Micro- and nanoplastics concepts for particle and fibre toxicologists.

Micro- and nanoplastic particles (MNP) are omnipresent as either pollution or intentionally used in consumer products, released from packaging or even food. There is an exponential increase in the production of plastics. With the realization of bioaccumulation in humans, toxicity research is quickly expanding. There is a rapid increase in the number of papers published on the potential implications of exposure to MNP which necessitates a call for quality criteria to be applied when doing the research. At present, most papers on MNP describe the effects of commercially available polymer (mostly polystyrene) beads that are typically not the MNP of greatest concern. This is not a fault of the research community, necessarily, as the MNPs to which humans are exposed are usually not available in the quantities needed for toxicological research and innovations are needed to supply environmentally-relevant MNP models. In addition, like we have learned from decades of research with particulate matter and engineered nanomaterials, sample physicochemical characteristics and preparation can have major impacts on the biological responses and interpretation of the research findings. Lastly, MNP dosimetry may pose challenges as (1) we are seeing early evidence that plastics are already in the human body at quite high levels that may be difficult to achieve in acute in vitro studies and (2) plastics are already in the diets fed to preclinical models. This commentary highlights the pitfalls and recommendations for particle and fibre toxicologists that should be considered when performing and disseminating the research.

Pilot Study of Group Interpersonal Psychotherapy for Depression Among Young People With Chronic Illness.

OBJECTIVE: Interpersonal psychotherapy (IPT) is an evidence-based treatment for depression, demonstrating efficacy with adolescents and young adults. Social support is proposed to be an important treatment component and may be helpful for adolescents and young adults with chronic illness. The authors sought to assess the feasibility of delivering IPT to this population and to examine changes in depressive symptoms and perceived social support. METHODS: An open-label feasibility trial of group-based IPT was conducted for adolescents and young adults with chronic illness (N=17). The 12-session group IPT was concurrent with group members' individual psychotherapy, and group IPT was focused on providing support in navigating interpersonal challenges related to the participants' chronic illness. Participants completed questionnaires assessing depressive symptoms and social support before treatment, midtreatment (6 weeks), and after treatment (12 weeks). Generalized estimating equation models, adjusted for repeated measures, were used to assess changes in depressive symptoms and social support over the course of treatment. RESULTS: Deidentified clinical examples illustrated how IPT was practiced in a community mental health setting. Evidence for the feasibility of group IPT was mixed. Although participants had poor session attendance, there was a significant decrease in depressive symptoms (ß=-2.94, 95% CI=-5.30 to -0.59, p=0.014) and a significant increase in perceived social support (ß=4.24, 95% CI=0.51 to 7.98, p=0.026) by the end of treatment. CONCLUSIONS: IPT may help address depressive symptoms and enhance social support among adolescents and young adults with chronic illness. Further research and adaptation are needed to address feasibility challenges in delivering group IPT to this population.

Outcomes of Patients with Sarcoma and COVID-19 Infection: A Single Institution Cohort Analysis.

Outcomes for patients (pts) with sarcoma and COVID-19 are unknown. This is a single institution retrospective study of adults with sarcoma and COVID-19. Ten pts [median age 60 (range 24-69)] were identified. Five were hospitalized; two died from COVID-19 complications; another died from sarcoma. Time between last systemic treatment dose and COVID-19 diagnosis was 6-41 days in pts who died. 5 underwent prior radiation (RT); time between RT and COVID-19 diagnosis was 20-62 days for pts who died. All three pts with WBC differential data (two died) were lymphopenic. Efforts to capture outcomes for a larger cohort are urgently needed.

Global Plastic Pollution Observation System to Aid Policy.

Plastic pollution has become one of the most pressing environmental challenges and has received commensurate widespread attention. Although it is a top priority for policymakers and scientists alike, the knowledge required to guide decisions, implement mitigation actions, and assess their outcomes remains inadequate. We argue that an integrated, global monitoring system for plastic pollution is needed to provide comprehensive, harmonized data for environmental, societal, and economic assessments. The initial focus on marine ecosystems has been expanded here to include atmospheric transport and terrestrial and freshwater ecosystems. An earth-system-level plastic observation system is proposed as a hub for collecting and assessing the scale and impacts of plastic pollution across a wide array of particle sizes and ecosystems including air, land, water, and biota and to monitor progress toward ameliorating this problem. The proposed observation system strives to integrate new information and to identify pollution hotspots (i.e., production facilities, cities, roads, ports, etc.) and expands monitoring from marine environments to encompass all ecosystem types. Eventually, such a system will deliver knowledge to support public policy and corporate contributions to the relevant United Nations (UN) Sustainable Development Goals (SDGs).

