Extracellular Vesicles and Bacteriophages: New Directions in Environmental Biocolloid Research.

There is a long-standing appreciation among environmental engineers and scientists regarding the importance of biologically derived colloidal particles and their environmental fate. This interest has been recently renewed in considering bacteriophages and extracellular vesicles, which are each poised to offer engineers unique insights into fundamental aspects of environmental microbiology and novel approaches for engineering applications, including advances in wastewater treatment and sustainable agricultural practices. Challenges persist due to our limited understanding of interactions between these nanoscale particles with unique surface properties and their local environments. This review considers these biological particles through the lens of colloid science with attention given to their environmental impact and surface properties. We discuss methods developed for the study of inert (nonbiological) particle-particle interactions and the potential to use these to advance our understanding of the environmental fate and transport of extracellular vesicles and bacteriophages.

Characterizing the Transport and Surface Affinity of Extracellular Vesicles Isolated from Yeast and Bacteria in Well-Characterized Porous Media.

Extracellular vesicles (EVs) are membrane-bounded, nanosized particles, produced and secreted by all biological cell types. EVs are ubiquitous in the environment, operating in various roles including intercellular communication and plant immune modulation. Despite their ubiquity, the role of EV surface chemistry in determining transport has been minimally investigated. Using the zeta (ζ)-potential as a surrogate for surface charge, this work considers the deposition of EVs from the yeast, Saccharomyces cerevisiae, and two bacterial species, Staphylococcus aureus and Pseudomonas fluorescens, in well-characterized porous medium under various background conditions shown to influence the transport of other environmental colloidal particles: ionic strength and humic acid concentration. The affinity of S. cerevisiae EVs for the porous medium (glass beads) appeared to be sensitive to changes in ionic strength, as predicted by colloid stability (Derjaguin, Landau, Verwey, and Overbeek or DLVO) theory, and humic acid concentration, while P. fluorescens EVs deviated from DLVO predictions, suggesting that mechanisms other than charge stabilization may control the deposition of P. fluorescens. Calculations of attachment efficiency from these deposition studies were used to estimate EV transport using a clean-bed filtration model. Based on these calculations, EVs could be transported through such homogeneous porous media up to 15 m.

Lack of Detectable Direct Effects of Silver and Silver Nanoparticles on Mitochondria in Mouse Hepatocytes.

Silver nanoparticles (AgNPs) are well-proven antimicrobial nanomaterials, yet little is elucidated regarding the mechanism underlying cytotoxicity induced by these nanoparticles. Here, we tested the hypothesis that mitochondria are primary intracellular targets of two AgNPs and silver ions in mouse hepatocytes (AML12) cultured in glucose- and galactose-based media. AML12 cells were more sensitive to mitochondrial uncoupling when grown with galactose rather than glucose. However, 24 h treatments with 15 nm AgNPs and 6 nm GA-AgNPs (5 and 10 µg/mL) and AgNO3 (1 and 3 µg/mL), concentrations that resulted in either 10 or 30% cytotoxicity, failed to cause more toxicity to AML12 cells grown on galactose than glucose. Furthermore, colocalization analysis and subcellular Ag quantification did not show any enrichment of silver content in mitochondria in either medium. Finally, the effects of the same exposures on mitochondrial respiration were mild or undetectable, a result inconsistent with mitochondrial toxicity causing cell death. Our results suggest that neither ionic Ag nor the AgNPs that we tested specifically target mitochondria and are inconsistent with mitochondrial dysfunction being the primary cause of cell death after Ag exposure under these conditions.

Implementation of Early Intervention Protocol in Australia for 'High Risk' Injured Workers is Associated with Fewer Lost Work Days Over 2 Years Than Usual (Stepped) Care.

