, but they also minimize the use of animal models for pre-clinical studies. This study aims to characterize XGel, a new human-derived hydrogel as an alternative to current murine-derived and synthetic recombinant hydrogels that features unique physiochemical, biochemical, and biological properties that support adipocyte and bone differentiation. Rheology studies determine the viscosity, stiffness, and gelation features of XGel. Quantitative studies for quality control support consistency in the protein content between lots. Proteomics studies reveal that XGel is predominantly composed of extracellular matrix proteins, including fibrillin, collagens I-VI, and fibronectin. Electron microscopy of the hydrogel provides phenotypic characteristics in terms of porosity and fiber size. The hydrogel demonstrates biocompatibility as a coating material and as a 3D scaffold for the growth of multiple cell types. The results provide insight into the biological compatibility of this human-derived hydrogel for tissue engineering.

Exploring barriers to living donor kidney transplant for African, Caribbean and Black communities in the Greater Toronto Area, Ontario: a qualitative study protocol.

INTRODUCTION: Living donor (LD) kidney transplant (KT) is the best treatment option for many patients with kidney failure as it improves quality of life and survival compared with dialysis and deceased donor KT. Unfortunately, LDKT is underused, especially among groups marginalised by race and ethnicity. African, Caribbean and Black (ACB) patients are 60%-70% less likely to receive LDKT in Canada compared with white patients. Research from the USA and the UK suggests that mistrust, cultural and generational norms, access, and affordability may contribute to inequities. To date, no Canadian studies have explored the beliefs and behaviours related to LDKT in ACB communities. Research approaches that use a critical, community-based approach can help illuminate broader structural factors that may shape individual beliefs and behaviours. In this qualitative study, we will investigate barriers to accessing LDKT in ACB communities in the Greater Toronto Area, to enhance our understanding of the perspectives and experiences of ACB community members, both with and without lived experience of chronic kidney disease (CKD). METHODS AND ANALYSIS: Hospital-based and community-based recruitment strategies will be used to recruit participants for focus groups and individual interviews. Participants will include self-identified ACB individuals with and without experiences of CKD and nephrology professionals. Collaboration with ACB community partners will facilitate a community-based research approach. Data will be analysed using reflexive thematic analysis and critical race theory. Findings will be revised based on feedback from ACB community partners. ETHICS AND DISSEMINATION: This study has been approved by the University Health Network Research Ethics Board UHN REB file #15-9775. Study findings will contribute to the codevelopment of culturally safe and responsive educational materials to raise awareness about CKD and its treatments and to improve equitable access to high-quality kidney care, including LDKT, for ACB patients.

Pretransplant Patient Education in Solid-organ Transplant: A Narrative Review.

Education for pretransplant, solid-organ recipient candidates aims to improve knowledge and understanding about the transplant process, outcomes, and potential complications to support informed, shared decision-making to reduce fears and anxieties about transplant, inform expectations, and facilitate adjustment to posttransplant life. In this review, we summarize novel pretransplant initiatives and approaches to educate solid-organ transplant recipient candidates. First, we review approaches that may be common to all solid-organ transplants, then we summarize interventions specific to kidney, liver, lung, and heart transplant. We describe evidence that emphasizes the need for multidisciplinary approaches to transplant education. We also summarize initiatives that consider online (eHealth) and mobile (mHealth) solutions. Finally, we highlight education initiatives that support racialized or otherwise marginalized communities to improve equitable access to solid-organ transplant. A considerable amount of work has been done in solid-organ transplant since the early 2000s with promising results. However, many studies on education for pretransplant recipient candidates involve relatively small samples and nonrandomized designs and focus on short-term surrogate outcomes. Overall, many of these studies have a high risk of bias. Frequently, interventions assessed are not well characterized or they are combined with administrative and data-driven initiatives into multifaceted interventions, which makes it difficult to assess the impact of the education component on outcomes. In the future, well-designed studies rigorously assessing well-defined surrogate and clinical outcomes will be needed to evaluate the impact of many promising initiatives.

Examining Benchmarks for the Daily Report Card Intervention in a Therapeutic Recreational Setting.

