Genome-wide imaging screen uncovers molecular determinants of arsenite-induced protein aggregation and toxicity.

The toxic metalloid arsenic causes widespread misfolding and aggregation of cellular proteins. How these protein aggregates are formed in vivo, the mechanisms by which they affect cells and how cells prevent their accumulation is not fully understood. To find components involved in these processes, we performed a genome-wide imaging screen and identified Saccharomyces cerevisiae deletion mutants with either enhanced or reduced protein aggregation levels during arsenite exposure. We show that many of the identified factors are crucial to safeguard protein homeostasis (proteostasis) and to protect cells against arsenite toxicity. The hits were enriched for various functions including protein biosynthesis and transcription, and dedicated follow-up experiments highlight the importance of accurate transcriptional and translational control for mitigating protein aggregation and toxicity during arsenite stress. Some of the hits are associated with pathological conditions, suggesting that arsenite-induced protein aggregation may affect disease processes. The broad network of cellular systems that impinge on proteostasis during arsenic stress identified in this current study provides a valuable resource and a framework for further elucidation of the mechanistic details of metalloid toxicity and pathogenesis. This article has an associated First Person interview with the first authors of the paper.

Per- and polyfluoroalkyl substances and fluorine mass balance in cosmetic products from the Swedish market: implications for environmental emissions and human exposure.

Per- and polyfluoroalkyl substances (PFASs) are a diverse class of >4700 chemicals used in commercial products and industrial processes. Concerns surrounding PFASs are principally due to their widespread occurrence in humans and the environment and links to adverse health effects. One of the lesser known uses for PFASs is in cosmetic products (CPs) which come into contact with the skin (e.g. hair products, powders, sunblocks, etc.). In the present work, thirty-one CPs from five product categories (cream, foundation, pencil, powder and shaving foam) were analyzed for 39 PFASs by liquid chromatography-tandem mass spectrometry, as well as extractable organic fluorine (EOF) and total fluorine (TF) by combustion ion chromatography (CIC). This multi-platform approach enabled determination of the fraction of fluorine accounted for by known PFASs (i.e. fluorine mass balance). Foundations and powders contained 25 different PFASs with the most frequently detected being perfluorinated carboxylic acids (perfluoroheptanoic acid and perfluorohexanoic acid) and polyfluoroalkyl phosphate esters (PAPs). Σ14PAP concentrations up to 470 µg g-1 were measured in products listing mixtures of PAPs as an ingredient. For all samples, Σ39PFAS concentrations only explained a small fraction of the EOF and TF, pointing to the presence of unknown organic and/or inorganic fluorinated substances, including polymers. While creams, pencil and shaving foams did not contain measurable concentrations of any of the 39 PFASs targeted here, CIC revealed high to moderate TF content. Overall, these data highlight the need for further investigations into the occurrence of PFASs in CPs and their importance with regards to human and environmental exposure.

Cadmium Causes Misfolding and Aggregation of Cytosolic Proteins in Yeast.

Cadmium is a highly poisonous metal and is classified as a human carcinogen. While its toxicity is undisputed, the underlying in vivo molecular mechanisms are not fully understood. Here, we demonstrate that cadmium induces aggregation of cytosolic proteins in living Saccharomyces cerevisiae cells. Cadmium primarily targets proteins in the process of synthesis or folding, probably by interacting with exposed thiol groups in not-yet-folded proteins. On the basis of in vitro and in vivo data, we show that cadmium-aggregated proteins form seeds that increase the misfolding of other proteins. Cells that cannot efficiently protect the proteome from cadmium-induced aggregation or clear the cytosol of protein aggregates are sensitized to cadmium. Thus, protein aggregation may contribute to cadmium toxicity. This is the first report on how cadmium causes misfolding and aggregation of cytosolic proteins in vivo The proposed mechanism might explain not only the molecular basis of the toxic effects of cadmium but also the suggested role of this poisonous metal in the pathogenesis of certain protein-folding disorders.

Enhancing Documentation of Pressure Ulcer Prevention Interventions: A Quality Improvement Strategy to Reduce Pressure Ulcers.