Purpose To evaluate whether a protocol for early intervention addressing the psychosocial risk factors for delayed return to work in workers with soft tissue injuries would achieve better long-term outcomes than usual (stepped) care. Methods The study used a controlled, non-randomised prospective design to compare two case management approaches. For the intervention condition, workers screened within 1-3 weeks of injury as being at high risk of delayed returned to work by the Örebro Musculoskeletal Pain Screening Questionnaire-short version (ÖMPSQ-SF) were offered psychological assessment and a comprehensive protocol to address the identified obstacles for return to work. Similarly identified injured workers in the control condition were managed under usual (stepped) care arrangements. Results At 2-year follow-up, the mean lost work days for the Intervention group was less than half that of the usual care group, their claim costs were 30% lower, as was the growth trajectory of their costs after 11 months. Conclusions The findings supported the hypothesis that brief psychological risk factor screening, combined with a protocol for active collaboration between key stakeholders to address identified psychological and workplace factors for delayed return to work, can achieve better return on investment than usual (stepped) care.

Correction to: Implementation of Early Intervention Protocol in Australia for 'High Risk' Injured Workers is Associated with Fewer Lost Work Days Over 2 Years Than Usual (Stepped) Care.

The original version of this article unfortunately contained a spelling error in one of the co-authors's names. The family name of the co-author was incorrectly displayed as "James McCauley" instead of "James McAuley. The original article has been corrected.

Predicting Return to Work in a Heterogeneous Sample of Recently Injured Workers Using the Brief ÖMPSQ-SF.

Purpose (1) to examine the ability of the Örebro Musculoskeletal Pain Screening Questionnaire-short version (ÖMPSQ-SF) to predict time to return to pre-injury work duties (PID) following a work-related soft tissue injury (regardless of body location); and (2) to examine the appropriateness of 50/100 as a suitable cut-off score for case identification. Methods Injured workers (IW) from six public hospitals in Sydney, Australia, who had taken medically-sanctioned time off work due to their injury, were recruited by insurance case managers within 5-15 days of their injury. Eligible participants (N = 213 in total) were administered the ÖMPSQ-SF over the telephone by the case manager. For objective (1) Cox proportional hazards regression analysis was used to predict days to return to PID using the ÖMPSQ-SF. For objective (2) receiver operator characteristic (ROC) analysis was used to determine the ÖMPSQ-SF total score that optimises sensitivity and specificity in detecting whether or not participants had returned to PID within 2-7 weeks. Results The total ÖMPSQ-SF score significantly predicted number of days to return to PID, such that for every 1-point increase in the total ÖMPSQ-SF score the predicted chance of returning to work reduced by 4% (i.e., hazard ratio = 0.96), p < 0.001. Sensitivity and specificity for the ROC analysis comparing ÖMPSQ-SF total score to return to PID within 2-7 weeks suggested 48 as the optimal cut off (sensitivity = 0.65, specificity = 0.79). Conclusion The results provide strong support for the use of the ÖMPSQ-SF in an applied setting for identifying those IW likely to have delayed RTW when administered within 15 days of the injury. While a score of 48/100 was the optimal cut point for sensitivity and specificity, pragmatically, 50/100 should be acceptable as a cut-off in future studies of this type.

Leptomeningeal carcinomatosis in esophageal cancer: a case series and systematic review of the literature.

The aim of this study was to more clearly define the clinical course of leptomeningeal carcinomatosis due to esophageal cancer. A single institution retrospective case series was conducted. Additionally, a systematic review of the literature was performed. We present a large case series (n = 7) of leptomeningeal carcinomatosis due to esophageal cancer. Our case series and systematic review of the literature report similar findings. In our series, we report a predominance of male patients (86%) with adenocarcinoma histology (77%). Variable onset of leptomeningeal involvement of esophageal cancer in relation to the original diagnosis of the primary disease (5 months to 3 years and 11 weeks) was noted. Disease progresses quickly and overall survival is poor, measured in weeks (2.5-16 weeks) from the diagnosis of leptomeningeal involvement. Four of our patients initiated whole-brain radiation therapy with only two completing the course prior to clinical deterioration. Our patient with the longest survival (16 weeks) received intrathecal topotecan and oral temozolomide. Leptomeningeal carcinomatosis secondary to esophageal cancer has a poor prognosis. A clearly beneficial treatment modality is lacking.

Methods for the Characterization of the Colloidal Properties of Bacterial Membrane Vesicles.