OBJECTIVE: This study aimed to (1) examine benchmarks for the benefits of the Daily Report Card (DRC) within a therapeutic recreation setting, that is, the Summer Treatment Program (STP) and (2) explore differences in baseline characteristics and treatment outcomes among optimal and suboptimal responders. Benchmarks were examined for children's DRC target behaviors using standardized mean difference (SMD) effect sizes (ES) across 2-week periods of the STP. METHOD: Participants were 38 children attending an STP. RESULTS: Aside from teasing, all DRC targets showed improvement by the second 2-week period that was sustained through the third 2-week period. Optimal responders demonstrated greater improvement in parent-rated impairment and camp behaviors than suboptimal responders. Some baseline differences between responder groups were found. CONCLUSION: This study provides the first benchmarks for change in DRC targets within a therapeutic recreational setting, offering guidelines for treatment expectations. Implications for clinical decision-making, treatment planning, and future research are discussed.

Non-homologous use of adipose-derived cell and tissue therapies: Osteoarthritis as a case study.

Adipose tissue is widely recognized as an abundant and accessible human tissue that serves as a source of cells and extracellular matrix scaffolds for regenerative surgical applications. Increasingly, orthopedic surgeons are turning to adipose tissue as a resource in their treatment of osteoarthritis and related conditions. In the U.S., the regulatory landscape governing the orthopedic surgical utilization of autologous and allogeneic adipose tissue remains complex. This manuscript reviews the Food and Drug Administration's nomenclature and guidance regarding adipose tissue products. Additionally, it surveys recent pre-clinical and clinical trial literature relating to the application of adipose-derived cells and tissues in the treatment of osteoarthritis.

Validating clinical practice guidelines for the management of febrile infants presenting to the emergency department in the UK and Ireland.

OBJECTIVE: To report the performance of clinical practice guidelines (CPG) in the diagnosis of serious/invasive bacterial infections (SBI/IBI) in infants presenting with a fever to emergency care in the UK and Ireland. Two CPGs were from the National Institutes for Health and Care Excellence (NICE guidelines NG51 and NG143) and one was from the British Society for Antimicrobial Chemotherapy (BSAC). DESIGN: Retrospective multicentre cohort study. PATIENTS: Febrile infants aged 90 days or less attending between the 31 August 2018 to 1 September 2019. MAIN OUTCOME MEASURES: The sensitivity, specificity and predictive values of CPGs in identifying SBI and IBI. SETTING: Six paediatric Emergency Departments in the UK/Ireland. RESULTS: 555 participants were included in the analysis. The median age was 53 days (IQR 32 to 70), 447 (81%) underwent blood testing and 421 (76%) received parenteral antibiotics. There were five participants with bacterial meningitis (1%), seven with bacteraemia (1%) and 66 (12%) with urinary tract infections. The NICE NG51 CPG was the most sensitive: 1.00 (95% CI 0.95 to 1.00). This was significantly more sensitive than NICE NG143: 0.91 (95% CI 0.82 to 0.96, p=0.0233) and BSAC: 0.82 (95% 0.72 to 0.90, p=0.0005). NICE NG51 was the least specific 0.0 (95% CI 0.0 to 0.01), and this was significantly lower than the NICE NG143: 0.09 (95% CI 0.07 to 0.12, p<0.0001) and BSAC: 0.14 (95% CI 0.1 to 0.17, p<0.0001). CONCLUSION: None of the studied CPGs demonstrated ideal performance characteristics. CPGs should be improved to guide initial clinical decision making. TRIAL REGISTRATION NUMBER: NCT04196192.

Adipose-derived cells: building blocks of three-dimensional microphysiological systems.

Microphysiological systems (MPS) created with human-derived cells and biomaterial scaffolds offer a potential in vitro alternative to in vivo animal models. The adoption of three-dimensional MPS models has economic, ethical, regulatory, and scientific implications for the fields of regenerative medicine, metabolism/obesity, oncology, and pharmaceutical drug discovery. Key opinion leaders acknowledge that MPS tools are uniquely positioned to aid in the objective to reduce, refine, and eventually replace animal experimentation while improving the accuracy of the finding's clinical translation. Adipose tissue has proven to be an accessible and available source of human-derived stromal vascular fraction (SVF) cells, a heterogeneous population available at point of care, and adipose-derived stromal/stem cells, a relatively homogeneous population requiring plastic adherence and culture expansion of the SVF cells. The adipose-derived stromal/stem cells or SVF cells, in combination with human tissue or synthetic biomaterial scaffolds, can be maintained for extended culture periods as three-dimensional MPS models under angiogenic, stromal, adipogenic, or osteogenic conditions. This review highlights recent literature relating to the versatile use of adipose-derived cells as fundamental components of three-dimensional MPS models for discovery research and development. In this context, it compares the merits and limitations of the adipose-derived stromal/stem cells relative to SVF cell models and considers the likely directions that this emerging field of scientific discovery will take in the near future.