Prevention of hospital-acquired pressure ulcers requires the implementation of evidence-based interventions. A quality improvement project was conducted to provide nurses with data on the frequency with which pressure ulcer prevention interventions were performed as measured by documentation. Documentation reports provided feedback to stakeholders, triggering reminders and reeducation. Intervention reports and modifications to the documentation system were effective both in increasing the documentation of pressure ulcer prevention interventions and in decreasing the number of avoidable hospital-acquired pressure ulcers.

Comparison of Cervical Range-of-Motion Restriction and Craniofacial Tissue-Interface Pressure With 2 Adjustable and 2 Standard Cervical Collars.

STUDY DESIGN: Randomized controlled trial. OBJECTIVE: The aim of the study was to compare and contrast the restrictiveness and tissue-interface pressure (TIP) characteristics of 2 standard and 2 adjustable cervical collars. SUMMARY OF BACKGROUND DATA: This study compared the restrictiveness and TIP of 4 commercially available cervical collars (2 standard and 2 adjustable). Adjustable collars offer potential advantages of individualized fit for patients and decreased inventory for institutions. The overall goal was to determine whether the adjustable collars provided the same benefits of cervical range-of-motion (CROM) restriction as the standard collars without increasing TIP and risk of pressure-related complications. METHODS: A total of 48 adult volunteer subjects (24 men and 24 women) were fitted with 4 collars (Aspen, Aspen Vista, Miami J, and Miami J Advanced) in random order. Data collection included assessment of CROM restrictiveness and measurement of TIP on the mandible and occiput in upright and supine positions. The experimental, repeated measures design stratified the sample by body mass index (BMI) and sex. RESULTS: All collars restricted CROM as compared with no collar (P ≤ 0.001 each). Aspen was more restrictive than Aspen Vista and Miami J in 4 movement planes (P ≤ 0.003 each), but not significantly different from Miami J Advanced. The Miami J standard collar was associated with significantly lower peak TIPs on all sites and in all positions compared with Aspen (P ≤ 0.001), Miami J Advanced (P < 0.001), and Aspen Vista (P = 0.01 for mandible site and upright position, P < 0.001 for remaining sites and positions). Increased peak TIP correlated with high BMI across all collar types, but was significantly lower for the Miami J collar than the Aspen collar. CONCLUSION: All collars, compared with no collar, significantly restricted CROM. Although the collar-to-collar comparisons were statistically significant, the differences may have little clinical significance in the acutely injured trauma patient. The Miami J standard collar had the lowest overall TIP in both sites and positions. Ongoing effort should be devoted to staff education in proper sizing and fit, particularly for patients with high BMI.

Improving Quality by Taking Aim at Incontinence-Associated Dermatitis in Hospitalized Adults.

A practice-improvement project was launched to implement an evidence-based intervention bundle for incontinence-associated dermatitis (IAD) and evaluate its impact on the identification, prevention, and management of IAD in hospitalized adults.

Improving Quality by Taking Aim at Incontinence-Associated Dermatitis in Hospitalized Adults.

A practice-improvement project was launched to implement an evidence-based intervention bundle for incontinence-associated dermatitis (IAD) and evaluate its impact on the identification, prevention, and management of IAD in hospitalized adults.

Heavy metals and metalloids as a cause for protein misfolding and aggregation.

While the toxicity of metals and metalloids, like arsenic, cadmium, mercury, lead and chromium, is undisputed, the underlying molecular mechanisms are not entirely clear. General consensus holds that proteins are the prime targets; heavy metals interfere with the physiological activity of specific, particularly susceptible proteins, either by forming a complex with functional side chain groups or by displacing essential metal ions in metalloproteins. Recent studies have revealed an additional mode of metal action targeted at proteins in a non-native state; certain heavy metals and metalloids have been found to inhibit the in vitro refolding of chemically denatured proteins, to interfere with protein folding in vivo and to cause aggregation of nascent proteins in living cells. Apparently, unfolded proteins with motile backbone and side chains are considerably more prone to engage in stable, pluridentate metal complexes than native proteins with their well-defined 3D structure. By interfering with the folding process, heavy metal ions and metalloids profoundly affect protein homeostasis and cell viability. This review describes how heavy metals impede protein folding and promote protein aggregation, how cells regulate quality control systems to protect themselves from metal toxicity and how metals might contribute to protein misfolding disorders.