Bacterial membrane vesicles (BMVs) are extracellular vesicles secreted by either Gram-positive or Gram-negative bacteria. These BMVs typically possess a diameter between 20 and 250 nm. Due to their size, when these BMVs are suspended in another medium, they could be constituents of a colloidal system. It has been hypothesized that investigating BMVs as colloidal particles could help characterize BMV interactions with other environmentally relevant surfaces. Developing a more thorough understanding of BMV interactions with other surfaces would be critical for developing predictive models of their environmental fate. However, this bio-colloidal perspective has been largely overlooked for BMVs, despite the wealth of methods and expertise available to characterize colloidal particles. A particular strength of taking a more colloid-centric approach to BMV characterization is the potential to quantify a particle's attachment efficiency (α). These values describe the likelihood of attachment during particle-particle or particle-surface interactions, especially those interactions which are governed by physicochemical interactions (such as those described by DLVO and xDLVO theory). Elucidating the influence of physical and electrochemical properties on these attachment efficiency values could give insights into the primary factors driving interactions between BMVs and other surfaces. This chapter details methods for the characterization of BMVs as colloids, beginning with size and surface charge (i.e., electrophoretic mobility/zeta potential) measurements. Afterward, this chapter will address experimental design, especially column experiments, targeted for BMV investigation and the determination of α values.

Nanobubble transport in porous media: Towards agro- and environmental applications.

Nanobubbles have been increasingly used in various applications involving porous media, such as groundwater remediation and irrigation. However, the fundamental scientific knowledge regarding the interactions between nanobubbles and the media is still limited. The interactions can be repulsive, attractive, or inert, and can involve reversible or irreversible attachment as well as destructive mechanisms. Specifically, the stability and mobility of nanobubbles in porous media is expected to be dependent on the dynamic conditions and the physicochemical properties of the porous media, solutions, and nanobubbles themselves. In this study, we investigated how changes in solution chemistry (pH, ionic strength, and valence) and media characteristics (size and wettability) affect the size and concentration of nanobubbles under dynamic conditions using column experiments. Quartz crystal microbalance with dissipation monitoring provided a deeper understanding of irreversible and elastic nanobubbles' interactions with silica-coated surfaces. Our findings suggest that nanobubbles are less mobile in solutions of higher ionic strength and valence, acidic pH and smaller porous media sizes, while the wettability of porous media has a negligible influence on the retention of nanobubbles. Overall, our findings provide insights into the underlying mechanisms of nanobubble interactions and suggest potential strategies to optimize their delivery in various applications.

Comparative electrokinetic properties of extracellular vesicles produced by yeast and bacteria.

Extracellular vesicles (EVs) are nano-sized, biocolloidal proteoliposomes that have been shown to be produced by all cell types studied to date and are ubiquitous in the environment. Extensive literature on colloidal particles has demonstrated the implications of surface chemistry on transport behavior. Hence, one may anticipate that physicochemical properties of EVs, particularly surface charge-associated properties, may influence EV transport and specificity of interactions with surfaces. Here we compare the surface chemistry of EVs as expressed by zeta potential (calculated from electrophoretic mobility measurements). The zeta potentials of EVs produced by Pseudomonas fluorescens, Staphylococcus aureus, and Saccharomyces cerevisiae were largely unaffected by changes in ionic strength and electrolyte type, but were affected by changes in pH. The addition of humic acid altered the calculated zeta potential of the EVs, especially for those from S. cerevisiae. Differences in zeta potential were compared between EVs and their respective parent cell with no consistent trend emerging; however, significant differences were discovered between the different cell types and their EVs. These findings imply that, while EV surface charge (as estimated from zeta potential) is relatively insensitive to the evaluated environmental conditions, EVs from different organisms can differ regarding which conditions will cause colloidal instability.

Suppressor and cytolytic cell function in multiple sclerosis. Effects of cyclosporine A and interleukin 2.

Patients with progressive multiple sclerosis (MS) demonstrated persistent reductions in levels of concanavalin A (Con A)-induced suppressor activity and heightened levels of in vitro pokeweed mitogen (PWM)-induced IgG secretion. The reduced Con A suppressor activity could not be reversed by addition of interleukin 2 (IL-2). Cyclosporine A (CsA) treatment did not alter the defect in Con A-induced suppressor activity, but did markedly inhibit T8+ cell-mediated alloantigen directed cytolytic activity; this latter defect was reversible by in vitro addition of IL-2. CsA-treated patients did not differ from placebo-treated patients with regard to levels of PWM-induced IgG secretion or proliferative responses of their mononuclear cells to Con A. The results indicate that CsA treatment of MS patients reduces cytolytic function from baseline normal values, but does not alter aberrant suppressor cell function.