Human Adipose-Derived Stromal/Stem Cell Culture and Analysis Methods for Adipose Tissue Modeling In Vitro: A Systematic Review.

Human adipose-derived stromal/stem cells (hASC) are widely used for in vitro modeling of physiologically relevant human adipose tissue. These models are useful for the development of tissue constructs for soft tissue regeneration and 3-dimensional (3D) microphysiological systems (MPS) for drug discovery. In this systematic review, we report on the current state of hASC culture and assessment methods for adipose tissue engineering using 3D MPS. Our search efforts resulted in the identification of 184 independent records, of which 27 were determined to be most relevant to the goals of the present review. Our results demonstrate a lack of consensus on methods for hASC culture and assessment for the production of physiologically relevant in vitro models of human adipose tissue. Few studies have assessed the impact of different 3D culture conditions on hASC adipogenesis. Additionally, there has been a limited use of assays for characterizing the functionality of adipose tissue in vitro. Results from this study suggest the need for more standardized culture methods and further analysis on in vitro tissue functionality. These will be necessary to validate the utility of 3D MPS as an in vitro model to reduce, refine, and replace in vivo experiments in the drug discovery regulatory process.

Histology Scoring System for Murine Cutaneous Wounds.

Monitoring wound progression over time is a critical aspect for studies focused on in-depth molecular analysis or on evaluating the efficacy of potential novel therapies. Histopathological analysis of wound biopsies can provide significant insight into healing dynamics, yet there is no standardized and reproducible scoring system currently available. The purpose of this study was to develop and statistically validate a scoring system based on parameters in each phase of healing that can be easily and accurately assessed using either Hematoxylin & Eosin (H&E) or Masson's Trichrome (MT) staining. These parameters included re-epithelization, epithelial thickness index, keratinization, granulation tissue thickness, remodeling, and the scar elevation index. The initial phase of the study was to (1) optimize and clarify healing parameters to limit investigator bias and variability; (2) compare the consistency of parameters assessed using H&E versus MT staining. During the validation phase of this study, the accuracy and reproducibility of this scoring system was independently iterated upon and validated in four different types of murine skin wound models (Excisional; punch biopsy; pressure ulcers; burn wounds). A total of n = 54 histology sections were randomized, blinded, and assigned to two groups of independent investigators (n = 5 per group) for analysis. The sensitivity of each parameter (ranging between 80% and 95%) is reported with illustrations on the appropriate assessment method using ImageJ software. In the validated scoring system, the lowest score (score:0) is associated with an open/unhealed wound as is evident immediately and within the first day postinjury, whereas the highest score (score:12) is associated with a completely closed and healed wound without excessive scarring. This study defines and describes the minimum recommended criteria for assessing wound healing dynamics using the SPOT skin wound score. The acronym SPOT refers to the academic and scientific institutions that were involved in the development of the scoring system, namely, Stellenbosch University, Polish Academy of Sciences, Obatala Sciences, and the University of Texas Southwestern.

Breast Cancer Reconstruction: Design Criteria for a Humanized Microphysiological System.

International regulatory agencies such as the Food and Drug Administration have mandated that the scientific community develop humanized microphysiological systems (MPS) as an in vitro alternative to animal models in the near future. While the breast cancer research community has long appreciated the importance of three-dimensional growth dynamics in their experimental models, there are remaining obstacles preventing a full conversion to humanized MPS for drug discovery and pathophysiological studies. This perspective evaluates the current status of human tissue-derived cells and scaffolds as building blocks for an "idealized" breast cancer MPS based on bioengineering design principles. It considers the utility of adipose tissue as a potential source of endothelial, lymphohematopoietic, and stromal cells for the support of breast cancer epithelial cells. The relative merits of potential MPS scaffolds derived from adipose tissue, blood components, and synthetic biomaterials is evaluated relative to the current "gold standard" material, Matrigel, a murine chondrosarcoma-derived basement membrane-enriched hydrogel. The advantages and limitations of a humanized breast cancer MPS are discussed in the context of in-process and destructive read-out assays. Impact statement Regulatory authorities have highlighted microphysiological systems as an emerging tool in breast cancer research. This has been led by calls for more predictive human models and reduced animal experimentation. This perspective describes how human-derived cells, extracellular matrices, and hydrogels will provide the building blocks to create breast cancer models that accurately reflect diversity at multiple levels, that is, patient ethnicity, pathophysiology, and metabolic status.