Mathematical modelling of arsenic transport, distribution and detoxification processes in yeast.

Arsenic has a dual role as causative and curative agent of human disease. Therefore, there is considerable interest in elucidating arsenic toxicity and detoxification mechanisms. By an ensemble modelling approach, we identified a best parsimonious mathematical model which recapitulates and predicts intracellular arsenic dynamics for different conditions and mutants, thereby providing novel insights into arsenic toxicity and detoxification mechanisms in yeast, which could partly be confirmed experimentally by dedicated experiments. Specifically, our analyses suggest that: (i) arsenic is mainly protein-bound during short-term (acute) exposure, whereas glutathione-conjugated arsenic dominates during long-term (chronic) exposure, (ii) arsenic is not stably retained, but can leave the vacuole via an export mechanism, and (iii) Fps1 is controlled by Hog1-dependent and Hog1-independent mechanisms during arsenite stress. Our results challenge glutathione depletion as a key mechanism for arsenic toxicity and instead suggest that (iv) increased glutathione biosynthesis protects the proteome against the damaging effects of arsenic and that (v) widespread protein inactivation contributes to the toxicity of this metalloid. Our work in yeast may prove useful to elucidate similar mechanisms in higher eukaryotes and have implications for the use of arsenic in medical therapy.

Patient safety improvement through in situ simulation interdisciplinary team training.

In situ simulation is an education strategy that promotes patient safety and enhances interdisciplinary teamwork. When a patient is experiencing an acute health status change or a rapidly emerging condition, teamwork is necessary to adequately and appropriately provide treatment. A unit-based quality improvement project was designed to enhance these skills. In situ simulation was used as the training venue for nurses and physicians to practice the techniques recommended in the evidence-based team-building model, TeamSTEPPS.

Quantitative analysis of glycerol accumulation, glycolysis and growth under hyper osmotic stress.

We provide an integrated dynamic view on a eukaryotic osmolyte system, linking signaling with regulation of gene expression, metabolic control and growth. Adaptation to osmotic changes enables cells to adjust cellular activity and turgor pressure to an altered environment. The yeast Saccharomyces cerevisiae adapts to hyperosmotic stress by activating the HOG signaling cascade, which controls glycerol accumulation. The Hog1 kinase stimulates transcription of genes encoding enzymes required for glycerol production (Gpd1, Gpp2) and glycerol import (Stl1) and activates a regulatory enzyme in glycolysis (Pfk26/27). In addition, glycerol outflow is prevented by closure of the Fps1 glycerol facilitator. In order to better understand the contributions to glycerol accumulation of these different mechanisms and how redox and energy metabolism as well as biomass production are maintained under such conditions we collected an extensive dataset. Over a period of 180 min after hyperosmotic shock we monitored in wild type and different mutant cells the concentrations of key metabolites and proteins relevant for osmoadaptation. The dataset was used to parameterize an ODE model that reproduces the generated data very well. A detailed computational analysis using time-dependent response coefficients showed that Pfk26/27 contributes to rerouting glycolytic flux towards lower glycolysis. The transient growth arrest following hyperosmotic shock further adds to redirecting almost all glycolytic flux from biomass towards glycerol production. Osmoadaptation is robust to loss of individual adaptation pathways because of the existence and upregulation of alternative routes of glycerol accumulation. For instance, the Stl1 glycerol importer contributes to glycerol accumulation in a mutant with diminished glycerol production capacity. In addition, our observations suggest a role for trehalose accumulation in osmoadaptation and that Hog1 probably directly contributes to the regulation of the Fps1 glycerol facilitator. Taken together, we elucidated how different metabolic adaptation mechanisms cooperate and provide hypotheses for further experimental studies.

Effects of urinary catheter education for patients undergoing prostatectomy.

In a nonrandomized prospective study, significant decreases in patient anxiety with home urinary catheter management and in length of stay were reported when patients attended the preoperative prostatectomy class with standard postoperative education versus standard postoperative education.