Threat and fear of pain induces attentional bias to pain words: An eye-tracking study.

BACKGROUND: This study aimed to investigate the effects of fear of pain (FOP) and threat on attentional biases, using eye-tracking methods. METHOD: One hundred and seven undergraduate students were randomized to receive threatening or reassuring information about the cold pressor task; and divided into high and low FOP groups. Participants completed the dot-probe task, while their eye movements were tracked. RESULTS: Results showed that those who received threatening information were less likely to have their first fixation on pain words, particularly affective pain words. Furthermore, under conditions of high threat, the high FOP group who did fixate on affective pain words, fixated more quickly than for sensory pain words, whereas the opposite was the case under low threat. In regression analyses, initial vigilance towards affective pain words was a significant predictor of reporting pain more quickly on the cold pressor. CONCLUSIONS: Taken together, these results suggest that initial vigilance of affective pain stimuli predicts actual hypervigilance to an acute experimental pain task. However, under conditions of high threat, participants show evidence of avoidance of affective pain words, even though when they do fixate on these stimuli, the high FOP group does so more quickly. These results confirm that attentional processes, characterized by vigilance avoidance, appear important. SIGNIFICANCE: Interventions that change attention towards pain to reduce vigilance and subsequent avoidance may be indicated to improve pain outcomes.

The pain course: a randomised controlled trial comparing a remote-delivered chronic pain management program when provided in online and workbook formats.

This study compared a remote-delivered pain management program, the Pain Course, when delivered in online and workbook formats. Participants (n = 178) were randomised into 2 groups: (1) an Internet Group (n = 84) who were provided with secure accounts to the program in an online format; or (2) a Workbook Group (n = 94) who were mailed workbook versions of the program. The content of both programs was identical and comprised 5 core lessons, which participants were encouraged to work through over an 8-week period, according to a prescribed timetable. All participants were provided with weekly contact with a clinical psychologist through email and telephone throughout the program. The overall findings suggest that the workbook format was no less effective or acceptable than the validated online format. Significant improvements (avg. improvement; Internet Group vs Workbook Group) in levels of disability (PDI: 16% vs 24%; RMDQ: 12% vs 15%), anxiety (GAD-7: 36% vs 26%), and depression (PHQ-9: 36% vs 36%) were observed in both groups immediately posttreatment. Further improvements were observed in disability levels to 3-month follow-up, and improvements across the other primary outcomes were maintained until 12-month follow-up. High treatment completion rates and levels of satisfaction were reported in both groups, and both groups required a similarly small amount of clinician contact per participant (M = 74.85 minutes; SD = 41.03). These results highlight the public health potential of remote-delivered pain management programs, delivered in either workbook or online formats, as methods of increasing access to pain management.

Pharmacokinetics and pharmacodynamics of 9-aminocamptothecin infused over 72 hours in phase II studies.

A novel derivative of camptothecin, 9-aminocamptothecin (9-AC), is currently under Phase II evaluation in various cancers. Exceptionally mild toxicities were observed in patients with brain tumors who were treated with anticonvulsants. To investigate a pharmacokinetic interaction between 9-AC and anticonvulsants, and to evaluate the pharmacodynamics of 9-AC, we investigated the clinical pharmacology of 9-AC, administered by a 72-h infusion, in three Phase II studies. Plasma concentrations of total 9-AC (lactone plus carboxylate) at a steady state were measured in 56, 10, and 14 patients with non-small cell lung cancer, malignant glioma, and head and neck cancer, respectively. For lung cancer or glioma patients, 9-AC was infused at 45 (51 patients) or 59 (15 patients) microg/m2/h, and 9-AC was infused at 35.4 microg/m2/h in head and neck cancer patients. All glioma patients had been treated with phenytoin or carbamazepine. 9-AC clearance did not differ among the dosage rates, but differed according to the diseases (P = 0.002). Glioma patients had a higher clearance (1.0-18.0; median, 2.0 liters/h/m2) than lung cancer patients (0.3-5.1; median, 0.9 liters/h/m2). A logistic regression model described the relationship between the 9-AC concentration and the probability of grade 4 neutropenia, which was the main toxicity. Observed incidences of grade 4 neutropenia for patients with model-predicted probability of 0-20%, 20-40%, and 40-100% were 10%, 32%, and 67%, respectively, and corresponded to 9-AC concentration of <54, 54-86, and >86 ng/ml, respectively. Anticonvulsants seem to induce the clearance of 9-AC, and the concentration of 9-AC predicts the probability of grade 4 neutropenia.