Detection of Microplastics in Ambient Particulate Matter Using Raman Spectral Imaging and Chemometric Analysis.

Microplastics have been observed in indoor and outdoor air. This raises concern for human exposure, especially should they occur in small enough sizes, which if inhaled, reach the central airway and distal lung. As yet, methods for their detection have not spectroscopically verified the chemical composition of microplastics in this size-range. One proposed method is an automated spectroscopic technique, Raman spectral imaging; however, this generates large and complex data sets. This study aims to optimize Raman spectral imaging for the identification of microplastics (≥2 µm) in ambient particulate matter, using different chemometric techniques. We show that Raman spectral images analyzed using chemometric statistical approaches are appropriate for the identification of both virgin and environmental microplastics ≥2 µm in size. On the basis of the sensitivity, we recommend using the developed Pearson's correlation and agglomerative hierarchical cluster analysis for the identification of microplastics in spectral data sets. Finally, we show their applicability by identifying airborne microplastics >4.7 µm in an outdoor particulate matter sample obtained at an urban sampling site in London, United Kingdom. This semiquantitative method will enable the procurement of exposure concentrations of airborne microplastics guiding future toxicological assessments.

Raman Spectral Imaging for the Detection of Inhalable Microplastics in Ambient Particulate Matter Samples.

Microplastics are ubiquitous contaminants, with preliminary evidence indicating they are a novel component of air pollution. This presents a plausible inhalation exposure pathway, should microplastics occur in the inhalable size range; however, this remains an analytical challenge. Here, we develop a filter-based sampling method compatible with both air quality monitoring and Raman spectral imaging (RSI) for the detection of inhalable-sized microplastics. Clean and particulate matter (PM) contaminated filters of a range of compositions were screened. RSI was validated using a plastic microbead suspension (poly(methyl methacrylate) (5-27 µm), polyethylene (10-27 µm), and polystyrene (4 and 10 µm)). Filters were loaded with the suspension before being analyzed. RSI analysis was conducted using a univariate analysis, fitting unique plastic bands to the spectral data sets, where high spatial intensity indicated the presence of microplastics. Inhalable microplastics were not visibly detectable against quartz or spectroscopically detectable against polytetrafluoroethylene (PTFE)- and alumina-based filters. While microplastics were detectable against cellulose, the PM-contaminated filters (4 and 24 h) burned during analysis. The greatest intensities for microplastics were observed against the silver membrane filter, and inhalable microplastics were still detectable in a 24 h PM sample. These findings will facilitate the acquisition of inhalable microplastic concentrations, which are necessary for understanding microplastic exposure and, ultimately, what their potential role in PM-associated health effects might be.

Plastic and Human Health: A Micro Issue?

Microplastics are a pollutant of environmental concern. Their presence in food destined for human consumption and in air samples has been reported. Thus, microplastic exposure via diet or inhalation could occur, the human health effects of which are unknown. The current review article draws upon cross-disciplinary scientific literature to discuss and evaluate the potential human health impacts of microplastics and outlines urgent areas for future research. Key literature up to September 2016 relating to accumulation, particle toxicity, and chemical and microbial contaminants was critically examined. Although microplastics and human health is an emerging field, complementary existing fields indicate potential particle, chemical and microbial hazards. If inhaled or ingested, microplastics may accumulate and exert localized particle toxicity by inducing or enhancing an immune response. Chemical toxicity could occur due to the localized leaching of component monomers, endogenous additives, and adsorbed environmental pollutants. Chronic exposure is anticipated to be of greater concern due to the accumulative effect that could occur. This is expected to be dose-dependent, and a robust evidence-base of exposure levels is currently lacking. Although there is potential for microplastics to impact human health, assessing current exposure levels and burdens is key. This information will guide future research into the potential mechanisms of toxicity and hence therein possible health effects.

Using Evidence-Based Practice and an Educational Intervention to Improve Vascular Access Management: A Pilot Project.

Abstract.

A review on methods for extracting and quantifying microplastic in biological tissues.