Modification and implications of changes in electrochemical responses encountered when undertaking deoxygenation in ionic liquids.

Physicochemical changes and substantially modified electrochemical behavior have been reported when ionic liquids are degassed with nitrogen. In conventional experiments in aqueous and organic media, degassing with N(2) is commonly used to remove the electroactive dissolved oxygen. However, in hydrophilic ionic liquid media, degassing with N(2) removes not only the dissolved oxygen but also a significant amount of the adventitious water present. Given the low viscosity of water, this in turn leads to a dramatic change of the viscosity of the degassed ionic liquid and hence mass transport properties that influence voltammetric responses. In the widely used and relatively viscous room temperature ionic liquid, 1-n-butyl-3-methylimidazolium tetrafluoroborate (BMIMBF(4)) containing the redox probe tetracyanoquinodimethane (TCNQ) and 9% (v/v) deliberately added water, 1 h degassing with very dry N(2) under benchtop conditions results in a dramatic decrease of the TCNQ reduction current obtained under steady-state conditions at a 1 mum diameter microdisc electrode. This is reflected by a change of diffusion coefficient of TCNQ (D(TCNQ)) from 2.6 x 10(-7) to 4.6 x 10(-8) cm(2) s(-1). Karl Fischer titration measurements show that almost complete removal of the deliberately added 9% water is achieved by degassing under benchtop conditions. However, displacement of oxygen by nitrogen in the ionic liquid solution results in the decrease of electrochemical reduction current by 6%, implying that dissolved gases need not be inert with respect to solvent properties. Oxygen removal by placing the BMIMBF(4) ionic liquid in a nitrogen-filled glovebox or in a vacuum cell also simultaneously leads to removal of water and alteration of voltammetric data. This study highlights that (i) important physicochemical differences may arise upon addition or removal of a solute from viscous ionic liquids; (ii) degassing with dry nitrogen removes water as well as oxygen from ionic liquids, which may have implications on the viscosity and structure of the medium; (iii) particular caution must be exercised when deoxygenation is applied in ionic liquid media as part of the protocol used in electrochemical experiments to remove oxygen; (iv) gases such as oxygen, argon, and nitrogen dissolved in ionic liquids need not be innocent with respect to the properties of an ionic liquid. The use of vacuum based techniques to eliminate all volatile solutes, including water and oxygen, is advocated.

Characterization and Proteomic Analysis of Decellularized Adipose Tissue Hydrogels Derived from Lean and Overweight/Obese Human Donors.

While decellularized adipose tissue (DAT) has potential as an "off-the-shelf" biomaterial product for regenerative medicine, it remains to be determined if donor-source body mass index (BMI) impacts the functionality of DAT. This study set out to comparatively characterize lean versus overweight/obese-donor derived DAT hydrogel based on proteome and to analyze their respective effects on adipose stromal/stem cell (ASC) viability, and differentiation in vitro. Decellularized adipose tissue from lean (lDAT) and overweight/obese (oDAT) donors is produced and characterized. Variability in the fibril microstructures is found, with dense fibrotic fiber clusters and large pore area uniquely present in the oDAT samples. Proteomic analysis reveals that lDAT contains a greater proportion of enriched extracellular proteins and a smaller proportion of enriched intracellular proteins relative to oDAT. Biocompatibility studies show that ASCs cultured in lDAT and oDAT hydrogels remain viable. The adipogenic and osteogenic differentiation capability of ASCs seeded in lDAT and oDAT hydrogels is confirmed by an upregulation in marker gene expression and phenotypic analysis. In conclusion, this study establishes that DAT hydrogels derived from lean and overweight/obese adipose donors present similar physicochemical profiles with some distinctive features while comparably supporting the viability and adipogenic differentiation of ASCs in vitro.