Assessing the significant others of chronic pain patients: the psychometric properties of significant other questionnaires.

Contemporary reviews of psychological models of chronic pain have favoured behavioural and cognitive-behavioural formulations. These have often assumed that pain behaviours are maintained by environmental reinforcers. One of the most commonly hypothesized sources of reinforcement has been patients' significant others. Further, it has often been recognized that significant others may also be affected by pain behaviours and that they may experience changes in their lifesyles and in their mood as a consequence of living with someone who has pain. Somewhat surprisingly, relatively little clinical research has been published investigating significant others and their relationships with pain patients. Among other things, one of the limiting factors has been the lack of measurement tools available for assessing the relevant variables thought to be important with regards to significant others (such as their responses to, and perceptions of, chronic pain). This study attempted to remedy this situation by developing and testing the psychometric properties of a number of questionnaires specifically designed for significant others of chronic pain patients. The questionnaires have been selected to assess both significant others' (behavioural and cognitive) responses to pain as well as the extent to which pain impacts on their lives. Although not all of the questionnaires were found to possess equally strong psychometric properties, the availability of several solid measures opens the way for more empirical analyses of significant others and their interactions with chronic pain patients.

Generalizing from a controlled trial: the effects of patient preference versus randomization on the outcome of inpatient versus outpatient chronic pain management.

Patients accepting randomization in a randomized controlled trial (RCT) may not be representative of the clinical population from which they are drawn, calling into question the generalizability of study findings. Comparison of randomized and non-randomized inpatient and outpatient samples at baseline and in treatment outcomes up to one year was made to determine whether the findings of the RCT generalized to non-randomized patients in the same treatment program. One hundred and twenty one patients with intractable pain, randomized between inpatient, outpatient and waiting list control, were compared with 128 who elected for either inpatient or outpatient treatment. Treatment was a group-based multidisciplinary cognitive-behavioral treatment program aimed at enabling patients to return to more normal function despite persistent pain, delivered to mixed groups of randomized and elective patients, and outcome was measured by physical performance, pain impact on function, mood, and drug use. Agreement to randomization was a function of travelling distance from home to hospital. Non-randomized patients largely resembled their randomized counterparts before and after treatment. In order to indicate the clinical significance of results, analyses were conducted using numbers needed to treat (NNTs). NNTs estimate the number of patients required in the treatment condition for one of them to achieve the specified outcome who would not have achieved it in the comparison condition. Across a range of measures at one month follow-up, comparison of inpatients with outpatients gave NNTs between 2.3 and 7.5, and comparison of inpatients with waiting list controls gave NNTs between 2.3 and 3.6. At one year inpatients showed greater likelihood than outpatients of maintaining these treatment gains.

An investigation of the placebo effect and age-related factors in the report of needle pain from venipuncture in children.