Literature about the occurrence of microplastic in biological tissues has increased over the last few years. This review aims to synthesis the evidence on the preparation of biological tissues, chemical identification of microplastic and accumulation in tissues. Several microplastic's extraction approaches from biological tissues emerged (i.e., alkaline, acids, oxidizing and enzymatic). However, criteria used for the selection of the extraction method have yet to be clarified. Similarly, analytical methodologies for chemical identification often does not align with the size of particles. Furthermore, sizes of microplastics found in biological tissues are likely to be biologically implausible, due to the size of the biological barriers. From this review, it emerged that further assessment are required to determine whether microplastic particles were truly internalized, were in the vasculature serving these organs, or were an artefact of the methodological process. The importance of a standardisation of quality control/quality assurance emerged. Findings arose from this review could have a broad implication, and could be used as a basis for further investigations, to reduce artifact results and clearly assess the fate of microplastics in biological tissues.

Changes in environmental and engineered conditions alter the plasma membrane lipidome of fractured shale bacteria.

IMPORTANCE: Microorganisms inadvertently introduced into the shale reservoir during fracturing face multiple stressors including brine-level salinities and starvation. However, some anaerobic halotolerant bacteria adapt and persist for long periods of time. They produce hydrogen sulfide, which sours the reservoir and corrodes engineering infrastructure. In addition, they form biofilms on rock matrices, which decrease shale permeability and clog fracture networks. These reduce well productivity and increase extraction costs. Under stress, microbes remodel their plasma membrane to optimize its roles in protection and mediating cellular processes such as signaling, transport, and energy metabolism. Hence, by observing changes in the membrane lipidome of model shale bacteria, Halanaerobium congolense WG10, and mixed consortia enriched from produced fluids under varying subsurface conditions and growth modes, we provide insight that advances our knowledge of the fractured shale biosystem. We also offer data-driven recommendations for improving biocontrol efficacy and the efficiency of energy recovery from unconventional formations.

The potential impacts of micro-and-nano plastics on various organ systems in humans.

Humans are exposed to micro-and-nano plastics (MNPs) through various routes, but the adverse health effects of MNPs on different organ systems are not yet fully understood. This review aims to provide an overview of the potential impacts of MNPs on various organ systems and identify knowledge gaps in current research. The summarized results suggest that exposure to MNPs can lead to health effects through oxidative stress, inflammation, immune dysfunction, altered biochemical and energy metabolism, impaired cell proliferation, disrupted microbial metabolic pathways, abnormal organ development, and carcinogenicity. There is limited human data on the health effects of MNPs, despite evidence from animal and cellular studies. Most of the published research has focused on specific types of MNPs to assess their toxicity, while other types of plastic particles commonly found in the environment remain unstudied. Future studies should investigate MNPs exposure by considering realistic concentrations, dose-dependent effects, individual susceptibility, and confounding factors.

Nano- and microplastic PBK modeling in the context of human exposure and risk assessment.

Insufficient data on nano- and microplastics (NMP) hinder robust evaluation of their potential health risks. Methodological disparities and the absence of established toxicity thresholds impede the comparability and practical application of research findings. The diverse attributes of NMP, such as variations in sizes, shapes, and compositions, complicate human health risk assessment. Although probability density functions (PDFs) show promise in capturing this diversity, their integration into risk assessment frameworks is limited. Physiologically based kinetic (PBK) models offer a potential solution to bridge the gap between external exposure and internal dosimetry for risk evaluation. However, the heterogeneity of NMP poses challenges for accurate biodistribution modeling. A literature review, encompassing both experimental and modeling studies, was conducted to examine biodistribution studies of monodisperse micro- and nanoparticles. The literature search in PubMed and Scopus databases yielded 39 studies that met the inclusion criteria. Evaluation criteria were adapted from previous Quality Assurance and Quality Control (QA-QC) studies, best practice guidelines from WHO (2010), OECD guidance (2021), and additional criteria specific to NMP risk assessment. Subsequently, a conceptual framework for a comprehensive NMP-PBK model was developed, addressing the multidimensionality of NMP particles. Parameters for an NMP-PBK model are presented. QA-QC evaluations revealed that most experimental studies scored relatively well (>0) in particle characterizations and environmental settings but fell short in criteria application for biodistribution modeling. The evaluation of modeling studies revealed that information regarding the model type and allometric scaling requires improvement. Three potential applications of PDFs in PBK modeling of NMP are identified: capturing the multidimensionality of the NMP continuum, quantifying the probabilistic definition of external exposure, and calculating the bio-accessibility fraction of NMP in the human body. A framework for an NMP-PBK model is proposed, integrating PDFs to enhance the assessment of NMP's impact on human health.