Arsenite interferes with protein folding and triggers formation of protein aggregates in yeast.

Several metals and metalloids profoundly affect biological systems, but their impact on the proteome and mechanisms of toxicity are not fully understood. Here, we demonstrate that arsenite causes protein aggregation in Saccharomyces cerevisiae. Various molecular chaperones were found to be associated with arsenite-induced aggregates indicating that this metalloid promotes protein misfolding. Using in vivo and in vitro assays, we show that proteins in the process of synthesis/folding are particularly sensitive to arsenite-induced aggregation, that arsenite interferes with protein folding by acting on unfolded polypeptides, and that arsenite directly inhibits chaperone activity. Thus, folding inhibition contributes to arsenite toxicity in two ways: by aggregate formation and by chaperone inhibition. Importantly, arsenite-induced protein aggregates can act as seeds committing other, labile proteins to misfold and aggregate. Our findings describe a novel mechanism of toxicity that may explain the suggested role of this metalloid in the etiology and pathogenesis of protein folding disorders associated with arsenic poisoning.

Glutathione serves an extracellular defence function to decrease arsenite accumulation and toxicity in yeast.

Arsenic is an environmental toxin and a worldwide health hazard. Since this metalloid is ubiquitous in nature, virtually all living organisms require systems for detoxification and tolerance acquisition. Here, we show that during chronic exposure to arsenite [As(III)], Saccharomyces cerevisiae (budding yeast) exports and accumulates the low-molecular-weight thiol molecule glutathione (GSH) outside of cells. Extracellular accumulation of the arsenite triglutathione complex As(GS)3 was also detected and direct transport assays demonstrate that As(GS)3 does not readily enter cells. Yeast cells with increased extracellular GSH levels accumulate less arsenic and display improved growth when challenged with As(III). Conversely, cells defective in export and extracellular accumulation of GSH are As(III) sensitive. Taken together, our data are consistent with a novel detoxification mechanism in which GSH is exported to protect yeast cells from arsenite toxicity by preventing its uptake.

Cleaning urinary drainage bags with vinegar following radical prostatectomy surgery: is it necessary?

Following a radical prostatectomy in the authors' institution, patients are sent home with an indwelling urinary catheter. Nurses on the urology unit questioned the standard practice of teaching patients to clean their urinary drainage bags daily with a vinegar solution after discharge and the impact, if any, in reducing catheter-associated urinary tract infections (CAUTI). Using the Mayo Clinic Nursing Framework for Evidence-Based Decision Making (EBDM), the literature was searched and evaluated, and the evidence was compared to current practice. Findings from this literature review did not support the current practice of cleaning the urinary drainage bags with a vinegar solution. This article describes the process taken to make an effective change in the practice at the authors' institution based on the current best evidence.

Gene expression analysis using long-term preserved formalin-fixed and paraffin-embedded tissue of non-small cell lung cancer.

This study was performed to evaluate RNA extraction and gene expression analysis of non-small cell lung cancer (NSCLC) using formalin-fixed and paraffin-embedded (FFPE) specimens stored for more than 20 years by quantitative PCR (qPCR) and DNA microarrays. Long-term preserved FFPE materials enable large retrospective studies correlating molecular features with therapeutic response and clinical outcome. qPCR was used to evaluate RNA extraction methods and to compare DNA microarray gene expression profiles of FFPE and fresh frozen (FF) tissue. The Ambion RecoverAll kit appeared to be suited for RNA extraction of long-term preserved FFPE tissues. Microarray analysis using the Affymetrix platform displayed a high degree of correlation for endogenous control genes comparing FF and FFPE tissues and identified known NSCLC signature genes in both specimens. We conclude that high quality gene expression signatures can be recognized using the Affymetrix gene expression platform on FFPE tissue stored for more than 20 years. However, a general interpretation must be done with caution as different FFPE procedures have varying effects on RNA quality.

Low dose TBT exposure decreases amphipod immunocompetence and reproductive fitness.