To examine the potential role for a placebo cream in reducing reported needle pain severity in children, and the impact of age-related factors on pain self-report, a convenience sample of 117 children scheduled for venipuncture were randomly assigned to one of three treatments: (a) placebo cream with the suggestion that it might help reduce needle pain, (b) placebo cream with no indication as to the cream's purpose, and (c) no cream (control group). In allocation to treatment, children were stratified by age group, (3-7, 8-11, 12-17 years). They rated their needle pain severity (both predicted and reported) using the Faces Pain Scale, and rated their anxiety about the procedure using the Children's Anxiety and Pain Scale. Children in the cream groups were also asked whether they thought the cream had helped. Using video-tapes, an independent observer, blind to the placebo manipulation, rated each child's reaction to the needle. For the two groups receiving cream, 83% of those children told it might help stated that they believed it did, as compared with only 33% of children who received the cream but were told nothing of its purpose. These beliefs, however, were not reflected in self-report ratings of pain which showed no statistically significant treatment effect. Similarly, children who gave higher preprocedural anxiety ratings were no more likely to report less pain as a result of receiving the cream. There was, however, a treatment effect on the observer's ratings: children receiving cream plus suggestion were assigned significantly lower ratings of pain-related behaviour than those children who received the cream alone. While venipuncture was associated with only mild levels of pain, younger children, irrespective of treatment group, did report more pain than older children. Hierarchical regression analysis indicated that 60% of the variance in self-reported pain severity scores could be accounted for by how much the child thought the needle would hurt, how anxious the child was about receiving the needle, gender (higher pain ratings associated with girls), and estimated body surface area (higher pain ratings associated with smaller bodies). We conclude that the efficacy of placebo treatments for needle pain in children may depend on the suggestion of a possible benefit rather than upon treatment application per se.

Inpatient vs. outpatient pain management: results of a randomised controlled trial.

Inpatient and outpatient cognitive behavioural pain management programmes for mixed chronic pain patients were compared. Patients were randomly allocated to the 4 week inpatient programme or to the 8 half day per week outpatient programme, or to a waiting list control group. Staff, teaching materials, and setting were the same for the two treatment groups. Patients were assessed pre-treatment, and at 1 month after discharge, and treated patients also at 6 months and 1 year after discharge, by assessors blind to treatment group; assessments included physical, functional and psychological measures, and medication use. In total, 121 mixed chronic pain patients (mean age 50 years; mean chronicity 8.1 years) were included in the study, following medical examination to ensure that no further medical treatment was appropriate. There was no change in the control group; inpatients and outpatients, comparable before treatment, both made significant improvements in physical performance and psychological function, and reduced medication use. Inpatients made greater gains, and maintained them better at 1 year; they also used less health care than outpatients. There were no outstanding predictors of improvement other than treatment group.

Activated suppressor cell function in multiple sclerosis--clinical correlations.

Activated suppressor cell function mediated by either freshly isolated peripheral blood mononuclear cells (MNCs), freshly isolated CD8+ lymphocytes or by CD8+ cell lines, has previously been found to be reduced compared to controls in multiple sclerosis (MS) patients with progressive disease (MS-P). In this study, we found that suppressor activity mediated by CD8+ cell lines, derived from MS patients with stable disease (MS-S) patients and maintained in culture for 14 days, was significantly greater (45 +/- 6%) compared to that mediated by MS-P patients' CD8+ cells (11 +/- 4%, P less than 0.005). The MS-S suppressor values were, however, suggestively reduced compared to controls (60 +/- 6%, P less than 0.05). MNC-mediated suppressor values for the MS-S group (61 +/- 5%) did not differ from the control group (67 +/- 6%). Values for the MS-P group (7 +/- 6%) were significantly reduced compared to MS-S and control groups. Cytotoxic activity mediated by CD8+ cell lines showing defective suppressor function did not differ from control values. The cell lines in MS and control did not differ with respect to their rate of proliferation in the presence of IL-2 and OKT3. Suppressor function in this assay was ablated if exogenous IL-2 was removed from the culture media. These data suggest that defective activated suppressor function is characteristic of the progressive form of MS, although a suppressor defect is also partially expressed in stable MS patients when CD8+ cell lines are studied.

Comparison of T8+ cell-mediated suppressor and cytotoxic functions in multiple sclerosis.

Patients with progressive multiple sclerosis (MS) and controls were compared with regard to: (a) in vitro pokeweed mitogen (pwm)-induced IgG secretion, as an indirect measure of T8+ cell-mediated suppressor function; (b) alloantigen-directed cytotoxic activity, a predominantly T8+ cell-mediated function. The MS group had increased IgG secretion (4790 +/- 372 ng/ml vs. 1866 +/- 233 ng/ml, P less than 0.001) compared to controls. In contrast, alloantigen-directed cytotoxic activity did not differ between MS and control groups. These results suggest a selective defect of suppressor cell function in MS rather than a generalized dysfunction of T8+ cells. Defective immunoregulatory control coupled with preserved effector functions may contribute to the autoimmune process, suspected to underlie the pathogenesis of MS.