Structural basis of high-order oligomerization of the cullin-3 adaptor SPOP.

Protein ubiquitination in eukaryotic cells is mediated by diverse E3 ligase enzymes that each target specific substrates. The cullin E3 ligase complexes are the most abundant class of E3 ligases; they contain various cullin components that serve as scaffolds for interaction with substrate-recruiting adaptor proteins. SPOP is a BTB-domain adaptor of the cullin-3 E3 ligase complexes; it selectively recruits substrates via its N-terminal MATH domain, whereas its BTB domain mediates dimerization and interactions with cullin-3. It has recently been recognized that the high-order oligomerization of SPOP enhances the ubiquitination of substrates. Here, a dimerization interface in the SPOP C-terminus is identified and it is shown that the dimerization interfaces of the BTB domain and of the C-terminus act independently and in tandem to generate high-order SPOP oligomers. The crystal structure of the dimeric SPOP C-terminal domain is reported at 1.5 Šresolution and it is shown that Tyr353 plays a critical role in high-order oligomerization. A model of the high-order SPOP oligomer is presented that depicts a helical organization that could enhance the efficiency of substrate ubiquitination.

Dialysis disequilibrium syndrome: rapid recognition and rapid intervention decrease the risk of mortality--a case study.

Dialysis disequilibrium syndrome is a potentially fatal complication of hemodialysis that is often undetected and under-reported. Early recognition and intervention are essential to prevent the potential deadly effects of this disorder and improve outcomes for patients with end stage renal disease (ESRD) on hemodialysis. Using a case study, this article discusses the pathophysiology, clinical manifestations, prevention, and management of dialysis disequilibrium syndrome.

'Facts that are declared proven': sexual violence, forensic medicine, and the courtroom in early Francoist Spain.

This article examines the Spanish court system as a site for the secondary victimisation or 'second rape' of sexual assault victims under the right-wing, Catholic dictatorship of Francisco Franco in Spain. Medical evidence enjoyed a high level of prestige as a modern and 'objective' arbiter of truth in Francoist Spain, precisely because of widespread recognition of the legal system's corruptible nature. As such, contemporary court records reveal how victims in fact sometimes sought out medical examinations, even before reporting sexual crimes to law enforcement. However, the discretional nature of the Francoist legal system, heavily reliant on character references, allowed investigating judges to exploit the ambiguities of medical evidence to fit their vision of who constituted the legitimate 'victims' and 'perpetrators' of sexual violence. Medical forensic evidence therefore served an important purpose in Francoist rape trials; this was not the pursuit of justice or reparations for victims, but rather to reinforce conservative, patriarchal societal structures while providing a veneer of legitimacy to an otherwise distrusted legal system.

Application of Infrared and Near-Infrared Microspectroscopy to Microplastic Human Exposure Measurements.

Microplastic pollution is a global issue for the environment and human health. The potential for human exposure to microplastic through drinking water, dust, food, and air raises concern, since experimental in vitro and in vivo toxicology studies suggest there is a level of hazard associated with high microplastic concentrations. However, to infer the likelihood of hazards manifesting in the human population, a robust understanding of exposure concentrations is needed. Infrared and near-infrared microspectroscopies have routinely been used to analyze microplastic in different exposure matrices (air, dust, food, and water), with technological advances coupling multivariate and machine learning algorithms to spectral data. This focal point article will highlight the application of infrared and Raman modes of spectroscopy to detect, characterize, and quantify microplastic particles, with a focus on human exposure to microplastic. Methodologies and state-of-the-art approaches will be reported and potential confounding variables and challenges in microplastic analysis discussed. The article provides an up-to-date review of the literature on microplastic exposure measurement using (near) infrared spectroscopies as an analytical tool, highlighting the recent advances in this rapidly advancing field.

A critical review of microplastics toxicity and potential adverse outcome pathway in human gastrointestinal tract following oral exposure.