The antifouling agent tributyltin (TBT) is a highly toxic pollutant present in many aquatic ecosystems. Despite of regulations on the usage of TBT, it remains in high concentrations in sediments both in harbors and in off-shore sites. The toxicity of TBT in mollusks is well documented. However, adverse effects in other aquatic organisms, such as crustaceans, are less well known. This study is an effort to assess the effects of environmentally realistic concentrations of TBT on an ecologically important species in Swedish fresh and brackish water ecosystems, the benthic amphipod Monoporeia affinis. Field collected animals were exposed during gonad maturation to TBT (70 and 170 ng/g sediment d wt) for five weeks in static microcosms with natural sediment. Exposure concentrations were chosen to reflect effects at concentrations found in Swedish coastal sediment, but below expected effects on survival. TBT exposure resulted in a statistically significant adverse effect on oocyte viability and a doubling of the prevalence of microsporidian parasites in females, from 17% in the control to 34% in the 170 ng TBT/g sediment d wt exposure. No effects on survival were observed. Borderline significant effects were observed on male sexual maturation in the 70 ng TBT/g d wt exposure and on ecdysteroid levels in the 170 ng/g sediment d wt exposure. Both reproduction and parasite infection effects are of ecological importance since they have the potential to affect population viability in the field. This study gives further evidence to the connection between low dose contaminant exposure and increases in microsporidian parasite infection.

Expression of neutrophil SOD2 is reduced after lipopolysaccharide stimulation: a potential cause of neutrophil dysfunction in chronic kidney disease.

BACKGROUND: Neutrophils from patients with chronic kidney disease (CKD) are dysfunctional and thus a contributing factor to the risk of infections. The mechanisms for leucocyte dysfunction in CKD are not fully understood. It is known that lipopolysaccharide (LPS) activates transcription of several genes encoding proinflammatory cytokines. We therefore aimed to study the effect of LPS on neutrophil expression of genes related to the inflammatory response to address the hypothesis that LPS-induced gene transcriptions are altered in CKD patients. METHODS: We analysed gene expression of LPS-stimulated neutrophils from 30 patients with CKD and 15 healthy controls. Superoxide dismutase-2 (SOD2), IL1A, IL-1R1, IL-1R2 and IL8RA gene expression from both neutrophils and differentiated HL60 cells were measured by quantitative polymerase chain reaction. Differentiated HL60 cells were stimulated with phorbol-12-myristate-7-acetate (PMA) after inhibition of SOD2 by small interfering RNA followed by respiratory burst assessment using flow cytometry. RESULTS: LPS stimulation induced a significant mobilization of CD11b on neutrophils from CKD and healthy controls. Upregulation of SOD2, IL1A, IL-1R1 and IL-1R2 gene expression in neutrophils from healthy controls after LPS stimulation was contrasted by no change in gene transcription (IL-1R1 and IL-1R2) or even a downregulation in patients with CKD (SOD2 and IL1A). Inhibition of SOD2 reduced the PMA-induced respiratory burst and IL1A, IL-1R1, IL-1R2 and IL8RA gene expression in neutrophil-differentiated HL60 cells. CONCLUSIONS: Because of the critical role of SOD2 in the generation of hydrogen peroxide during phagocytosis, downregulation of SOD2 gene expression after LPS stimulation in neutrophils from patients with CKD indicates a potential mechanism for neutrophil dysfunction and cytokine dysregulation in these patients.

Clinical scenarios: enhancing the skill set of the nurse as a vigilant guardian.

Patient safety is enhanced when nursing staff recognize and respond to subtle changes in a patient's condition. In this quality improvement project, simulated clinical scenarios were conducted with staff nurses on a multi-specialty surgical unit. Scenarios were developed from actual patient situations as well as from calls to the rapid response team. Nurses were given the opportunity to practice assessment, critical thinking, and communication skills. Pre- and post-project surveys were used to assess nurses' perceived level of confidence and skill in handling emergency situations. Post-project survey data showed that nurses perceived that the scenario exercises improved their confidence and skill in managing critical patient situations. In addition, the findings supported the continued use of the scenarios as a teaching strategy. The scenarios have increased nurses' awareness of early signs of patients' conditions deteriorating and have the potential to decrease the number of patient situations that escalate to emergencies.