Microplastics (MPs) are typically produced via environmental degradation of larger plastics, where they enter the human food chain. MPs are complex materials containing chemical and physical characteristics that can potentially affect their hazard and exposure. These physical properties can be altered by environmental exposure potentially altering any risk assessment conducted on the primary material. We conducted a literature review using an Adverse Outcome Pathway (AOP)-based approach from Molecular Initiating Event (MIE) to cell effect event to identify multiple knowledge gaps that affect MPs hazard assessment. There is some convergence of key biological events but could relate to most lying along well-established biological effector pathways such as apoptosis which can respond to many MIEs. In contrast, MIEs of chemicals will be via protein interaction. As MPs may occur in the lumen of the alimentary canal for example to the mucus, therefore, not requiring translocation of MPs across the epithelial membrane. At the other end of the AOP, currently it is not possible to identify a single adverse outcome at the organ level. This work did establish a clear need to understand both external and internal exposure (resulting from translocation) and develop hazard data at both levels to inform on risk assessments.

There's something in the air: A review of sources, prevalence and behaviour of microplastics in the atmosphere.

Literature regarding microplastics in the atmosphere has advanced in recent years. However, studies have been undertaken in isolation with minimal collaboration and exploration of the relationships between air, deposition and dust. This review collates concentrations (particle count and mass-based), shape, size and polymetric characteristics for microplastics in ambient air (m3), deposition (m2/day), dust (microplastics/g) and snow (microplastics/L) from 124 peer-reviewed articles to provide a holistic overview and analysis of our current knowledge. In summary, ambient air featured concentrations between <1 to >1000 microplastics/m3 (outdoor) and <1 microplastic/m3 to 1583 ± 1181 (mean) microplastics/m3 (indoor), consisting of polyethylene terephthalate, polyethylene, polypropylene. No difference (p > 0.05) was observed between indoor and outdoor concentrations or the minimum size of microplastics (p > 0.5). Maximum microplastic sizes were larger indoors (p < 0.05). Deposition concentrations ranged between 0.5 and 1357 microplastics/m2/day (outdoor) and 475 to 19,600 microplastics/m2/day (indoor), including polyethylene, polystyrene, polypropylene, polyethylene terephthalate. Concentrations varied between indoor and outdoor deposition (p < 0.05), being more abundant indoors, potentially closer to sources/sinks. No difference was observed between the minimum or maximum reported microplastic sizes within indoor and outdoor deposition (p > 0.05). Road dust concentrations varied between 2 ± 2 and 477 microplastics/g (mean), consisting of polyvinyl chloride, polyethylene, polypropylene. Mean outdoor dust concentrations ranged from <1 microplastic/g (remote desert) to between 18 and 225 microplastics/g, comprised of polyethylene terephthalate, polyamide, polypropylene. Snow concentrations varied between 0.1 and 30,000 microplastics/L, containing polyethylene, polyamide, polypropylene. Concentrations within indoor dust varied between 10 and 67,000 microplastics/g, including polyethylene terephthalate, polyethylene, polypropylene. No difference was observed between indoor and outdoor concentrations (microplastics/g) or maximum size (p > 0.05). The minimum size of microplastics were smaller within outdoor dust (p > 0.05). Although comparability is hindered by differing sampling methods, analytical techniques, polymers investigated, spectral libraries and inconsistent terminology, this review provides a synopsis of knowledge to date regarding atmospheric microplastics.

The structure of the Bach2 POZ-domain dimer reveals an intersubunit disulfide bond.

Bach2 is a transcriptional repressor that is expressed during specific stages of B-cell development and in neuronal cells. It plays a critical role in modulating class-switch recombination during the differentiation of mature B cells to antibody-secreting plasma cells and it is also an important regulator of apoptotic responses to oxidative stress. Bach2 has been implicated both as an oncogene and as a tumour suppressor in human malignancy. The interaction of Bach2 with its target genes is mediated via its basic leucine-zipper region, whereas the N-terminal POZ domain recruits transcriptional co-repressors and class II histone deacetylases. Here, the crystal structure of the human Bach2 POZ domain is reported at 2.1 Å resolution. The Bach2 POZ-domain dimer resembles the POZ-domain dimers of the POZ zinc finger transcription factors and dimerization is independent of an N-terminal region that has previously been implicated in the dimerization of the POZ basic leucine-zipper protein Bach1. The Bach2 POZ domain crystallized in two forms which differed by the presence of an intersubunit disulfide bond. The intersubunit disulfide bond is present both in bacterially expressed Bach2 POZ domain in solution and in protein expressed in transfected eukaryotic cells. These crystal structures will be relevant for understanding the regulation of Bach2 in response to oxidative stress and for the design of therapeutics that target the Bach2 POZ domain in human malignancy.